Re: Web Service -- WEB400

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 feelabout 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 XMLis so broad you can drive an aircraft carrier through it.

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

However, frequently when people refer to SOAP they're referring totoolkits that convert a virtual procedure call into XML, send it, receivethe 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 XMLcreation 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 theexamples I have seen call an RPG-CGI program. I'm not opposed to usingSOAP and WDSL, but it is necessary in order for the RPG-CGI program tobe considered a web service?

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

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

What the SOAP toolkits and wizards and all the Java and .NET stuff thatyou see are doing is taking all of those steps for you, so that you don'thave to do all of the XML parsing and generating. If you consider them tobe simple, then by all means do it manually! :)