Update Flask

libs/flask/ctx.py

@@ -9,16 +9,44 @@
     :license: BSD, see LICENSE for more details.
 """
 
+import sys
+
 from werkzeug.exceptions import HTTPException
 
-from .globals import _request_ctx_stack
+from .globals import _request_ctx_stack, _app_ctx_stack
 from .module import blueprint_is_module
 
 
 class _RequestGlobals(object):
+    """A plain object."""
     pass
 
 
+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 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
@@ -51,6 +79,57 @@ def has_request_context():
     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)
+
+        # 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)
+
+    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)
+
+    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
@@ -85,17 +164,28 @@ class RequestContext(object):
         self.app = app
         self.request = app.request_class(environ)
         self.url_adapter = app.create_url_adapter(self.request)
-        self.g = _RequestGlobals()
+        self.g = app.request_globals_class()
         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
 
+        # 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 doing away with
+        # XXX: Support for deprecated functionality.  This is going away with
         # Flask 1.0
         blueprint = self.request.blueprint
         if blueprint is not None:
@@ -130,6 +220,16 @@ class RequestContext(object):
         if top is not None and top.preserved:
             top.pop()
 
+        # 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
@@ -139,20 +239,36 @@ class RequestContext(object):
         if self.session is None:
             self.session = self.app.make_null_session()
 
-    def pop(self):
+    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.
         """
-        self.preserved = False
-        self.app.do_teardown_request()
+        app_ctx = self._implicit_app_ctx_stack.pop()
+
+        clear_request = False
+        if not self._implicit_app_ctx_stack:
+            self.preserved = False
+            if exc is None:
+                exc = sys.exc_info()[1]
+            self.app.do_teardown_request(exc)
+            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.
-        rv.request.environ['werkzeug.request'] = None
+        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 __enter__(self):
         self.push()
@@ -168,7 +284,7 @@ class RequestContext(object):
            (tb is not None and self.app.preserve_context_on_exception):
             self.preserved = True
         else:
-            self.pop()
+            self.pop(exc_value)
 
     def __repr__(self):
         return '<%s \'%s\' [%s] of %s>' % (