libURL gone mad

[Richard Gaskin]

My quest today began with a seemingly simple question:

If I have a button that gets data from a URL via libURL, how do I 
prevent a second request if the user double-clicks?

In this case we have too many entry points to disable and re-enable the 
controls that trigger URL access for that to be a practical option. 
Besides, occasionally libURL neither completes a URL request nor 
provides an error for it, so relying on disabling a control risks 
getting into a state where the control is disabled with no way to know 
to re-enable it.

In brief, sometimes GET or POST with libURL returns with no data in 
either "it" or "the result".

And looking through the forum and list archives, it seems I'm far from 
alone in this experience.

Then today I was working on this code in v8.1, when I encountered this 
new error message:

   tsneterr: Sync request already in progress

Hmmm...so now we need to rewrite the error handling for our URL code to 
account for new strings?  Good to know.

So....

Does anyone here have a handler which reliably accesses a URL while 
preventing re-entrant attempts until the first one completes?

The example Dave Cragg offers on his web site is:

  global gUrlBlocking
  on mouseUp
       put "http://www.xxxxxx.com/images/mykids1.jpg" into tUrl
       if gUrlBlocking is true then
         beep
       else
         put true into gUrlBlocking
         get url tUrl
         put false into gUrlBlocking
         if the result is empty then
           put it into image 1
         else
           answer the result
         end if
       end if
   end mouseUp
http://www.lacscentre.com/liburl/liburldoc.html#post

...but in practice I find libURL occasionally doesn't complete a 
request, nor provides any way of letting me know that, so gUrlBlocking 
never get cleared.

Who among us mortals has found a way to adequately handle error-checking 
in libURL with reliable consistency?

I imagine I'm missing something simple here.  Hoping that's the case, 
anyway.

Fingers crossed....looking forward to any reasonable tips for reliable 
URL access....

-- 
  Richard Gaskin
  Fourth World Systems
  Software Design and Development for the Desktop, Mobile, and the Web
  ____________________________________________________________________
  Ambassador at FourthWorld.com                http://www.FourthWorld.com