1. Introduction to Google App Engine (GAE) 2. GAE for Python 3. Using Static Files in GAE 4. Using Google User Service in GAE

1. Google App Engine (GAE)
Wei-Tsung Su (蘇維宗)
ellington.su@gmail.com
06/30/2014 (Ver. 1.0)
Ubiquitous Computing and Ambient Networking Laboratory 1

2. Change Log
Date Ver. Authors Description
6/30/2014 1.0 Wei-Tsung Su Google App Engine (GAE); GAE for Python; Using Static Files; Google User Service
Ubiquitous Computing and Ambient Networking Laboratory 2

3. What?
• Google Cloud Platform
– App Engine provides Platform as a Service (PaaS)
– Compute Engine provides Infrastrcture as a Servce (IaaS)
– CloudSQL, Cloud Storage, and Cloud Datastore provide storage options
– BigQuery and Hadoop provide big data processing capability
• Language supported by GAE
– Python, Java, PHP, and GO
– Different languages may provide different features.
Ubiquitous Computing and Ambient Networking Laboratory 3

4. Why?
• Easily deploy your web services to public
• Seamlessly integrate with other Google services
• Free quotas (https://developers.google.com/appengine/docs/quotas)
– Code & Static Data Store (1GB free)
– Google Cloud Storage (5GB free)
– Blobstore Stored Data (5GB free)
– API access (which depends on different Google API)
– ...
Ubiquitous Computing and Ambient Networking Laboratory 4

5. How?
• Read Support Documentation
– https://developers.google.com/appengine/
• Try Administration Console
– https://appengine.google.com/
– https://console.developers.google.com
• Download SDK
– https://developers.google.com/appengine/downloads
Start Your Engine
3, 2, 1
Ubiquitous Computing and Ambient Networking Laboratory 5

6. GAE for Python
Ubiquitous Computing and Ambient Networking Laboratory 6

7. Setup Development Environment
• Install Python 2.7
– https://www.python.org/download/releases/2.7.7/
• Install App Engine SDK for Python
– https://developers.google.com/appengine/downloads
– Ex. we assume that google_appengine/ is the SDK directory.
• Install Git (optional)
– http://git-scm.com/downloads
Ubiquitous Computing and Ambient Networking Laboratory 7

8. How GAE for Python Works
• A Python web app interacts with the App Engine web server using
Web Server Gateway Interface (WSGI) protocol.
• WSGI-compatible web application frameworks, such as
– webapp2 (by default, simple)
– Django
– CherryPy
– Pylons
– web.py
– web2py
Ubiquitous Computing and Ambient Networking Laboratory 8

9. Project Structure of GAE for Python
• Modules
– Dynamic web page generation
– http://webapp-improved.appspot.com/
– Filename: xxx.py (ex. helloword.py)
• Configuration File
– Project configuration
– Routing requests to modules
– https://developers.google.com/appengine/docs/python/config/appconfig
– Filename: app.yaml (壓謀!)
• Ex. we assume that helloworld/ is the project directory
Ubiquitous Computing and Ambient Networking Laboratory 9

10. Module: helloworld. py
• import webapp2
class MainPage(webapp2.RequestHandler):
def get(self):
self.response.headers['Content-Type'] = 'text/ html'
self.response.write('Hello, World!')
app = webapp2.WSGIApplication([
('/', MainPage),
], debug=True)
• For security issue, you should disable debug which will display a
stack trace in the browser when a handler raises an exception.
Ubiquitous Computing and Ambient Networking Laboratory 10

11. Configuration File: app.yaml
• application: your-app-id
version: 1
runtime: python27
api_version: 1
threadsafe: true
handlers:
- url: /.*
script: helloworld.app
• How to test your project locally
– # google_appengine/dev_appserver.py helloworld/
– Test your web app by visiting the URL: http://localhost:8080
Ubiquitous Computing and Ambient Networking Laboratory 11

12. Hello, World!
Ubiquitous Computing and Ambient Networking Laboratory 12

13. Using Static Files
• Sometimes, you may put static files, such images, CSS stylesheets,
JavaScript code, and so on, into your web applications.
• For example,
– <img src="/images/logo.png" >
• Unfortunately, you cannot just
create a directory and put the
static files into the directory.
• You also need to add route into
con figuration file: app.yaml
– - url: /images
static_dir: images
Ubiquitous Computing and Ambient Networking Laboratory 13

14. Google User Service
• Google user service (https://developers.google.com/appengine/docs/python/users/)
• Import user service module
– from google.appengine.api import users
• Get current user
– user = users.get_current_user() # Google Account, Google Apps Account, OpenID
• Access user information
– user.nickname()
– user.email()
– user.user_id()
• Administrator check
– user.is_current_user_admin()
• Create login/logout pages
– users.create_login_url('[destination URL]')
– users.create_logout_url('[destination URL]')
Ubiquitous Computing and Ambient Networking Laboratory 14

15. Google User Service - Example
• from google.appengine.api import users
import webapp2
class MainPage(webapp2.RequestHandler):
def get(self):
user = users.get_current_user()
if user:
self.response.headers['Content-Type'] = 'text/ html'
self.response.write('Hello, World, %s!<br>', %(user.nickname()))
self.response.write('<a href="%s">Sign Out</a>'
% users.create_logout_url(self.request.url))
else:
self.redirect(users.create_login_url(self.request.url) )
app = webapp2.WSGIApplication([
('/', MainPage),
], debug=True)
Ubiquitous Computing and Ambient Networking Laboratory 15

16. Hello, World, User!
Ubiquitous Computing and Ambient Networking Laboratory 16

17. Deploy Your Application
• Step 1: Create Project in Developer Console
– https://console.developers.google.com
– You will get a random project id (Ex. your-app-id).
– The public URL of your web application will be
• http://your-app-id.appspot.com
• Step 2: Check if the application ID in app.yaml matches your-app-id
– application: your-app-id
• Step 3: Deploy your local project
– #google_appengine/appcfg.py update helloworld/
– Test your web app by visiting the URL: http://your-app-id.appspot.com
Ubiquitous Computing and Ambient Networking Laboratory 17

18. Q&A
You can clone the sample code by
git clone https://github.com/ucanlab/gae_python_basic_helloworld.git
or visiting
https://github.com/ucanlab/gae_python_basic_helloworld
Ubiquitous Computing and Ambient Networking Laboratory 18