Update Google App Engine example. Thanks @jeunito!

examples/appengine/app.yaml

@@ -1,8 +1,13 @@
-application: facebook-example
+application: facebook-example-py27
 version: 1
-runtime: python
+runtime: python27
 api_version: 1
+threadsafe: true
 
 handlers:
 - url: /.*
-  script: example.py
+  script: example.app
+
+libraries:
+- name: jinja2
+  version: latest

examples/appengine/example.html

@@ -18,7 +18,7 @@
 	    <div>
 	    Upload photo test: 
 		   <form method="post">
-		   Enter URL to URLFecth from:<input type="text" name="url"/>
+		   Enter URL to URLFetch from:<input type="text" name="url"/>
 		   <input type="submit"/>
 		   </form>
 	    </div>
@@ -28,7 +28,7 @@
         FB.init({appId: '{{ facebook_app_id }}', status: true, cookie: true,
                  xfbml: true});
         FB.Event.subscribe('{% if current_user %}auth.logout{% else %}auth.login{% endif %}', function(response) {
-          window.location.reload();
+          {% if current_user %} window.location = "/logout" {% else %} window.location.reload(); {% endif %}
         });
       };
       (function() {

examples/appengine/example.py

@@ -16,24 +16,31 @@
 
 """
 A barebones AppEngine application that uses Facebook for login.
-Make sure you add a copy of facebook.py (from python-sdk/src/) into this
-directory so it can be imported.
-"""
 
+1.  Make sure you add a copy of facebook.py (from python-sdk/src/)
+    into this directory so it can be imported.
+2.  Don't forget to tick Login With Facebook on your facebook app's
+    dashboard and place the app's url wherever it is hosted
+3.  Place a random, unguessable string as a session secret below in
+    config dict.
+4.  Fill app id and app secret.
+5.  Change the application name in app.yaml.
+
+"""
 FACEBOOK_APP_ID = "your app id"
 FACEBOOK_APP_SECRET = "your app secret"
 
 import facebook
-import os.path
-import wsgiref.handlers
-import logging
+import webapp2
+import os
+import jinja2
 import urllib2
 
 from google.appengine.ext import db
-from google.appengine.ext import webapp
-from google.appengine.ext.webapp import util
-from google.appengine.ext.webapp import template
-from google.appengine.api.urlfetch import fetch
+from webapp2_extras import sessions
+
+config = {}
+config['webapp2_extras.sessions'] = dict(secret_key='')
 
 
 class User(db.Model):
@@ -45,7 +52,7 @@ class User(db.Model):
     access_token = db.StringProperty(required=True)
 
 
-class BaseHandler(webapp.RequestHandler):
+class BaseHandler(webapp2.RequestHandler):
     """Provides access to the active Facebook user in self.current_user
 
     The property is lazy-loaded on first access, using the cookie saved
@@ -55,48 +62,99 @@ class BaseHandler(webapp.RequestHandler):
     """
     @property
     def current_user(self):
-        if not hasattr(self, "_current_user"):
-            self._current_user = None
-            cookie = facebook.get_user_from_cookie(
-                self.request.cookies, FACEBOOK_APP_ID, FACEBOOK_APP_SECRET)
+        if self.session.get("user"):
+            # User is logged in
+            return self.session.get("user")
+        else:
+            # Either used just logged in or just saw the first page
+            # We'll see here
+            cookie = facebook.get_user_from_cookie(self.request.cookies,
+                                                   FACEBOOK_APP_ID,
+                                                   FACEBOOK_APP_SECRET)
             if cookie:
-                # Store a local instance of the user data so we don't need
-                # a round-trip to Facebook on every request
+                # Okay so user logged in.
+                # Now, check to see if existing user
                 user = User.get_by_key_name(cookie["uid"])
                 if not user:
+                    # Not an existing user so get user info
                     graph = facebook.GraphAPI(cookie["access_token"])
                     profile = graph.get_object("me")
-                    user = User(key_name=str(profile["id"]),
-                                id=str(profile["id"]),
-                                name=profile["name"],
-                                profile_url=profile["link"],
-                                access_token=cookie["access_token"])
+                    user = User(
+                        key_name=str(profile["id"]),
+                        id=str(profile["id"]),
+                        name=profile["name"],
+                        profile_url=profile["link"],
+                        access_token=cookie["access_token"]
+                    )
                     user.put()
                 elif user.access_token != cookie["access_token"]:
                     user.access_token = cookie["access_token"]
                     user.put()
-                self._current_user = user
-        return self._current_user
+                # User is now logged in
+                self.session["user"] = dict(
+                    name=user.name,
+                    profile_url=user.profile_url,
+                    id=user.id,
+                    access_token=user.access_token
+                )
+                return self.session.get("user")
+        return None
+
+    def dispatch(self):
+        """
+        This snippet of code is taken from the webapp2 framework documentation.
+        See more at
+        http://webapp-improved.appspot.com/api/webapp2_extras/sessions.html
+
+        """
+        self.session_store = sessions.get_store(request=self.request)
+        try:
+            webapp2.RequestHandler.dispatch(self)
+        finally:
+            self.session_store.save_sessions(self.response)
+
+    @webapp2.cached_property
+    def session(self):
+        """
+        This snippet of code is taken from the webapp2 framework documentation.
+        See more at
+        http://webapp-improved.appspot.com/api/webapp2_extras/sessions.html
+
+        """
+        return self.session_store.get_session()
 
 
 class HomeHandler(BaseHandler):
     def get(self):
-        path = os.path.join(os.path.dirname(__file__), "example.html")
-        args = dict(current_user=self.current_user,
-                    facebook_app_id=FACEBOOK_APP_ID)
-        self.response.out.write(template.render(path, args))
+        template = jinja_environment.get_template('example.html')
+        self.response.out.write(template.render(dict(
+            facebook_app_id=FACEBOOK_APP_ID,
+            current_user=self.current_user
+        )))
 
     def post(self):
         url = self.request.get('url')
         file = urllib2.urlopen(url)
-        graph = facebook.GraphAPI(self.current_user.access_token)
-        graph.put_photo(file, "Test Image")
+        graph = facebook.GraphAPI(self.current_user['access_token'])
+        response = graph.put_photo(file, "Test Image")
+        photo_url = ("http://www.facebook.com/"
+                     "photo.php?fbid={0}".format(response['id']))
+        self.redirect(str(photo_url))
+
 
+class LogoutHandler(BaseHandler):
+    def get(self):
+        if self.current_user is not None:
+            self.session['user'] = None
 
-def main():
-    logging.getLogger().setLevel(logging.DEBUG)
-    util.run_wsgi_app(webapp.WSGIApplication([(r"/", HomeHandler)]))
+        self.redirect('/')
 
+jinja_environment = jinja2.Environment(
+    loader=jinja2.FileSystemLoader(os.path.dirname(__file__))
+)
 
-if __name__ == "__main__":
-    main()
+app = webapp2.WSGIApplication(
+    [('/', HomeHandler), ('/logout', LogoutHandler)],
+    debug=True,
+    config=config
+)