Web Service Related Technologies

SOAP Web Service Tutorials - Herong's Tutorial Examples

∟Web Service Related Technologies

This section describes a list of technologies that related to Web services.

There are several technologies that are related to Web services:

UDDI (Universal Description, Discovery and Integration) - A server acting like a Web service directory. Web services can be registered and discovered on a UDDI server.
WSDL (Web Services Description Language) - An XML based language to describe a Web service.
SOAP (Simple Object Access Protocol) - An XML based protocol used to define requests and responses for a Web service.
HTTP (Hyper-Text Transport Protocol) - An Internet communication protocol used by the World Wild Web system. HTTP are used to deliver Web service requests and responses.
XML (eXtensible Markup Language) - A markup language used to organize information in clear text format.

The following diagram is an illustration of how these technologies are used to deliver a Web service from a provider to a consumer:

                       Query for a service                             
Web service <-----------------------------------------> UDDI server 
consumer             Return provider location           |  
                                                        |
                                                        |
                Query for the service description       v        
Web service <-----------------------------------------> WSDL document
consumer            Return service description          server    
                                                        |
                                                        |
                Send service request (SOAP + HTTP)      v
Web service <-----------------------------------------> Web Service
consumer       Return service response (SOAP + HTTP)    provider

As you can see from this diagram, UDDI and WSDL are really optional. If you know the location and the description of a Web service, you don't need to query the UDDI server and fetch the WSDL document. All you need to do is to build a request in SOAP format, and sent it via HTTP to the provider.