by Tien Loi Nguyen @ Multinc with guidance from Huy Zing BarCamp Saigon 1 November 15, 2008

echo-o The features of echo-o Application: Index page Speaker page Audience page Moderator page

The features of echo-o Application:

Index page

Speaker page

Audience page

Moderator page

echo-o Index page:

Index page:

echo-o Graph in speaker page:

Graph in speaker page:

echo-o Audience page:

Audience page:

echo-o Moderator page:

Moderator page:

Google app engine Google App Engine lets you run your web applications on Google's infrastructure easy to start easy to scale

Google App Engine lets you run your web applications on Google's infrastructure

easy to start

easy to scale

Prepare for developing app engine applications python 2.5 ( http://www.python.org/download/ ) google app engine SDK ( http://code.google.com/appengine/downloads.html )

python 2.5 ( http://www.python.org/download/ )

google app engine SDK ( http://code.google.com/appengine/downloads.html )

Hello World Create a configuration file called “app.yaml”

Create a configuration file called “app.yaml”

Hello World Create a script file called “helloworld.py”

Create a script file called “helloworld.py”

Hello World Run the application at localhost: Upload your application to google app engine:

Run the application at localhost:

Upload your application to google app engine:

Some notices Cannot join the tables(models) Cannot get more than 1000 results from a database Inequality filters are allowed on one property only Properties in inequality filters must be sorted before other sort orders GQL does not have an OR operator, but it has an IN operator

Cannot join the tables(models)

Cannot get more than 1000 results from a database

Inequality filters are allowed on one property only

Properties in inequality filters must be sorted before other sort orders

GQL does not have an OR operator, but it has an IN operator

Problems we ran into Server error

Server error

Problems we ran into Limited CPU quota

Limited CPU quota

Problems we ran into Problem: How to detect how many audiences are still alive Solution: Polling request every few seconds

Problem: How to detect how many audiences are still alive

Solution: Polling request every few seconds

http://multinc.com/ http://code.google.com/appengine/