CASHMERE-int

Web Services

Dhanapalan Kulandai Vadivel, University of Osnabrück

Slides

Abstract

A Web Service is a method that is remotely callable across a network (such as a corporate intranet or the internet itself). Web services differ from traditional content-based internet services. The fundamental differences are:

• Content-based services serve up web pages (whether statically or dynamically generated) for human consumption.
• Web Services serve up data for computers.

SOAP stands for Simple Object Access Protocol. SOAP is a communication protocol that is used for communication between applications. SOAP is designed to communicate via Internet and is developed as a W3C standard.

SOAP is a simple and extensible messaging protocol based on XML. It defines a set of rules for structuring messages that can be used for simple one-way messaging but is particularly useful for performing RPC-style (Remote Procedure Call) request-response dialogues. It is not tied to any particular transport protocol. Also it is not tied to any particular operating system or programming language.

One significant advantage of SOAP being XML-based is that it is human readable and writable. This means you can easily read and process the messages that are going over the wire. This is extremely useful when debugging.

Structure of a SOAP message:

      <?xml version="1.0"?>
	<soap:Envelope
		xmlns:soap="http://www.w3.org/2001/12/soap-envelope"
		soap:encodingStyle="http://www.w3.org/2001/12/soap-encoding">
		<soap:Header>
			...
		</soap:Header>
		<soap:Body>
			...
			<soap:Fault>
				...
			</soap:Fault>
		</soap:Body>
	</soap:Envelope>
      

UDDI stands for Universal Description, Discovery and Integration. UDDI is a directory service for storing information about web services. UDDI is a directory of web service interfaces described by WSDL. UDDI communicates via SOAP.

The UDDI benefits are:

• Making it possible to discover the right business from the millions currently online.
• Defining how to enable commerce once the preferred business is discovered.
• Describing services and business processes programmatically in a single, open and secure environment.
• Reaching new customers and increasing access to current customers.