The Dark Side of Web Services

[Guest.Visitor]

Joe wrote: " I tried to debug a Web Service but found it very difficult to dig through the complexities of the interface. The generated code that comes from WDSc is so dense that I was able to modify only one part of the application. " I have been able to walk thru the tutorials and generate the resources to make them work as described. But, I am having a heck of a time trying to determine how I can use them in a production application. I have the Stock Quote web service working using the client proxy that was generated in WDSc. So, now I have proven that the resources can be generated by WDSc. Can RPG somehow be used to be a web service consumer ? Or must Java be used. Can the Java methods generated by the web service be prototyped in an RPG to call them and invoke the web service ? I would ultimately like to use the UPS Online Tools to update the shipping rate in DB2 on the iSeries. WDSc gets me part of the way there. But, I'm still not sure how I tie it all together.

[J.Pluta]

The short answer is "Yes, RPG can be a consumer of web services." The long answer, though, is that it's far from simple to do so. Since web services (at least those generated by WDSC) rely on the SOAP protocol for communication, that means that any consumer will need to follow that protocol. And while the Java client code generated by WDSC hides you from all that complexity, there is no such wrapper for RPG. So you will have to write a standard sockets interface, but on top of that you will have to layer all the SOAP protocol. This is the part I have a problem with. The standard has gotten so complex that it's all but impossible for a normal programmer to actually interact with wizard-generated code. And thus, you are stuck using wizards on each end. And God forbid one side's wizard is not compatbile with the other side's wizard: since the code is all but unreadable, I don't know how you're going to identify an error. For now, at least, Web Services remains a good idea that has yet to see a good implementation. For the short term, I'd probably stick with something like XML-RPC, or a fixed-format messaging system. At least those I can interface to RPG and debug myself. Joe

[MCWebsite.Staff]

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