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difference b/w web service and XML/HTTP


2005-07-13 02:50:35 AM
delphi115
I'm a web services newbie and am trying to understand the difference between
a SOAP web service and XML-over-http.
What does a SOAP web service do versus sending an XML package using an http
POST to an ISAPI dll for example?
 
 

Re:difference b/w web service and XML/HTTP

I'll try and explain this as best I can.
SOAP essentially is sending XML over HTTP, except that with SOAP you're
sending a specifically structured XML document, as pre-defined in the SOAP
protocol. It is designed to handle standard data types, as well as more
complex data types, and is also designed to deal with error handling too.
If you have an ISAPI DLL and you send XML requests to it, then that is fine
and it is essentially achieving the same end goal. However, you are going to
have to come up with your own XML document schema so that it is consistent
every time, one for the request and one for the response. Your DLL will have
to deconstruct the XML request to figure out what is being asked for, and
will have to build up the XML response to return the result.
SOAP simply does all that hard work for you. Plus you get the added bonus of
WSDL, which explains to any one coming to use the web service how to use it,
what the types are and what functions can be called via the web service,
with what parameters.
HTH,
J.
Jason Sweby
Software Developer,
Carval Computing Limited
Plymouth, UK
"larry" <XXXX@XXXXX.COM>writes
Quote
I'm a web services newbie and am trying to understand the difference
between
a SOAP web service and XML-over-http.

What does a SOAP web service do versus sending an XML package using an
http
POST to an ISAPI dll for example?