Thursday, September 23, 2010

How to set executionTimeout for individual requests?

You probably know that you can change http request processing timeout for specific page like this:
 <location path="MyLongRunningHttpHandler.ashx">
<httpRuntime executionTimeout="600" />
But what if you want to set it up for a control or just a function and do not have predefined list of pages to specify it in web.config?
Of maybe you don't want to pollute web.config with junk like that?

There should be some way to do it in C# code, right?
Here's how you do it:
    HttpContext.Current.Server.ScriptTimeout = 600; // 10 minutes
If that's what you were looking for, you probably want to test it.
I tried to test it too, and it turned out to be tricky.

First I set web.config's timeout to 2 seconds:
<httpRuntime executionTimeout="2" />

Then I put 10 seconds delay to my ashx handler's code-behind:
System.Threading.Thread.Sleep(10000); // 10 seconds

Then I commented this line:
// HttpContext.Current.Server.ScriptTimeout = 600; // 10 minutes

and opened my ashx handler's url in browser.

I expected it to crash with timeout error... but it did not happen.
Few experiments showed that executionTimeout works only if all of the following is true:
1) Domain name is not localhost (to test timeout you should use "YourComputerName" instead of "localhost").
2) Project is compiled in Release mode.
3) <compilation debug="false">
If any of the above is not true then executionTimeout length is virtually unlimited.
On top of that IIS typically times out later than executionTimeout limit asks it too.
When I set executionTimeout=2 and made my page request to sleep for 10 seconds, I was getting "Request timed out." response only in ~40% of requests.

1 comment:

iL said...

I've heard that it sometimes take longer to timeout because it has sort of a service that runs from every 15 seconds e fire the timeouts.


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