The Google APIs Client Generator is an awesome tool that automates this process. It takes a service description and generates a complete client library:

https://code.google.com/p/google-apis-client-generator/

The service is defined in a platform-neutral discovery document, which can be used by any provider:

https://developers.google.com/discovery/v1/reference/apis

There are generators for Python, Java, .NET, Objective-C, PHP, Go, GWT, Node.js, Ruby, and others.