In this chapter, we introduced some of the basic web services concepts so that you could get acquainted with these technologies before using them to enhance your ticket application.

Then, we went through SOAP-based web services that are based on a contract between the service and client defined by the WSDL file. SOAP web services are an excellent option to integrate systems when you have well-defined, abstract operations exposed using standard XML files.

Then, we discussed REST services. The key to the REST methodology is to write web services using an interface that is already well known and widely used: the URI. The twist here is to identify the key system resources (this can be entities, collections, or anything else the designer thinks is worthy of having its own URI) and expose them using standard methods that are mapped to standard methods. In this case, the HTTP verbs are mapped to resource-specific semantics.

We created two applications that use our REST API: one console-based...