Web service

A Web Service is a string-based service (i.e. functionality) provided over
the Internet, usually in a data language, meant as communication between
computer software.

EDI was a precursor to web services, and is relatively difficult and
expensive to implement, but reputedly reliable.

The World Wide Web Consortium has recognized that web services are an
integral part of their work with XML and related technologies, and have
several working groups appointed to the subject.

Characteristics

   * The communication between Web services are implemented in one of the
     standard Internet Protocols. The most common Protocol is HTTP, but
     others like EMail and FTP are possible.
   * XML is used for all communication purposes- for metadata WSDL is one of
     the more common formats, for data itself Simple Object Access Protocol
     (SOAP) is dominant.
   * On top of those protocols sits another layer, which is in the process
     of being standardized. These protocols are embedded in SOAP and deal
     with transactions, security and relating of messages.

Protocols defined within the XML framework include the XML-RPC protocol for
simple web services, and the SOAP and WSDL protocols for both simple and
more complex web services. UDDI is for directories of services and RSS (Rich
Site Summary) is an example of a very simple Web service. The composition of
Web Services can be described by WSFL or the new BPEL4WS.

The use of SOAP implies that the peers in a Web service application will be
using object-oriented programming or component-oriented programming paradigms.

Advantages of Web Services

The main reason as to why Web Services are used seem to be that they rely on
HTTP over TCP port 80. To understand this, keep in mind that many
enterprises have protected themselves (see computer security) using
firewalls, that filter and block much Internet traffic for security reasons.
In this milieu, typically many ports, almost all, are closed to incoming and
outgoing traffic, and the administrators of these firewalls are not eager to
open them up to any traffic. However port 80 is always open, as it is used
for web browsers, and thus, Web Services are appealing as they tunnel
everything through port 80.

Another reason may be that prior to SOAP there were not really good
interfaces to accessing functionality on different computers on a network,
most of them were ad hoc and few people knew or could handle EDI, RPC and
similar APIs. Web Services may have more solid frameworks and are thus
easier to use.

Platforms

Web services usually run on dedicated computers called application servers.
There are a few brands of these:

   * Websphere Application Server from IBM (based on the Apache server and
     the J2EE platform)
   * WebLogic Application Server from BEA
   * Microsoft .NET servers from Microsoft
   * Axis and the Jakarta-Tomcat server (both at the Apache project)
   * ColdFusion MX from Macromedia

How to - Physics - History - Companies - Internet - Video Games - List of Phobias - September 11, 2001
Radio - Timelines - Chemistry - Genealogy - Family - Film - SARS - Cancer - Medicine - DVD - Calendar
Countries - Disease - Health Science - Dentistry - Economics - AIDS - Law - Autism - Statistics - Bible
Recipes - Architecture - Computers - History of the Internet - Personal computer - Apple Macintosh
War - Presidents of the United States - United States Constitution - Universe - Philosophy - Animals
Biology - United States Constitution - Marketing Topics - Sports - Television - History of Computing

Debt Help - Free Credit Report - Mortgages - Loans - Cheap Flights