Web Services are the underpinning of Microsoft's .NET strategy. The concepts and the innovations behind this initiative have struck a chord with developer's building the next generation of Internet applications.
In this month's column, we're going to take a look at the features within ASP.NET to enable Web Services. Before we dig into the technical details let's start with an overview of Web Services.
Web Services Overview
A Web Service is programmable application logic accessible via standard Web protocols. One of these Web protocols is the Simple Object Access Protocol (SOAP). SOAP is a W3C submitted note (as of May 2000) that uses standards based technologies (XML for data description and HTTP for transport) to encode and transmit application data.
Consumers of a Web Service do not need to know anything about the platform, object model, or programming language used to implement the service; they only need to understand how to send and receive SOAP messages (HTTP and XML).
A SOAP message consists of several elements, most notably an envelope. The envelope encapsulates the data transmitted within the SOAP message. Below is a simple SOAP message complete with HTTP headers: