An Introduction to SOAP (Simple Object Access Protocol)

Have you ever thought if it was possible to be able to transfer data between two servers without having to open too many ports on the firewall? Yes, it is possible with the help of the latest development that comes from the World Wide Web Consortium and Microsoft called SOAP. SOAP is a new protocol that is already creating waves in the world of distributed computing.

The word SOAP stands for Simple Object Access Protocol. SOAP was originally developed by Microsoft, IBM, DevelopMentor and UserLand Software and was then recommended by Internet Engineering Task Force (IETF). SOAP is used to communicate between applications via HTTP using XML or extensible Markup Language. Soap is a protocol that is neither a distributed object system nor an RPC system or even a Web application, but a messaging format for machine-to-machine construction. Soap applications communicate with each other over the internet.

Some of the features worth noting are:

--Uses standard internet HTTP.
--Uses XML to send and receive messages.
--Platform independent
--Language independent
--A protocol for exchanging information in a decentralized and distributed environment
--Soap happens to be one of the key features of Microsoft's .Net Architecture especially, Web Services.

What is SOAP?

SOAP stands for Simple Object Access Protocol
SOAP is a communication protocol
SOAP is for communication between applications
SOAP is a format for sending messages
SOAP is designed to communicate via Internet
SOAP is platform independent
SOAP is language independent
SOAP is based on XML
SOAP is simple and extensible
SOAP allows you to get around firewalls
SOAP will be developed as a W3C standard

How is Soap different from other RPCs?

There are other RPC (Remote Procedure Calls) style protocols that help in communication between applications like DCOM (Distributed component object model), IIOP (Internet Inter Orb Protocol) and RMI (Remote Method Invocations). The advantages of Soap over these protocols are that Soap uses XML and is text based, whereas the others are dependent on object-model-specific protocols. Moreover they are not adaptable to the internet whereas Soap uses HTTP protocol.

Where is SOAP used?

One of the most important uses of SOAP is to help enable XML Web Services. A web Service is an application provided as a service on the web. They are functional software components that can be accessed over the Internet. Web Services combines the best of component-based development and are based on Internet Standards that supports communication over the net.