Google Developers Blog: Using Google App Engine to power Web APIs

Using Google App Engine to power Web APIs

Monday, April 20, 2009

This post is part of the Who's @ Google I/O, a series of blog posts that give a closer look at developers who'll be speaking or demoing at Google I/O. Today's post is a guest post written by Steven Willmott of 3scale.

First we set up a standard App Engine account giving us the standard dashboard and deployment environment. This provides the runtime environment plus a range of tools to monitor the application - all useful to track resource usage which we'll need to worry about later.

The service itself in this case is a simple wrap of wrapping App Engine's available image manipulation features which provide standard image manipulation features, but it could easily be more complex.

Next up, the functionality is wrapped in a simple RESTful interface. There are multiple ways to do this, libraries such as the App Engine Rest Server and the Django rest interface or a port of the Ning-like REST interface can be used to do most of the heavy lifting. Gae-Rest for example includes indexes and memcache and other features to optimise response times on the API. These give the API standard GET, POST, PUT, DELETE operations we'll need to push images in and out of the application.

Finally, while we have the service ready to roll we still need a way for developers to access the service, manage their resource usage and track activity on the API. To do this we can use 3scale's API management platform which provides these features out of the box. Connection works using a standard python plugin and the system creates a configurable management portal for the service which handles signup keys, usage limits, traffic analysis and the documentation needed to support developers using the new API. For heavy users we can also add paid plans to cover any App Engine costs or make a small profit - check out the appspotimage portal here: