Question

I’m reading a book about programming ASP.NET in C#. The book makes the following comment:

Previous editions of this book tackled web services, a feature that allows you to create code routines that can be called by other applications over the Internet.Web services are more interesting when
considering rich client development (because they allow you to give web features to ordinary desktop
applications),and they’re in the process of being replaced by a new technology known as WCF (Windows
Communication Foundation). For those reasons, web services aren’t covered in this book.However,if you
want to branch out and explore the web service world,you can download the web service chapters from the
previous edition of this book from the book’s download page.The information in these chapters still applies
to ASP.NET 3.5,because the web service feature hasn’t changed.

Can someone offer, in “layman’s terms” what exactly a web service is and if, indeed, they are being replaced, at least in .Net, with WCF? What would be a practical example of a web service? Are they stand alone programs that run on a web server and are invoked by a client or clients?

Answer 1

Web Services, at a high level, are just like applications that run over the web. However there are a number of fairly sophisticated protocols and methods that constitute main-stream webservices:

1. SOAP (another link) and WSDL (another link) are the two grand-daddy acronyms that are significant in webservices, and they get a lot of press.
2. REST, and JSON are two other acronyms that are pretty important when thinking about webservices…
3. HTTP and TCP protocols are two of the most common transports that most webservices run on.

WCF is another layer of sophistication on these protocols and formats that Microsoft introduced. WCF gives flexible, configurable, debuggable infrastructure (plus much more) for writing and using web-services.