Spy++ for PowerBuilder applications

Question

I'm trying to write a tool which lets me inspect the state of a PowerBuilder-based application. What I'm thinking of is something like Spy++ (or, even nicer, 'Snoop' as it exists for .NET applications) which lets me inspect the object tree (and properties of objects) of some PowerBuilder-based GUI.

I did the same for ordinary (MFC-based) applications as well as .NET applications already, but unfortunately I never developed an application in PowerBuilder myself, so I'm generally thinking about two problems at this point:

1. Is there some API (preferably in Java or C/C++) available which lets one traverse the tree of visual objects of a PowerBuilder application? I read up a bit on the PowerBuilder Native Interface system, but it seems that this is meant to write PowerBuilder extensions in C/C++ which can then be called from the PowerBuilder script language, right?

2. If there is some API available - maybe PowerBuilder applications even expose some sort of IPC-enabled API which lets me inspect the state of a PowerBuilder object hierarchy without being within the process of the PowerBuilder application? Maybe there's an automation interface available, or something COM-based - or maybe something else?

Right now, my impression is that probably need to inject a DLL into the process of the PowerBuilder application and then gain access to the running PowerBuilder VM so that I can query it for the object tree. Some sort of IPC mechanism will then let me transport this information out of the PowerBuilder application's process.

Does anybody have some experience with this or can shed some light on whether anybody tried to do this already?

Best regards,

• Frerich

Answer 1

First, the easy answer: I think what you're trying to do has been done, sort of. Rex from Enable does what I think you're after, but IIRC from talking with the developers, it depends on code hooks built into the application.

Which leads to the suggestion that I don't think you'll be able to do what I think you're trying to do completely externally from the application. You can grab window handles with WinAPIs and do some basic things with that, but not as much as you want. And getting information about DataWindows with WinAPIs? Forget it.

I believe I've heard of an API like the one you're asking about, but I've never heard of anyone other that automated testing software tool manufacturers getting their hands on it. If this is true (and the quality of this information is along the lines of "heard it in the hallway"), I suspect there might be some application security issues in letting this get out. (I know you'd never want to infect my application, or poke around and find out my secrets. grin)

Even with hooks into the PowerBuilder VM memory space, I'm not aware of being able to get a list of objects in memory without some PowerScript framework hooks (e.g. populating a list on every open and constructor with object handles). Once you've got a window handle, you can easily traverse its control arrays (and its subclasses control arrays) to get a list of objects on the window, but things like handles to NVO instance variables would be problematic.

I admire the idea. I wish I had better news (other than maybe Rex might solve your problem without the headaches of doing it yourself). Now I'm looking forward even more to what eran may release! grin

Good luck,

Terry.