Web Service

A web service is any service that is available over the Internet, uses a standardized XML messaging system. Is not tiled to any one operating system or programming language, is self-describing via a common XML grammar and is discoverable via simple find mechanism.

There are several alternatives for XML messaging:

  1. XML-RPC (XML Remote Procedure Call)
  2. SOAP

There are two ways to see a Web Service architecture:

  • web service role:
    1. service provider
    2. service requester
    3. service registry
  • web service protocol stack:
    1. service transport – HTTP, SMTP, FTP – responsible for transport message between applications;
    2. XML Messaging – XML-RPC, SOAP, HTTP GET/POST – responsible for convert message in XML format;
    3. service description – WSDL – responsible for description of web service
    4. service discovery – UDDI – responsible for centralize services for a common registry and provide access to publisher