Web Services: Overview

Description
Description

What is it

Method do communicate between two end points over the network running on different applications independently of the platform, object model, or language used for implementation and
where interaction between systems is achived through the use of standard technologies and protocols.

Other systems interact with the Web service in a manner prescribed by its description using messages, typically transmited using HTTP with an XML serialization in conjunction with other Web-related standards.

Categories of web services

Two categories of web services can be considered:

1) Representational state transfer (ReST)

This category of web services follows the ReST architecture: The web service interface
is constrained to the use of the HTTP protocol and the HTTP methods.

The input data is sent within the request (POST and PUT methods) or parameterized within the query string of the URL (GET and DELETE methods).

The input and output data normally both formatted as plain text, XML or JSON.
The description of ReST web services can be found HERE.

2) Major  web services

This category of web services use XML messages that follow the SOAP standard
as the service interface, which includes the input and output well-formatted data and embbeded within the SOAP message (called the SOAP envelope).

The service interface is described using machine-readable description language (WSDL).

The Web Services Description Language (WSDL) is the language used to describes the interface of the service in a machine-readable manner

How to implement

The .NET framework provides two methodologies for deploying web services, namelly:

  • ASP.NET Web Services (available from version 1.0), where
  1. Exchange of messages is carried using SOAP over HTTP transport protocol only.
  2. Services can only be hosted on IIS;
  3. The structure of the messages include basic or complex types and are defined using a XML schema;
  • WFC Services (available from version 3.0), where
  1. Exchange of messages is carried using any format – SOAP as default – over any transport protocol including HTTP, TCP/IP, MSMQ, Named Pipes, etc
  2. Services can be hosted not only in IIS but also in any type of application that include NET domain, namelly a Windows Service, WinForms application, and a Console application
  3. The structure of the messages include basic or complex types and are defined using a XML schema
Help

Refer to these articles for description of how to develop ASP.NET Web Services

Refer to these articles for description of how to develop ReST Web Services as HTTP requests

Refer to these articles for description of how to develop WCF Web Services

Refer to these articles for description of how to develop WCF ReST Web Services