Asynchronous upload via post?

[Dave Cragg]

On 12 Jun 2007, at 17:11, David Bovill wrote:

> You can load a url and you can do asynch ftp upload - but how about  
> if you
> want to send a large amount of data to a remote location without  
> using ftp?
> Can you do an "asynch post"? I guess you could do an asynch ftp  
> upload and
> then a quick sychronous post on completion - any thoughts?

If by "asynch" you mean keeping your application alive and running  
while the posts take place, it should be possible. The posts would  
occur sequentially, but your application should still be responsive  
during the transfers. Although "post" is described as "blocking" it  
only blocks the script it is called in. Other scripts can run at the  
same time.

The approach taken would depend on your circumstances, but the idea  
is to set up some "out of synch" psuedo thread to handle the posts.  
The simplest way to do this might be using a "send ... in time"  
message. You can use liburlSetStatusCallback to display progress if  
needed.

Rough idea (untested):

local postUrlQ
local asynchPostRunning = false

on someHandler
  ---code
  -- code
   asynchPost someUrl, someData
-- code
-- code
end someHandler

on asynchPost purl, pData
   put pUrl & return after postUrlQ
   if not asynchPostRunning then
     send asynchPostHandler to me in 0 milliseconds
   end if
end asynchPost pUrl

on asynchPostHandler
   if not asynchPostRunning AND the number of lines of postUrlQ > 0 then
         put line 1 of postUrlQ into tUrl
         delete line 1 of tUrl
         put true into asynchPostRunning
         post pData to url pUrl
         put it into tRetData
         put the result into tRes
         if tRes <> empty then
             ## error handling
             ## maybe send a callback message
         else
            ## success routine, do something with tData
            ## maybe send callback
         end if
         put false into asynchPostRunning
         if the number of lines of postUrlQ > 0 then
            send asynchPostHandler to me in 0 milliseconds
        end if
   end if
end asynchPostHandler