Google App Engine (GAE) is an interesting foundation for running web applications. Running web applications on GAE, however, comes at a price: GAE applications are subject to Google's infrastructure. At first glance, GAE severely restricts your freedom to use the idioms that have been used for more than a decade, but most restrictions are there for good reason.

In this case study, Jakob Dam describes the design and implementation of a global wind sports mashup for wind- and kitesurfers based on GAE. The mashup utilizes global weather data, Google Maps, and a number of other web services. It is highlighted how GAE's restrictions change fundamental design principles, their effect on the resulting application, and how these restrictions are reflected in the application's design.

Keywords:GAE, mashup, geographical information systems, Geohash, REST