HydraExpress uses handlers internally, and they are also used extensively throughout its feature set to provide a high degree of flexibility. This chapter discusses the SOAP handlers that process SOAP messages, which may be either the client request or the server response.

HydraExpress's message handlers helps you build agile applications with pluggable message handlers that can be swapped in or out as needed. Using handlers allows you to decouple your application's components, giving you unlimited flexibility. In addition, handlers don't need to know about each other, so you can chain them in any order you wish, or even reuse them.

In HydraExpress, nearly everything that processes a message is a handler. Most generated client and server classes are handlers, and you can create customized handlers. For example, you could insert a handler that adds security information into the processing chain. Or you could add a handler that compresses the messages right before they are sent over the transport, thus decreasing network traffic.

You do not need to manipulate or create handlers yourself in order to use HydraExpress's basic features. However, if you wish to enhance the power of your service-oriented applications, you may create and chain your own handlers. This chapter discusses how to create and chain handlers for requests, transports, and responses.