flask.g is now on the app context and not the request context

Author: mitsuhiko

CHANGES

@@ -34,6 +34,11 @@ Release date to be decided.
   in less bytes being transmitted over the network.  It's disabled by
   default to not cause confusion with existing libraries that might expect
   ``flask.json.dumps`` to return bytestrings by default.
+- ``flask.g`` is now stored on the app context instead of the request
+  context.
+- ``flask.Flask.request_globals_class`` got renamed to
+  ``flask.Flask.app_ctx_globals_class`` which is a better name to what it
+  does since 0.10.
 
 Version 0.9
 -----------

docs/api.rst

@@ -258,6 +258,10 @@ thing, like it does for :class:`request` and :class:`session`.
    Just store on this whatever you want.  For example a database
    connection or the user that is currently logged in.
 
+   Starting with Flask 0.10 this is stored on the application context and
+   no longer on the request context which means it becomes available if
+   only the application context is bound and not yet a request.
+
    This is a proxy.  See :ref:`notes-on-proxies` for more information.
 
 

docs/upgrading.rst

@@ -36,6 +36,13 @@ extensions for tuples and strings with HTML markup.
 In order to not break people's sessions it is possible to continue using
 the old session system by using the `Flask-OldSessions_` extension.
 
+Flask also started storing the :data:`flask.g` object on the application
+context instead of the request context.  This change should be transparent
+for you but it means that you now can store things on the ``g`` object
+when there is no request context yet but an application context.  The old
+``flask.Flask.request_globals_class`` attribute was renamed to
+:attr:`flask.Flask.app_ctx_globals_class`.
+
 .. _Flask-OldSessions: http://packages.python.org/Flask-OldSessions/
 
 Version 0.9

flask/app.py

@@ -28,7 +28,7 @@
 from . import json
 from .wrappers import Request, Response
 from .config import ConfigAttribute, Config
-from .ctx import RequestContext, AppContext, _RequestGlobals
+from .ctx import RequestContext, AppContext, _AppCtxGlobals
 from .globals import _request_ctx_stack, request
 from .sessions import SecureCookieSessionInterface
 from .module import blueprint_is_module
@@ -157,8 +157,24 @@ class Flask(_PackageBoundObject):
     #: 3. Return None instead of AttributeError on expected attributes.
     #: 4. Raise exception if an unexpected attr is set, a "controlled" flask.g.
     #:
-    #: .. versionadded:: 0.9
-    request_globals_class = _RequestGlobals
+    #: In Flask 0.9 this property was called `request_globals_class` but it
+    #: was changed in 0.10 to :attr:`app_ctx_globals_class` because the
+    #: flask.g object is not application context scoped.
+    #:
+    #: .. versionadded:: 0.10
+    app_ctx_globals_class = _AppCtxGlobals
+
+    # Backwards compatibility support
+    def _get_request_globals_class(self):
+        return self.app_ctx_globals_class
+    def _set_request_globals_class(self, value):
+        from warnings import warn
+        warn(DeprecationWarning('request_globals_class attribute is now '
+                                'called app_ctx_globals_class'))
+        self.app_ctx_globals_class = value
+    request_globals_class = property(_get_request_globals_class,
+                                     _set_request_globals_class)
+    del _get_request_globals_class, _set_request_globals_class
 
     #: The debug flag.  Set this to `True` to enable debugging of the
     #: application.  In debug mode the debugger will kick in when an unhandled

flask/ctx.py

@@ -17,7 +17,7 @@
 from .module import blueprint_is_module
 
 
-class _RequestGlobals(object):
+class _AppCtxGlobals(object):
     """A plain object."""
     pass
 
@@ -101,6 +101,7 @@ class AppContext(object):
     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.
@@ -164,7 +165,6 @@ def __init__(self, app, environ):
         self.app = app
         self.request = app.request_class(environ)
         self.url_adapter = app.create_url_adapter(self.request)
-        self.g = app.request_globals_class()
         self.flashes = None
         self.session = None
 
@@ -195,6 +195,13 @@ def __init__(self, app, environ):
             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 match_request(self):
         """Can be overridden by a subclass to hook into the matching
         of the request.

flask/globals.py

@@ -13,13 +13,21 @@
 from functools import partial
 from werkzeug.local import LocalStack, LocalProxy
 
-def _lookup_object(name):
+
+def _lookup_req_object(name):
     top = _request_ctx_stack.top
     if top is None:
         raise RuntimeError('working outside of request context')
     return getattr(top, name)
 
 
+def _lookup_app_object(name):
+    top = _app_ctx_stack.top
+    if top is None:
+        raise RuntimeError('working outside of application context')
+    return getattr(top, name)
+
+
 def _find_app():
     top = _app_ctx_stack.top
     if top is None:
@@ -31,6 +39,6 @@ def _find_app():
 _request_ctx_stack = LocalStack()
 _app_ctx_stack = LocalStack()
 current_app = LocalProxy(_find_app)
-request = LocalProxy(partial(_lookup_object, 'request'))
-session = LocalProxy(partial(_lookup_object, 'session'))
-g = LocalProxy(partial(_lookup_object, 'g'))
+request = LocalProxy(partial(_lookup_req_object, 'request'))
+session = LocalProxy(partial(_lookup_req_object, 'session'))
+g = LocalProxy(partial(_lookup_app_object, 'g'))

flask/templating.py

@@ -22,13 +22,14 @@ def _default_template_ctx_processor():
     `session` and `g`.
     """
     reqctx = _request_ctx_stack.top
-    if reqctx is None:
-        return {}
-    return dict(
-        request=reqctx.request,
-        session=reqctx.session,
-        g=reqctx.g
-    )
+    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):

flask/testsuite/appctx.py

@@ -65,13 +65,13 @@ def cleanup(exception):
 
         self.assert_equal(cleanup_stuff, [None])
 
-    def test_custom_request_globals_class(self):
+    def test_custom_app_ctx_globals_class(self):
         class CustomRequestGlobals(object):
             def __init__(self):
                 self.spam = 'eggs'
         app = flask.Flask(__name__)
-        app.request_globals_class = CustomRequestGlobals
-        with app.test_request_context():
+        app.app_ctx_globals_class = CustomRequestGlobals
+        with app.app_context():
             self.assert_equal(
                 flask.render_template_string('{{ g.spam }}'), 'eggs')
 

flask/testsuite/basic.py

@@ -1104,8 +1104,11 @@ def fail_func():
                 c.get('/fail')
 
         self.assert_(flask._request_ctx_stack.top is not None)
-        flask._request_ctx_stack.pop()
+        self.assert_(flask._app_ctx_stack.top is not None)
+        # implicit appctx disappears too
+        flask._request_ctx_stack.top.pop()
         self.assert_(flask._request_ctx_stack.top is None)
+        self.assert_(flask._app_ctx_stack.top is None)
 
 
 class ContextTestCase(FlaskTestCase):