Re: Web Service

[web400@xxxxxxxxxxxxxxxx]

> I'm looking into a way to use an RPG program as a web service (server
> side). Is it as simple as creating a RPG-CGI program that receives xml
> formatted data and writes xml formatted data back to the browser or is
> there more to it?

Yes, it's that simple.  Or that complicated, depending on how you feel 
about parsing and generating XML!

> My understanding is that SOAP will be used to post xml formatted data to
> the web service and the web service will return xml formatted data.

Okay...  this leads to the questions "What is XML?" and "What is SOAP?".

XML is a language for creating markup languages.  By itself, the term XML 
is so broad you can drive an aircraft carrier through it.

SOAP is a specific markup language that was created from XML.  So 
technically, SOAP _is_ XML.

However, frequently when people refer to SOAP they're referring to 
toolkits that convert a virtual procedure call into XML, send it, receive 
the response and convert it back to look like the virtual procedure call. 
But, again, what they're doing in that case is trying to SIMPLIFY things 
(not complicate them) by making it so that you don't HAVE to do the XML 
creation and parsing.  The SOAP toolkit does it for you.

That's why I responded the way I did to the first question. :)

> All of the examples I have seen use SOAP and WSDL and none of the 
> examples I have seen call an RPG-CGI program.  I'm not opposed to using 
> SOAP and WDSL, but it is necessary in order for the RPG-CGI program to 
> be considered a web service?

You could parse the incoming SOAP message (using an XML parser) and get 
the data you need from it, then do your processing, and write out a new 
SOAP message (again, by writing out an XML message) and this would 
certainly be considered a web service.

Once you know what the SOAP messages need to look like, it'd be easy 
enough to hand-code the WSDL document so that other poeple would know how 
to format and send the SOAP messages.

What the SOAP toolkits and wizards and all the Java and .NET stuff that 
you see are doing is taking all of those steps for you, so that you don't 
have to do all of the XML parsing and generating.  If you consider them to 
be simple, then by all means do it manually! :)