395 lines
14 KiB
Python
395 lines
14 KiB
Python
# -*- coding: utf-8 -*-
|
|
"""
|
|
flask.ctx
|
|
~~~~~~~~~
|
|
|
|
Implements the objects required to keep the context.
|
|
|
|
:copyright: (c) 2011 by Armin Ronacher.
|
|
:license: BSD, see LICENSE for more details.
|
|
"""
|
|
|
|
from __future__ import with_statement
|
|
|
|
import sys
|
|
from functools import update_wrapper
|
|
|
|
from werkzeug.exceptions import HTTPException
|
|
|
|
from .globals import _request_ctx_stack, _app_ctx_stack
|
|
from .module import blueprint_is_module
|
|
from .signals import appcontext_pushed, appcontext_popped
|
|
|
|
|
|
class _AppCtxGlobals(object):
|
|
"""A plain object."""
|
|
|
|
def get(self, name, default=None):
|
|
return self.__dict__.get(name, default)
|
|
|
|
def __contains__(self, item):
|
|
return item in self.__dict__
|
|
|
|
def __iter__(self):
|
|
return iter(self.__dict__)
|
|
|
|
def __repr__(self):
|
|
top = _app_ctx_stack.top
|
|
if top is not None:
|
|
return '<flask.g of %r>' % top.app.name
|
|
return object.__repr__(self)
|
|
|
|
|
|
def after_this_request(f):
|
|
"""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
|
|
"""
|
|
_request_ctx_stack.top._after_request_functions.append(f)
|
|
return f
|
|
|
|
|
|
def copy_current_request_context(f):
|
|
"""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.
|
|
|
|
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 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 at local scopes '
|
|
'when a request context is on the stack. For instance within '
|
|
'view functions.')
|
|
reqctx = top.copy()
|
|
def wrapper(*args, **kwargs):
|
|
with reqctx:
|
|
return f(*args, **kwargs)
|
|
return update_wrapper(wrapper, f)
|
|
|
|
|
|
def has_request_context():
|
|
"""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():
|
|
"""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(object):
|
|
"""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):
|
|
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):
|
|
"""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=None):
|
|
"""Pops the app context."""
|
|
self._refcnt -= 1
|
|
if self._refcnt <= 0:
|
|
if exc is None:
|
|
exc = sys.exc_info()[1]
|
|
self.app.do_teardown_appcontext(exc)
|
|
rv = _app_ctx_stack.pop()
|
|
assert rv is self, 'Popped wrong app context. (%r instead of %r)' \
|
|
% (rv, self)
|
|
appcontext_popped.send(self.app)
|
|
|
|
def __enter__(self):
|
|
self.push()
|
|
return self
|
|
|
|
def __exit__(self, exc_type, exc_value, tb):
|
|
self.pop(exc_value)
|
|
|
|
|
|
class RequestContext(object):
|
|
"""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, environ, request=None):
|
|
self.app = app
|
|
if request is None:
|
|
request = app.request_class(environ)
|
|
self.request = request
|
|
self.url_adapter = app.create_url_adapter(self.request)
|
|
self.flashes = None
|
|
self.session = None
|
|
|
|
# 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 = []
|
|
|
|
# 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 = []
|
|
|
|
self.match_request()
|
|
|
|
# XXX: Support for deprecated functionality. This is going away with
|
|
# Flask 1.0
|
|
blueprint = self.request.blueprint
|
|
if blueprint is not None:
|
|
# better safe than sorry, we don't want to break code that
|
|
# already worked
|
|
bp = app.blueprints.get(blueprint)
|
|
if bp is not None and blueprint_is_module(bp):
|
|
self.request._is_old_module = True
|
|
|
|
def _get_g(self):
|
|
return _app_ctx_stack.top.g
|
|
def _set_g(self, value):
|
|
_app_ctx_stack.top.g = value
|
|
g = property(_get_g, _set_g)
|
|
del _get_g, _set_g
|
|
|
|
def copy(self):
|
|
"""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
|
|
"""
|
|
return self.__class__(self.app,
|
|
environ=self.request.environ,
|
|
request=self.request
|
|
)
|
|
|
|
def match_request(self):
|
|
"""Can be overridden by a subclass to hook into the matching
|
|
of the request.
|
|
"""
|
|
try:
|
|
url_rule, self.request.view_args = \
|
|
self.url_adapter.match(return_rule=True)
|
|
self.request.url_rule = url_rule
|
|
except HTTPException as e:
|
|
self.request.routing_exception = e
|
|
|
|
def push(self):
|
|
"""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 testsuite 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 (e.g. code that access database information
|
|
# stored on `g` instead of the appcontext).
|
|
self.session = self.app.open_session(self.request)
|
|
if self.session is None:
|
|
self.session = self.app.make_null_session()
|
|
|
|
def pop(self, exc=None):
|
|
"""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
|
|
if not self._implicit_app_ctx_stack:
|
|
self.preserved = False
|
|
self._preserved_exc = None
|
|
if exc is None:
|
|
exc = sys.exc_info()[1]
|
|
self.app.do_teardown_request(exc)
|
|
|
|
# If this interpreter supports clearing the exception information
|
|
# we do that now. This will only go into effect on Python 2.x,
|
|
# on 3.x it disappears automatically at the end of the exception
|
|
# stack.
|
|
if hasattr(sys, 'exc_clear'):
|
|
sys.exc_clear()
|
|
|
|
request_close = getattr(self.request, 'close', None)
|
|
if request_close is not None:
|
|
request_close()
|
|
clear_request = True
|
|
|
|
rv = _request_ctx_stack.pop()
|
|
assert rv is self, 'Popped wrong request context. (%r instead of %r)' \
|
|
% (rv, self)
|
|
|
|
# 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)
|
|
|
|
def auto_pop(self, exc):
|
|
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
|
|
else:
|
|
self.pop(exc)
|
|
|
|
def __enter__(self):
|
|
self.push()
|
|
return self
|
|
|
|
def __exit__(self, exc_type, exc_value, tb):
|
|
# 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):
|
|
return '<%s \'%s\' [%s] of %s>' % (
|
|
self.__class__.__name__,
|
|
self.request.url,
|
|
self.request.method,
|
|
self.app.name,
|
|
)
|