This is a presentation given by Chris Schalk and Dave Westwood at the FBMeetup in Palo Alto on Jan 20 2010.

1. Google App Engine and
Social Apps
Chris Schalk, Developer Advocate, Google
Ikai Lan, Developer Programs Engineer, Google
Dave Westwood, Creator of BuddyPoke
January 20, 2010

2. 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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3. Some App Engine Partners
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4. Gartner’s view on Cloud Computing
• 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
4 * Source: Yefim Natis, Gartner, AADI 2009

5. App Engine Platform Details
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6. Specialized services
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7. Language runtimes
Duke, the Java mascot
Copyright © Sun Microsystems Inc., all rights reserved.
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8. Ensuring Portability
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9. Extended Language support through JVM
• Java
• Scala
• JRuby (Ruby)
• Groovy
• Quercus (PHP)
• Rhino (JavaScript) Duke, the Java mascot
• Jython (Python)
Copyright © Sun Microsystems Inc., all rights reserved.
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10. Application management in the cloud
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11. App Engine Dashboard
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12. Development Tools for App Engine
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13. Google App Engine Launcher
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14. SDK Console
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15. Google Plugin for Eclipse
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16. Feature Roadmap
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17. 18+ months in review
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
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18. Demos!
• Dashboard
• AppLauncher
• Eclipse Plugin
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19. App Engine as a Social Platform
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20. 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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21. A social example: BuddyPoke
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22. A social example: BuddyPoke (on FaceBook)
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23. BuddyPoke Architecture at a glance
Main Functionality
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
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24. 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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25. 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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26. BuddyPoke User Data in GAE
Data models for user data
• 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 …
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27. Storing Unique Icons per User
On FB, a unique icon is generated for each poke/mood change.
These icons appear in the feed/wall.
• 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!
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28. 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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29. 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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30. 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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31. 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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32. code.google.com/appengine
twitter.com/cschalk
twitter.com/ikai
Thank you! twitter.com/app_engine
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