Chris Schalk, Developer Advocate, Google Ikai Lan, Developer Programs Engineer, Google Dave Westwood, Creator of BuddyPoke
January 20, 2010
Google App Engine and Social Apps
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Google App Engine
• Easy to build
• Easy to maintain
• Easy to scale
Leveraging Google’s platform to better serve your customers
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Some App Engine Partners
Gartner’s view on Cloud Computing
4 * Source: Yefim Natis, Gartner, AADI 2009
• Correctly sees App Engine as a “Platform as a Service”
• Just focus on the code, don’t worry about infrastructure • Application infrastructure • System infrastructure
• Rapid application deployment and change
• Fully delegated data center responsibility
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App Engine Platform Details
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Specialized services
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Language runtimes
Duke, the Java mascot Copyright © Sun Microsystems Inc., all rights reserved.
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Ensuring Portability
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Extended Language support through JVM
• Java • Scala • JRuby (Ruby) • Groovy • Quercus (PHP) • Rhino (JavaScript) • Jython (Python)
Duke, the Java mascot Copyright © Sun Microsystems Inc., all rights reserved.
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Application management in the cloud
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App Engine Dashboard
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Development Tools for App Engine
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Google App Engine Launcher
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SDK Console
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Google Plugin for Eclipse
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Feature Roadmap
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Apr 2008 Python launch
May 2008 Memcache, Images API
Jul 2008 Logs export
Aug 2008 Batch write/delete
Oct 2008 HTTPS support
Dec 2008 Status dashboard, quota details
Feb 2009 Billing, larger files
Apr 2009 Java launch, DB import, cron support, SDC
May 2009 Key-only queries
Jun 2009 Task queues
Aug 2009 Kindless queries
Sep 2009 XMPP
Oct 2009 Incoming Email
Dec 2009 Blobstore
18+ months in review
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• Dashboard • AppLauncher • Eclipse Plugin
Demos!
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App Engine as a Social Platform
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App Engine + Social Apps (mobile too!)
• App Engine works well as a backend server for Social Apps of all types – OpenSocial
• Tutorials, example code - “Building an OpenSocial App with Google App Engine”
• http://wiki.opensocial.org/index.php?title=Building_an_OpenSocial_App_with_Google_App_Engine
– Facebook • BuddyPoke
– Dave Westwood here to speak on his FB implementation of BuddyPoke on GAE
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A social example: BuddyPoke
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A social example: BuddyPoke (on FaceBook)
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BuddyPoke Architecture at a glance
Is an fbml application, with an embedded fb:swf to load the Flash swf file.
Services include:
• Save avatar appearance • Hug, Kiss, Poke a friend • Change mood • Create & Upload image to FB
Main Functionality
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BuddyPoke User Validation
• FB automatically passes fb_sig params to the fb:swf file
• Makes direct calls from the swf file to GAE for Avatar saving functionality (appearance, mood, etc).
• Pass the fb_sig params along with any http call to GAE
• GAE then uses fb_sig params to validate any calls from a user
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Making calls to FaceBook
• fb:swf will have a session key that can be used to make direct calls to Facebook, so a lot of the time you can just do requests straight from Flash -> facebook.
• This is great for things like loading user data, friend data, fql queries etc.
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BuddyPoke User Data in GAE
• Main ‘User’ data model • Used 99% of time • not indexed, no queries, use keys • key name based on FB id • fast performance
• Additional User info model • Stores additional user info • ex: install date • Is indexed, can be queried • Used less
• Additional models for: • Virtual currency, blobs for user icons …
Data models for user data
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Storing Unique Icons per User
• Each user has maximum of N icons to avoid using up too much datastore space.
• When a user does a hug, poke, changes mood etc, an icon is sent to GAE using multi-part message. The icon will overwrite the previous oldest icon in the datastore and return a unique icon url to use in the feed.
• Icons are mem-cached, so better performance & saves money!
On FB, a unique icon is generated for each poke/mood change. These icons appear in the feed/wall.
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Updating profile page FBML
• BuddyPoke has a box on the profile page. It contains fbml that shows icons for the last 4 activities.
• When you hug a friend it will update your profile page, and your friend's profile page. Facebook's servers can be very slow.. So rather than tie up App Engine I create a facebook batch request, sign it on App Engine, and then pass it back to the Flash swf client.
• The client then makes the call to FaceBook's servers with the signed request to update the profile data.
• For OpenSocial, I'd just make the calls directly from App Engine to an OpenSocial server. But if you have 4+ operations to do on facebook those calls can take a long time, so I just get the Flash client to send the request and do all the waiting.
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Updating profile page FBML, cont.
So let's say I wanted to update 20 images on facebook's image caching servers I'd sign a request on App Engine using something like:
def sig_batch_refreshImgSrc(self, urls, call_id): methods = [] for url in urls: sig_param = {} sig_param['url'] = url sig_param['call_id'] = str(call_id) call_id = call_id+1 self._build_post_args("facebook.fbml.refreshImgSrc", sig_param) methods.append(urllib.urlencode(sig_param)) batch_param = {} batch_param['method_feed'] = json.write(methods, True) batch_param['call_id'] = str(call_id) self._build_post_args("facebook.batch.run", batch_param) return '"run":%s' % json.write(batch_param, True)
Then I'd pass that back to the Flash client, and the Flash client can send the request and sit their waiting for 10 seconds while FaceBook forces the image refresh.
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Payments using Paypal
I have Paypal hit App Engine any time there is a new transaction. Paypal will pass a bunch of params, you then ping Paypals server with a _notify-validate using a urlfetch to verify the params came from paypal.
if self.request.get('payment_status') == 'Completed': parameters = self.request.POST.copy() if parameters: parameters['cmd']='_notify-validate’ status = urlfetch.fetch(url = PP_URL, method = urlfetch.POST, payload = urllib.urlencode(parameters) ).content if status == "VERIFIED": ...
Then I'd pass that back to the Flash client, and the Flash client can send the request and sit their waiting for 10 seconds while FaceBook forces the image refresh.
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Communicating with via Email
“Use the email API to send yourself messages about anything important.
Very soon, with the FaceBook changes, I expect I'll be using the email API a lot more.
And the beauty of App Engine is I can just pay for as much email quota as I need. No hassles setting up email servers..”
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Thank you!
code.google.com/appengine
twitter.com/cschalk twitter.com/ikai twitter.com/app_engine
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