Web Services Essentials

Scenario 1: Glue Code with XML-RPC

As distributed systems have become more and more common (by design or by accident), developers have had to address integration problems more and more frequently. Systems that originally ran their own show have to work with other systems as organizations try to rationalize their information management and reduce duplication. This often means that Unix systems need to speak with Windows, which needs to speak with Linux, which needs to speak with mainframes. A lot of programmers have spent a lot of time building custom protocols and formats to let different systems speak to each other.

Instead of creating custom systems that need extensive testing, documentation, and debugging, developers can use XML-RPC to connect programs running on different systems and environments. Using this approach, developers can use existing APIs and add connections to those APIs as necessary. Some problems can be solved with a single procedure, while others require more complex interactions, but the overall approach is much like developing any other set of interfaces. In glue code situations, the distinction between client and server isn’t especially significant—the terms only identify the program making the request and the program responding. The same program may have both client and server implementations, allowing it to use XML-RPC for both incoming and outgoing requests.