Implemented flask.has_request_context()

Author: mitsuhiko

CHANGES

@@ -39,6 +39,7 @@ Release date to be announced, codename to be selected
 - Implemented a silent flag for `config.from_pyfile`.
 - Added `teardown_request` decorator, for functions that should run at the end
   of a request regardless of whether an exception occurred.
+- Implemented :func:`flask.has_request_context`
 
 Version 0.6.1
 -------------

docs/api.rst

@@ -224,6 +224,8 @@ Useful Functions and Classes
 
    This is a proxy.  See :ref:`notes-on-proxies` for more information.
 
+.. autofunction:: has_request_context
+
 .. autofunction:: url_for
 
 .. function:: abort(code)

flask/__init__.py

@@ -21,6 +21,7 @@
     send_file, send_from_directory, get_flashed_messages, \
     get_template_attribute, make_response
 from .globals import current_app, g, request, session, _request_ctx_stack
+from .ctx import has_request_context
 from .module import Module
 from .templating import render_template, render_template_string
 from .session import Session

flask/ctx.py

@@ -19,6 +19,38 @@ class _RequestGlobals(object):
     pass
 
 
+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 if you want to take advantage
+    of request information is it's available but fail silently if the request
+    object 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
+
+
 class _RequestContext(object):
     """The request context contains all request relevant information.  It is
     created at the beginning of the request and pushed to the

tests/flask_tests.py

@@ -89,6 +89,18 @@ def meh():
             assert meh() == 'http://localhost/meh'
         assert flask._request_ctx_stack.top is None
 
+    def test_context_test(self):
+        app = flask.Flask(__name__)
+        assert not flask.request
+        assert not flask.has_request_context()
+        ctx = app.test_request_context()
+        ctx.push()
+        try:
+            assert flask.request
+            assert flask.has_request_context()
+        finally:
+            ctx.pop()
+
     def test_manual_context_binding(self):
         app = flask.Flask(__name__)
         @app.route('/')