ASP/Microsoft.XMLHTTP asynchronous request

[logx]

Hi,

I have a script which takes ~20 minutes to fully process and it runs in the background. I want to be able to run multiple instances of this script at the same time, all initiated manually through a webpage.

I use Microsoft.XMLHTTP to send an asynchronous request, however once the first request is sent, when I try to initiate another one it won't kick in until the first has completed (it queues up).

Here is the code I am using to achieve this:

---
Set xmlhttp = CreateObject("Microsoft.XMLHTTP")
xmlhttp.open "POST", "

http://website.com/process.asp?action=1&launch="

& LAUNCH_ID, true

xmlhttp.setRequestHeader "Content-Type", "application/x-

http://www-form-urlencoded"

xmlhttp.send

Set xmlhttp=Nothing
response.redirect "index.asp"
---

When the user is redirected to index.asp, they should be able to add new variables, fire up a new request and have the script start processing in the background again. However, if they do, the script would start processing only after the previous one has finished.

I am open to suggestions/workaround on how this can be achieved.

Thanks!

 

[foxbox]

Mmmmmm, my initial thought is: 20 minutes processing??!!! if your script does database operations: use a stored procedure. Most likely that will speed up things.
Besides that: with programs like this there will be a maximum number of simultaneous jobs (performance wise).
I would store every user request into a table (id, action, launch_id, jobstatus). Then an trigger is set on that table:
if number of records with jobstatus = 1 (running) > x then: nothing (maximum number of jobs in the system)
else pick the first record with jobstatus = 0 and launch a processing job.
The processing job would end with updating the jobstatus eg into 2 (job ended). That would fire the trigger again.
That job table is also a way to inform your end-users (you could provide more detailed status info. and of course a job could fail).

 

[logx]

Hi,

Thank for replying. Maybe I should have added few extra details.

The script uses, among other things, psexec in order to execute certain set of commands on Windows based machines.

I like the idea you have proposed, but that would mean I would need to trigger this script through other means and not via web-browser accessible by the end-user, correct? As I would end up using the same type of request (async Microsoft.XMLHTTP) which would then want to queue up.

Ideally, if I could somehow make multiple requests through async Microsoft.XMLHTTP kick off at the same time, that would be excellent.

 

[ChrisHirst]

http://www.tek-tips.com/viewthread.cfm?qid=1626379&page=1

Post #2

Chris.

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