All the standard Web Services works using following components
- SOAP (Simple Object Access Protocol)
- UDDI (Universal Description, Discovery and Integration)
- WSDL (Web Services Description Language) All these components have been discussed in Web Services Architecture section.
XML-RPC is the easiest way to get started with web services and simplest XML based protocol for exchanging information between computers. XML-RPC is a simple protocol that uses XML messages to perform RPCs, requests are encoded in XML and sent via HTTP POST. All XML responses are platform-independent and embedded in the body of the HTTP response and also diverse applications to communicate. A Java client can speak XML-RPC to a Perl server.
SOAP is a simple and extensible communication protocol for exchanging information between computers and for communication between applications. It is a format for sending messages and designed to communicate via Internet. SOAP is platform independent and language independent. It allows you to get around firewalls and developed as a W3C standard.
WSDL is an XML-based language, pronounced as 'wiz-dull' and spelled out as 'W-S-D-L' for describing Web services and how to access them. WSDL stands for Web Services Description Language. WSDL is an XML based protocol is the standard format for describing a web service for information exchange in decentralized and distributed environments. WSDL is an integral part of UDDI, an XML-based worldwide business registry definition describes how to access a web service and what operations it will perform.
UDDI is platform independent, open framework XML-based standard for describing, publishing, and finding Web services and stands for Universal Description, Discovery and Integration. UDDI can communicate via SOAP, CORBA, and Java RMI Protocol and uses WSDL to describe interfaces to web services. UDDI is seen with SOAP and WSDL as one of the three foundation standards of web services.