A web service enables a software application to work over the Internet. A programmer creates a web service and uploads it onto a web server and from then on the service is available for use. The server on which the service is residing is a web host. The web host will allow anyone to access the Web service, over the Internet.
A web service software application has a Web API using which other software applications communicate with it. When we say other applications, they can be a web application, windows applications or a mobile application. Services and web applications communicate with each other using XML, SOAP.
Commercial vendors refer to a webservice as “Software-as-a service”. when we use the software application as a pay and use service, then the service can be referred to as a SAAS. Programmers should remember that there are hundreds of implementations of webservices. One such implementation is integration of disparate heterogeneous software applications. How do these services work? Let us list some salient points.
A client application sends a SOAP request using HTTP to the web server. The client application can be from any client computer located any where in the world, with an internet connection. The service responds and fulfils its functionality and provides a service which is used by the client application.
When do we create a web service. There are many instances when we create a service. One common implementation is when we wish to integrate heterogeneous applications. We also create a web service when the Client Environment is not known.
When there is a need for Multichannel Client Formats we create a one. This is because, a web service works using XML, and XML can be transformed into any format.
A service represents the convergence of three main technologies, the web, XML and SOA.
To gain a better knowledge, one has to become familiar with answering the following questions. Working, When do we create, Why do we create, Technologies to create, Tools to create, How do we create a web service in Visual Studio.Net, Testing, Deploy, Consuming service by a client application and importantly When not to create one.