Added template_global, fixes #657

CHANGES

@@ -13,6 +13,8 @@ Release date to be decided.
   :ref:`upgrading-to-010` for more information.
 - Added ``template_test`` methods in addition to the already existing
   ``template_filter`` method family.
+- Added ``template_global`` methods in addition to the already existing
+  ``template_filter`` method family.
 - Set the content-length header for x-sendfile.
 - ``tojson`` filter now does not escape script blocks in HTML5 parsers.
 - Flask will now raise an error if you attempt to register a new function

flask/app.py

@@ -1165,6 +1165,38 @@ class Flask(_PackageBoundObject):
         self.jinja_env.tests[name or f.__name__] = f
 
 
+    @setupmethod
+    def template_global(self, name=None):
+        """A decorator that is used to register a custom template global function.
+        You can specify a name for the global function, otherwise the function
+        name will be used. Example::
+
+        @app.template_global()
+        def double(n):
+            return 2 * n
+
+        .. versionadded:: 0.10
+
+        :param name: the optional name of the global function, otherwise the
+        function name will be used.
+        """
+        def decorator(f):
+            self.add_template_global(f, name=name)
+            return f
+        return decorator
+
+    @setupmethod
+    def add_template_global(self, f, name=None):
+        """Register a custom template global function. Works exactly like the
+        :meth:`template_global` decorator.
+
+        .. versionadded:: 0.10
+
+        :param name: the optional name of the global function, otherwise the
+        function name will be used.
+        """
+        self.jinja_env.globals[name or f.__name__] = f
+
     @setupmethod
     def before_request(self, f):
         """Registers a function to run before each request."""

flask/blueprints.py

@@ -237,6 +237,34 @@ class Blueprint(_PackageBoundObject):
             state.app.jinja_env.tests[name or f.__name__] = f
         self.record_once(register_template)
 
+    def app_template_global(self, name=None):
+        """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):
+            self.add_app_template_global(f, name=name)
+            return f
+        return decorator
+
+    def add_app_template_global(self, f, name=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):
+            state.app.jinja_env.globals[name or f.__name__] = f
+        self.record_once(register_template)
+
     def before_request(self, f):
         """Like :meth:`Flask.before_request` but for a blueprint.  This function
         is only executed before each request that is handled by a function of

flask/testsuite/templating.py

@@ -256,6 +256,18 @@ class TemplatingTestCase(FlaskTestCase):
         rv = app.test_client().get('/')
         self.assert_('Success!' in rv.data)
 
+    def test_add_template_global(self):
+        app = flask.Flask(__name__)
+        @app.template_global()
+        def get_stuff():
+            return 42
+        self.assert_('get_stuff' in app.jinja_env.globals.keys())
+        self.assert_equal(app.jinja_env.globals['get_stuff'], get_stuff)
+        self.assert_(app.jinja_env.globals['get_stuff'](), 42)
+        with app.app_context():
+            rv = flask.render_template_string('{{ get_stuff() }}')
+            self.assert_equal(rv, '42')
+
     def test_custom_template_loader(self):
         class MyFlask(flask.Flask):
             def create_global_jinja_loader(self):