SOA

In this post I continue a review of my last day in XML Training class. We briefly mentioned web services today. Web services run on a server. Clients communicate with the server via XML messages over the HTTP protocol. It is platform independent. The umbrella technology is referred to as Service Oriented Architecture (SOA).

There are three main components to SOA. There is a registry that lists all the service. Providers are the servers that implement the services. Finally requestors are the clients that look up needs in the registry, and communicate directly with the providers.

The registry information is provided in the Web Services Definition Language (WSDL). This acronym is pronounced wiz-dull. WSDL gives information on where the service is located, the format of the input messages, and the format of the output messages. The formatting information is given in XML Schema notation.

Web Service communication is done via messages in XML format. Furthermore these messages adhere to the Simple Object Access Protocol (SOAP). SOAP is a format which is some tags in XML which stipulate that the XML messages are enclosed in a SOAP envelope. The SOAP format is sent over the HTTP protocol.

There were a couple other miscellaneous topics covered in class such as Ajax and XML Security. I will defer these to a future post.