1. Introduction To
Google
app engine

2. About speaker
Speaker: NAGA ROHIT S
COnTACT: snagarohit@gmail.com
education: Final Year Under Graudate,
Department of CSE,
Indian Institute of Technology Guwahati
Experience: The speaker has explored about an year
developing applications on Google App
Engine.

3. What we will learn today
• Why Cloud ?
• Platform as a Service
• Who are in the race ?
• Why Google App Engine is the Ge3k’s choice ?
• Languages Supported
• Getting Started
• Hello World App
• Frameworks
• Webapp Framework
• Users API
• Handling GET & POST
• Guest Book App
• What’s Next ?
• BigTable
• GQL (Not SQL)
INTRODUCTION
• Static Content
• Templates & Stuff
• Creating & Uploading Your Application
• Problems with IITG Proxy
• Problems Patched 

4. Why cloud ?
• Scalability
• Redundancy
• Security
• High Initial Investment
• Pay As You Grow
• Pay only for What You Use
•…
• Cloud is the future of Internet

5. Platform as a service

6. Who are in the race ?
• Microsoft Azure  (not free)
• Amazon AWS  (free + meh! :P)
• Google App Engine  (free + awesome)
•…
•…

7. Languages supported
• PYTHON [2.5 + 2.7]
• GO [EXPERIMENTAL]
• JAVA [JAVA 6 JVM]

8. Getting started
• Minimum Requirements
• Python 2.5+
• Linux (Windows Fan? Sorry, You are alone )
•Download App Engine SDK
https://developers.google.com/appengine/downloads
[Google App Engine SDK for Python]
• Extract SDK
• cd to google_appengine
• Lock and Load!

9. Hello world app
• Inside the google_appengine directory, create a
directory with the name helloworld
• Create a file named helloworld.py inside
helloworld directory.
google_appengine/helloworld/helloworld.py:
HTTP Header.
Never mind! Just accept that you
need to write this line when you want
to print to the client’s browser
This actually goes to the browser

10. Hello world app
• App engine application has a configuration file
called app.yaml which tells the app engine
about the application being developed and its
configuration.
• Create a file app.yaml in the helloworld
directory.
• Wait! What is YAML ?
• YAML Ain’t Markup Language
• Yet Another Markup Language
In short, it’s a more human readable form of
data storage.

11. Hello world app
google_appengine/helloworld/app.yaml:
Application Identifier
Version of the Application you are building
Python/Java/Go/whatever
Google API version that this application
is built on. Basically this is for supporting
legacy applications in case APIs change
Handles every request of
http://localhost/<AnyJunkHere>
The script which needs to be run for
the above handle match

12. Hello world app
• Summarizing,
google_appengine/helloworld/
• helloworld.py
• app.yaml
• Now, RUN!
$ ~/google_appengine/dev_appserver.py helloworld/
Starts the server by default on Folder in which the app.yaml
port 8080. Can be changed by file for helloworld application resides
command line options

13. Voila! It works!
• In your browser, type:
http://localhost:8080 ⏎

14. Framework support
• Supports any Python-CGI Framework including
• Django
• CherryPy
• Pylons
• Web2Py
• Natively supports webapp Framework.

15. Webapp framework
google_appengine/helloworld/helloworld.py: Import webapp and
run_wsgi_app modules
Set Headers
HTTP Get Request Print this to browser
URL Match
Handling Class

16. Voila! It works!
• In your browser, type:
http://localhost:8080 ⏎

17. USERS API
• Users API uses Google Accounts Sign-In
google_appengine/helloworld/helloworld.py:
Import users module
If user signs himself using Google Accounts
to your web site, do the following
Otherwise, redirect to Sign-In/Sign-Up powered by Google Accounts

18. Voila! It works!
• In your browser, type:
http://localhost:8080 ⏎

19. Guest book app (hadnling forms)
google_appengine/helloworld/helloworld.py:
Good Ol’ HTTP Form that POSTs to
http://localhost:8080/sign page
http://localhost:8080/sign
is handled by Guestbook class

20. Voila! It works!
• In your browser, type:
http://localhost:8080 ⏎

21. What’s next ?
• Using DataStore
• Using GQL
Explore!
• Using Templates
• Using Static Files in App Engine
• Uploading Your Application

22. Uploading application
• We use appcfg.py for application deploying
• Create and Manage your application at
https://appengine.google.com/
• Click “Create Application”
• Follow the instructions and create an Application
ID
• Application ID is unique throughout App Engine!

23. Uploading application
• Edit app.yaml file from your helloworld directory
and change the value of “application:” setting
from “helloworld” to your registered ID
• Now, RUN!
$ ~/google_appengine/appcfg.py update helloworld/
• If you setup a free *.appspot.com domain name,
the URL of your application begins with the
application ID.
http://your_app_id.appspot.com

24. Is that it ?
• That’s all ?
NO

25. problems
• App Engine SDK doesn’t work with Proxy!!

• So, basically, your time is wasted in hearing this
lecture!

26. solution
• Kidding!
• I have patched an SDK. I will inform you shortly
about its download link 

27. questions

28. Thanks
Drop me a mail at
snagarohit@gmail.com