[#2842] Wrap Pylons requests in a Flask application context

On this particular branch this is needed so the common CKAN config
object can forward config options to the Flask app config object, but
this will be required anyway as more Flask features need to be available
during a Pylons request (see 62f55d2).

ckan/config/middleware/__init__.py

@@ -132,4 +132,13 @@ def __call__(self, environ, start_response):
 
         log.debug('Serving request via {0} app'.format(app_name))
         environ['ckan.app'] = app_name
-        return self.apps[app_name](environ, start_response)
+        if app_name == 'flask_app':
+            return self.apps[app_name](environ, start_response)
+        else:
+            # Although this request will be served by Pylons we still
+            # need an application context in order for the Flask URL
+            # builder to work and to be able to access the Flask config
+            flask_app = self.apps['flask_app']._wsgi_app
+
+            with flask_app.app_context():
+                return self.apps[app_name](environ, start_response)

ckan/config/middleware/flask_app.py

@@ -17,7 +17,7 @@ def make_flask_stack(conf, **app_conf):
     """ This has to pass the flask app through all the same middleware that
     Pylons used """
 
-    app = CKANFlask(__name__)
+    app = flask_app = CKANFlask(__name__)
 
     # Update Flask config with the CKAN values
     app.config.update(conf)
@@ -31,6 +31,9 @@ def hello_world():
     def hello_world_post():
         return 'Hello World, this was posted to Flask'
 
+    # Add a reference to the actual Flask app so it's easier to access
+    app._wsgi_app = flask_app
+
     return app