This commit is contained in:
Justine Pelletreau
2022-03-16 17:55:11 +01:00
parent e5adfa2d64
commit 8eea39ea07
1407 changed files with 52 additions and 29 deletions

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from markupsafe import escape
from markupsafe import Markup
from werkzeug.exceptions import abort as abort
from werkzeug.utils import redirect as redirect
from . import json as json
from .app import Flask as Flask
from .app import Request as Request
from .app import Response as Response
from .blueprints import Blueprint as Blueprint
from .config import Config as Config
from .ctx import after_this_request as after_this_request
from .ctx import copy_current_request_context as copy_current_request_context
from .ctx import has_app_context as has_app_context
from .ctx import has_request_context as has_request_context
from .globals import _app_ctx_stack as _app_ctx_stack
from .globals import _request_ctx_stack as _request_ctx_stack
from .globals import current_app as current_app
from .globals import g as g
from .globals import request as request
from .globals import session as session
from .helpers import flash as flash
from .helpers import get_flashed_messages as get_flashed_messages
from .helpers import get_template_attribute as get_template_attribute
from .helpers import make_response as make_response
from .helpers import safe_join as safe_join
from .helpers import send_file as send_file
from .helpers import send_from_directory as send_from_directory
from .helpers import stream_with_context as stream_with_context
from .helpers import url_for as url_for
from .json import jsonify as jsonify
from .signals import appcontext_popped as appcontext_popped
from .signals import appcontext_pushed as appcontext_pushed
from .signals import appcontext_tearing_down as appcontext_tearing_down
from .signals import before_render_template as before_render_template
from .signals import got_request_exception as got_request_exception
from .signals import message_flashed as message_flashed
from .signals import request_finished as request_finished
from .signals import request_started as request_started
from .signals import request_tearing_down as request_tearing_down
from .signals import signals_available as signals_available
from .signals import template_rendered as template_rendered
from .templating import render_template as render_template
from .templating import render_template_string as render_template_string
__version__ = "2.0.3"

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from .cli import main
main()

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import os
import typing as t
from collections import defaultdict
from functools import update_wrapper
from .scaffold import _endpoint_from_view_func
from .scaffold import _sentinel
from .scaffold import Scaffold
from .typing import AfterRequestCallable
from .typing import BeforeFirstRequestCallable
from .typing import BeforeRequestCallable
from .typing import TeardownCallable
from .typing import TemplateContextProcessorCallable
from .typing import TemplateFilterCallable
from .typing import TemplateGlobalCallable
from .typing import TemplateTestCallable
from .typing import URLDefaultCallable
from .typing import URLValuePreprocessorCallable
if t.TYPE_CHECKING:
from .app import Flask
from .typing import ErrorHandlerCallable
DeferredSetupFunction = t.Callable[["BlueprintSetupState"], t.Callable]
class BlueprintSetupState:
"""Temporary holder object for registering a blueprint with the
application. An instance of this class is created by the
:meth:`~flask.Blueprint.make_setup_state` method and later passed
to all register callback functions.
"""
def __init__(
self,
blueprint: "Blueprint",
app: "Flask",
options: t.Any,
first_registration: bool,
) -> None:
#: a reference to the current application
self.app = app
#: a reference to the blueprint that created this setup state.
self.blueprint = blueprint
#: a dictionary with all options that were passed to the
#: :meth:`~flask.Flask.register_blueprint` method.
self.options = options
#: as blueprints can be registered multiple times with the
#: application and not everything wants to be registered
#: multiple times on it, this attribute can be used to figure
#: out if the blueprint was registered in the past already.
self.first_registration = first_registration
subdomain = self.options.get("subdomain")
if subdomain is None:
subdomain = self.blueprint.subdomain
#: The subdomain that the blueprint should be active for, ``None``
#: otherwise.
self.subdomain = subdomain
url_prefix = self.options.get("url_prefix")
if url_prefix is None:
url_prefix = self.blueprint.url_prefix
#: The prefix that should be used for all URLs defined on the
#: blueprint.
self.url_prefix = url_prefix
self.name = self.options.get("name", blueprint.name)
self.name_prefix = self.options.get("name_prefix", "")
#: A dictionary with URL defaults that is added to each and every
#: URL that was defined with the blueprint.
self.url_defaults = dict(self.blueprint.url_values_defaults)
self.url_defaults.update(self.options.get("url_defaults", ()))
def add_url_rule(
self,
rule: str,
endpoint: t.Optional[str] = None,
view_func: t.Optional[t.Callable] = None,
**options: t.Any,
) -> None:
"""A helper method to register a rule (and optionally a view function)
to the application. The endpoint is automatically prefixed with the
blueprint's name.
"""
if self.url_prefix is not None:
if rule:
rule = "/".join((self.url_prefix.rstrip("/"), rule.lstrip("/")))
else:
rule = self.url_prefix
options.setdefault("subdomain", self.subdomain)
if endpoint is None:
endpoint = _endpoint_from_view_func(view_func) # type: ignore
defaults = self.url_defaults
if "defaults" in options:
defaults = dict(defaults, **options.pop("defaults"))
self.app.add_url_rule(
rule,
f"{self.name_prefix}.{self.name}.{endpoint}".lstrip("."),
view_func,
defaults=defaults,
**options,
)
class Blueprint(Scaffold):
"""Represents a blueprint, a collection of routes and other
app-related functions that can be registered on a real application
later.
A blueprint is an object that allows defining application functions
without requiring an application object ahead of time. It uses the
same decorators as :class:`~flask.Flask`, but defers the need for an
application by recording them for later registration.
Decorating a function with a blueprint creates a deferred function
that is called with :class:`~flask.blueprints.BlueprintSetupState`
when the blueprint is registered on an application.
See :doc:`/blueprints` for more information.
:param name: The name of the blueprint. Will be prepended to each
endpoint name.
:param import_name: The name of the blueprint package, usually
``__name__``. This helps locate the ``root_path`` for the
blueprint.
:param static_folder: A folder with static files that should be
served by the blueprint's static route. The path is relative to
the blueprint's root path. Blueprint static files are disabled
by default.
:param static_url_path: The url to serve static files from.
Defaults to ``static_folder``. If the blueprint does not have
a ``url_prefix``, the app's static route will take precedence,
and the blueprint's static files won't be accessible.
:param template_folder: A folder with templates that should be added
to the app's template search path. The path is relative to the
blueprint's root path. Blueprint templates are disabled by
default. Blueprint templates have a lower precedence than those
in the app's templates folder.
:param url_prefix: A path to prepend to all of the blueprint's URLs,
to make them distinct from the rest of the app's routes.
:param subdomain: A subdomain that blueprint routes will match on by
default.
:param url_defaults: A dict of default values that blueprint routes
will receive by default.
:param root_path: By default, the blueprint will automatically set
this based on ``import_name``. In certain situations this
automatic detection can fail, so the path can be specified
manually instead.
.. versionchanged:: 1.1.0
Blueprints have a ``cli`` group to register nested CLI commands.
The ``cli_group`` parameter controls the name of the group under
the ``flask`` command.
.. versionadded:: 0.7
"""
warn_on_modifications = False
_got_registered_once = False
#: Blueprint local JSON encoder class to use. Set to ``None`` to use
#: the app's :class:`~flask.Flask.json_encoder`.
json_encoder = None
#: Blueprint local JSON decoder class to use. Set to ``None`` to use
#: the app's :class:`~flask.Flask.json_decoder`.
json_decoder = None
def __init__(
self,
name: str,
import_name: str,
static_folder: t.Optional[t.Union[str, os.PathLike]] = None,
static_url_path: t.Optional[str] = None,
template_folder: t.Optional[str] = None,
url_prefix: t.Optional[str] = None,
subdomain: t.Optional[str] = None,
url_defaults: t.Optional[dict] = None,
root_path: t.Optional[str] = None,
cli_group: t.Optional[str] = _sentinel, # type: ignore
):
super().__init__(
import_name=import_name,
static_folder=static_folder,
static_url_path=static_url_path,
template_folder=template_folder,
root_path=root_path,
)
if "." in name:
raise ValueError("'name' may not contain a dot '.' character.")
self.name = name
self.url_prefix = url_prefix
self.subdomain = subdomain
self.deferred_functions: t.List[DeferredSetupFunction] = []
if url_defaults is None:
url_defaults = {}
self.url_values_defaults = url_defaults
self.cli_group = cli_group
self._blueprints: t.List[t.Tuple["Blueprint", dict]] = []
def _is_setup_finished(self) -> bool:
return self.warn_on_modifications and self._got_registered_once
def record(self, func: t.Callable) -> None:
"""Registers a function that is called when the blueprint is
registered on the application. This function is called with the
state as argument as returned by the :meth:`make_setup_state`
method.
"""
if self._got_registered_once and self.warn_on_modifications:
from warnings import warn
warn(
Warning(
"The blueprint was already registered once but is"
" getting modified now. These changes will not show"
" up."
)
)
self.deferred_functions.append(func)
def record_once(self, func: t.Callable) -> None:
"""Works like :meth:`record` but wraps the function in another
function that will ensure the function is only called once. If the
blueprint is registered a second time on the application, the
function passed is not called.
"""
def wrapper(state: BlueprintSetupState) -> None:
if state.first_registration:
func(state)
return self.record(update_wrapper(wrapper, func))
def make_setup_state(
self, app: "Flask", options: dict, first_registration: bool = False
) -> BlueprintSetupState:
"""Creates an instance of :meth:`~flask.blueprints.BlueprintSetupState`
object that is later passed to the register callback functions.
Subclasses can override this to return a subclass of the setup state.
"""
return BlueprintSetupState(self, app, options, first_registration)
def register_blueprint(self, blueprint: "Blueprint", **options: t.Any) -> None:
"""Register a :class:`~flask.Blueprint` on this blueprint. Keyword
arguments passed to this method will override the defaults set
on the blueprint.
.. versionchanged:: 2.0.1
The ``name`` option can be used to change the (pre-dotted)
name the blueprint is registered with. This allows the same
blueprint to be registered multiple times with unique names
for ``url_for``.
.. versionadded:: 2.0
"""
if blueprint is self:
raise ValueError("Cannot register a blueprint on itself")
self._blueprints.append((blueprint, options))
def register(self, app: "Flask", options: dict) -> None:
"""Called by :meth:`Flask.register_blueprint` to register all
views and callbacks registered on the blueprint with the
application. Creates a :class:`.BlueprintSetupState` and calls
each :meth:`record` callback with it.
:param app: The application this blueprint is being registered
with.
:param options: Keyword arguments forwarded from
:meth:`~Flask.register_blueprint`.
.. versionchanged:: 2.0.1
Nested blueprints are registered with their dotted name.
This allows different blueprints with the same name to be
nested at different locations.
.. versionchanged:: 2.0.1
The ``name`` option can be used to change the (pre-dotted)
name the blueprint is registered with. This allows the same
blueprint to be registered multiple times with unique names
for ``url_for``.
.. versionchanged:: 2.0.1
Registering the same blueprint with the same name multiple
times is deprecated and will become an error in Flask 2.1.
"""
name_prefix = options.get("name_prefix", "")
self_name = options.get("name", self.name)
name = f"{name_prefix}.{self_name}".lstrip(".")
if name in app.blueprints:
existing_at = f" '{name}'" if self_name != name else ""
if app.blueprints[name] is not self:
raise ValueError(
f"The name '{self_name}' is already registered for"
f" a different blueprint{existing_at}. Use 'name='"
" to provide a unique name."
)
else:
import warnings
warnings.warn(
f"The name '{self_name}' is already registered for"
f" this blueprint{existing_at}. Use 'name=' to"
" provide a unique name. This will become an error"
" in Flask 2.1.",
stacklevel=4,
)
first_bp_registration = not any(bp is self for bp in app.blueprints.values())
first_name_registration = name not in app.blueprints
app.blueprints[name] = self
self._got_registered_once = True
state = self.make_setup_state(app, options, first_bp_registration)
if self.has_static_folder:
state.add_url_rule(
f"{self.static_url_path}/<path:filename>",
view_func=self.send_static_file,
endpoint="static",
)
# Merge blueprint data into parent.
if first_bp_registration or first_name_registration:
def extend(bp_dict, parent_dict):
for key, values in bp_dict.items():
key = name if key is None else f"{name}.{key}"
parent_dict[key].extend(values)
for key, value in self.error_handler_spec.items():
key = name if key is None else f"{name}.{key}"
value = defaultdict(
dict,
{
code: {
exc_class: func for exc_class, func in code_values.items()
}
for code, code_values in value.items()
},
)
app.error_handler_spec[key] = value
for endpoint, func in self.view_functions.items():
app.view_functions[endpoint] = func
extend(self.before_request_funcs, app.before_request_funcs)
extend(self.after_request_funcs, app.after_request_funcs)
extend(
self.teardown_request_funcs,
app.teardown_request_funcs,
)
extend(self.url_default_functions, app.url_default_functions)
extend(self.url_value_preprocessors, app.url_value_preprocessors)
extend(self.template_context_processors, app.template_context_processors)
for deferred in self.deferred_functions:
deferred(state)
cli_resolved_group = options.get("cli_group", self.cli_group)
if self.cli.commands:
if cli_resolved_group is None:
app.cli.commands.update(self.cli.commands)
elif cli_resolved_group is _sentinel:
self.cli.name = name
app.cli.add_command(self.cli)
else:
self.cli.name = cli_resolved_group
app.cli.add_command(self.cli)
for blueprint, bp_options in self._blueprints:
bp_options = bp_options.copy()
bp_url_prefix = bp_options.get("url_prefix")
if bp_url_prefix is None:
bp_url_prefix = blueprint.url_prefix
if state.url_prefix is not None and bp_url_prefix is not None:
bp_options["url_prefix"] = (
state.url_prefix.rstrip("/") + "/" + bp_url_prefix.lstrip("/")
)
elif bp_url_prefix is not None:
bp_options["url_prefix"] = bp_url_prefix
elif state.url_prefix is not None:
bp_options["url_prefix"] = state.url_prefix
bp_options["name_prefix"] = name
blueprint.register(app, bp_options)
def add_url_rule(
self,
rule: str,
endpoint: t.Optional[str] = None,
view_func: t.Optional[t.Callable] = None,
provide_automatic_options: t.Optional[bool] = None,
**options: t.Any,
) -> None:
"""Like :meth:`Flask.add_url_rule` but for a blueprint. The endpoint for
the :func:`url_for` function is prefixed with the name of the blueprint.
"""
if endpoint and "." in endpoint:
raise ValueError("'endpoint' may not contain a dot '.' character.")
if view_func and hasattr(view_func, "__name__") and "." in view_func.__name__:
raise ValueError("'view_func' name may not contain a dot '.' character.")
self.record(
lambda s: s.add_url_rule(
rule,
endpoint,
view_func,
provide_automatic_options=provide_automatic_options,
**options,
)
)
def app_template_filter(
self, name: t.Optional[str] = None
) -> t.Callable[[TemplateFilterCallable], TemplateFilterCallable]:
"""Register a custom template filter, available application wide. Like
:meth:`Flask.template_filter` but for a blueprint.
:param name: the optional name of the filter, otherwise the
function name will be used.
"""
def decorator(f: TemplateFilterCallable) -> TemplateFilterCallable:
self.add_app_template_filter(f, name=name)
return f
return decorator
def add_app_template_filter(
self, f: TemplateFilterCallable, name: t.Optional[str] = None
) -> None:
"""Register a custom template filter, available application wide. Like
:meth:`Flask.add_template_filter` but for a blueprint. Works exactly
like the :meth:`app_template_filter` decorator.
:param name: the optional name of the filter, otherwise the
function name will be used.
"""
def register_template(state: BlueprintSetupState) -> None:
state.app.jinja_env.filters[name or f.__name__] = f
self.record_once(register_template)
def app_template_test(
self, name: t.Optional[str] = None
) -> t.Callable[[TemplateTestCallable], TemplateTestCallable]:
"""Register a custom template test, available application wide. Like
:meth:`Flask.template_test` but for a blueprint.
.. versionadded:: 0.10
:param name: the optional name of the test, otherwise the
function name will be used.
"""
def decorator(f: TemplateTestCallable) -> TemplateTestCallable:
self.add_app_template_test(f, name=name)
return f
return decorator
def add_app_template_test(
self, f: TemplateTestCallable, name: t.Optional[str] = None
) -> None:
"""Register a custom template test, available application wide. Like
:meth:`Flask.add_template_test` but for a blueprint. Works exactly
like the :meth:`app_template_test` decorator.
.. versionadded:: 0.10
:param name: the optional name of the test, otherwise the
function name will be used.
"""
def register_template(state: BlueprintSetupState) -> None:
state.app.jinja_env.tests[name or f.__name__] = f
self.record_once(register_template)
def app_template_global(
self, name: t.Optional[str] = None
) -> t.Callable[[TemplateGlobalCallable], TemplateGlobalCallable]:
"""Register a custom template global, available application wide. Like
:meth:`Flask.template_global` but for a blueprint.
.. versionadded:: 0.10
:param name: the optional name of the global, otherwise the
function name will be used.
"""
def decorator(f: TemplateGlobalCallable) -> TemplateGlobalCallable:
self.add_app_template_global(f, name=name)
return f
return decorator
def add_app_template_global(
self, f: TemplateGlobalCallable, name: t.Optional[str] = None
) -> None:
"""Register a custom template global, available application wide. Like
:meth:`Flask.add_template_global` but for a blueprint. Works exactly
like the :meth:`app_template_global` decorator.
.. versionadded:: 0.10
:param name: the optional name of the global, otherwise the
function name will be used.
"""
def register_template(state: BlueprintSetupState) -> None:
state.app.jinja_env.globals[name or f.__name__] = f
self.record_once(register_template)
def before_app_request(self, f: BeforeRequestCallable) -> BeforeRequestCallable:
"""Like :meth:`Flask.before_request`. Such a function is executed
before each request, even if outside of a blueprint.
"""
self.record_once(
lambda s: s.app.before_request_funcs.setdefault(None, []).append(f)
)
return f
def before_app_first_request(
self, f: BeforeFirstRequestCallable
) -> BeforeFirstRequestCallable:
"""Like :meth:`Flask.before_first_request`. Such a function is
executed before the first request to the application.
"""
self.record_once(lambda s: s.app.before_first_request_funcs.append(f))
return f
def after_app_request(self, f: AfterRequestCallable) -> AfterRequestCallable:
"""Like :meth:`Flask.after_request` but for a blueprint. Such a function
is executed after each request, even if outside of the blueprint.
"""
self.record_once(
lambda s: s.app.after_request_funcs.setdefault(None, []).append(f)
)
return f
def teardown_app_request(self, f: TeardownCallable) -> TeardownCallable:
"""Like :meth:`Flask.teardown_request` but for a blueprint. Such a
function is executed when tearing down each request, even if outside of
the blueprint.
"""
self.record_once(
lambda s: s.app.teardown_request_funcs.setdefault(None, []).append(f)
)
return f
def app_context_processor(
self, f: TemplateContextProcessorCallable
) -> TemplateContextProcessorCallable:
"""Like :meth:`Flask.context_processor` but for a blueprint. Such a
function is executed each request, even if outside of the blueprint.
"""
self.record_once(
lambda s: s.app.template_context_processors.setdefault(None, []).append(f)
)
return f
def app_errorhandler(self, code: t.Union[t.Type[Exception], int]) -> t.Callable:
"""Like :meth:`Flask.errorhandler` but for a blueprint. This
handler is used for all requests, even if outside of the blueprint.
"""
def decorator(
f: "ErrorHandlerCallable[Exception]",
) -> "ErrorHandlerCallable[Exception]":
self.record_once(lambda s: s.app.errorhandler(code)(f))
return f
return decorator
def app_url_value_preprocessor(
self, f: URLValuePreprocessorCallable
) -> URLValuePreprocessorCallable:
"""Same as :meth:`url_value_preprocessor` but application wide."""
self.record_once(
lambda s: s.app.url_value_preprocessors.setdefault(None, []).append(f)
)
return f
def app_url_defaults(self, f: URLDefaultCallable) -> URLDefaultCallable:
"""Same as :meth:`url_defaults` but application wide."""
self.record_once(
lambda s: s.app.url_default_functions.setdefault(None, []).append(f)
)
return f

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import ast
import inspect
import os
import platform
import re
import sys
import traceback
import warnings
from functools import update_wrapper
from operator import attrgetter
from threading import Lock
from threading import Thread
import click
from werkzeug.utils import import_string
from .globals import current_app
from .helpers import get_debug_flag
from .helpers import get_env
from .helpers import get_load_dotenv
try:
import dotenv
except ImportError:
dotenv = None
try:
import ssl
except ImportError:
ssl = None # type: ignore
class NoAppException(click.UsageError):
"""Raised if an application cannot be found or loaded."""
def find_best_app(script_info, module):
"""Given a module instance this tries to find the best possible
application in the module or raises an exception.
"""
from . import Flask
# Search for the most common names first.
for attr_name in ("app", "application"):
app = getattr(module, attr_name, None)
if isinstance(app, Flask):
return app
# Otherwise find the only object that is a Flask instance.
matches = [v for v in module.__dict__.values() if isinstance(v, Flask)]
if len(matches) == 1:
return matches[0]
elif len(matches) > 1:
raise NoAppException(
"Detected multiple Flask applications in module"
f" {module.__name__!r}. Use 'FLASK_APP={module.__name__}:name'"
f" to specify the correct one."
)
# Search for app factory functions.
for attr_name in ("create_app", "make_app"):
app_factory = getattr(module, attr_name, None)
if inspect.isfunction(app_factory):
try:
app = call_factory(script_info, app_factory)
if isinstance(app, Flask):
return app
except TypeError as e:
if not _called_with_wrong_args(app_factory):
raise
raise NoAppException(
f"Detected factory {attr_name!r} in module {module.__name__!r},"
" but could not call it without arguments. Use"
f" \"FLASK_APP='{module.__name__}:{attr_name}(args)'\""
" to specify arguments."
) from e
raise NoAppException(
"Failed to find Flask application or factory in module"
f" {module.__name__!r}. Use 'FLASK_APP={module.__name__}:name'"
" to specify one."
)
def call_factory(script_info, app_factory, args=None, kwargs=None):
"""Takes an app factory, a ``script_info` object and optionally a tuple
of arguments. Checks for the existence of a script_info argument and calls
the app_factory depending on that and the arguments provided.
"""
sig = inspect.signature(app_factory)
args = [] if args is None else args
kwargs = {} if kwargs is None else kwargs
if "script_info" in sig.parameters:
warnings.warn(
"The 'script_info' argument is deprecated and will not be"
" passed to the app factory function in Flask 2.1.",
DeprecationWarning,
)
kwargs["script_info"] = script_info
if not args and len(sig.parameters) == 1:
first_parameter = next(iter(sig.parameters.values()))
if (
first_parameter.default is inspect.Parameter.empty
# **kwargs is reported as an empty default, ignore it
and first_parameter.kind is not inspect.Parameter.VAR_KEYWORD
):
warnings.warn(
"Script info is deprecated and will not be passed as the"
" single argument to the app factory function in Flask"
" 2.1.",
DeprecationWarning,
)
args.append(script_info)
return app_factory(*args, **kwargs)
def _called_with_wrong_args(f):
"""Check whether calling a function raised a ``TypeError`` because
the call failed or because something in the factory raised the
error.
:param f: The function that was called.
:return: ``True`` if the call failed.
"""
tb = sys.exc_info()[2]
try:
while tb is not None:
if tb.tb_frame.f_code is f.__code__:
# In the function, it was called successfully.
return False
tb = tb.tb_next
# Didn't reach the function.
return True
finally:
# Delete tb to break a circular reference.
# https://docs.python.org/2/library/sys.html#sys.exc_info
del tb
def find_app_by_string(script_info, module, app_name):
"""Check if the given string is a variable name or a function. Call
a function to get the app instance, or return the variable directly.
"""
from . import Flask
# Parse app_name as a single expression to determine if it's a valid
# attribute name or function call.
try:
expr = ast.parse(app_name.strip(), mode="eval").body
except SyntaxError:
raise NoAppException(
f"Failed to parse {app_name!r} as an attribute name or function call."
) from None
if isinstance(expr, ast.Name):
name = expr.id
args = kwargs = None
elif isinstance(expr, ast.Call):
# Ensure the function name is an attribute name only.
if not isinstance(expr.func, ast.Name):
raise NoAppException(
f"Function reference must be a simple name: {app_name!r}."
)
name = expr.func.id
# Parse the positional and keyword arguments as literals.
try:
args = [ast.literal_eval(arg) for arg in expr.args]
kwargs = {kw.arg: ast.literal_eval(kw.value) for kw in expr.keywords}
except ValueError:
# literal_eval gives cryptic error messages, show a generic
# message with the full expression instead.
raise NoAppException(
f"Failed to parse arguments as literal values: {app_name!r}."
) from None
else:
raise NoAppException(
f"Failed to parse {app_name!r} as an attribute name or function call."
)
try:
attr = getattr(module, name)
except AttributeError as e:
raise NoAppException(
f"Failed to find attribute {name!r} in {module.__name__!r}."
) from e
# If the attribute is a function, call it with any args and kwargs
# to get the real application.
if inspect.isfunction(attr):
try:
app = call_factory(script_info, attr, args, kwargs)
except TypeError as e:
if not _called_with_wrong_args(attr):
raise
raise NoAppException(
f"The factory {app_name!r} in module"
f" {module.__name__!r} could not be called with the"
" specified arguments."
) from e
else:
app = attr
if isinstance(app, Flask):
return app
raise NoAppException(
"A valid Flask application was not obtained from"
f" '{module.__name__}:{app_name}'."
)
def prepare_import(path):
"""Given a filename this will try to calculate the python path, add it
to the search path and return the actual module name that is expected.
"""
path = os.path.realpath(path)
fname, ext = os.path.splitext(path)
if ext == ".py":
path = fname
if os.path.basename(path) == "__init__":
path = os.path.dirname(path)
module_name = []
# move up until outside package structure (no __init__.py)
while True:
path, name = os.path.split(path)
module_name.append(name)
if not os.path.exists(os.path.join(path, "__init__.py")):
break
if sys.path[0] != path:
sys.path.insert(0, path)
return ".".join(module_name[::-1])
def locate_app(script_info, module_name, app_name, raise_if_not_found=True):
__traceback_hide__ = True # noqa: F841
try:
__import__(module_name)
except ImportError:
# Reraise the ImportError if it occurred within the imported module.
# Determine this by checking whether the trace has a depth > 1.
if sys.exc_info()[2].tb_next:
raise NoAppException(
f"While importing {module_name!r}, an ImportError was"
f" raised:\n\n{traceback.format_exc()}"
) from None
elif raise_if_not_found:
raise NoAppException(f"Could not import {module_name!r}.") from None
else:
return
module = sys.modules[module_name]
if app_name is None:
return find_best_app(script_info, module)
else:
return find_app_by_string(script_info, module, app_name)
def get_version(ctx, param, value):
if not value or ctx.resilient_parsing:
return
import werkzeug
from . import __version__
click.echo(
f"Python {platform.python_version()}\n"
f"Flask {__version__}\n"
f"Werkzeug {werkzeug.__version__}",
color=ctx.color,
)
ctx.exit()
version_option = click.Option(
["--version"],
help="Show the flask version",
expose_value=False,
callback=get_version,
is_flag=True,
is_eager=True,
)
class DispatchingApp:
"""Special application that dispatches to a Flask application which
is imported by name in a background thread. If an error happens
it is recorded and shown as part of the WSGI handling which in case
of the Werkzeug debugger means that it shows up in the browser.
"""
def __init__(self, loader, use_eager_loading=None):
self.loader = loader
self._app = None
self._lock = Lock()
self._bg_loading_exc = None
if use_eager_loading is None:
use_eager_loading = os.environ.get("WERKZEUG_RUN_MAIN") != "true"
if use_eager_loading:
self._load_unlocked()
else:
self._load_in_background()
def _load_in_background(self):
def _load_app():
__traceback_hide__ = True # noqa: F841
with self._lock:
try:
self._load_unlocked()
except Exception as e:
self._bg_loading_exc = e
t = Thread(target=_load_app, args=())
t.start()
def _flush_bg_loading_exception(self):
__traceback_hide__ = True # noqa: F841
exc = self._bg_loading_exc
if exc is not None:
self._bg_loading_exc = None
raise exc
def _load_unlocked(self):
__traceback_hide__ = True # noqa: F841
self._app = rv = self.loader()
self._bg_loading_exc = None
return rv
def __call__(self, environ, start_response):
__traceback_hide__ = True # noqa: F841
if self._app is not None:
return self._app(environ, start_response)
self._flush_bg_loading_exception()
with self._lock:
if self._app is not None:
rv = self._app
else:
rv = self._load_unlocked()
return rv(environ, start_response)
class ScriptInfo:
"""Helper object to deal with Flask applications. This is usually not
necessary to interface with as it's used internally in the dispatching
to click. In future versions of Flask this object will most likely play
a bigger role. Typically it's created automatically by the
:class:`FlaskGroup` but you can also manually create it and pass it
onwards as click object.
"""
def __init__(self, app_import_path=None, create_app=None, set_debug_flag=True):
#: Optionally the import path for the Flask application.
self.app_import_path = app_import_path or os.environ.get("FLASK_APP")
#: Optionally a function that is passed the script info to create
#: the instance of the application.
self.create_app = create_app
#: A dictionary with arbitrary data that can be associated with
#: this script info.
self.data = {}
self.set_debug_flag = set_debug_flag
self._loaded_app = None
def load_app(self):
"""Loads the Flask app (if not yet loaded) and returns it. Calling
this multiple times will just result in the already loaded app to
be returned.
"""
__traceback_hide__ = True # noqa: F841
if self._loaded_app is not None:
return self._loaded_app
if self.create_app is not None:
app = call_factory(self, self.create_app)
else:
if self.app_import_path:
path, name = (
re.split(r":(?![\\/])", self.app_import_path, 1) + [None]
)[:2]
import_name = prepare_import(path)
app = locate_app(self, import_name, name)
else:
for path in ("wsgi.py", "app.py"):
import_name = prepare_import(path)
app = locate_app(self, import_name, None, raise_if_not_found=False)
if app:
break
if not app:
raise NoAppException(
"Could not locate a Flask application. You did not provide "
'the "FLASK_APP" environment variable, and a "wsgi.py" or '
'"app.py" module was not found in the current directory.'
)
if self.set_debug_flag:
# Update the app's debug flag through the descriptor so that
# other values repopulate as well.
app.debug = get_debug_flag()
self._loaded_app = app
return app
pass_script_info = click.make_pass_decorator(ScriptInfo, ensure=True)
def with_appcontext(f):
"""Wraps a callback so that it's guaranteed to be executed with the
script's application context. If callbacks are registered directly
to the ``app.cli`` object then they are wrapped with this function
by default unless it's disabled.
"""
@click.pass_context
def decorator(__ctx, *args, **kwargs):
with __ctx.ensure_object(ScriptInfo).load_app().app_context():
return __ctx.invoke(f, *args, **kwargs)
return update_wrapper(decorator, f)
class AppGroup(click.Group):
"""This works similar to a regular click :class:`~click.Group` but it
changes the behavior of the :meth:`command` decorator so that it
automatically wraps the functions in :func:`with_appcontext`.
Not to be confused with :class:`FlaskGroup`.
"""
def command(self, *args, **kwargs):
"""This works exactly like the method of the same name on a regular
:class:`click.Group` but it wraps callbacks in :func:`with_appcontext`
unless it's disabled by passing ``with_appcontext=False``.
"""
wrap_for_ctx = kwargs.pop("with_appcontext", True)
def decorator(f):
if wrap_for_ctx:
f = with_appcontext(f)
return click.Group.command(self, *args, **kwargs)(f)
return decorator
def group(self, *args, **kwargs):
"""This works exactly like the method of the same name on a regular
:class:`click.Group` but it defaults the group class to
:class:`AppGroup`.
"""
kwargs.setdefault("cls", AppGroup)
return click.Group.group(self, *args, **kwargs)
class FlaskGroup(AppGroup):
"""Special subclass of the :class:`AppGroup` group that supports
loading more commands from the configured Flask app. Normally a
developer does not have to interface with this class but there are
some very advanced use cases for which it makes sense to create an
instance of this. see :ref:`custom-scripts`.
:param add_default_commands: if this is True then the default run and
shell commands will be added.
:param add_version_option: adds the ``--version`` option.
:param create_app: an optional callback that is passed the script info and
returns the loaded app.
:param load_dotenv: Load the nearest :file:`.env` and :file:`.flaskenv`
files to set environment variables. Will also change the working
directory to the directory containing the first file found.
:param set_debug_flag: Set the app's debug flag based on the active
environment
.. versionchanged:: 1.0
If installed, python-dotenv will be used to load environment variables
from :file:`.env` and :file:`.flaskenv` files.
"""
def __init__(
self,
add_default_commands=True,
create_app=None,
add_version_option=True,
load_dotenv=True,
set_debug_flag=True,
**extra,
):
params = list(extra.pop("params", None) or ())
if add_version_option:
params.append(version_option)
AppGroup.__init__(self, params=params, **extra)
self.create_app = create_app
self.load_dotenv = load_dotenv
self.set_debug_flag = set_debug_flag
if add_default_commands:
self.add_command(run_command)
self.add_command(shell_command)
self.add_command(routes_command)
self._loaded_plugin_commands = False
def _load_plugin_commands(self):
if self._loaded_plugin_commands:
return
try:
import pkg_resources
except ImportError:
self._loaded_plugin_commands = True
return
for ep in pkg_resources.iter_entry_points("flask.commands"):
self.add_command(ep.load(), ep.name)
self._loaded_plugin_commands = True
def get_command(self, ctx, name):
self._load_plugin_commands()
# Look up built-in and plugin commands, which should be
# available even if the app fails to load.
rv = super().get_command(ctx, name)
if rv is not None:
return rv
info = ctx.ensure_object(ScriptInfo)
# Look up commands provided by the app, showing an error and
# continuing if the app couldn't be loaded.
try:
return info.load_app().cli.get_command(ctx, name)
except NoAppException as e:
click.secho(f"Error: {e.format_message()}\n", err=True, fg="red")
def list_commands(self, ctx):
self._load_plugin_commands()
# Start with the built-in and plugin commands.
rv = set(super().list_commands(ctx))
info = ctx.ensure_object(ScriptInfo)
# Add commands provided by the app, showing an error and
# continuing if the app couldn't be loaded.
try:
rv.update(info.load_app().cli.list_commands(ctx))
except NoAppException as e:
# When an app couldn't be loaded, show the error message
# without the traceback.
click.secho(f"Error: {e.format_message()}\n", err=True, fg="red")
except Exception:
# When any other errors occurred during loading, show the
# full traceback.
click.secho(f"{traceback.format_exc()}\n", err=True, fg="red")
return sorted(rv)
def main(self, *args, **kwargs):
# Set a global flag that indicates that we were invoked from the
# command line interface. This is detected by Flask.run to make the
# call into a no-op. This is necessary to avoid ugly errors when the
# script that is loaded here also attempts to start a server.
os.environ["FLASK_RUN_FROM_CLI"] = "true"
if get_load_dotenv(self.load_dotenv):
load_dotenv()
obj = kwargs.get("obj")
if obj is None:
obj = ScriptInfo(
create_app=self.create_app, set_debug_flag=self.set_debug_flag
)
kwargs["obj"] = obj
kwargs.setdefault("auto_envvar_prefix", "FLASK")
return super().main(*args, **kwargs)
def _path_is_ancestor(path, other):
"""Take ``other`` and remove the length of ``path`` from it. Then join it
to ``path``. If it is the original value, ``path`` is an ancestor of
``other``."""
return os.path.join(path, other[len(path) :].lstrip(os.sep)) == other
def load_dotenv(path=None):
"""Load "dotenv" files in order of precedence to set environment variables.
If an env var is already set it is not overwritten, so earlier files in the
list are preferred over later files.
This is a no-op if `python-dotenv`_ is not installed.
.. _python-dotenv: https://github.com/theskumar/python-dotenv#readme
:param path: Load the file at this location instead of searching.
:return: ``True`` if a file was loaded.
.. versionchanged:: 1.1.0
Returns ``False`` when python-dotenv is not installed, or when
the given path isn't a file.
.. versionchanged:: 2.0
When loading the env files, set the default encoding to UTF-8.
.. versionadded:: 1.0
"""
if dotenv is None:
if path or os.path.isfile(".env") or os.path.isfile(".flaskenv"):
click.secho(
" * Tip: There are .env or .flaskenv files present."
' Do "pip install python-dotenv" to use them.',
fg="yellow",
err=True,
)
return False
# if the given path specifies the actual file then return True,
# else False
if path is not None:
if os.path.isfile(path):
return dotenv.load_dotenv(path, encoding="utf-8")
return False
new_dir = None
for name in (".env", ".flaskenv"):
path = dotenv.find_dotenv(name, usecwd=True)
if not path:
continue
if new_dir is None:
new_dir = os.path.dirname(path)
dotenv.load_dotenv(path, encoding="utf-8")
return new_dir is not None # at least one file was located and loaded
def show_server_banner(env, debug, app_import_path, eager_loading):
"""Show extra startup messages the first time the server is run,
ignoring the reloader.
"""
if os.environ.get("WERKZEUG_RUN_MAIN") == "true":
return
if app_import_path is not None:
message = f" * Serving Flask app {app_import_path!r}"
if not eager_loading:
message += " (lazy loading)"
click.echo(message)
click.echo(f" * Environment: {env}")
if env == "production":
click.secho(
" WARNING: This is a development server. Do not use it in"
" a production deployment.",
fg="red",
)
click.secho(" Use a production WSGI server instead.", dim=True)
if debug is not None:
click.echo(f" * Debug mode: {'on' if debug else 'off'}")
class CertParamType(click.ParamType):
"""Click option type for the ``--cert`` option. Allows either an
existing file, the string ``'adhoc'``, or an import for a
:class:`~ssl.SSLContext` object.
"""
name = "path"
def __init__(self):
self.path_type = click.Path(exists=True, dir_okay=False, resolve_path=True)
def convert(self, value, param, ctx):
if ssl is None:
raise click.BadParameter(
'Using "--cert" requires Python to be compiled with SSL support.',
ctx,
param,
)
try:
return self.path_type(value, param, ctx)
except click.BadParameter:
value = click.STRING(value, param, ctx).lower()
if value == "adhoc":
try:
import cryptography # noqa: F401
except ImportError:
raise click.BadParameter(
"Using ad-hoc certificates requires the cryptography library.",
ctx,
param,
) from None
return value
obj = import_string(value, silent=True)
if isinstance(obj, ssl.SSLContext):
return obj
raise
def _validate_key(ctx, param, value):
"""The ``--key`` option must be specified when ``--cert`` is a file.
Modifies the ``cert`` param to be a ``(cert, key)`` pair if needed.
"""
cert = ctx.params.get("cert")
is_adhoc = cert == "adhoc"
is_context = ssl and isinstance(cert, ssl.SSLContext)
if value is not None:
if is_adhoc:
raise click.BadParameter(
'When "--cert" is "adhoc", "--key" is not used.', ctx, param
)
if is_context:
raise click.BadParameter(
'When "--cert" is an SSLContext object, "--key is not used.', ctx, param
)
if not cert:
raise click.BadParameter('"--cert" must also be specified.', ctx, param)
ctx.params["cert"] = cert, value
else:
if cert and not (is_adhoc or is_context):
raise click.BadParameter('Required when using "--cert".', ctx, param)
return value
class SeparatedPathType(click.Path):
"""Click option type that accepts a list of values separated by the
OS's path separator (``:``, ``;`` on Windows). Each value is
validated as a :class:`click.Path` type.
"""
def convert(self, value, param, ctx):
items = self.split_envvar_value(value)
super_convert = super().convert
return [super_convert(item, param, ctx) for item in items]
@click.command("run", short_help="Run a development server.")
@click.option("--host", "-h", default="127.0.0.1", help="The interface to bind to.")
@click.option("--port", "-p", default=5000, help="The port to bind to.")
@click.option(
"--cert", type=CertParamType(), help="Specify a certificate file to use HTTPS."
)
@click.option(
"--key",
type=click.Path(exists=True, dir_okay=False, resolve_path=True),
callback=_validate_key,
expose_value=False,
help="The key file to use when specifying a certificate.",
)
@click.option(
"--reload/--no-reload",
default=None,
help="Enable or disable the reloader. By default the reloader "
"is active if debug is enabled.",
)
@click.option(
"--debugger/--no-debugger",
default=None,
help="Enable or disable the debugger. By default the debugger "
"is active if debug is enabled.",
)
@click.option(
"--eager-loading/--lazy-loading",
default=None,
help="Enable or disable eager loading. By default eager "
"loading is enabled if the reloader is disabled.",
)
@click.option(
"--with-threads/--without-threads",
default=True,
help="Enable or disable multithreading.",
)
@click.option(
"--extra-files",
default=None,
type=SeparatedPathType(),
help=(
"Extra files that trigger a reload on change. Multiple paths"
f" are separated by {os.path.pathsep!r}."
),
)
@pass_script_info
def run_command(
info, host, port, reload, debugger, eager_loading, with_threads, cert, extra_files
):
"""Run a local development server.
This server is for development purposes only. It does not provide
the stability, security, or performance of production WSGI servers.
The reloader and debugger are enabled by default if
FLASK_ENV=development or FLASK_DEBUG=1.
"""
debug = get_debug_flag()
if reload is None:
reload = debug
if debugger is None:
debugger = debug
show_server_banner(get_env(), debug, info.app_import_path, eager_loading)
app = DispatchingApp(info.load_app, use_eager_loading=eager_loading)
from werkzeug.serving import run_simple
run_simple(
host,
port,
app,
use_reloader=reload,
use_debugger=debugger,
threaded=with_threads,
ssl_context=cert,
extra_files=extra_files,
)
@click.command("shell", short_help="Run a shell in the app context.")
@with_appcontext
def shell_command() -> None:
"""Run an interactive Python shell in the context of a given
Flask application. The application will populate the default
namespace of this shell according to its configuration.
This is useful for executing small snippets of management code
without having to manually configure the application.
"""
import code
from .globals import _app_ctx_stack
app = _app_ctx_stack.top.app
banner = (
f"Python {sys.version} on {sys.platform}\n"
f"App: {app.import_name} [{app.env}]\n"
f"Instance: {app.instance_path}"
)
ctx: dict = {}
# Support the regular Python interpreter startup script if someone
# is using it.
startup = os.environ.get("PYTHONSTARTUP")
if startup and os.path.isfile(startup):
with open(startup) as f:
eval(compile(f.read(), startup, "exec"), ctx)
ctx.update(app.make_shell_context())
# Site, customize, or startup script can set a hook to call when
# entering interactive mode. The default one sets up readline with
# tab and history completion.
interactive_hook = getattr(sys, "__interactivehook__", None)
if interactive_hook is not None:
try:
import readline
from rlcompleter import Completer
except ImportError:
pass
else:
# rlcompleter uses __main__.__dict__ by default, which is
# flask.__main__. Use the shell context instead.
readline.set_completer(Completer(ctx).complete)
interactive_hook()
code.interact(banner=banner, local=ctx)
@click.command("routes", short_help="Show the routes for the app.")
@click.option(
"--sort",
"-s",
type=click.Choice(("endpoint", "methods", "rule", "match")),
default="endpoint",
help=(
'Method to sort routes by. "match" is the order that Flask will match '
"routes when dispatching a request."
),
)
@click.option("--all-methods", is_flag=True, help="Show HEAD and OPTIONS methods.")
@with_appcontext
def routes_command(sort: str, all_methods: bool) -> None:
"""Show all registered routes with endpoints and methods."""
rules = list(current_app.url_map.iter_rules())
if not rules:
click.echo("No routes were registered.")
return
ignored_methods = set(() if all_methods else ("HEAD", "OPTIONS"))
if sort in ("endpoint", "rule"):
rules = sorted(rules, key=attrgetter(sort))
elif sort == "methods":
rules = sorted(rules, key=lambda rule: sorted(rule.methods)) # type: ignore
rule_methods = [
", ".join(sorted(rule.methods - ignored_methods)) # type: ignore
for rule in rules
]
headers = ("Endpoint", "Methods", "Rule")
widths = (
max(len(rule.endpoint) for rule in rules),
max(len(methods) for methods in rule_methods),
max(len(rule.rule) for rule in rules),
)
widths = [max(len(h), w) for h, w in zip(headers, widths)]
row = "{{0:<{0}}} {{1:<{1}}} {{2:<{2}}}".format(*widths)
click.echo(row.format(*headers).strip())
click.echo(row.format(*("-" * width for width in widths)))
for rule, methods in zip(rules, rule_methods):
click.echo(row.format(rule.endpoint, methods, rule.rule).rstrip())
cli = FlaskGroup(
help="""\
A general utility script for Flask applications.
Provides commands from Flask, extensions, and the application. Loads the
application defined in the FLASK_APP environment variable, or from a wsgi.py
file. Setting the FLASK_ENV environment variable to 'development' will enable
debug mode.
\b
{prefix}{cmd} FLASK_APP=hello.py
{prefix}{cmd} FLASK_ENV=development
{prefix}flask run
""".format(
cmd="export" if os.name == "posix" else "set",
prefix="$ " if os.name == "posix" else "> ",
)
)
def main() -> None:
if int(click.__version__[0]) < 8:
warnings.warn(
"Using the `flask` cli with Click 7 is deprecated and"
" will not be supported starting with Flask 2.1."
" Please upgrade to Click 8 as soon as possible.",
DeprecationWarning,
)
# TODO omit sys.argv once https://github.com/pallets/click/issues/536 is fixed
cli.main(args=sys.argv[1:])
if __name__ == "__main__":
main()

View File

@ -0,0 +1,295 @@
import errno
import os
import types
import typing as t
from werkzeug.utils import import_string
class ConfigAttribute:
"""Makes an attribute forward to the config"""
def __init__(self, name: str, get_converter: t.Optional[t.Callable] = None) -> None:
self.__name__ = name
self.get_converter = get_converter
def __get__(self, obj: t.Any, owner: t.Any = None) -> t.Any:
if obj is None:
return self
rv = obj.config[self.__name__]
if self.get_converter is not None:
rv = self.get_converter(rv)
return rv
def __set__(self, obj: t.Any, value: t.Any) -> None:
obj.config[self.__name__] = value
class Config(dict):
"""Works exactly like a dict but provides ways to fill it from files
or special dictionaries. There are two common patterns to populate the
config.
Either you can fill the config from a config file::
app.config.from_pyfile('yourconfig.cfg')
Or alternatively you can define the configuration options in the
module that calls :meth:`from_object` or provide an import path to
a module that should be loaded. It is also possible to tell it to
use the same module and with that provide the configuration values
just before the call::
DEBUG = True
SECRET_KEY = 'development key'
app.config.from_object(__name__)
In both cases (loading from any Python file or loading from modules),
only uppercase keys are added to the config. This makes it possible to use
lowercase values in the config file for temporary values that are not added
to the config or to define the config keys in the same file that implements
the application.
Probably the most interesting way to load configurations is from an
environment variable pointing to a file::
app.config.from_envvar('YOURAPPLICATION_SETTINGS')
In this case before launching the application you have to set this
environment variable to the file you want to use. On Linux and OS X
use the export statement::
export YOURAPPLICATION_SETTINGS='/path/to/config/file'
On windows use `set` instead.
:param root_path: path to which files are read relative from. When the
config object is created by the application, this is
the application's :attr:`~flask.Flask.root_path`.
:param defaults: an optional dictionary of default values
"""
def __init__(self, root_path: str, defaults: t.Optional[dict] = None) -> None:
dict.__init__(self, defaults or {})
self.root_path = root_path
def from_envvar(self, variable_name: str, silent: bool = False) -> bool:
"""Loads a configuration from an environment variable pointing to
a configuration file. This is basically just a shortcut with nicer
error messages for this line of code::
app.config.from_pyfile(os.environ['YOURAPPLICATION_SETTINGS'])
:param variable_name: name of the environment variable
:param silent: set to ``True`` if you want silent failure for missing
files.
:return: ``True`` if the file was loaded successfully.
"""
rv = os.environ.get(variable_name)
if not rv:
if silent:
return False
raise RuntimeError(
f"The environment variable {variable_name!r} is not set"
" and as such configuration could not be loaded. Set"
" this variable and make it point to a configuration"
" file"
)
return self.from_pyfile(rv, silent=silent)
def from_pyfile(self, filename: str, silent: bool = False) -> bool:
"""Updates the values in the config from a Python file. This function
behaves as if the file was imported as module with the
:meth:`from_object` function.
:param filename: the filename of the config. This can either be an
absolute filename or a filename relative to the
root path.
:param silent: set to ``True`` if you want silent failure for missing
files.
:return: ``True`` if the file was loaded successfully.
.. versionadded:: 0.7
`silent` parameter.
"""
filename = os.path.join(self.root_path, filename)
d = types.ModuleType("config")
d.__file__ = filename
try:
with open(filename, mode="rb") as config_file:
exec(compile(config_file.read(), filename, "exec"), d.__dict__)
except OSError as e:
if silent and e.errno in (errno.ENOENT, errno.EISDIR, errno.ENOTDIR):
return False
e.strerror = f"Unable to load configuration file ({e.strerror})"
raise
self.from_object(d)
return True
def from_object(self, obj: t.Union[object, str]) -> None:
"""Updates the values from the given object. An object can be of one
of the following two types:
- a string: in this case the object with that name will be imported
- an actual object reference: that object is used directly
Objects are usually either modules or classes. :meth:`from_object`
loads only the uppercase attributes of the module/class. A ``dict``
object will not work with :meth:`from_object` because the keys of a
``dict`` are not attributes of the ``dict`` class.
Example of module-based configuration::
app.config.from_object('yourapplication.default_config')
from yourapplication import default_config
app.config.from_object(default_config)
Nothing is done to the object before loading. If the object is a
class and has ``@property`` attributes, it needs to be
instantiated before being passed to this method.
You should not use this function to load the actual configuration but
rather configuration defaults. The actual config should be loaded
with :meth:`from_pyfile` and ideally from a location not within the
package because the package might be installed system wide.
See :ref:`config-dev-prod` for an example of class-based configuration
using :meth:`from_object`.
:param obj: an import name or object
"""
if isinstance(obj, str):
obj = import_string(obj)
for key in dir(obj):
if key.isupper():
self[key] = getattr(obj, key)
def from_file(
self,
filename: str,
load: t.Callable[[t.IO[t.Any]], t.Mapping],
silent: bool = False,
) -> bool:
"""Update the values in the config from a file that is loaded
using the ``load`` parameter. The loaded data is passed to the
:meth:`from_mapping` method.
.. code-block:: python
import toml
app.config.from_file("config.toml", load=toml.load)
:param filename: The path to the data file. This can be an
absolute path or relative to the config root path.
:param load: A callable that takes a file handle and returns a
mapping of loaded data from the file.
:type load: ``Callable[[Reader], Mapping]`` where ``Reader``
implements a ``read`` method.
:param silent: Ignore the file if it doesn't exist.
:return: ``True`` if the file was loaded successfully.
.. versionadded:: 2.0
"""
filename = os.path.join(self.root_path, filename)
try:
with open(filename) as f:
obj = load(f)
except OSError as e:
if silent and e.errno in (errno.ENOENT, errno.EISDIR):
return False
e.strerror = f"Unable to load configuration file ({e.strerror})"
raise
return self.from_mapping(obj)
def from_json(self, filename: str, silent: bool = False) -> bool:
"""Update the values in the config from a JSON file. The loaded
data is passed to the :meth:`from_mapping` method.
:param filename: The path to the JSON file. This can be an
absolute path or relative to the config root path.
:param silent: Ignore the file if it doesn't exist.
:return: ``True`` if the file was loaded successfully.
.. deprecated:: 2.0.0
Will be removed in Flask 2.1. Use :meth:`from_file` instead.
This was removed early in 2.0.0, was added back in 2.0.1.
.. versionadded:: 0.11
"""
import warnings
from . import json
warnings.warn(
"'from_json' is deprecated and will be removed in Flask"
" 2.1. Use 'from_file(path, json.load)' instead.",
DeprecationWarning,
stacklevel=2,
)
return self.from_file(filename, json.load, silent=silent)
def from_mapping(
self, mapping: t.Optional[t.Mapping[str, t.Any]] = None, **kwargs: t.Any
) -> bool:
"""Updates the config like :meth:`update` ignoring items with non-upper
keys.
:return: Always returns ``True``.
.. versionadded:: 0.11
"""
mappings: t.Dict[str, t.Any] = {}
if mapping is not None:
mappings.update(mapping)
mappings.update(kwargs)
for key, value in mappings.items():
if key.isupper():
self[key] = value
return True
def get_namespace(
self, namespace: str, lowercase: bool = True, trim_namespace: bool = True
) -> t.Dict[str, t.Any]:
"""Returns a dictionary containing a subset of configuration options
that match the specified namespace/prefix. Example usage::
app.config['IMAGE_STORE_TYPE'] = 'fs'
app.config['IMAGE_STORE_PATH'] = '/var/app/images'
app.config['IMAGE_STORE_BASE_URL'] = 'http://img.website.com'
image_store_config = app.config.get_namespace('IMAGE_STORE_')
The resulting dictionary `image_store_config` would look like::
{
'type': 'fs',
'path': '/var/app/images',
'base_url': 'http://img.website.com'
}
This is often useful when configuration options map directly to
keyword arguments in functions or class constructors.
:param namespace: a configuration namespace
:param lowercase: a flag indicating if the keys of the resulting
dictionary should be lowercase
:param trim_namespace: a flag indicating if the keys of the resulting
dictionary should not include the namespace
.. versionadded:: 0.11
"""
rv = {}
for k, v in self.items():
if not k.startswith(namespace):
continue
if trim_namespace:
key = k[len(namespace) :]
else:
key = k
if lowercase:
key = key.lower()
rv[key] = v
return rv
def __repr__(self) -> str:
return f"<{type(self).__name__} {dict.__repr__(self)}>"

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@ -0,0 +1,489 @@
import sys
import typing as t
from functools import update_wrapper
from types import TracebackType
from werkzeug.exceptions import HTTPException
from .globals import _app_ctx_stack
from .globals import _request_ctx_stack
from .signals import appcontext_popped
from .signals import appcontext_pushed
from .typing import AfterRequestCallable
if t.TYPE_CHECKING:
from .app import Flask
from .sessions import SessionMixin
from .wrappers import Request
# a singleton sentinel value for parameter defaults
_sentinel = object()
class _AppCtxGlobals:
"""A plain object. Used as a namespace for storing data during an
application context.
Creating an app context automatically creates this object, which is
made available as the :data:`g` proxy.
.. describe:: 'key' in g
Check whether an attribute is present.
.. versionadded:: 0.10
.. describe:: iter(g)
Return an iterator over the attribute names.
.. versionadded:: 0.10
"""
# Define attr methods to let mypy know this is a namespace object
# that has arbitrary attributes.
def __getattr__(self, name: str) -> t.Any:
try:
return self.__dict__[name]
except KeyError:
raise AttributeError(name) from None
def __setattr__(self, name: str, value: t.Any) -> None:
self.__dict__[name] = value
def __delattr__(self, name: str) -> None:
try:
del self.__dict__[name]
except KeyError:
raise AttributeError(name) from None
def get(self, name: str, default: t.Optional[t.Any] = None) -> t.Any:
"""Get an attribute by name, or a default value. Like
:meth:`dict.get`.
:param name: Name of attribute to get.
:param default: Value to return if the attribute is not present.
.. versionadded:: 0.10
"""
return self.__dict__.get(name, default)
def pop(self, name: str, default: t.Any = _sentinel) -> t.Any:
"""Get and remove an attribute by name. Like :meth:`dict.pop`.
:param name: Name of attribute to pop.
:param default: Value to return if the attribute is not present,
instead of raising a ``KeyError``.
.. versionadded:: 0.11
"""
if default is _sentinel:
return self.__dict__.pop(name)
else:
return self.__dict__.pop(name, default)
def setdefault(self, name: str, default: t.Any = None) -> t.Any:
"""Get the value of an attribute if it is present, otherwise
set and return a default value. Like :meth:`dict.setdefault`.
:param name: Name of attribute to get.
:param default: Value to set and return if the attribute is not
present.
.. versionadded:: 0.11
"""
return self.__dict__.setdefault(name, default)
def __contains__(self, item: str) -> bool:
return item in self.__dict__
def __iter__(self) -> t.Iterator[str]:
return iter(self.__dict__)
def __repr__(self) -> str:
top = _app_ctx_stack.top
if top is not None:
return f"<flask.g of {top.app.name!r}>"
return object.__repr__(self)
def after_this_request(f: AfterRequestCallable) -> AfterRequestCallable:
"""Executes a function after this request. This is useful to modify
response objects. The function is passed the response object and has
to return the same or a new one.
Example::
@app.route('/')
def index():
@after_this_request
def add_header(response):
response.headers['X-Foo'] = 'Parachute'
return response
return 'Hello World!'
This is more useful if a function other than the view function wants to
modify a response. For instance think of a decorator that wants to add
some headers without converting the return value into a response object.
.. versionadded:: 0.9
"""
top = _request_ctx_stack.top
if top is None:
raise RuntimeError(
"This decorator can only be used when a request context is"
" active, such as within a view function."
)
top._after_request_functions.append(f)
return f
def copy_current_request_context(f: t.Callable) -> t.Callable:
"""A helper function that decorates a function to retain the current
request context. This is useful when working with greenlets. The moment
the function is decorated a copy of the request context is created and
then pushed when the function is called. The current session is also
included in the copied request context.
Example::
import gevent
from flask import copy_current_request_context
@app.route('/')
def index():
@copy_current_request_context
def do_some_work():
# do some work here, it can access flask.request or
# flask.session like you would otherwise in the view function.
...
gevent.spawn(do_some_work)
return 'Regular response'
.. versionadded:: 0.10
"""
top = _request_ctx_stack.top
if top is None:
raise RuntimeError(
"This decorator can only be used when a request context is"
" active, such as within a view function."
)
reqctx = top.copy()
def wrapper(*args, **kwargs):
with reqctx:
return f(*args, **kwargs)
return update_wrapper(wrapper, f)
def has_request_context() -> bool:
"""If you have code that wants to test if a request context is there or
not this function can be used. For instance, you may want to take advantage
of request information if the request object is available, but fail
silently if it is unavailable.
::
class User(db.Model):
def __init__(self, username, remote_addr=None):
self.username = username
if remote_addr is None and has_request_context():
remote_addr = request.remote_addr
self.remote_addr = remote_addr
Alternatively you can also just test any of the context bound objects
(such as :class:`request` or :class:`g`) for truthness::
class User(db.Model):
def __init__(self, username, remote_addr=None):
self.username = username
if remote_addr is None and request:
remote_addr = request.remote_addr
self.remote_addr = remote_addr
.. versionadded:: 0.7
"""
return _request_ctx_stack.top is not None
def has_app_context() -> bool:
"""Works like :func:`has_request_context` but for the application
context. You can also just do a boolean check on the
:data:`current_app` object instead.
.. versionadded:: 0.9
"""
return _app_ctx_stack.top is not None
class AppContext:
"""The application context binds an application object implicitly
to the current thread or greenlet, similar to how the
:class:`RequestContext` binds request information. The application
context is also implicitly created if a request context is created
but the application is not on top of the individual application
context.
"""
def __init__(self, app: "Flask") -> None:
self.app = app
self.url_adapter = app.create_url_adapter(None)
self.g = app.app_ctx_globals_class()
# Like request context, app contexts can be pushed multiple times
# but there a basic "refcount" is enough to track them.
self._refcnt = 0
def push(self) -> None:
"""Binds the app context to the current context."""
self._refcnt += 1
_app_ctx_stack.push(self)
appcontext_pushed.send(self.app)
def pop(self, exc: t.Optional[BaseException] = _sentinel) -> None: # type: ignore
"""Pops the app context."""
try:
self._refcnt -= 1
if self._refcnt <= 0:
if exc is _sentinel:
exc = sys.exc_info()[1]
self.app.do_teardown_appcontext(exc)
finally:
rv = _app_ctx_stack.pop()
assert rv is self, f"Popped wrong app context. ({rv!r} instead of {self!r})"
appcontext_popped.send(self.app)
def __enter__(self) -> "AppContext":
self.push()
return self
def __exit__(
self, exc_type: type, exc_value: BaseException, tb: TracebackType
) -> None:
self.pop(exc_value)
class RequestContext:
"""The request context contains all request relevant information. It is
created at the beginning of the request and pushed to the
`_request_ctx_stack` and removed at the end of it. It will create the
URL adapter and request object for the WSGI environment provided.
Do not attempt to use this class directly, instead use
:meth:`~flask.Flask.test_request_context` and
:meth:`~flask.Flask.request_context` to create this object.
When the request context is popped, it will evaluate all the
functions registered on the application for teardown execution
(:meth:`~flask.Flask.teardown_request`).
The request context is automatically popped at the end of the request
for you. In debug mode the request context is kept around if
exceptions happen so that interactive debuggers have a chance to
introspect the data. With 0.4 this can also be forced for requests
that did not fail and outside of ``DEBUG`` mode. By setting
``'flask._preserve_context'`` to ``True`` on the WSGI environment the
context will not pop itself at the end of the request. This is used by
the :meth:`~flask.Flask.test_client` for example to implement the
deferred cleanup functionality.
You might find this helpful for unittests where you need the
information from the context local around for a little longer. Make
sure to properly :meth:`~werkzeug.LocalStack.pop` the stack yourself in
that situation, otherwise your unittests will leak memory.
"""
def __init__(
self,
app: "Flask",
environ: dict,
request: t.Optional["Request"] = None,
session: t.Optional["SessionMixin"] = None,
) -> None:
self.app = app
if request is None:
request = app.request_class(environ)
self.request = request
self.url_adapter = None
try:
self.url_adapter = app.create_url_adapter(self.request)
except HTTPException as e:
self.request.routing_exception = e
self.flashes = None
self.session = session
# Request contexts can be pushed multiple times and interleaved with
# other request contexts. Now only if the last level is popped we
# get rid of them. Additionally if an application context is missing
# one is created implicitly so for each level we add this information
self._implicit_app_ctx_stack: t.List[t.Optional["AppContext"]] = []
# indicator if the context was preserved. Next time another context
# is pushed the preserved context is popped.
self.preserved = False
# remembers the exception for pop if there is one in case the context
# preservation kicks in.
self._preserved_exc = None
# Functions that should be executed after the request on the response
# object. These will be called before the regular "after_request"
# functions.
self._after_request_functions: t.List[AfterRequestCallable] = []
@property
def g(self) -> AppContext:
return _app_ctx_stack.top.g
@g.setter
def g(self, value: AppContext) -> None:
_app_ctx_stack.top.g = value
def copy(self) -> "RequestContext":
"""Creates a copy of this request context with the same request object.
This can be used to move a request context to a different greenlet.
Because the actual request object is the same this cannot be used to
move a request context to a different thread unless access to the
request object is locked.
.. versionadded:: 0.10
.. versionchanged:: 1.1
The current session object is used instead of reloading the original
data. This prevents `flask.session` pointing to an out-of-date object.
"""
return self.__class__(
self.app,
environ=self.request.environ,
request=self.request,
session=self.session,
)
def match_request(self) -> None:
"""Can be overridden by a subclass to hook into the matching
of the request.
"""
try:
result = self.url_adapter.match(return_rule=True) # type: ignore
self.request.url_rule, self.request.view_args = result # type: ignore
except HTTPException as e:
self.request.routing_exception = e
def push(self) -> None:
"""Binds the request context to the current context."""
# If an exception occurs in debug mode or if context preservation is
# activated under exception situations exactly one context stays
# on the stack. The rationale is that you want to access that
# information under debug situations. However if someone forgets to
# pop that context again we want to make sure that on the next push
# it's invalidated, otherwise we run at risk that something leaks
# memory. This is usually only a problem in test suite since this
# functionality is not active in production environments.
top = _request_ctx_stack.top
if top is not None and top.preserved:
top.pop(top._preserved_exc)
# Before we push the request context we have to ensure that there
# is an application context.
app_ctx = _app_ctx_stack.top
if app_ctx is None or app_ctx.app != self.app:
app_ctx = self.app.app_context()
app_ctx.push()
self._implicit_app_ctx_stack.append(app_ctx)
else:
self._implicit_app_ctx_stack.append(None)
_request_ctx_stack.push(self)
# Open the session at the moment that the request context is available.
# This allows a custom open_session method to use the request context.
# Only open a new session if this is the first time the request was
# pushed, otherwise stream_with_context loses the session.
if self.session is None:
session_interface = self.app.session_interface
self.session = session_interface.open_session(self.app, self.request)
if self.session is None:
self.session = session_interface.make_null_session(self.app)
# Match the request URL after loading the session, so that the
# session is available in custom URL converters.
if self.url_adapter is not None:
self.match_request()
def pop(self, exc: t.Optional[BaseException] = _sentinel) -> None: # type: ignore
"""Pops the request context and unbinds it by doing that. This will
also trigger the execution of functions registered by the
:meth:`~flask.Flask.teardown_request` decorator.
.. versionchanged:: 0.9
Added the `exc` argument.
"""
app_ctx = self._implicit_app_ctx_stack.pop()
clear_request = False
try:
if not self._implicit_app_ctx_stack:
self.preserved = False
self._preserved_exc = None
if exc is _sentinel:
exc = sys.exc_info()[1]
self.app.do_teardown_request(exc)
request_close = getattr(self.request, "close", None)
if request_close is not None:
request_close()
clear_request = True
finally:
rv = _request_ctx_stack.pop()
# get rid of circular dependencies at the end of the request
# so that we don't require the GC to be active.
if clear_request:
rv.request.environ["werkzeug.request"] = None
# Get rid of the app as well if necessary.
if app_ctx is not None:
app_ctx.pop(exc)
assert (
rv is self
), f"Popped wrong request context. ({rv!r} instead of {self!r})"
def auto_pop(self, exc: t.Optional[BaseException]) -> None:
if self.request.environ.get("flask._preserve_context") or (
exc is not None and self.app.preserve_context_on_exception
):
self.preserved = True
self._preserved_exc = exc # type: ignore
else:
self.pop(exc)
def __enter__(self) -> "RequestContext":
self.push()
return self
def __exit__(
self, exc_type: type, exc_value: BaseException, tb: TracebackType
) -> None:
# do not pop the request stack if we are in debug mode and an
# exception happened. This will allow the debugger to still
# access the request object in the interactive shell. Furthermore
# the context can be force kept alive for the test client.
# See flask.testing for how this works.
self.auto_pop(exc_value)
def __repr__(self) -> str:
return (
f"<{type(self).__name__} {self.request.url!r}"
f" [{self.request.method}] of {self.app.name}>"
)

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@ -0,0 +1,172 @@
import os
import typing as t
from warnings import warn
from .app import Flask
from .blueprints import Blueprint
from .globals import _request_ctx_stack
class UnexpectedUnicodeError(AssertionError, UnicodeError):
"""Raised in places where we want some better error reporting for
unexpected unicode or binary data.
"""
class DebugFilesKeyError(KeyError, AssertionError):
"""Raised from request.files during debugging. The idea is that it can
provide a better error message than just a generic KeyError/BadRequest.
"""
def __init__(self, request, key):
form_matches = request.form.getlist(key)
buf = [
f"You tried to access the file {key!r} in the request.files"
" dictionary but it does not exist. The mimetype for the"
f" request is {request.mimetype!r} instead of"
" 'multipart/form-data' which means that no file contents"
" were transmitted. To fix this error you should provide"
' enctype="multipart/form-data" in your form.'
]
if form_matches:
names = ", ".join(repr(x) for x in form_matches)
buf.append(
"\n\nThe browser instead transmitted some file names. "
f"This was submitted: {names}"
)
self.msg = "".join(buf)
def __str__(self):
return self.msg
class FormDataRoutingRedirect(AssertionError):
"""This exception is raised by Flask in debug mode if it detects a
redirect caused by the routing system when the request method is not
GET, HEAD or OPTIONS. Reasoning: form data will be dropped.
"""
def __init__(self, request):
exc = request.routing_exception
buf = [
f"A request was sent to this URL ({request.url}) but a"
" redirect was issued automatically by the routing system"
f" to {exc.new_url!r}."
]
# In case just a slash was appended we can be extra helpful
if f"{request.base_url}/" == exc.new_url.split("?")[0]:
buf.append(
" The URL was defined with a trailing slash so Flask"
" will automatically redirect to the URL with the"
" trailing slash if it was accessed without one."
)
buf.append(
" Make sure to directly send your"
f" {request.method}-request to this URL since we can't make"
" browsers or HTTP clients redirect with form data reliably"
" or without user interaction."
)
buf.append("\n\nNote: this exception is only raised in debug mode")
AssertionError.__init__(self, "".join(buf).encode("utf-8"))
def attach_enctype_error_multidict(request):
"""Since Flask 0.8 we're monkeypatching the files object in case a
request is detected that does not use multipart form data but the files
object is accessed.
"""
oldcls = request.files.__class__
class newcls(oldcls):
def __getitem__(self, key):
try:
return oldcls.__getitem__(self, key)
except KeyError as e:
if key not in request.form:
raise
raise DebugFilesKeyError(request, key) from e
newcls.__name__ = oldcls.__name__
newcls.__module__ = oldcls.__module__
request.files.__class__ = newcls
def _dump_loader_info(loader) -> t.Generator:
yield f"class: {type(loader).__module__}.{type(loader).__name__}"
for key, value in sorted(loader.__dict__.items()):
if key.startswith("_"):
continue
if isinstance(value, (tuple, list)):
if not all(isinstance(x, str) for x in value):
continue
yield f"{key}:"
for item in value:
yield f" - {item}"
continue
elif not isinstance(value, (str, int, float, bool)):
continue
yield f"{key}: {value!r}"
def explain_template_loading_attempts(app: Flask, template, attempts) -> None:
"""This should help developers understand what failed"""
info = [f"Locating template {template!r}:"]
total_found = 0
blueprint = None
reqctx = _request_ctx_stack.top
if reqctx is not None and reqctx.request.blueprint is not None:
blueprint = reqctx.request.blueprint
for idx, (loader, srcobj, triple) in enumerate(attempts):
if isinstance(srcobj, Flask):
src_info = f"application {srcobj.import_name!r}"
elif isinstance(srcobj, Blueprint):
src_info = f"blueprint {srcobj.name!r} ({srcobj.import_name})"
else:
src_info = repr(srcobj)
info.append(f"{idx + 1:5}: trying loader of {src_info}")
for line in _dump_loader_info(loader):
info.append(f" {line}")
if triple is None:
detail = "no match"
else:
detail = f"found ({triple[1] or '<string>'!r})"
total_found += 1
info.append(f" -> {detail}")
seems_fishy = False
if total_found == 0:
info.append("Error: the template could not be found.")
seems_fishy = True
elif total_found > 1:
info.append("Warning: multiple loaders returned a match for the template.")
seems_fishy = True
if blueprint is not None and seems_fishy:
info.append(
" The template was looked up from an endpoint that belongs"
f" to the blueprint {blueprint!r}."
)
info.append(" Maybe you did not place a template in the right folder?")
info.append(" See https://flask.palletsprojects.com/blueprints/#templates")
app.logger.info("\n".join(info))
def explain_ignored_app_run() -> None:
if os.environ.get("WERKZEUG_RUN_MAIN") != "true":
warn(
Warning(
"Silently ignoring app.run() because the application is"
" run from the flask command line executable. Consider"
' putting app.run() behind an if __name__ == "__main__"'
" guard to silence this warning."
),
stacklevel=3,
)

View File

@ -0,0 +1,59 @@
import typing as t
from functools import partial
from werkzeug.local import LocalProxy
from werkzeug.local import LocalStack
if t.TYPE_CHECKING:
from .app import Flask
from .ctx import _AppCtxGlobals
from .sessions import SessionMixin
from .wrappers import Request
_request_ctx_err_msg = """\
Working outside of request context.
This typically means that you attempted to use functionality that needed
an active HTTP request. Consult the documentation on testing for
information about how to avoid this problem.\
"""
_app_ctx_err_msg = """\
Working outside of application context.
This typically means that you attempted to use functionality that needed
to interface with the current application object in some way. To solve
this, set up an application context with app.app_context(). See the
documentation for more information.\
"""
def _lookup_req_object(name):
top = _request_ctx_stack.top
if top is None:
raise RuntimeError(_request_ctx_err_msg)
return getattr(top, name)
def _lookup_app_object(name):
top = _app_ctx_stack.top
if top is None:
raise RuntimeError(_app_ctx_err_msg)
return getattr(top, name)
def _find_app():
top = _app_ctx_stack.top
if top is None:
raise RuntimeError(_app_ctx_err_msg)
return top.app
# context locals
_request_ctx_stack = LocalStack()
_app_ctx_stack = LocalStack()
current_app: "Flask" = LocalProxy(_find_app) # type: ignore
request: "Request" = LocalProxy(partial(_lookup_req_object, "request")) # type: ignore
session: "SessionMixin" = LocalProxy( # type: ignore
partial(_lookup_req_object, "session")
)
g: "_AppCtxGlobals" = LocalProxy(partial(_lookup_app_object, "g")) # type: ignore

View File

@ -0,0 +1,836 @@
import os
import pkgutil
import socket
import sys
import typing as t
import warnings
from datetime import datetime
from datetime import timedelta
from functools import lru_cache
from functools import update_wrapper
from threading import RLock
import werkzeug.utils
from werkzeug.exceptions import NotFound
from werkzeug.routing import BuildError
from werkzeug.urls import url_quote
from .globals import _app_ctx_stack
from .globals import _request_ctx_stack
from .globals import current_app
from .globals import request
from .globals import session
from .signals import message_flashed
if t.TYPE_CHECKING:
from .wrappers import Response
def get_env() -> str:
"""Get the environment the app is running in, indicated by the
:envvar:`FLASK_ENV` environment variable. The default is
``'production'``.
"""
return os.environ.get("FLASK_ENV") or "production"
def get_debug_flag() -> bool:
"""Get whether debug mode should be enabled for the app, indicated
by the :envvar:`FLASK_DEBUG` environment variable. The default is
``True`` if :func:`.get_env` returns ``'development'``, or ``False``
otherwise.
"""
val = os.environ.get("FLASK_DEBUG")
if not val:
return get_env() == "development"
return val.lower() not in ("0", "false", "no")
def get_load_dotenv(default: bool = True) -> bool:
"""Get whether the user has disabled loading dotenv files by setting
:envvar:`FLASK_SKIP_DOTENV`. The default is ``True``, load the
files.
:param default: What to return if the env var isn't set.
"""
val = os.environ.get("FLASK_SKIP_DOTENV")
if not val:
return default
return val.lower() in ("0", "false", "no")
def stream_with_context(
generator_or_function: t.Union[
t.Iterator[t.AnyStr], t.Callable[..., t.Iterator[t.AnyStr]]
]
) -> t.Iterator[t.AnyStr]:
"""Request contexts disappear when the response is started on the server.
This is done for efficiency reasons and to make it less likely to encounter
memory leaks with badly written WSGI middlewares. The downside is that if
you are using streamed responses, the generator cannot access request bound
information any more.
This function however can help you keep the context around for longer::
from flask import stream_with_context, request, Response
@app.route('/stream')
def streamed_response():
@stream_with_context
def generate():
yield 'Hello '
yield request.args['name']
yield '!'
return Response(generate())
Alternatively it can also be used around a specific generator::
from flask import stream_with_context, request, Response
@app.route('/stream')
def streamed_response():
def generate():
yield 'Hello '
yield request.args['name']
yield '!'
return Response(stream_with_context(generate()))
.. versionadded:: 0.9
"""
try:
gen = iter(generator_or_function) # type: ignore
except TypeError:
def decorator(*args: t.Any, **kwargs: t.Any) -> t.Any:
gen = generator_or_function(*args, **kwargs) # type: ignore
return stream_with_context(gen)
return update_wrapper(decorator, generator_or_function) # type: ignore
def generator() -> t.Generator:
ctx = _request_ctx_stack.top
if ctx is None:
raise RuntimeError(
"Attempted to stream with context but "
"there was no context in the first place to keep around."
)
with ctx:
# Dummy sentinel. Has to be inside the context block or we're
# not actually keeping the context around.
yield None
# The try/finally is here so that if someone passes a WSGI level
# iterator in we're still running the cleanup logic. Generators
# don't need that because they are closed on their destruction
# automatically.
try:
yield from gen
finally:
if hasattr(gen, "close"):
gen.close() # type: ignore
# The trick is to start the generator. Then the code execution runs until
# the first dummy None is yielded at which point the context was already
# pushed. This item is discarded. Then when the iteration continues the
# real generator is executed.
wrapped_g = generator()
next(wrapped_g)
return wrapped_g
def make_response(*args: t.Any) -> "Response":
"""Sometimes it is necessary to set additional headers in a view. Because
views do not have to return response objects but can return a value that
is converted into a response object by Flask itself, it becomes tricky to
add headers to it. This function can be called instead of using a return
and you will get a response object which you can use to attach headers.
If view looked like this and you want to add a new header::
def index():
return render_template('index.html', foo=42)
You can now do something like this::
def index():
response = make_response(render_template('index.html', foo=42))
response.headers['X-Parachutes'] = 'parachutes are cool'
return response
This function accepts the very same arguments you can return from a
view function. This for example creates a response with a 404 error
code::
response = make_response(render_template('not_found.html'), 404)
The other use case of this function is to force the return value of a
view function into a response which is helpful with view
decorators::
response = make_response(view_function())
response.headers['X-Parachutes'] = 'parachutes are cool'
Internally this function does the following things:
- if no arguments are passed, it creates a new response argument
- if one argument is passed, :meth:`flask.Flask.make_response`
is invoked with it.
- if more than one argument is passed, the arguments are passed
to the :meth:`flask.Flask.make_response` function as tuple.
.. versionadded:: 0.6
"""
if not args:
return current_app.response_class()
if len(args) == 1:
args = args[0]
return current_app.make_response(args)
def url_for(endpoint: str, **values: t.Any) -> str:
"""Generates a URL to the given endpoint with the method provided.
Variable arguments that are unknown to the target endpoint are appended
to the generated URL as query arguments. If the value of a query argument
is ``None``, the whole pair is skipped. In case blueprints are active
you can shortcut references to the same blueprint by prefixing the
local endpoint with a dot (``.``).
This will reference the index function local to the current blueprint::
url_for('.index')
See :ref:`url-building`.
Configuration values ``APPLICATION_ROOT`` and ``SERVER_NAME`` are only used when
generating URLs outside of a request context.
To integrate applications, :class:`Flask` has a hook to intercept URL build
errors through :attr:`Flask.url_build_error_handlers`. The `url_for`
function results in a :exc:`~werkzeug.routing.BuildError` when the current
app does not have a URL for the given endpoint and values. When it does, the
:data:`~flask.current_app` calls its :attr:`~Flask.url_build_error_handlers` if
it is not ``None``, which can return a string to use as the result of
`url_for` (instead of `url_for`'s default to raise the
:exc:`~werkzeug.routing.BuildError` exception) or re-raise the exception.
An example::
def external_url_handler(error, endpoint, values):
"Looks up an external URL when `url_for` cannot build a URL."
# This is an example of hooking the build_error_handler.
# Here, lookup_url is some utility function you've built
# which looks up the endpoint in some external URL registry.
url = lookup_url(endpoint, **values)
if url is None:
# External lookup did not have a URL.
# Re-raise the BuildError, in context of original traceback.
exc_type, exc_value, tb = sys.exc_info()
if exc_value is error:
raise exc_type(exc_value).with_traceback(tb)
else:
raise error
# url_for will use this result, instead of raising BuildError.
return url
app.url_build_error_handlers.append(external_url_handler)
Here, `error` is the instance of :exc:`~werkzeug.routing.BuildError`, and
`endpoint` and `values` are the arguments passed into `url_for`. Note
that this is for building URLs outside the current application, and not for
handling 404 NotFound errors.
.. versionadded:: 0.10
The `_scheme` parameter was added.
.. versionadded:: 0.9
The `_anchor` and `_method` parameters were added.
.. versionadded:: 0.9
Calls :meth:`Flask.handle_build_error` on
:exc:`~werkzeug.routing.BuildError`.
:param endpoint: the endpoint of the URL (name of the function)
:param values: the variable arguments of the URL rule
:param _external: if set to ``True``, an absolute URL is generated. Server
address can be changed via ``SERVER_NAME`` configuration variable which
falls back to the `Host` header, then to the IP and port of the request.
:param _scheme: a string specifying the desired URL scheme. The `_external`
parameter must be set to ``True`` or a :exc:`ValueError` is raised. The default
behavior uses the same scheme as the current request, or
:data:`PREFERRED_URL_SCHEME` if no request context is available.
This also can be set to an empty string to build protocol-relative
URLs.
:param _anchor: if provided this is added as anchor to the URL.
:param _method: if provided this explicitly specifies an HTTP method.
"""
appctx = _app_ctx_stack.top
reqctx = _request_ctx_stack.top
if appctx is None:
raise RuntimeError(
"Attempted to generate a URL without the application context being"
" pushed. This has to be executed when application context is"
" available."
)
# If request specific information is available we have some extra
# features that support "relative" URLs.
if reqctx is not None:
url_adapter = reqctx.url_adapter
blueprint_name = request.blueprint
if endpoint[:1] == ".":
if blueprint_name is not None:
endpoint = f"{blueprint_name}{endpoint}"
else:
endpoint = endpoint[1:]
external = values.pop("_external", False)
# Otherwise go with the url adapter from the appctx and make
# the URLs external by default.
else:
url_adapter = appctx.url_adapter
if url_adapter is None:
raise RuntimeError(
"Application was not able to create a URL adapter for request"
" independent URL generation. You might be able to fix this by"
" setting the SERVER_NAME config variable."
)
external = values.pop("_external", True)
anchor = values.pop("_anchor", None)
method = values.pop("_method", None)
scheme = values.pop("_scheme", None)
appctx.app.inject_url_defaults(endpoint, values)
# This is not the best way to deal with this but currently the
# underlying Werkzeug router does not support overriding the scheme on
# a per build call basis.
old_scheme = None
if scheme is not None:
if not external:
raise ValueError("When specifying _scheme, _external must be True")
old_scheme = url_adapter.url_scheme
url_adapter.url_scheme = scheme
try:
try:
rv = url_adapter.build(
endpoint, values, method=method, force_external=external
)
finally:
if old_scheme is not None:
url_adapter.url_scheme = old_scheme
except BuildError as error:
# We need to inject the values again so that the app callback can
# deal with that sort of stuff.
values["_external"] = external
values["_anchor"] = anchor
values["_method"] = method
values["_scheme"] = scheme
return appctx.app.handle_url_build_error(error, endpoint, values)
if anchor is not None:
rv += f"#{url_quote(anchor)}"
return rv
def get_template_attribute(template_name: str, attribute: str) -> t.Any:
"""Loads a macro (or variable) a template exports. This can be used to
invoke a macro from within Python code. If you for example have a
template named :file:`_cider.html` with the following contents:
.. sourcecode:: html+jinja
{% macro hello(name) %}Hello {{ name }}!{% endmacro %}
You can access this from Python code like this::
hello = get_template_attribute('_cider.html', 'hello')
return hello('World')
.. versionadded:: 0.2
:param template_name: the name of the template
:param attribute: the name of the variable of macro to access
"""
return getattr(current_app.jinja_env.get_template(template_name).module, attribute)
def flash(message: str, category: str = "message") -> None:
"""Flashes a message to the next request. In order to remove the
flashed message from the session and to display it to the user,
the template has to call :func:`get_flashed_messages`.
.. versionchanged:: 0.3
`category` parameter added.
:param message: the message to be flashed.
:param category: the category for the message. The following values
are recommended: ``'message'`` for any kind of message,
``'error'`` for errors, ``'info'`` for information
messages and ``'warning'`` for warnings. However any
kind of string can be used as category.
"""
# Original implementation:
#
# session.setdefault('_flashes', []).append((category, message))
#
# This assumed that changes made to mutable structures in the session are
# always in sync with the session object, which is not true for session
# implementations that use external storage for keeping their keys/values.
flashes = session.get("_flashes", [])
flashes.append((category, message))
session["_flashes"] = flashes
message_flashed.send(
current_app._get_current_object(), # type: ignore
message=message,
category=category,
)
def get_flashed_messages(
with_categories: bool = False, category_filter: t.Iterable[str] = ()
) -> t.Union[t.List[str], t.List[t.Tuple[str, str]]]:
"""Pulls all flashed messages from the session and returns them.
Further calls in the same request to the function will return
the same messages. By default just the messages are returned,
but when `with_categories` is set to ``True``, the return value will
be a list of tuples in the form ``(category, message)`` instead.
Filter the flashed messages to one or more categories by providing those
categories in `category_filter`. This allows rendering categories in
separate html blocks. The `with_categories` and `category_filter`
arguments are distinct:
* `with_categories` controls whether categories are returned with message
text (``True`` gives a tuple, where ``False`` gives just the message text).
* `category_filter` filters the messages down to only those matching the
provided categories.
See :doc:`/patterns/flashing` for examples.
.. versionchanged:: 0.3
`with_categories` parameter added.
.. versionchanged:: 0.9
`category_filter` parameter added.
:param with_categories: set to ``True`` to also receive categories.
:param category_filter: filter of categories to limit return values. Only
categories in the list will be returned.
"""
flashes = _request_ctx_stack.top.flashes
if flashes is None:
_request_ctx_stack.top.flashes = flashes = (
session.pop("_flashes") if "_flashes" in session else []
)
if category_filter:
flashes = list(filter(lambda f: f[0] in category_filter, flashes))
if not with_categories:
return [x[1] for x in flashes]
return flashes
def _prepare_send_file_kwargs(
download_name: t.Optional[str] = None,
attachment_filename: t.Optional[str] = None,
etag: t.Optional[t.Union[bool, str]] = None,
add_etags: t.Optional[t.Union[bool]] = None,
max_age: t.Optional[
t.Union[int, t.Callable[[t.Optional[str]], t.Optional[int]]]
] = None,
cache_timeout: t.Optional[int] = None,
**kwargs: t.Any,
) -> t.Dict[str, t.Any]:
if attachment_filename is not None:
warnings.warn(
"The 'attachment_filename' parameter has been renamed to"
" 'download_name'. The old name will be removed in Flask"
" 2.1.",
DeprecationWarning,
stacklevel=3,
)
download_name = attachment_filename
if cache_timeout is not None:
warnings.warn(
"The 'cache_timeout' parameter has been renamed to"
" 'max_age'. The old name will be removed in Flask 2.1.",
DeprecationWarning,
stacklevel=3,
)
max_age = cache_timeout
if add_etags is not None:
warnings.warn(
"The 'add_etags' parameter has been renamed to 'etag'. The"
" old name will be removed in Flask 2.1.",
DeprecationWarning,
stacklevel=3,
)
etag = add_etags
if max_age is None:
max_age = current_app.get_send_file_max_age
kwargs.update(
environ=request.environ,
download_name=download_name,
etag=etag,
max_age=max_age,
use_x_sendfile=current_app.use_x_sendfile,
response_class=current_app.response_class,
_root_path=current_app.root_path, # type: ignore
)
return kwargs
def send_file(
path_or_file: t.Union[os.PathLike, str, t.BinaryIO],
mimetype: t.Optional[str] = None,
as_attachment: bool = False,
download_name: t.Optional[str] = None,
attachment_filename: t.Optional[str] = None,
conditional: bool = True,
etag: t.Union[bool, str] = True,
add_etags: t.Optional[bool] = None,
last_modified: t.Optional[t.Union[datetime, int, float]] = None,
max_age: t.Optional[
t.Union[int, t.Callable[[t.Optional[str]], t.Optional[int]]]
] = None,
cache_timeout: t.Optional[int] = None,
):
"""Send the contents of a file to the client.
The first argument can be a file path or a file-like object. Paths
are preferred in most cases because Werkzeug can manage the file and
get extra information from the path. Passing a file-like object
requires that the file is opened in binary mode, and is mostly
useful when building a file in memory with :class:`io.BytesIO`.
Never pass file paths provided by a user. The path is assumed to be
trusted, so a user could craft a path to access a file you didn't
intend. Use :func:`send_from_directory` to safely serve
user-requested paths from within a directory.
If the WSGI server sets a ``file_wrapper`` in ``environ``, it is
used, otherwise Werkzeug's built-in wrapper is used. Alternatively,
if the HTTP server supports ``X-Sendfile``, configuring Flask with
``USE_X_SENDFILE = True`` will tell the server to send the given
path, which is much more efficient than reading it in Python.
:param path_or_file: The path to the file to send, relative to the
current working directory if a relative path is given.
Alternatively, a file-like object opened in binary mode. Make
sure the file pointer is seeked to the start of the data.
:param mimetype: The MIME type to send for the file. If not
provided, it will try to detect it from the file name.
:param as_attachment: Indicate to a browser that it should offer to
save the file instead of displaying it.
:param download_name: The default name browsers will use when saving
the file. Defaults to the passed file name.
:param conditional: Enable conditional and range responses based on
request headers. Requires passing a file path and ``environ``.
:param etag: Calculate an ETag for the file, which requires passing
a file path. Can also be a string to use instead.
:param last_modified: The last modified time to send for the file,
in seconds. If not provided, it will try to detect it from the
file path.
:param max_age: How long the client should cache the file, in
seconds. If set, ``Cache-Control`` will be ``public``, otherwise
it will be ``no-cache`` to prefer conditional caching.
.. versionchanged:: 2.0
``download_name`` replaces the ``attachment_filename``
parameter. If ``as_attachment=False``, it is passed with
``Content-Disposition: inline`` instead.
.. versionchanged:: 2.0
``max_age`` replaces the ``cache_timeout`` parameter.
``conditional`` is enabled and ``max_age`` is not set by
default.
.. versionchanged:: 2.0
``etag`` replaces the ``add_etags`` parameter. It can be a
string to use instead of generating one.
.. versionchanged:: 2.0
Passing a file-like object that inherits from
:class:`~io.TextIOBase` will raise a :exc:`ValueError` rather
than sending an empty file.
.. versionadded:: 2.0
Moved the implementation to Werkzeug. This is now a wrapper to
pass some Flask-specific arguments.
.. versionchanged:: 1.1
``filename`` may be a :class:`~os.PathLike` object.
.. versionchanged:: 1.1
Passing a :class:`~io.BytesIO` object supports range requests.
.. versionchanged:: 1.0.3
Filenames are encoded with ASCII instead of Latin-1 for broader
compatibility with WSGI servers.
.. versionchanged:: 1.0
UTF-8 filenames as specified in :rfc:`2231` are supported.
.. versionchanged:: 0.12
The filename is no longer automatically inferred from file
objects. If you want to use automatic MIME and etag support,
pass a filename via ``filename_or_fp`` or
``attachment_filename``.
.. versionchanged:: 0.12
``attachment_filename`` is preferred over ``filename`` for MIME
detection.
.. versionchanged:: 0.9
``cache_timeout`` defaults to
:meth:`Flask.get_send_file_max_age`.
.. versionchanged:: 0.7
MIME guessing and etag support for file-like objects was
deprecated because it was unreliable. Pass a filename if you are
able to, otherwise attach an etag yourself.
.. versionchanged:: 0.5
The ``add_etags``, ``cache_timeout`` and ``conditional``
parameters were added. The default behavior is to add etags.
.. versionadded:: 0.2
"""
return werkzeug.utils.send_file(
**_prepare_send_file_kwargs(
path_or_file=path_or_file,
environ=request.environ,
mimetype=mimetype,
as_attachment=as_attachment,
download_name=download_name,
attachment_filename=attachment_filename,
conditional=conditional,
etag=etag,
add_etags=add_etags,
last_modified=last_modified,
max_age=max_age,
cache_timeout=cache_timeout,
)
)
def safe_join(directory: str, *pathnames: str) -> str:
"""Safely join zero or more untrusted path components to a base
directory to avoid escaping the base directory.
:param directory: The trusted base directory.
:param pathnames: The untrusted path components relative to the
base directory.
:return: A safe path, otherwise ``None``.
"""
warnings.warn(
"'flask.helpers.safe_join' is deprecated and will be removed in"
" Flask 2.1. Use 'werkzeug.utils.safe_join' instead.",
DeprecationWarning,
stacklevel=2,
)
path = werkzeug.utils.safe_join(directory, *pathnames)
if path is None:
raise NotFound()
return path
def send_from_directory(
directory: t.Union[os.PathLike, str],
path: t.Union[os.PathLike, str],
filename: t.Optional[str] = None,
**kwargs: t.Any,
) -> "Response":
"""Send a file from within a directory using :func:`send_file`.
.. code-block:: python
@app.route("/uploads/<path:name>")
def download_file(name):
return send_from_directory(
app.config['UPLOAD_FOLDER'], name, as_attachment=True
)
This is a secure way to serve files from a folder, such as static
files or uploads. Uses :func:`~werkzeug.security.safe_join` to
ensure the path coming from the client is not maliciously crafted to
point outside the specified directory.
If the final path does not point to an existing regular file,
raises a 404 :exc:`~werkzeug.exceptions.NotFound` error.
:param directory: The directory that ``path`` must be located under.
:param path: The path to the file to send, relative to
``directory``.
:param kwargs: Arguments to pass to :func:`send_file`.
.. versionchanged:: 2.0
``path`` replaces the ``filename`` parameter.
.. versionadded:: 2.0
Moved the implementation to Werkzeug. This is now a wrapper to
pass some Flask-specific arguments.
.. versionadded:: 0.5
"""
if filename is not None:
warnings.warn(
"The 'filename' parameter has been renamed to 'path'. The"
" old name will be removed in Flask 2.1.",
DeprecationWarning,
stacklevel=2,
)
path = filename
return werkzeug.utils.send_from_directory( # type: ignore
directory, path, **_prepare_send_file_kwargs(**kwargs)
)
def get_root_path(import_name: str) -> str:
"""Find the root path of a package, or the path that contains a
module. If it cannot be found, returns the current working
directory.
Not to be confused with the value returned by :func:`find_package`.
:meta private:
"""
# Module already imported and has a file attribute. Use that first.
mod = sys.modules.get(import_name)
if mod is not None and hasattr(mod, "__file__") and mod.__file__ is not None:
return os.path.dirname(os.path.abspath(mod.__file__))
# Next attempt: check the loader.
loader = pkgutil.get_loader(import_name)
# Loader does not exist or we're referring to an unloaded main
# module or a main module without path (interactive sessions), go
# with the current working directory.
if loader is None or import_name == "__main__":
return os.getcwd()
if hasattr(loader, "get_filename"):
filepath = loader.get_filename(import_name) # type: ignore
else:
# Fall back to imports.
__import__(import_name)
mod = sys.modules[import_name]
filepath = getattr(mod, "__file__", None)
# If we don't have a file path it might be because it is a
# namespace package. In this case pick the root path from the
# first module that is contained in the package.
if filepath is None:
raise RuntimeError(
"No root path can be found for the provided module"
f" {import_name!r}. This can happen because the module"
" came from an import hook that does not provide file"
" name information or because it's a namespace package."
" In this case the root path needs to be explicitly"
" provided."
)
# filepath is import_name.py for a module, or __init__.py for a package.
return os.path.dirname(os.path.abspath(filepath))
class locked_cached_property(werkzeug.utils.cached_property):
"""A :func:`property` that is only evaluated once. Like
:class:`werkzeug.utils.cached_property` except access uses a lock
for thread safety.
.. versionchanged:: 2.0
Inherits from Werkzeug's ``cached_property`` (and ``property``).
"""
def __init__(
self,
fget: t.Callable[[t.Any], t.Any],
name: t.Optional[str] = None,
doc: t.Optional[str] = None,
) -> None:
super().__init__(fget, name=name, doc=doc)
self.lock = RLock()
def __get__(self, obj: object, type: type = None) -> t.Any: # type: ignore
if obj is None:
return self
with self.lock:
return super().__get__(obj, type=type)
def __set__(self, obj: object, value: t.Any) -> None:
with self.lock:
super().__set__(obj, value)
def __delete__(self, obj: object) -> None:
with self.lock:
super().__delete__(obj)
def total_seconds(td: timedelta) -> int:
"""Returns the total seconds from a timedelta object.
:param timedelta td: the timedelta to be converted in seconds
:returns: number of seconds
:rtype: int
.. deprecated:: 2.0
Will be removed in Flask 2.1. Use
:meth:`timedelta.total_seconds` instead.
"""
warnings.warn(
"'total_seconds' is deprecated and will be removed in Flask"
" 2.1. Use 'timedelta.total_seconds' instead.",
DeprecationWarning,
stacklevel=2,
)
return td.days * 60 * 60 * 24 + td.seconds
def is_ip(value: str) -> bool:
"""Determine if the given string is an IP address.
:param value: value to check
:type value: str
:return: True if string is an IP address
:rtype: bool
"""
for family in (socket.AF_INET, socket.AF_INET6):
try:
socket.inet_pton(family, value)
except OSError:
pass
else:
return True
return False
@lru_cache(maxsize=None)
def _split_blueprint_path(name: str) -> t.List[str]:
out: t.List[str] = [name]
if "." in name:
out.extend(_split_blueprint_path(name.rpartition(".")[0]))
return out

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@ -0,0 +1,363 @@
import decimal
import io
import json as _json
import typing as t
import uuid
import warnings
from datetime import date
from jinja2.utils import htmlsafe_json_dumps as _jinja_htmlsafe_dumps
from werkzeug.http import http_date
from ..globals import current_app
from ..globals import request
if t.TYPE_CHECKING:
from ..app import Flask
from ..wrappers import Response
try:
import dataclasses
except ImportError:
# Python < 3.7
dataclasses = None # type: ignore
class JSONEncoder(_json.JSONEncoder):
"""The default JSON encoder. Handles extra types compared to the
built-in :class:`json.JSONEncoder`.
- :class:`datetime.datetime` and :class:`datetime.date` are
serialized to :rfc:`822` strings. This is the same as the HTTP
date format.
- :class:`uuid.UUID` is serialized to a string.
- :class:`dataclasses.dataclass` is passed to
:func:`dataclasses.asdict`.
- :class:`~markupsafe.Markup` (or any object with a ``__html__``
method) will call the ``__html__`` method to get a string.
Assign a subclass of this to :attr:`flask.Flask.json_encoder` or
:attr:`flask.Blueprint.json_encoder` to override the default.
"""
def default(self, o: t.Any) -> t.Any:
"""Convert ``o`` to a JSON serializable type. See
:meth:`json.JSONEncoder.default`. Python does not support
overriding how basic types like ``str`` or ``list`` are
serialized, they are handled before this method.
"""
if isinstance(o, date):
return http_date(o)
if isinstance(o, (decimal.Decimal, uuid.UUID)):
return str(o)
if dataclasses and dataclasses.is_dataclass(o):
return dataclasses.asdict(o)
if hasattr(o, "__html__"):
return str(o.__html__())
return super().default(o)
class JSONDecoder(_json.JSONDecoder):
"""The default JSON decoder.
This does not change any behavior from the built-in
:class:`json.JSONDecoder`.
Assign a subclass of this to :attr:`flask.Flask.json_decoder` or
:attr:`flask.Blueprint.json_decoder` to override the default.
"""
def _dump_arg_defaults(
kwargs: t.Dict[str, t.Any], app: t.Optional["Flask"] = None
) -> None:
"""Inject default arguments for dump functions."""
if app is None:
app = current_app
if app:
cls = app.json_encoder
bp = app.blueprints.get(request.blueprint) if request else None # type: ignore
if bp is not None and bp.json_encoder is not None:
cls = bp.json_encoder
# Only set a custom encoder if it has custom behavior. This is
# faster on PyPy.
if cls is not _json.JSONEncoder:
kwargs.setdefault("cls", cls)
kwargs.setdefault("cls", cls)
kwargs.setdefault("ensure_ascii", app.config["JSON_AS_ASCII"])
kwargs.setdefault("sort_keys", app.config["JSON_SORT_KEYS"])
else:
kwargs.setdefault("sort_keys", True)
kwargs.setdefault("cls", JSONEncoder)
def _load_arg_defaults(
kwargs: t.Dict[str, t.Any], app: t.Optional["Flask"] = None
) -> None:
"""Inject default arguments for load functions."""
if app is None:
app = current_app
if app:
cls = app.json_decoder
bp = app.blueprints.get(request.blueprint) if request else None # type: ignore
if bp is not None and bp.json_decoder is not None:
cls = bp.json_decoder
# Only set a custom decoder if it has custom behavior. This is
# faster on PyPy.
if cls not in {JSONDecoder, _json.JSONDecoder}:
kwargs.setdefault("cls", cls)
def dumps(obj: t.Any, app: t.Optional["Flask"] = None, **kwargs: t.Any) -> str:
"""Serialize an object to a string of JSON.
Takes the same arguments as the built-in :func:`json.dumps`, with
some defaults from application configuration.
:param obj: Object to serialize to JSON.
:param app: Use this app's config instead of the active app context
or defaults.
:param kwargs: Extra arguments passed to :func:`json.dumps`.
.. versionchanged:: 2.0.2
:class:`decimal.Decimal` is supported by converting to a string.
.. versionchanged:: 2.0
``encoding`` is deprecated and will be removed in Flask 2.1.
.. versionchanged:: 1.0.3
``app`` can be passed directly, rather than requiring an app
context for configuration.
"""
_dump_arg_defaults(kwargs, app=app)
encoding = kwargs.pop("encoding", None)
rv = _json.dumps(obj, **kwargs)
if encoding is not None:
warnings.warn(
"'encoding' is deprecated and will be removed in Flask 2.1.",
DeprecationWarning,
stacklevel=2,
)
if isinstance(rv, str):
return rv.encode(encoding) # type: ignore
return rv
def dump(
obj: t.Any, fp: t.IO[str], app: t.Optional["Flask"] = None, **kwargs: t.Any
) -> None:
"""Serialize an object to JSON written to a file object.
Takes the same arguments as the built-in :func:`json.dump`, with
some defaults from application configuration.
:param obj: Object to serialize to JSON.
:param fp: File object to write JSON to.
:param app: Use this app's config instead of the active app context
or defaults.
:param kwargs: Extra arguments passed to :func:`json.dump`.
.. versionchanged:: 2.0
Writing to a binary file, and the ``encoding`` argument, is
deprecated and will be removed in Flask 2.1.
"""
_dump_arg_defaults(kwargs, app=app)
encoding = kwargs.pop("encoding", None)
show_warning = encoding is not None
try:
fp.write("")
except TypeError:
show_warning = True
fp = io.TextIOWrapper(fp, encoding or "utf-8") # type: ignore
if show_warning:
warnings.warn(
"Writing to a binary file, and the 'encoding' argument, is"
" deprecated and will be removed in Flask 2.1.",
DeprecationWarning,
stacklevel=2,
)
_json.dump(obj, fp, **kwargs)
def loads(s: str, app: t.Optional["Flask"] = None, **kwargs: t.Any) -> t.Any:
"""Deserialize an object from a string of JSON.
Takes the same arguments as the built-in :func:`json.loads`, with
some defaults from application configuration.
:param s: JSON string to deserialize.
:param app: Use this app's config instead of the active app context
or defaults.
:param kwargs: Extra arguments passed to :func:`json.loads`.
.. versionchanged:: 2.0
``encoding`` is deprecated and will be removed in Flask 2.1. The
data must be a string or UTF-8 bytes.
.. versionchanged:: 1.0.3
``app`` can be passed directly, rather than requiring an app
context for configuration.
"""
_load_arg_defaults(kwargs, app=app)
encoding = kwargs.pop("encoding", None)
if encoding is not None:
warnings.warn(
"'encoding' is deprecated and will be removed in Flask 2.1."
" The data must be a string or UTF-8 bytes.",
DeprecationWarning,
stacklevel=2,
)
if isinstance(s, bytes):
s = s.decode(encoding)
return _json.loads(s, **kwargs)
def load(fp: t.IO[str], app: t.Optional["Flask"] = None, **kwargs: t.Any) -> t.Any:
"""Deserialize an object from JSON read from a file object.
Takes the same arguments as the built-in :func:`json.load`, with
some defaults from application configuration.
:param fp: File object to read JSON from.
:param app: Use this app's config instead of the active app context
or defaults.
:param kwargs: Extra arguments passed to :func:`json.load`.
.. versionchanged:: 2.0
``encoding`` is deprecated and will be removed in Flask 2.1. The
file must be text mode, or binary mode with UTF-8 bytes.
"""
_load_arg_defaults(kwargs, app=app)
encoding = kwargs.pop("encoding", None)
if encoding is not None:
warnings.warn(
"'encoding' is deprecated and will be removed in Flask 2.1."
" The file must be text mode, or binary mode with UTF-8"
" bytes.",
DeprecationWarning,
stacklevel=2,
)
if isinstance(fp.read(0), bytes):
fp = io.TextIOWrapper(fp, encoding) # type: ignore
return _json.load(fp, **kwargs)
def htmlsafe_dumps(obj: t.Any, **kwargs: t.Any) -> str:
"""Serialize an object to a string of JSON with :func:`dumps`, then
replace HTML-unsafe characters with Unicode escapes and mark the
result safe with :class:`~markupsafe.Markup`.
This is available in templates as the ``|tojson`` filter.
The returned string is safe to render in HTML documents and
``<script>`` tags. The exception is in HTML attributes that are
double quoted; either use single quotes or the ``|forceescape``
filter.
.. versionchanged:: 2.0
Uses :func:`jinja2.utils.htmlsafe_json_dumps`. The returned
value is marked safe by wrapping in :class:`~markupsafe.Markup`.
.. versionchanged:: 0.10
Single quotes are escaped, making this safe to use in HTML,
``<script>`` tags, and single-quoted attributes without further
escaping.
"""
return _jinja_htmlsafe_dumps(obj, dumps=dumps, **kwargs)
def htmlsafe_dump(obj: t.Any, fp: t.IO[str], **kwargs: t.Any) -> None:
"""Serialize an object to JSON written to a file object, replacing
HTML-unsafe characters with Unicode escapes. See
:func:`htmlsafe_dumps` and :func:`dumps`.
"""
fp.write(htmlsafe_dumps(obj, **kwargs))
def jsonify(*args: t.Any, **kwargs: t.Any) -> "Response":
"""Serialize data to JSON and wrap it in a :class:`~flask.Response`
with the :mimetype:`application/json` mimetype.
Uses :func:`dumps` to serialize the data, but ``args`` and
``kwargs`` are treated as data rather than arguments to
:func:`json.dumps`.
1. Single argument: Treated as a single value.
2. Multiple arguments: Treated as a list of values.
``jsonify(1, 2, 3)`` is the same as ``jsonify([1, 2, 3])``.
3. Keyword arguments: Treated as a dict of values.
``jsonify(data=data, errors=errors)`` is the same as
``jsonify({"data": data, "errors": errors})``.
4. Passing both arguments and keyword arguments is not allowed as
it's not clear what should happen.
.. code-block:: python
from flask import jsonify
@app.route("/users/me")
def get_current_user():
return jsonify(
username=g.user.username,
email=g.user.email,
id=g.user.id,
)
Will return a JSON response like this:
.. code-block:: javascript
{
"username": "admin",
"email": "admin@localhost",
"id": 42
}
The default output omits indents and spaces after separators. In
debug mode or if :data:`JSONIFY_PRETTYPRINT_REGULAR` is ``True``,
the output will be formatted to be easier to read.
.. versionchanged:: 2.0.2
:class:`decimal.Decimal` is supported by converting to a string.
.. versionchanged:: 0.11
Added support for serializing top-level arrays. This introduces
a security risk in ancient browsers. See :ref:`security-json`.
.. versionadded:: 0.2
"""
indent = None
separators = (",", ":")
if current_app.config["JSONIFY_PRETTYPRINT_REGULAR"] or current_app.debug:
indent = 2
separators = (", ", ": ")
if args and kwargs:
raise TypeError("jsonify() behavior undefined when passed both args and kwargs")
elif len(args) == 1: # single args are passed directly to dumps()
data = args[0]
else:
data = args or kwargs
return current_app.response_class(
f"{dumps(data, indent=indent, separators=separators)}\n",
mimetype=current_app.config["JSONIFY_MIMETYPE"],
)

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"""
Tagged JSON
~~~~~~~~~~~
A compact representation for lossless serialization of non-standard JSON
types. :class:`~flask.sessions.SecureCookieSessionInterface` uses this
to serialize the session data, but it may be useful in other places. It
can be extended to support other types.
.. autoclass:: TaggedJSONSerializer
:members:
.. autoclass:: JSONTag
:members:
Let's see an example that adds support for
:class:`~collections.OrderedDict`. Dicts don't have an order in JSON, so
to handle this we will dump the items as a list of ``[key, value]``
pairs. Subclass :class:`JSONTag` and give it the new key ``' od'`` to
identify the type. The session serializer processes dicts first, so
insert the new tag at the front of the order since ``OrderedDict`` must
be processed before ``dict``.
.. code-block:: python
from flask.json.tag import JSONTag
class TagOrderedDict(JSONTag):
__slots__ = ('serializer',)
key = ' od'
def check(self, value):
return isinstance(value, OrderedDict)
def to_json(self, value):
return [[k, self.serializer.tag(v)] for k, v in iteritems(value)]
def to_python(self, value):
return OrderedDict(value)
app.session_interface.serializer.register(TagOrderedDict, index=0)
"""
import typing as t
from base64 import b64decode
from base64 import b64encode
from datetime import datetime
from uuid import UUID
from markupsafe import Markup
from werkzeug.http import http_date
from werkzeug.http import parse_date
from ..json import dumps
from ..json import loads
class JSONTag:
"""Base class for defining type tags for :class:`TaggedJSONSerializer`."""
__slots__ = ("serializer",)
#: The tag to mark the serialized object with. If ``None``, this tag is
#: only used as an intermediate step during tagging.
key: t.Optional[str] = None
def __init__(self, serializer: "TaggedJSONSerializer") -> None:
"""Create a tagger for the given serializer."""
self.serializer = serializer
def check(self, value: t.Any) -> bool:
"""Check if the given value should be tagged by this tag."""
raise NotImplementedError
def to_json(self, value: t.Any) -> t.Any:
"""Convert the Python object to an object that is a valid JSON type.
The tag will be added later."""
raise NotImplementedError
def to_python(self, value: t.Any) -> t.Any:
"""Convert the JSON representation back to the correct type. The tag
will already be removed."""
raise NotImplementedError
def tag(self, value: t.Any) -> t.Any:
"""Convert the value to a valid JSON type and add the tag structure
around it."""
return {self.key: self.to_json(value)}
class TagDict(JSONTag):
"""Tag for 1-item dicts whose only key matches a registered tag.
Internally, the dict key is suffixed with `__`, and the suffix is removed
when deserializing.
"""
__slots__ = ()
key = " di"
def check(self, value: t.Any) -> bool:
return (
isinstance(value, dict)
and len(value) == 1
and next(iter(value)) in self.serializer.tags
)
def to_json(self, value: t.Any) -> t.Any:
key = next(iter(value))
return {f"{key}__": self.serializer.tag(value[key])}
def to_python(self, value: t.Any) -> t.Any:
key = next(iter(value))
return {key[:-2]: value[key]}
class PassDict(JSONTag):
__slots__ = ()
def check(self, value: t.Any) -> bool:
return isinstance(value, dict)
def to_json(self, value: t.Any) -> t.Any:
# JSON objects may only have string keys, so don't bother tagging the
# key here.
return {k: self.serializer.tag(v) for k, v in value.items()}
tag = to_json
class TagTuple(JSONTag):
__slots__ = ()
key = " t"
def check(self, value: t.Any) -> bool:
return isinstance(value, tuple)
def to_json(self, value: t.Any) -> t.Any:
return [self.serializer.tag(item) for item in value]
def to_python(self, value: t.Any) -> t.Any:
return tuple(value)
class PassList(JSONTag):
__slots__ = ()
def check(self, value: t.Any) -> bool:
return isinstance(value, list)
def to_json(self, value: t.Any) -> t.Any:
return [self.serializer.tag(item) for item in value]
tag = to_json
class TagBytes(JSONTag):
__slots__ = ()
key = " b"
def check(self, value: t.Any) -> bool:
return isinstance(value, bytes)
def to_json(self, value: t.Any) -> t.Any:
return b64encode(value).decode("ascii")
def to_python(self, value: t.Any) -> t.Any:
return b64decode(value)
class TagMarkup(JSONTag):
"""Serialize anything matching the :class:`~markupsafe.Markup` API by
having a ``__html__`` method to the result of that method. Always
deserializes to an instance of :class:`~markupsafe.Markup`."""
__slots__ = ()
key = " m"
def check(self, value: t.Any) -> bool:
return callable(getattr(value, "__html__", None))
def to_json(self, value: t.Any) -> t.Any:
return str(value.__html__())
def to_python(self, value: t.Any) -> t.Any:
return Markup(value)
class TagUUID(JSONTag):
__slots__ = ()
key = " u"
def check(self, value: t.Any) -> bool:
return isinstance(value, UUID)
def to_json(self, value: t.Any) -> t.Any:
return value.hex
def to_python(self, value: t.Any) -> t.Any:
return UUID(value)
class TagDateTime(JSONTag):
__slots__ = ()
key = " d"
def check(self, value: t.Any) -> bool:
return isinstance(value, datetime)
def to_json(self, value: t.Any) -> t.Any:
return http_date(value)
def to_python(self, value: t.Any) -> t.Any:
return parse_date(value)
class TaggedJSONSerializer:
"""Serializer that uses a tag system to compactly represent objects that
are not JSON types. Passed as the intermediate serializer to
:class:`itsdangerous.Serializer`.
The following extra types are supported:
* :class:`dict`
* :class:`tuple`
* :class:`bytes`
* :class:`~markupsafe.Markup`
* :class:`~uuid.UUID`
* :class:`~datetime.datetime`
"""
__slots__ = ("tags", "order")
#: Tag classes to bind when creating the serializer. Other tags can be
#: added later using :meth:`~register`.
default_tags = [
TagDict,
PassDict,
TagTuple,
PassList,
TagBytes,
TagMarkup,
TagUUID,
TagDateTime,
]
def __init__(self) -> None:
self.tags: t.Dict[str, JSONTag] = {}
self.order: t.List[JSONTag] = []
for cls in self.default_tags:
self.register(cls)
def register(
self,
tag_class: t.Type[JSONTag],
force: bool = False,
index: t.Optional[int] = None,
) -> None:
"""Register a new tag with this serializer.
:param tag_class: tag class to register. Will be instantiated with this
serializer instance.
:param force: overwrite an existing tag. If false (default), a
:exc:`KeyError` is raised.
:param index: index to insert the new tag in the tag order. Useful when
the new tag is a special case of an existing tag. If ``None``
(default), the tag is appended to the end of the order.
:raise KeyError: if the tag key is already registered and ``force`` is
not true.
"""
tag = tag_class(self)
key = tag.key
if key is not None:
if not force and key in self.tags:
raise KeyError(f"Tag '{key}' is already registered.")
self.tags[key] = tag
if index is None:
self.order.append(tag)
else:
self.order.insert(index, tag)
def tag(self, value: t.Any) -> t.Dict[str, t.Any]:
"""Convert a value to a tagged representation if necessary."""
for tag in self.order:
if tag.check(value):
return tag.tag(value)
return value
def untag(self, value: t.Dict[str, t.Any]) -> t.Any:
"""Convert a tagged representation back to the original type."""
if len(value) != 1:
return value
key = next(iter(value))
if key not in self.tags:
return value
return self.tags[key].to_python(value[key])
def dumps(self, value: t.Any) -> str:
"""Tag the value and dump it to a compact JSON string."""
return dumps(self.tag(value), separators=(",", ":"))
def loads(self, value: str) -> t.Any:
"""Load data from a JSON string and deserialized any tagged objects."""
return loads(value, object_hook=self.untag)

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@ -0,0 +1,74 @@
import logging
import sys
import typing as t
from werkzeug.local import LocalProxy
from .globals import request
if t.TYPE_CHECKING:
from .app import Flask
@LocalProxy
def wsgi_errors_stream() -> t.TextIO:
"""Find the most appropriate error stream for the application. If a request
is active, log to ``wsgi.errors``, otherwise use ``sys.stderr``.
If you configure your own :class:`logging.StreamHandler`, you may want to
use this for the stream. If you are using file or dict configuration and
can't import this directly, you can refer to it as
``ext://flask.logging.wsgi_errors_stream``.
"""
return request.environ["wsgi.errors"] if request else sys.stderr
def has_level_handler(logger: logging.Logger) -> bool:
"""Check if there is a handler in the logging chain that will handle the
given logger's :meth:`effective level <~logging.Logger.getEffectiveLevel>`.
"""
level = logger.getEffectiveLevel()
current = logger
while current:
if any(handler.level <= level for handler in current.handlers):
return True
if not current.propagate:
break
current = current.parent # type: ignore
return False
#: Log messages to :func:`~flask.logging.wsgi_errors_stream` with the format
#: ``[%(asctime)s] %(levelname)s in %(module)s: %(message)s``.
default_handler = logging.StreamHandler(wsgi_errors_stream) # type: ignore
default_handler.setFormatter(
logging.Formatter("[%(asctime)s] %(levelname)s in %(module)s: %(message)s")
)
def create_logger(app: "Flask") -> logging.Logger:
"""Get the Flask app's logger and configure it if needed.
The logger name will be the same as
:attr:`app.import_name <flask.Flask.name>`.
When :attr:`~flask.Flask.debug` is enabled, set the logger level to
:data:`logging.DEBUG` if it is not set.
If there is no handler for the logger's effective level, add a
:class:`~logging.StreamHandler` for
:func:`~flask.logging.wsgi_errors_stream` with a basic format.
"""
logger = logging.getLogger(app.name)
if app.debug and not logger.level:
logger.setLevel(logging.DEBUG)
if not has_level_handler(logger):
logger.addHandler(default_handler)
return logger

View File

@ -0,0 +1,875 @@
import importlib.util
import os
import pkgutil
import sys
import typing as t
from collections import defaultdict
from functools import update_wrapper
from json import JSONDecoder
from json import JSONEncoder
from jinja2 import FileSystemLoader
from werkzeug.exceptions import default_exceptions
from werkzeug.exceptions import HTTPException
from .cli import AppGroup
from .globals import current_app
from .helpers import get_root_path
from .helpers import locked_cached_property
from .helpers import send_from_directory
from .templating import _default_template_ctx_processor
from .typing import AfterRequestCallable
from .typing import AppOrBlueprintKey
from .typing import BeforeRequestCallable
from .typing import GenericException
from .typing import TeardownCallable
from .typing import TemplateContextProcessorCallable
from .typing import URLDefaultCallable
from .typing import URLValuePreprocessorCallable
if t.TYPE_CHECKING:
from .wrappers import Response
from .typing import ErrorHandlerCallable
# a singleton sentinel value for parameter defaults
_sentinel = object()
F = t.TypeVar("F", bound=t.Callable[..., t.Any])
def setupmethod(f: F) -> F:
"""Wraps a method so that it performs a check in debug mode if the
first request was already handled.
"""
def wrapper_func(self, *args: t.Any, **kwargs: t.Any) -> t.Any:
if self._is_setup_finished():
raise AssertionError(
"A setup function was called after the first request "
"was handled. This usually indicates a bug in the"
" application where a module was not imported and"
" decorators or other functionality was called too"
" late.\nTo fix this make sure to import all your view"
" modules, database models, and everything related at a"
" central place before the application starts serving"
" requests."
)
return f(self, *args, **kwargs)
return t.cast(F, update_wrapper(wrapper_func, f))
class Scaffold:
"""Common behavior shared between :class:`~flask.Flask` and
:class:`~flask.blueprints.Blueprint`.
:param import_name: The import name of the module where this object
is defined. Usually :attr:`__name__` should be used.
:param static_folder: Path to a folder of static files to serve.
If this is set, a static route will be added.
:param static_url_path: URL prefix for the static route.
:param template_folder: Path to a folder containing template files.
for rendering. If this is set, a Jinja loader will be added.
:param root_path: The path that static, template, and resource files
are relative to. Typically not set, it is discovered based on
the ``import_name``.
.. versionadded:: 2.0
"""
name: str
_static_folder: t.Optional[str] = None
_static_url_path: t.Optional[str] = None
#: JSON encoder class used by :func:`flask.json.dumps`. If a
#: blueprint sets this, it will be used instead of the app's value.
json_encoder: t.Optional[t.Type[JSONEncoder]] = None
#: JSON decoder class used by :func:`flask.json.loads`. If a
#: blueprint sets this, it will be used instead of the app's value.
json_decoder: t.Optional[t.Type[JSONDecoder]] = None
def __init__(
self,
import_name: str,
static_folder: t.Optional[t.Union[str, os.PathLike]] = None,
static_url_path: t.Optional[str] = None,
template_folder: t.Optional[str] = None,
root_path: t.Optional[str] = None,
):
#: The name of the package or module that this object belongs
#: to. Do not change this once it is set by the constructor.
self.import_name = import_name
self.static_folder = static_folder # type: ignore
self.static_url_path = static_url_path
#: The path to the templates folder, relative to
#: :attr:`root_path`, to add to the template loader. ``None`` if
#: templates should not be added.
self.template_folder = template_folder
if root_path is None:
root_path = get_root_path(self.import_name)
#: Absolute path to the package on the filesystem. Used to look
#: up resources contained in the package.
self.root_path = root_path
#: The Click command group for registering CLI commands for this
#: object. The commands are available from the ``flask`` command
#: once the application has been discovered and blueprints have
#: been registered.
self.cli = AppGroup()
#: A dictionary mapping endpoint names to view functions.
#:
#: To register a view function, use the :meth:`route` decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.view_functions: t.Dict[str, t.Callable] = {}
#: A data structure of registered error handlers, in the format
#: ``{scope: {code: {class: handler}}}```. The ``scope`` key is
#: the name of a blueprint the handlers are active for, or
#: ``None`` for all requests. The ``code`` key is the HTTP
#: status code for ``HTTPException``, or ``None`` for
#: other exceptions. The innermost dictionary maps exception
#: classes to handler functions.
#:
#: To register an error handler, use the :meth:`errorhandler`
#: decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.error_handler_spec: t.Dict[
AppOrBlueprintKey,
t.Dict[
t.Optional[int],
t.Dict[t.Type[Exception], "ErrorHandlerCallable[Exception]"],
],
] = defaultdict(lambda: defaultdict(dict))
#: A data structure of functions to call at the beginning of
#: each request, in the format ``{scope: [functions]}``. The
#: ``scope`` key is the name of a blueprint the functions are
#: active for, or ``None`` for all requests.
#:
#: To register a function, use the :meth:`before_request`
#: decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.before_request_funcs: t.Dict[
AppOrBlueprintKey, t.List[BeforeRequestCallable]
] = defaultdict(list)
#: A data structure of functions to call at the end of each
#: request, in the format ``{scope: [functions]}``. The
#: ``scope`` key is the name of a blueprint the functions are
#: active for, or ``None`` for all requests.
#:
#: To register a function, use the :meth:`after_request`
#: decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.after_request_funcs: t.Dict[
AppOrBlueprintKey, t.List[AfterRequestCallable]
] = defaultdict(list)
#: A data structure of functions to call at the end of each
#: request even if an exception is raised, in the format
#: ``{scope: [functions]}``. The ``scope`` key is the name of a
#: blueprint the functions are active for, or ``None`` for all
#: requests.
#:
#: To register a function, use the :meth:`teardown_request`
#: decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.teardown_request_funcs: t.Dict[
AppOrBlueprintKey, t.List[TeardownCallable]
] = defaultdict(list)
#: A data structure of functions to call to pass extra context
#: values when rendering templates, in the format
#: ``{scope: [functions]}``. The ``scope`` key is the name of a
#: blueprint the functions are active for, or ``None`` for all
#: requests.
#:
#: To register a function, use the :meth:`context_processor`
#: decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.template_context_processors: t.Dict[
AppOrBlueprintKey, t.List[TemplateContextProcessorCallable]
] = defaultdict(list, {None: [_default_template_ctx_processor]})
#: A data structure of functions to call to modify the keyword
#: arguments passed to the view function, in the format
#: ``{scope: [functions]}``. The ``scope`` key is the name of a
#: blueprint the functions are active for, or ``None`` for all
#: requests.
#:
#: To register a function, use the
#: :meth:`url_value_preprocessor` decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.url_value_preprocessors: t.Dict[
AppOrBlueprintKey,
t.List[URLValuePreprocessorCallable],
] = defaultdict(list)
#: A data structure of functions to call to modify the keyword
#: arguments when generating URLs, in the format
#: ``{scope: [functions]}``. The ``scope`` key is the name of a
#: blueprint the functions are active for, or ``None`` for all
#: requests.
#:
#: To register a function, use the :meth:`url_defaults`
#: decorator.
#:
#: This data structure is internal. It should not be modified
#: directly and its format may change at any time.
self.url_default_functions: t.Dict[
AppOrBlueprintKey, t.List[URLDefaultCallable]
] = defaultdict(list)
def __repr__(self) -> str:
return f"<{type(self).__name__} {self.name!r}>"
def _is_setup_finished(self) -> bool:
raise NotImplementedError
@property
def static_folder(self) -> t.Optional[str]:
"""The absolute path to the configured static folder. ``None``
if no static folder is set.
"""
if self._static_folder is not None:
return os.path.join(self.root_path, self._static_folder)
else:
return None
@static_folder.setter
def static_folder(self, value: t.Optional[t.Union[str, os.PathLike]]) -> None:
if value is not None:
value = os.fspath(value).rstrip(r"\/")
self._static_folder = value
@property
def has_static_folder(self) -> bool:
"""``True`` if :attr:`static_folder` is set.
.. versionadded:: 0.5
"""
return self.static_folder is not None
@property
def static_url_path(self) -> t.Optional[str]:
"""The URL prefix that the static route will be accessible from.
If it was not configured during init, it is derived from
:attr:`static_folder`.
"""
if self._static_url_path is not None:
return self._static_url_path
if self.static_folder is not None:
basename = os.path.basename(self.static_folder)
return f"/{basename}".rstrip("/")
return None
@static_url_path.setter
def static_url_path(self, value: t.Optional[str]) -> None:
if value is not None:
value = value.rstrip("/")
self._static_url_path = value
def get_send_file_max_age(self, filename: t.Optional[str]) -> t.Optional[int]:
"""Used by :func:`send_file` to determine the ``max_age`` cache
value for a given file path if it wasn't passed.
By default, this returns :data:`SEND_FILE_MAX_AGE_DEFAULT` from
the configuration of :data:`~flask.current_app`. This defaults
to ``None``, which tells the browser to use conditional requests
instead of a timed cache, which is usually preferable.
.. versionchanged:: 2.0
The default configuration is ``None`` instead of 12 hours.
.. versionadded:: 0.9
"""
value = current_app.send_file_max_age_default
if value is None:
return None
return int(value.total_seconds())
def send_static_file(self, filename: str) -> "Response":
"""The view function used to serve files from
:attr:`static_folder`. A route is automatically registered for
this view at :attr:`static_url_path` if :attr:`static_folder` is
set.
.. versionadded:: 0.5
"""
if not self.has_static_folder:
raise RuntimeError("'static_folder' must be set to serve static_files.")
# send_file only knows to call get_send_file_max_age on the app,
# call it here so it works for blueprints too.
max_age = self.get_send_file_max_age(filename)
return send_from_directory(
t.cast(str, self.static_folder), filename, max_age=max_age
)
@locked_cached_property
def jinja_loader(self) -> t.Optional[FileSystemLoader]:
"""The Jinja loader for this object's templates. By default this
is a class :class:`jinja2.loaders.FileSystemLoader` to
:attr:`template_folder` if it is set.
.. versionadded:: 0.5
"""
if self.template_folder is not None:
return FileSystemLoader(os.path.join(self.root_path, self.template_folder))
else:
return None
def open_resource(self, resource: str, mode: str = "rb") -> t.IO[t.AnyStr]:
"""Open a resource file relative to :attr:`root_path` for
reading.
For example, if the file ``schema.sql`` is next to the file
``app.py`` where the ``Flask`` app is defined, it can be opened
with:
.. code-block:: python
with app.open_resource("schema.sql") as f:
conn.executescript(f.read())
:param resource: Path to the resource relative to
:attr:`root_path`.
:param mode: Open the file in this mode. Only reading is
supported, valid values are "r" (or "rt") and "rb".
"""
if mode not in {"r", "rt", "rb"}:
raise ValueError("Resources can only be opened for reading.")
return open(os.path.join(self.root_path, resource), mode)
def _method_route(self, method: str, rule: str, options: dict) -> t.Callable:
if "methods" in options:
raise TypeError("Use the 'route' decorator to use the 'methods' argument.")
return self.route(rule, methods=[method], **options)
def get(self, rule: str, **options: t.Any) -> t.Callable:
"""Shortcut for :meth:`route` with ``methods=["GET"]``.
.. versionadded:: 2.0
"""
return self._method_route("GET", rule, options)
def post(self, rule: str, **options: t.Any) -> t.Callable:
"""Shortcut for :meth:`route` with ``methods=["POST"]``.
.. versionadded:: 2.0
"""
return self._method_route("POST", rule, options)
def put(self, rule: str, **options: t.Any) -> t.Callable:
"""Shortcut for :meth:`route` with ``methods=["PUT"]``.
.. versionadded:: 2.0
"""
return self._method_route("PUT", rule, options)
def delete(self, rule: str, **options: t.Any) -> t.Callable:
"""Shortcut for :meth:`route` with ``methods=["DELETE"]``.
.. versionadded:: 2.0
"""
return self._method_route("DELETE", rule, options)
def patch(self, rule: str, **options: t.Any) -> t.Callable:
"""Shortcut for :meth:`route` with ``methods=["PATCH"]``.
.. versionadded:: 2.0
"""
return self._method_route("PATCH", rule, options)
def route(self, rule: str, **options: t.Any) -> t.Callable:
"""Decorate a view function to register it with the given URL
rule and options. Calls :meth:`add_url_rule`, which has more
details about the implementation.
.. code-block:: python
@app.route("/")
def index():
return "Hello, World!"
See :ref:`url-route-registrations`.
The endpoint name for the route defaults to the name of the view
function if the ``endpoint`` parameter isn't passed.
The ``methods`` parameter defaults to ``["GET"]``. ``HEAD`` and
``OPTIONS`` are added automatically.
:param rule: The URL rule string.
:param options: Extra options passed to the
:class:`~werkzeug.routing.Rule` object.
"""
def decorator(f: t.Callable) -> t.Callable:
endpoint = options.pop("endpoint", None)
self.add_url_rule(rule, endpoint, f, **options)
return f
return decorator
@setupmethod
def add_url_rule(
self,
rule: str,
endpoint: t.Optional[str] = None,
view_func: t.Optional[t.Callable] = None,
provide_automatic_options: t.Optional[bool] = None,
**options: t.Any,
) -> None:
"""Register a rule for routing incoming requests and building
URLs. The :meth:`route` decorator is a shortcut to call this
with the ``view_func`` argument. These are equivalent:
.. code-block:: python
@app.route("/")
def index():
...
.. code-block:: python
def index():
...
app.add_url_rule("/", view_func=index)
See :ref:`url-route-registrations`.
The endpoint name for the route defaults to the name of the view
function if the ``endpoint`` parameter isn't passed. An error
will be raised if a function has already been registered for the
endpoint.
The ``methods`` parameter defaults to ``["GET"]``. ``HEAD`` is
always added automatically, and ``OPTIONS`` is added
automatically by default.
``view_func`` does not necessarily need to be passed, but if the
rule should participate in routing an endpoint name must be
associated with a view function at some point with the
:meth:`endpoint` decorator.
.. code-block:: python
app.add_url_rule("/", endpoint="index")
@app.endpoint("index")
def index():
...
If ``view_func`` has a ``required_methods`` attribute, those
methods are added to the passed and automatic methods. If it
has a ``provide_automatic_methods`` attribute, it is used as the
default if the parameter is not passed.
:param rule: The URL rule string.
:param endpoint: The endpoint name to associate with the rule
and view function. Used when routing and building URLs.
Defaults to ``view_func.__name__``.
:param view_func: The view function to associate with the
endpoint name.
:param provide_automatic_options: Add the ``OPTIONS`` method and
respond to ``OPTIONS`` requests automatically.
:param options: Extra options passed to the
:class:`~werkzeug.routing.Rule` object.
"""
raise NotImplementedError
def endpoint(self, endpoint: str) -> t.Callable:
"""Decorate a view function to register it for the given
endpoint. Used if a rule is added without a ``view_func`` with
:meth:`add_url_rule`.
.. code-block:: python
app.add_url_rule("/ex", endpoint="example")
@app.endpoint("example")
def example():
...
:param endpoint: The endpoint name to associate with the view
function.
"""
def decorator(f):
self.view_functions[endpoint] = f
return f
return decorator
@setupmethod
def before_request(self, f: BeforeRequestCallable) -> BeforeRequestCallable:
"""Register a function to run before each request.
For example, this can be used to open a database connection, or
to load the logged in user from the session.
.. code-block:: python
@app.before_request
def load_user():
if "user_id" in session:
g.user = db.session.get(session["user_id"])
The function will be called without any arguments. If it returns
a non-``None`` value, the value is handled as if it was the
return value from the view, and further request handling is
stopped.
"""
self.before_request_funcs.setdefault(None, []).append(f)
return f
@setupmethod
def after_request(self, f: AfterRequestCallable) -> AfterRequestCallable:
"""Register a function to run after each request to this object.
The function is called with the response object, and must return
a response object. This allows the functions to modify or
replace the response before it is sent.
If a function raises an exception, any remaining
``after_request`` functions will not be called. Therefore, this
should not be used for actions that must execute, such as to
close resources. Use :meth:`teardown_request` for that.
"""
self.after_request_funcs.setdefault(None, []).append(f)
return f
@setupmethod
def teardown_request(self, f: TeardownCallable) -> TeardownCallable:
"""Register a function to be run at the end of each request,
regardless of whether there was an exception or not. These functions
are executed when the request context is popped, even if not an
actual request was performed.
Example::
ctx = app.test_request_context()
ctx.push()
...
ctx.pop()
When ``ctx.pop()`` is executed in the above example, the teardown
functions are called just before the request context moves from the
stack of active contexts. This becomes relevant if you are using
such constructs in tests.
Teardown functions must avoid raising exceptions, since they . If they
execute code that might fail they
will have to surround the execution of these code by try/except
statements and log occurring errors.
When a teardown function was called because of an exception it will
be passed an error object.
The return values of teardown functions are ignored.
.. admonition:: Debug Note
In debug mode Flask will not tear down a request on an exception
immediately. Instead it will keep it alive so that the interactive
debugger can still access it. This behavior can be controlled
by the ``PRESERVE_CONTEXT_ON_EXCEPTION`` configuration variable.
"""
self.teardown_request_funcs.setdefault(None, []).append(f)
return f
@setupmethod
def context_processor(
self, f: TemplateContextProcessorCallable
) -> TemplateContextProcessorCallable:
"""Registers a template context processor function."""
self.template_context_processors[None].append(f)
return f
@setupmethod
def url_value_preprocessor(
self, f: URLValuePreprocessorCallable
) -> URLValuePreprocessorCallable:
"""Register a URL value preprocessor function for all view
functions in the application. These functions will be called before the
:meth:`before_request` functions.
The function can modify the values captured from the matched url before
they are passed to the view. For example, this can be used to pop a
common language code value and place it in ``g`` rather than pass it to
every view.
The function is passed the endpoint name and values dict. The return
value is ignored.
"""
self.url_value_preprocessors[None].append(f)
return f
@setupmethod
def url_defaults(self, f: URLDefaultCallable) -> URLDefaultCallable:
"""Callback function for URL defaults for all view functions of the
application. It's called with the endpoint and values and should
update the values passed in place.
"""
self.url_default_functions[None].append(f)
return f
@setupmethod
def errorhandler(
self, code_or_exception: t.Union[t.Type[GenericException], int]
) -> t.Callable[
["ErrorHandlerCallable[GenericException]"],
"ErrorHandlerCallable[GenericException]",
]:
"""Register a function to handle errors by code or exception class.
A decorator that is used to register a function given an
error code. Example::
@app.errorhandler(404)
def page_not_found(error):
return 'This page does not exist', 404
You can also register handlers for arbitrary exceptions::
@app.errorhandler(DatabaseError)
def special_exception_handler(error):
return 'Database connection failed', 500
.. versionadded:: 0.7
Use :meth:`register_error_handler` instead of modifying
:attr:`error_handler_spec` directly, for application wide error
handlers.
.. versionadded:: 0.7
One can now additionally also register custom exception types
that do not necessarily have to be a subclass of the
:class:`~werkzeug.exceptions.HTTPException` class.
:param code_or_exception: the code as integer for the handler, or
an arbitrary exception
"""
def decorator(
f: "ErrorHandlerCallable[GenericException]",
) -> "ErrorHandlerCallable[GenericException]":
self.register_error_handler(code_or_exception, f)
return f
return decorator
@setupmethod
def register_error_handler(
self,
code_or_exception: t.Union[t.Type[GenericException], int],
f: "ErrorHandlerCallable[GenericException]",
) -> None:
"""Alternative error attach function to the :meth:`errorhandler`
decorator that is more straightforward to use for non decorator
usage.
.. versionadded:: 0.7
"""
if isinstance(code_or_exception, HTTPException): # old broken behavior
raise ValueError(
"Tried to register a handler for an exception instance"
f" {code_or_exception!r}. Handlers can only be"
" registered for exception classes or HTTP error codes."
)
try:
exc_class, code = self._get_exc_class_and_code(code_or_exception)
except KeyError:
raise KeyError(
f"'{code_or_exception}' is not a recognized HTTP error"
" code. Use a subclass of HTTPException with that code"
" instead."
) from None
self.error_handler_spec[None][code][exc_class] = t.cast(
"ErrorHandlerCallable[Exception]", f
)
@staticmethod
def _get_exc_class_and_code(
exc_class_or_code: t.Union[t.Type[Exception], int]
) -> t.Tuple[t.Type[Exception], t.Optional[int]]:
"""Get the exception class being handled. For HTTP status codes
or ``HTTPException`` subclasses, return both the exception and
status code.
:param exc_class_or_code: Any exception class, or an HTTP status
code as an integer.
"""
exc_class: t.Type[Exception]
if isinstance(exc_class_or_code, int):
exc_class = default_exceptions[exc_class_or_code]
else:
exc_class = exc_class_or_code
assert issubclass(
exc_class, Exception
), "Custom exceptions must be subclasses of Exception."
if issubclass(exc_class, HTTPException):
return exc_class, exc_class.code
else:
return exc_class, None
def _endpoint_from_view_func(view_func: t.Callable) -> str:
"""Internal helper that returns the default endpoint for a given
function. This always is the function name.
"""
assert view_func is not None, "expected view func if endpoint is not provided."
return view_func.__name__
def _matching_loader_thinks_module_is_package(loader, mod_name):
"""Attempt to figure out if the given name is a package or a module.
:param: loader: The loader that handled the name.
:param mod_name: The name of the package or module.
"""
# Use loader.is_package if it's available.
if hasattr(loader, "is_package"):
return loader.is_package(mod_name)
cls = type(loader)
# NamespaceLoader doesn't implement is_package, but all names it
# loads must be packages.
if cls.__module__ == "_frozen_importlib" and cls.__name__ == "NamespaceLoader":
return True
# Otherwise we need to fail with an error that explains what went
# wrong.
raise AttributeError(
f"'{cls.__name__}.is_package()' must be implemented for PEP 302"
f" import hooks."
)
def _find_package_path(root_mod_name):
"""Find the path that contains the package or module."""
try:
spec = importlib.util.find_spec(root_mod_name)
if spec is None:
raise ValueError("not found")
# ImportError: the machinery told us it does not exist
# ValueError:
# - the module name was invalid
# - the module name is __main__
# - *we* raised `ValueError` due to `spec` being `None`
except (ImportError, ValueError):
pass # handled below
else:
# namespace package
if spec.origin in {"namespace", None}:
return os.path.dirname(next(iter(spec.submodule_search_locations)))
# a package (with __init__.py)
elif spec.submodule_search_locations:
return os.path.dirname(os.path.dirname(spec.origin))
# just a normal module
else:
return os.path.dirname(spec.origin)
# we were unable to find the `package_path` using PEP 451 loaders
loader = pkgutil.get_loader(root_mod_name)
if loader is None or root_mod_name == "__main__":
# import name is not found, or interactive/main module
return os.getcwd()
if hasattr(loader, "get_filename"):
filename = loader.get_filename(root_mod_name)
elif hasattr(loader, "archive"):
# zipimporter's loader.archive points to the .egg or .zip file.
filename = loader.archive
else:
# At least one loader is missing both get_filename and archive:
# Google App Engine's HardenedModulesHook, use __file__.
filename = importlib.import_module(root_mod_name).__file__
package_path = os.path.abspath(os.path.dirname(filename))
# If the imported name is a package, filename is currently pointing
# to the root of the package, need to get the current directory.
if _matching_loader_thinks_module_is_package(loader, root_mod_name):
package_path = os.path.dirname(package_path)
return package_path
def find_package(import_name: str):
"""Find the prefix that a package is installed under, and the path
that it would be imported from.
The prefix is the directory containing the standard directory
hierarchy (lib, bin, etc.). If the package is not installed to the
system (:attr:`sys.prefix`) or a virtualenv (``site-packages``),
``None`` is returned.
The path is the entry in :attr:`sys.path` that contains the package
for import. If the package is not installed, it's assumed that the
package was imported from the current working directory.
"""
root_mod_name, _, _ = import_name.partition(".")
package_path = _find_package_path(root_mod_name)
py_prefix = os.path.abspath(sys.prefix)
# installed to the system
if package_path.startswith(py_prefix):
return py_prefix, package_path
site_parent, site_folder = os.path.split(package_path)
# installed to a virtualenv
if site_folder.lower() == "site-packages":
parent, folder = os.path.split(site_parent)
# Windows (prefix/lib/site-packages)
if folder.lower() == "lib":
return parent, package_path
# Unix (prefix/lib/pythonX.Y/site-packages)
if os.path.basename(parent).lower() == "lib":
return os.path.dirname(parent), package_path
# something else (prefix/site-packages)
return site_parent, package_path
# not installed
return None, package_path

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@ -0,0 +1,416 @@
import hashlib
import typing as t
import warnings
from collections.abc import MutableMapping
from datetime import datetime
from itsdangerous import BadSignature
from itsdangerous import URLSafeTimedSerializer
from werkzeug.datastructures import CallbackDict
from .helpers import is_ip
from .json.tag import TaggedJSONSerializer
if t.TYPE_CHECKING:
import typing_extensions as te
from .app import Flask
from .wrappers import Request, Response
class SessionMixin(MutableMapping):
"""Expands a basic dictionary with session attributes."""
@property
def permanent(self) -> bool:
"""This reflects the ``'_permanent'`` key in the dict."""
return self.get("_permanent", False)
@permanent.setter
def permanent(self, value: bool) -> None:
self["_permanent"] = bool(value)
#: Some implementations can detect whether a session is newly
#: created, but that is not guaranteed. Use with caution. The mixin
# default is hard-coded ``False``.
new = False
#: Some implementations can detect changes to the session and set
#: this when that happens. The mixin default is hard coded to
#: ``True``.
modified = True
#: Some implementations can detect when session data is read or
#: written and set this when that happens. The mixin default is hard
#: coded to ``True``.
accessed = True
class SecureCookieSession(CallbackDict, SessionMixin):
"""Base class for sessions based on signed cookies.
This session backend will set the :attr:`modified` and
:attr:`accessed` attributes. It cannot reliably track whether a
session is new (vs. empty), so :attr:`new` remains hard coded to
``False``.
"""
#: When data is changed, this is set to ``True``. Only the session
#: dictionary itself is tracked; if the session contains mutable
#: data (for example a nested dict) then this must be set to
#: ``True`` manually when modifying that data. The session cookie
#: will only be written to the response if this is ``True``.
modified = False
#: When data is read or written, this is set to ``True``. Used by
# :class:`.SecureCookieSessionInterface` to add a ``Vary: Cookie``
#: header, which allows caching proxies to cache different pages for
#: different users.
accessed = False
def __init__(self, initial: t.Any = None) -> None:
def on_update(self) -> None:
self.modified = True
self.accessed = True
super().__init__(initial, on_update)
def __getitem__(self, key: str) -> t.Any:
self.accessed = True
return super().__getitem__(key)
def get(self, key: str, default: t.Any = None) -> t.Any:
self.accessed = True
return super().get(key, default)
def setdefault(self, key: str, default: t.Any = None) -> t.Any:
self.accessed = True
return super().setdefault(key, default)
class NullSession(SecureCookieSession):
"""Class used to generate nicer error messages if sessions are not
available. Will still allow read-only access to the empty session
but fail on setting.
"""
def _fail(self, *args: t.Any, **kwargs: t.Any) -> "te.NoReturn":
raise RuntimeError(
"The session is unavailable because no secret "
"key was set. Set the secret_key on the "
"application to something unique and secret."
)
__setitem__ = __delitem__ = clear = pop = popitem = update = setdefault = _fail # type: ignore # noqa: B950
del _fail
class SessionInterface:
"""The basic interface you have to implement in order to replace the
default session interface which uses werkzeug's securecookie
implementation. The only methods you have to implement are
:meth:`open_session` and :meth:`save_session`, the others have
useful defaults which you don't need to change.
The session object returned by the :meth:`open_session` method has to
provide a dictionary like interface plus the properties and methods
from the :class:`SessionMixin`. We recommend just subclassing a dict
and adding that mixin::
class Session(dict, SessionMixin):
pass
If :meth:`open_session` returns ``None`` Flask will call into
:meth:`make_null_session` to create a session that acts as replacement
if the session support cannot work because some requirement is not
fulfilled. The default :class:`NullSession` class that is created
will complain that the secret key was not set.
To replace the session interface on an application all you have to do
is to assign :attr:`flask.Flask.session_interface`::
app = Flask(__name__)
app.session_interface = MySessionInterface()
Multiple requests with the same session may be sent and handled
concurrently. When implementing a new session interface, consider
whether reads or writes to the backing store must be synchronized.
There is no guarantee on the order in which the session for each
request is opened or saved, it will occur in the order that requests
begin and end processing.
.. versionadded:: 0.8
"""
#: :meth:`make_null_session` will look here for the class that should
#: be created when a null session is requested. Likewise the
#: :meth:`is_null_session` method will perform a typecheck against
#: this type.
null_session_class = NullSession
#: A flag that indicates if the session interface is pickle based.
#: This can be used by Flask extensions to make a decision in regards
#: to how to deal with the session object.
#:
#: .. versionadded:: 0.10
pickle_based = False
def make_null_session(self, app: "Flask") -> NullSession:
"""Creates a null session which acts as a replacement object if the
real session support could not be loaded due to a configuration
error. This mainly aids the user experience because the job of the
null session is to still support lookup without complaining but
modifications are answered with a helpful error message of what
failed.
This creates an instance of :attr:`null_session_class` by default.
"""
return self.null_session_class()
def is_null_session(self, obj: object) -> bool:
"""Checks if a given object is a null session. Null sessions are
not asked to be saved.
This checks if the object is an instance of :attr:`null_session_class`
by default.
"""
return isinstance(obj, self.null_session_class)
def get_cookie_name(self, app: "Flask") -> str:
"""Returns the name of the session cookie.
Uses ``app.session_cookie_name`` which is set to ``SESSION_COOKIE_NAME``
"""
return app.session_cookie_name
def get_cookie_domain(self, app: "Flask") -> t.Optional[str]:
"""Returns the domain that should be set for the session cookie.
Uses ``SESSION_COOKIE_DOMAIN`` if it is configured, otherwise
falls back to detecting the domain based on ``SERVER_NAME``.
Once detected (or if not set at all), ``SESSION_COOKIE_DOMAIN`` is
updated to avoid re-running the logic.
"""
rv = app.config["SESSION_COOKIE_DOMAIN"]
# set explicitly, or cached from SERVER_NAME detection
# if False, return None
if rv is not None:
return rv if rv else None
rv = app.config["SERVER_NAME"]
# server name not set, cache False to return none next time
if not rv:
app.config["SESSION_COOKIE_DOMAIN"] = False
return None
# chop off the port which is usually not supported by browsers
# remove any leading '.' since we'll add that later
rv = rv.rsplit(":", 1)[0].lstrip(".")
if "." not in rv:
# Chrome doesn't allow names without a '.'. This should only
# come up with localhost. Hack around this by not setting
# the name, and show a warning.
warnings.warn(
f"{rv!r} is not a valid cookie domain, it must contain"
" a '.'. Add an entry to your hosts file, for example"
f" '{rv}.localdomain', and use that instead."
)
app.config["SESSION_COOKIE_DOMAIN"] = False
return None
ip = is_ip(rv)
if ip:
warnings.warn(
"The session cookie domain is an IP address. This may not work"
" as intended in some browsers. Add an entry to your hosts"
' file, for example "localhost.localdomain", and use that'
" instead."
)
# if this is not an ip and app is mounted at the root, allow subdomain
# matching by adding a '.' prefix
if self.get_cookie_path(app) == "/" and not ip:
rv = f".{rv}"
app.config["SESSION_COOKIE_DOMAIN"] = rv
return rv
def get_cookie_path(self, app: "Flask") -> str:
"""Returns the path for which the cookie should be valid. The
default implementation uses the value from the ``SESSION_COOKIE_PATH``
config var if it's set, and falls back to ``APPLICATION_ROOT`` or
uses ``/`` if it's ``None``.
"""
return app.config["SESSION_COOKIE_PATH"] or app.config["APPLICATION_ROOT"]
def get_cookie_httponly(self, app: "Flask") -> bool:
"""Returns True if the session cookie should be httponly. This
currently just returns the value of the ``SESSION_COOKIE_HTTPONLY``
config var.
"""
return app.config["SESSION_COOKIE_HTTPONLY"]
def get_cookie_secure(self, app: "Flask") -> bool:
"""Returns True if the cookie should be secure. This currently
just returns the value of the ``SESSION_COOKIE_SECURE`` setting.
"""
return app.config["SESSION_COOKIE_SECURE"]
def get_cookie_samesite(self, app: "Flask") -> str:
"""Return ``'Strict'`` or ``'Lax'`` if the cookie should use the
``SameSite`` attribute. This currently just returns the value of
the :data:`SESSION_COOKIE_SAMESITE` setting.
"""
return app.config["SESSION_COOKIE_SAMESITE"]
def get_expiration_time(
self, app: "Flask", session: SessionMixin
) -> t.Optional[datetime]:
"""A helper method that returns an expiration date for the session
or ``None`` if the session is linked to the browser session. The
default implementation returns now + the permanent session
lifetime configured on the application.
"""
if session.permanent:
return datetime.utcnow() + app.permanent_session_lifetime
return None
def should_set_cookie(self, app: "Flask", session: SessionMixin) -> bool:
"""Used by session backends to determine if a ``Set-Cookie`` header
should be set for this session cookie for this response. If the session
has been modified, the cookie is set. If the session is permanent and
the ``SESSION_REFRESH_EACH_REQUEST`` config is true, the cookie is
always set.
This check is usually skipped if the session was deleted.
.. versionadded:: 0.11
"""
return session.modified or (
session.permanent and app.config["SESSION_REFRESH_EACH_REQUEST"]
)
def open_session(
self, app: "Flask", request: "Request"
) -> t.Optional[SessionMixin]:
"""This is called at the beginning of each request, after
pushing the request context, before matching the URL.
This must return an object which implements a dictionary-like
interface as well as the :class:`SessionMixin` interface.
This will return ``None`` to indicate that loading failed in
some way that is not immediately an error. The request
context will fall back to using :meth:`make_null_session`
in this case.
"""
raise NotImplementedError()
def save_session(
self, app: "Flask", session: SessionMixin, response: "Response"
) -> None:
"""This is called at the end of each request, after generating
a response, before removing the request context. It is skipped
if :meth:`is_null_session` returns ``True``.
"""
raise NotImplementedError()
session_json_serializer = TaggedJSONSerializer()
class SecureCookieSessionInterface(SessionInterface):
"""The default session interface that stores sessions in signed cookies
through the :mod:`itsdangerous` module.
"""
#: the salt that should be applied on top of the secret key for the
#: signing of cookie based sessions.
salt = "cookie-session"
#: the hash function to use for the signature. The default is sha1
digest_method = staticmethod(hashlib.sha1)
#: the name of the itsdangerous supported key derivation. The default
#: is hmac.
key_derivation = "hmac"
#: A python serializer for the payload. The default is a compact
#: JSON derived serializer with support for some extra Python types
#: such as datetime objects or tuples.
serializer = session_json_serializer
session_class = SecureCookieSession
def get_signing_serializer(
self, app: "Flask"
) -> t.Optional[URLSafeTimedSerializer]:
if not app.secret_key:
return None
signer_kwargs = dict(
key_derivation=self.key_derivation, digest_method=self.digest_method
)
return URLSafeTimedSerializer(
app.secret_key,
salt=self.salt,
serializer=self.serializer,
signer_kwargs=signer_kwargs,
)
def open_session(
self, app: "Flask", request: "Request"
) -> t.Optional[SecureCookieSession]:
s = self.get_signing_serializer(app)
if s is None:
return None
val = request.cookies.get(self.get_cookie_name(app))
if not val:
return self.session_class()
max_age = int(app.permanent_session_lifetime.total_seconds())
try:
data = s.loads(val, max_age=max_age)
return self.session_class(data)
except BadSignature:
return self.session_class()
def save_session(
self, app: "Flask", session: SessionMixin, response: "Response"
) -> None:
name = self.get_cookie_name(app)
domain = self.get_cookie_domain(app)
path = self.get_cookie_path(app)
secure = self.get_cookie_secure(app)
samesite = self.get_cookie_samesite(app)
# If the session is modified to be empty, remove the cookie.
# If the session is empty, return without setting the cookie.
if not session:
if session.modified:
response.delete_cookie(
name, domain=domain, path=path, secure=secure, samesite=samesite
)
return
# Add a "Vary: Cookie" header if the session was accessed at all.
if session.accessed:
response.vary.add("Cookie")
if not self.should_set_cookie(app, session):
return
httponly = self.get_cookie_httponly(app)
expires = self.get_expiration_time(app, session)
val = self.get_signing_serializer(app).dumps(dict(session)) # type: ignore
response.set_cookie(
name,
val, # type: ignore
expires=expires,
httponly=httponly,
domain=domain,
path=path,
secure=secure,
samesite=samesite,
)

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import typing as t
try:
from blinker import Namespace
signals_available = True
except ImportError:
signals_available = False
class Namespace: # type: ignore
def signal(self, name: str, doc: t.Optional[str] = None) -> "_FakeSignal":
return _FakeSignal(name, doc)
class _FakeSignal:
"""If blinker is unavailable, create a fake class with the same
interface that allows sending of signals but will fail with an
error on anything else. Instead of doing anything on send, it
will just ignore the arguments and do nothing instead.
"""
def __init__(self, name: str, doc: t.Optional[str] = None) -> None:
self.name = name
self.__doc__ = doc
def send(self, *args: t.Any, **kwargs: t.Any) -> t.Any:
pass
def _fail(self, *args: t.Any, **kwargs: t.Any) -> t.Any:
raise RuntimeError(
"Signalling support is unavailable because the blinker"
" library is not installed."
) from None
connect = connect_via = connected_to = temporarily_connected_to = _fail
disconnect = _fail
has_receivers_for = receivers_for = _fail
del _fail
# The namespace for code signals. If you are not Flask code, do
# not put signals in here. Create your own namespace instead.
_signals = Namespace()
# Core signals. For usage examples grep the source code or consult
# the API documentation in docs/api.rst as well as docs/signals.rst
template_rendered = _signals.signal("template-rendered")
before_render_template = _signals.signal("before-render-template")
request_started = _signals.signal("request-started")
request_finished = _signals.signal("request-finished")
request_tearing_down = _signals.signal("request-tearing-down")
got_request_exception = _signals.signal("got-request-exception")
appcontext_tearing_down = _signals.signal("appcontext-tearing-down")
appcontext_pushed = _signals.signal("appcontext-pushed")
appcontext_popped = _signals.signal("appcontext-popped")
message_flashed = _signals.signal("message-flashed")

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import typing as t
from jinja2 import BaseLoader
from jinja2 import Environment as BaseEnvironment
from jinja2 import Template
from jinja2 import TemplateNotFound
from .globals import _app_ctx_stack
from .globals import _request_ctx_stack
from .signals import before_render_template
from .signals import template_rendered
if t.TYPE_CHECKING:
from .app import Flask
from .scaffold import Scaffold
def _default_template_ctx_processor() -> t.Dict[str, t.Any]:
"""Default template context processor. Injects `request`,
`session` and `g`.
"""
reqctx = _request_ctx_stack.top
appctx = _app_ctx_stack.top
rv = {}
if appctx is not None:
rv["g"] = appctx.g
if reqctx is not None:
rv["request"] = reqctx.request
rv["session"] = reqctx.session
return rv
class Environment(BaseEnvironment):
"""Works like a regular Jinja2 environment but has some additional
knowledge of how Flask's blueprint works so that it can prepend the
name of the blueprint to referenced templates if necessary.
"""
def __init__(self, app: "Flask", **options: t.Any) -> None:
if "loader" not in options:
options["loader"] = app.create_global_jinja_loader()
BaseEnvironment.__init__(self, **options)
self.app = app
class DispatchingJinjaLoader(BaseLoader):
"""A loader that looks for templates in the application and all
the blueprint folders.
"""
def __init__(self, app: "Flask") -> None:
self.app = app
def get_source( # type: ignore
self, environment: Environment, template: str
) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable]]:
if self.app.config["EXPLAIN_TEMPLATE_LOADING"]:
return self._get_source_explained(environment, template)
return self._get_source_fast(environment, template)
def _get_source_explained(
self, environment: Environment, template: str
) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable]]:
attempts = []
rv: t.Optional[t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]]
trv: t.Optional[
t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]
] = None
for srcobj, loader in self._iter_loaders(template):
try:
rv = loader.get_source(environment, template)
if trv is None:
trv = rv
except TemplateNotFound:
rv = None
attempts.append((loader, srcobj, rv))
from .debughelpers import explain_template_loading_attempts
explain_template_loading_attempts(self.app, template, attempts)
if trv is not None:
return trv
raise TemplateNotFound(template)
def _get_source_fast(
self, environment: Environment, template: str
) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable]]:
for _srcobj, loader in self._iter_loaders(template):
try:
return loader.get_source(environment, template)
except TemplateNotFound:
continue
raise TemplateNotFound(template)
def _iter_loaders(
self, template: str
) -> t.Generator[t.Tuple["Scaffold", BaseLoader], None, None]:
loader = self.app.jinja_loader
if loader is not None:
yield self.app, loader
for blueprint in self.app.iter_blueprints():
loader = blueprint.jinja_loader
if loader is not None:
yield blueprint, loader
def list_templates(self) -> t.List[str]:
result = set()
loader = self.app.jinja_loader
if loader is not None:
result.update(loader.list_templates())
for blueprint in self.app.iter_blueprints():
loader = blueprint.jinja_loader
if loader is not None:
for template in loader.list_templates():
result.add(template)
return list(result)
def _render(template: Template, context: dict, app: "Flask") -> str:
"""Renders the template and fires the signal"""
before_render_template.send(app, template=template, context=context)
rv = template.render(context)
template_rendered.send(app, template=template, context=context)
return rv
def render_template(
template_name_or_list: t.Union[str, t.List[str]], **context: t.Any
) -> str:
"""Renders a template from the template folder with the given
context.
:param template_name_or_list: the name of the template to be
rendered, or an iterable with template names
the first one existing will be rendered
:param context: the variables that should be available in the
context of the template.
"""
ctx = _app_ctx_stack.top
ctx.app.update_template_context(context)
return _render(
ctx.app.jinja_env.get_or_select_template(template_name_or_list),
context,
ctx.app,
)
def render_template_string(source: str, **context: t.Any) -> str:
"""Renders a template from the given template source string
with the given context. Template variables will be autoescaped.
:param source: the source code of the template to be
rendered
:param context: the variables that should be available in the
context of the template.
"""
ctx = _app_ctx_stack.top
ctx.app.update_template_context(context)
return _render(ctx.app.jinja_env.from_string(source), context, ctx.app)

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import typing as t
from contextlib import contextmanager
from copy import copy
from types import TracebackType
import werkzeug.test
from click.testing import CliRunner
from werkzeug.test import Client
from werkzeug.urls import url_parse
from werkzeug.wrappers import Request as BaseRequest
from .cli import ScriptInfo
from .globals import _request_ctx_stack
from .json import dumps as json_dumps
from .sessions import SessionMixin
if t.TYPE_CHECKING:
from werkzeug.test import TestResponse
from .app import Flask
class EnvironBuilder(werkzeug.test.EnvironBuilder):
"""An :class:`~werkzeug.test.EnvironBuilder`, that takes defaults from the
application.
:param app: The Flask application to configure the environment from.
:param path: URL path being requested.
:param base_url: Base URL where the app is being served, which
``path`` is relative to. If not given, built from
:data:`PREFERRED_URL_SCHEME`, ``subdomain``,
:data:`SERVER_NAME`, and :data:`APPLICATION_ROOT`.
:param subdomain: Subdomain name to append to :data:`SERVER_NAME`.
:param url_scheme: Scheme to use instead of
:data:`PREFERRED_URL_SCHEME`.
:param json: If given, this is serialized as JSON and passed as
``data``. Also defaults ``content_type`` to
``application/json``.
:param args: other positional arguments passed to
:class:`~werkzeug.test.EnvironBuilder`.
:param kwargs: other keyword arguments passed to
:class:`~werkzeug.test.EnvironBuilder`.
"""
def __init__(
self,
app: "Flask",
path: str = "/",
base_url: t.Optional[str] = None,
subdomain: t.Optional[str] = None,
url_scheme: t.Optional[str] = None,
*args: t.Any,
**kwargs: t.Any,
) -> None:
assert not (base_url or subdomain or url_scheme) or (
base_url is not None
) != bool(
subdomain or url_scheme
), 'Cannot pass "subdomain" or "url_scheme" with "base_url".'
if base_url is None:
http_host = app.config.get("SERVER_NAME") or "localhost"
app_root = app.config["APPLICATION_ROOT"]
if subdomain:
http_host = f"{subdomain}.{http_host}"
if url_scheme is None:
url_scheme = app.config["PREFERRED_URL_SCHEME"]
url = url_parse(path)
base_url = (
f"{url.scheme or url_scheme}://{url.netloc or http_host}"
f"/{app_root.lstrip('/')}"
)
path = url.path
if url.query:
sep = b"?" if isinstance(url.query, bytes) else "?"
path += sep + url.query
self.app = app
super().__init__(path, base_url, *args, **kwargs)
def json_dumps(self, obj: t.Any, **kwargs: t.Any) -> str: # type: ignore
"""Serialize ``obj`` to a JSON-formatted string.
The serialization will be configured according to the config associated
with this EnvironBuilder's ``app``.
"""
kwargs.setdefault("app", self.app)
return json_dumps(obj, **kwargs)
class FlaskClient(Client):
"""Works like a regular Werkzeug test client but has some knowledge about
how Flask works to defer the cleanup of the request context stack to the
end of a ``with`` body when used in a ``with`` statement. For general
information about how to use this class refer to
:class:`werkzeug.test.Client`.
.. versionchanged:: 0.12
`app.test_client()` includes preset default environment, which can be
set after instantiation of the `app.test_client()` object in
`client.environ_base`.
Basic usage is outlined in the :doc:`/testing` chapter.
"""
application: "Flask"
preserve_context = False
def __init__(self, *args: t.Any, **kwargs: t.Any) -> None:
super().__init__(*args, **kwargs)
self.environ_base = {
"REMOTE_ADDR": "127.0.0.1",
"HTTP_USER_AGENT": f"werkzeug/{werkzeug.__version__}",
}
@contextmanager
def session_transaction(
self, *args: t.Any, **kwargs: t.Any
) -> t.Generator[SessionMixin, None, None]:
"""When used in combination with a ``with`` statement this opens a
session transaction. This can be used to modify the session that
the test client uses. Once the ``with`` block is left the session is
stored back.
::
with client.session_transaction() as session:
session['value'] = 42
Internally this is implemented by going through a temporary test
request context and since session handling could depend on
request variables this function accepts the same arguments as
:meth:`~flask.Flask.test_request_context` which are directly
passed through.
"""
if self.cookie_jar is None:
raise RuntimeError(
"Session transactions only make sense with cookies enabled."
)
app = self.application
environ_overrides = kwargs.setdefault("environ_overrides", {})
self.cookie_jar.inject_wsgi(environ_overrides)
outer_reqctx = _request_ctx_stack.top
with app.test_request_context(*args, **kwargs) as c:
session_interface = app.session_interface
sess = session_interface.open_session(app, c.request)
if sess is None:
raise RuntimeError(
"Session backend did not open a session. Check the configuration"
)
# Since we have to open a new request context for the session
# handling we want to make sure that we hide out own context
# from the caller. By pushing the original request context
# (or None) on top of this and popping it we get exactly that
# behavior. It's important to not use the push and pop
# methods of the actual request context object since that would
# mean that cleanup handlers are called
_request_ctx_stack.push(outer_reqctx)
try:
yield sess
finally:
_request_ctx_stack.pop()
resp = app.response_class()
if not session_interface.is_null_session(sess):
session_interface.save_session(app, sess, resp)
headers = resp.get_wsgi_headers(c.request.environ)
self.cookie_jar.extract_wsgi(c.request.environ, headers)
def open(
self,
*args: t.Any,
buffered: bool = False,
follow_redirects: bool = False,
**kwargs: t.Any,
) -> "TestResponse":
as_tuple = kwargs.pop("as_tuple", None)
# Same logic as super.open, but apply environ_base and preserve_context.
request = None
def copy_environ(other):
return {
**self.environ_base,
**other,
"flask._preserve_context": self.preserve_context,
}
if not kwargs and len(args) == 1:
arg = args[0]
if isinstance(arg, werkzeug.test.EnvironBuilder):
builder = copy(arg)
builder.environ_base = copy_environ(builder.environ_base or {})
request = builder.get_request()
elif isinstance(arg, dict):
request = EnvironBuilder.from_environ(
arg, app=self.application, environ_base=copy_environ({})
).get_request()
elif isinstance(arg, BaseRequest):
request = copy(arg)
request.environ = copy_environ(request.environ)
if request is None:
kwargs["environ_base"] = copy_environ(kwargs.get("environ_base", {}))
builder = EnvironBuilder(self.application, *args, **kwargs)
try:
request = builder.get_request()
finally:
builder.close()
if as_tuple is not None:
import warnings
warnings.warn(
"'as_tuple' is deprecated and will be removed in"
" Werkzeug 2.1 and Flask 2.1. Use"
" 'response.request.environ' instead.",
DeprecationWarning,
stacklevel=3,
)
return super().open(
request,
as_tuple=as_tuple,
buffered=buffered,
follow_redirects=follow_redirects,
)
else:
return super().open(
request,
buffered=buffered,
follow_redirects=follow_redirects,
)
def __enter__(self) -> "FlaskClient":
if self.preserve_context:
raise RuntimeError("Cannot nest client invocations")
self.preserve_context = True
return self
def __exit__(
self, exc_type: type, exc_value: BaseException, tb: TracebackType
) -> None:
self.preserve_context = False
# Normally the request context is preserved until the next
# request in the same thread comes. When the client exits we
# want to clean up earlier. Pop request contexts until the stack
# is empty or a non-preserved one is found.
while True:
top = _request_ctx_stack.top
if top is not None and top.preserved:
top.pop()
else:
break
class FlaskCliRunner(CliRunner):
"""A :class:`~click.testing.CliRunner` for testing a Flask app's
CLI commands. Typically created using
:meth:`~flask.Flask.test_cli_runner`. See :ref:`testing-cli`.
"""
def __init__(self, app: "Flask", **kwargs: t.Any) -> None:
self.app = app
super().__init__(**kwargs)
def invoke( # type: ignore
self, cli: t.Any = None, args: t.Any = None, **kwargs: t.Any
) -> t.Any:
"""Invokes a CLI command in an isolated environment. See
:meth:`CliRunner.invoke <click.testing.CliRunner.invoke>` for
full method documentation. See :ref:`testing-cli` for examples.
If the ``obj`` argument is not given, passes an instance of
:class:`~flask.cli.ScriptInfo` that knows how to load the Flask
app being tested.
:param cli: Command object to invoke. Default is the app's
:attr:`~flask.app.Flask.cli` group.
:param args: List of strings to invoke the command with.
:return: a :class:`~click.testing.Result` object.
"""
if cli is None:
cli = self.app.cli # type: ignore
if "obj" not in kwargs:
kwargs["obj"] = ScriptInfo(create_app=lambda: self.app)
return super().invoke(cli, args, **kwargs)

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import typing as t
if t.TYPE_CHECKING:
from _typeshed.wsgi import WSGIApplication # noqa: F401
from werkzeug.datastructures import Headers # noqa: F401
from .wrappers import Response # noqa: F401
# The possible types that are directly convertible or are a Response object.
ResponseValue = t.Union[
"Response",
t.AnyStr,
t.Dict[str, t.Any], # any jsonify-able dict
t.Generator[t.AnyStr, None, None],
]
StatusCode = int
# the possible types for an individual HTTP header
HeaderName = str
HeaderValue = t.Union[str, t.List[str], t.Tuple[str, ...]]
# the possible types for HTTP headers
HeadersValue = t.Union[
"Headers", t.Dict[HeaderName, HeaderValue], t.List[t.Tuple[HeaderName, HeaderValue]]
]
# The possible types returned by a route function.
ResponseReturnValue = t.Union[
ResponseValue,
t.Tuple[ResponseValue, HeadersValue],
t.Tuple[ResponseValue, StatusCode],
t.Tuple[ResponseValue, StatusCode, HeadersValue],
"WSGIApplication",
]
GenericException = t.TypeVar("GenericException", bound=Exception, contravariant=True)
AppOrBlueprintKey = t.Optional[str] # The App key is None, whereas blueprints are named
AfterRequestCallable = t.Callable[["Response"], "Response"]
BeforeFirstRequestCallable = t.Callable[[], None]
BeforeRequestCallable = t.Callable[[], t.Optional[ResponseReturnValue]]
TeardownCallable = t.Callable[[t.Optional[BaseException]], None]
TemplateContextProcessorCallable = t.Callable[[], t.Dict[str, t.Any]]
TemplateFilterCallable = t.Callable[..., t.Any]
TemplateGlobalCallable = t.Callable[..., t.Any]
TemplateTestCallable = t.Callable[..., bool]
URLDefaultCallable = t.Callable[[str, dict], None]
URLValuePreprocessorCallable = t.Callable[[t.Optional[str], t.Optional[dict]], None]
ErrorHandlerCallable = t.Callable[[GenericException], ResponseReturnValue]

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@ -0,0 +1,158 @@
import typing as t
from .globals import current_app
from .globals import request
from .typing import ResponseReturnValue
http_method_funcs = frozenset(
["get", "post", "head", "options", "delete", "put", "trace", "patch"]
)
class View:
"""Alternative way to use view functions. A subclass has to implement
:meth:`dispatch_request` which is called with the view arguments from
the URL routing system. If :attr:`methods` is provided the methods
do not have to be passed to the :meth:`~flask.Flask.add_url_rule`
method explicitly::
class MyView(View):
methods = ['GET']
def dispatch_request(self, name):
return f"Hello {name}!"
app.add_url_rule('/hello/<name>', view_func=MyView.as_view('myview'))
When you want to decorate a pluggable view you will have to either do that
when the view function is created (by wrapping the return value of
:meth:`as_view`) or you can use the :attr:`decorators` attribute::
class SecretView(View):
methods = ['GET']
decorators = [superuser_required]
def dispatch_request(self):
...
The decorators stored in the decorators list are applied one after another
when the view function is created. Note that you can *not* use the class
based decorators since those would decorate the view class and not the
generated view function!
"""
#: A list of methods this view can handle.
methods: t.Optional[t.List[str]] = None
#: Setting this disables or force-enables the automatic options handling.
provide_automatic_options: t.Optional[bool] = None
#: The canonical way to decorate class-based views is to decorate the
#: return value of as_view(). However since this moves parts of the
#: logic from the class declaration to the place where it's hooked
#: into the routing system.
#:
#: You can place one or more decorators in this list and whenever the
#: view function is created the result is automatically decorated.
#:
#: .. versionadded:: 0.8
decorators: t.List[t.Callable] = []
def dispatch_request(self) -> ResponseReturnValue:
"""Subclasses have to override this method to implement the
actual view function code. This method is called with all
the arguments from the URL rule.
"""
raise NotImplementedError()
@classmethod
def as_view(
cls, name: str, *class_args: t.Any, **class_kwargs: t.Any
) -> t.Callable:
"""Converts the class into an actual view function that can be used
with the routing system. Internally this generates a function on the
fly which will instantiate the :class:`View` on each request and call
the :meth:`dispatch_request` method on it.
The arguments passed to :meth:`as_view` are forwarded to the
constructor of the class.
"""
def view(*args: t.Any, **kwargs: t.Any) -> ResponseReturnValue:
self = view.view_class(*class_args, **class_kwargs) # type: ignore
return current_app.ensure_sync(self.dispatch_request)(*args, **kwargs)
if cls.decorators:
view.__name__ = name
view.__module__ = cls.__module__
for decorator in cls.decorators:
view = decorator(view)
# We attach the view class to the view function for two reasons:
# first of all it allows us to easily figure out what class-based
# view this thing came from, secondly it's also used for instantiating
# the view class so you can actually replace it with something else
# for testing purposes and debugging.
view.view_class = cls # type: ignore
view.__name__ = name
view.__doc__ = cls.__doc__
view.__module__ = cls.__module__
view.methods = cls.methods # type: ignore
view.provide_automatic_options = cls.provide_automatic_options # type: ignore
return view
class MethodViewType(type):
"""Metaclass for :class:`MethodView` that determines what methods the view
defines.
"""
def __init__(cls, name, bases, d):
super().__init__(name, bases, d)
if "methods" not in d:
methods = set()
for base in bases:
if getattr(base, "methods", None):
methods.update(base.methods)
for key in http_method_funcs:
if hasattr(cls, key):
methods.add(key.upper())
# If we have no method at all in there we don't want to add a
# method list. This is for instance the case for the base class
# or another subclass of a base method view that does not introduce
# new methods.
if methods:
cls.methods = methods
class MethodView(View, metaclass=MethodViewType):
"""A class-based view that dispatches request methods to the corresponding
class methods. For example, if you implement a ``get`` method, it will be
used to handle ``GET`` requests. ::
class CounterAPI(MethodView):
def get(self):
return session.get('counter', 0)
def post(self):
session['counter'] = session.get('counter', 0) + 1
return 'OK'
app.add_url_rule('/counter', view_func=CounterAPI.as_view('counter'))
"""
def dispatch_request(self, *args: t.Any, **kwargs: t.Any) -> ResponseReturnValue:
meth = getattr(self, request.method.lower(), None)
# If the request method is HEAD and we don't have a handler for it
# retry with GET.
if meth is None and request.method == "HEAD":
meth = getattr(self, "get", None)
assert meth is not None, f"Unimplemented method {request.method!r}"
return current_app.ensure_sync(meth)(*args, **kwargs)

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@ -0,0 +1,167 @@
import typing as t
from werkzeug.exceptions import BadRequest
from werkzeug.wrappers import Request as RequestBase
from werkzeug.wrappers import Response as ResponseBase
from . import json
from .globals import current_app
from .helpers import _split_blueprint_path
if t.TYPE_CHECKING:
import typing_extensions as te
from werkzeug.routing import Rule
class Request(RequestBase):
"""The request object used by default in Flask. Remembers the
matched endpoint and view arguments.
It is what ends up as :class:`~flask.request`. If you want to replace
the request object used you can subclass this and set
:attr:`~flask.Flask.request_class` to your subclass.
The request object is a :class:`~werkzeug.wrappers.Request` subclass and
provides all of the attributes Werkzeug defines plus a few Flask
specific ones.
"""
json_module = json
#: The internal URL rule that matched the request. This can be
#: useful to inspect which methods are allowed for the URL from
#: a before/after handler (``request.url_rule.methods``) etc.
#: Though if the request's method was invalid for the URL rule,
#: the valid list is available in ``routing_exception.valid_methods``
#: instead (an attribute of the Werkzeug exception
#: :exc:`~werkzeug.exceptions.MethodNotAllowed`)
#: because the request was never internally bound.
#:
#: .. versionadded:: 0.6
url_rule: t.Optional["Rule"] = None
#: A dict of view arguments that matched the request. If an exception
#: happened when matching, this will be ``None``.
view_args: t.Optional[t.Dict[str, t.Any]] = None
#: If matching the URL failed, this is the exception that will be
#: raised / was raised as part of the request handling. This is
#: usually a :exc:`~werkzeug.exceptions.NotFound` exception or
#: something similar.
routing_exception: t.Optional[Exception] = None
@property
def max_content_length(self) -> t.Optional[int]: # type: ignore
"""Read-only view of the ``MAX_CONTENT_LENGTH`` config key."""
if current_app:
return current_app.config["MAX_CONTENT_LENGTH"]
else:
return None
@property
def endpoint(self) -> t.Optional[str]:
"""The endpoint that matched the request URL.
This will be ``None`` if matching failed or has not been
performed yet.
This in combination with :attr:`view_args` can be used to
reconstruct the same URL or a modified URL.
"""
if self.url_rule is not None:
return self.url_rule.endpoint
return None
@property
def blueprint(self) -> t.Optional[str]:
"""The registered name of the current blueprint.
This will be ``None`` if the endpoint is not part of a
blueprint, or if URL matching failed or has not been performed
yet.
This does not necessarily match the name the blueprint was
created with. It may have been nested, or registered with a
different name.
"""
endpoint = self.endpoint
if endpoint is not None and "." in endpoint:
return endpoint.rpartition(".")[0]
return None
@property
def blueprints(self) -> t.List[str]:
"""The registered names of the current blueprint upwards through
parent blueprints.
This will be an empty list if there is no current blueprint, or
if URL matching failed.
.. versionadded:: 2.0.1
"""
name = self.blueprint
if name is None:
return []
return _split_blueprint_path(name)
def _load_form_data(self) -> None:
RequestBase._load_form_data(self)
# In debug mode we're replacing the files multidict with an ad-hoc
# subclass that raises a different error for key errors.
if (
current_app
and current_app.debug
and self.mimetype != "multipart/form-data"
and not self.files
):
from .debughelpers import attach_enctype_error_multidict
attach_enctype_error_multidict(self)
def on_json_loading_failed(self, e: Exception) -> "te.NoReturn":
if current_app and current_app.debug:
raise BadRequest(f"Failed to decode JSON object: {e}")
raise BadRequest()
class Response(ResponseBase):
"""The response object that is used by default in Flask. Works like the
response object from Werkzeug but is set to have an HTML mimetype by
default. Quite often you don't have to create this object yourself because
:meth:`~flask.Flask.make_response` will take care of that for you.
If you want to replace the response object used you can subclass this and
set :attr:`~flask.Flask.response_class` to your subclass.
.. versionchanged:: 1.0
JSON support is added to the response, like the request. This is useful
when testing to get the test client response data as JSON.
.. versionchanged:: 1.0
Added :attr:`max_cookie_size`.
"""
default_mimetype = "text/html"
json_module = json
@property
def max_cookie_size(self) -> int: # type: ignore
"""Read-only view of the :data:`MAX_COOKIE_SIZE` config key.
See :attr:`~werkzeug.wrappers.Response.max_cookie_size` in
Werkzeug's docs.
"""
if current_app:
return current_app.config["MAX_COOKIE_SIZE"]
# return Werkzeug's default when not in an app context
return super().max_cookie_size