SOAP Basic

SOAP is acronym for Simple Object Access Protocol.

A SOAP method is an HTTP request/response that complies with the SOAP encoding rules.

Basically, SOAP = HTTP + XML

A SOAP request could be an HTTP POST or an HTTP GET request.

The HTTP POST request specifies at least two HTTP headers: Content-Type and Content-Length.

SOAP sends XML request to SOAP server over HTTP and receives the response back in XML. Since HTTP is the de facto mode of communication in Internet and all the web servers recognize and respond to HTTP request, it is an ideal protocol to use to enable integration of various systems. XML is emerging as a de facto standard to exchange information over disparate systems. SOAP's use of XML to send/receive message enables any system on any platform to read and process the message, unlike any proprietary format.

As SOAP uses XML over HTTP to communicate, it offers true distributed component support. The client and server can have different operating systems, run on different kind of machines and network.

Web Services

Web services can convert your applications into web-applications. They are application components and communicate using open protocols. It is self-contained and self-describing. Thus, with Web services, your accounting department's Win 2k server's billing system can connect with your IT supplier's UNIX server.

Web services can be discovered using UDDI and can be used by other applications

XML is the basis for Web services. By using XML, messages can be sent between applications. Web services use XML to code and to decode data, and SOAP to transport it (using open protocols).

WSDL

WSDL stands for Web Service Description Language. WSDL is an XML-based language for describing Web services and how to access them. For each operation, WSDL will define the schema for request and response XML string.

WSDL describes a web service, along with the message format and protocol details for the web service.

WSML

Web Service Meta Language maps a web service operation to a COM component's method.

Overall process of SOAP request

Client side

SOAP Client will initiate the process by making a SOAP request. In this process, client will refer the WSDL file which resides in the SOAP server, to form a valid SOAP request. Client will send the request to the SOAP server using HTTP.

Server side

SOAP Listener will receive the SOAP request from the client. Theoretically, Listener can be any server side CGI that can process HTTP request. Listener will make sure the request adheres to the schema defined in WSDL. Once the request is validated, listener will communicate with backend system if required. The result from the communication will be packaged into SOAP XML response in accordance with the scheme defined in WSDL.

Client side

Client will receive the SOAP response. Client can unpack the SOAP response and read the result.

Comments

Popular Posts