In the server-side architecture, messages arrive at a connector via some kind of transport, and are processed by one or more message handlers before being passed to the server implementation. If there is a return message, it passes through another chain of message handlers and out to the client through the same transport used for the incoming message. The message handler chains may or may not be symmetrical.

The transports shipped with HydraExpress are HTTP and HTTPS. These transports are configured in the file transports.xml on the server side and client-transports.xml on the client side. Configuring additional transports is a simple matter of adding an additional entry to these configuration files, and you can write and configure additional transports yourself.

Web service message handlers are equally configurable. The configuration files are <servicecontextname>_handlers.xml on the server side, and client-handlers.xml on the client side. In these files you can configure any number of message handlers and specify the order in which they should be applied to the incoming and outgoing messages.

For more information on configuring and creating transports and message handlers for Web services, see Chapter 14, SOAP Message Handlers.