Web Service

STANDARDS USED

or the older XML-RPC . The XML-RPC scheme ''calls functions'' remotely, whilst SOAP favours a more modern (object-oriented) approach based on the Command Pattern .

Common protocols: data can be transported between applications using any number of common protocols, such as HTTP , FTP , SMTP and XMPP .

WSDL : The public interface to the web service is described by Web Services Description Language, or WSDL. This is an XML-based service description on how to communicate using the web service.

UDDI : The web service information is published using this protocol. It should enable applications to look up web services information in order to determine whether to use them.

EbXML : A modular electronic business framework is enabled using this set of specifications. The vision of ebXML is to enable a global electronic marketplace where enterprises of any size and in any geographical location can meet and conduct business with each other through the exchange of XML-based messages.

standard. The standard allows authentication of actors and confidentiality of the messages sent.

WS-Management : This specification describes a SOAP-based protocol for systems management of personal computers, servers, devices, and other manageable hardware and Web services and other applications.

ADVANTAGES OF WEB SERVICES

Web services provide interoperability between various software applications running on disparate platforms.

Web services use open standards and protocols. Protocols and data formats are text-based where possible, making it easy for developers to comprehend.

By utilizing HTTP , web services can work through many common Firewall security measures without requiring changes to the firewall filtering rules. Other forms of RPC may more often be blocked.

Web services allow software and services from different companies and locations to be combined easily to provide an integrated service.

Web services allow the reuse of services and components within an infrastructure.

Web services are Loosely Coupled thereby facilitating a distributed approach to application integration.

DISADVANTAGES OF WEB SERVICES

Web services standards features such as Transaction s are currently nonexistent or still in their infancy compared to more mature Distributed Computing open standards such as CORBA . This is likely to be a temporary disadvantage as most vendors have committed to the OASIS standards to implement the Quality of Service aspects of their products.

Web services may suffer from poor Performance compared to other distributed computing approaches such as RMI , CORBA , or DCOM . This is a common trade-off when choosing text-based formats. XML explicitly does not count among its design goals either conciseness of encoding or Efficiency of Parsing . This could change with the XML Infoset standard, which describes XML-based languages in terms of abstractions (elements, attributes, logical nesting). The traditional angle-bracket representation is now seen as an ASCII (or Unicode ) Serialisation of XML, not XML itself. In this model, binary serialisation is an equally valid alternative. Binary representations such as SOAP MTOM promise to improve the wire efficiency of XML messaging.