In this article I will show how you can abort a jQuery ajax request, preventing your user experience from disappearing into space.

Introduction

We have all done it – opened a page which runs an infinite loop consisting of some form of while(true). But no-one means to do that on purpose….That said there may be occasions where we are making requests to pages which we know are really really slow. Keeping a long connection open on the server restricts the number of open threads and potentially causes lockups. It is also a terrible user experience more importantly.

It might not be quite as relevant nowadays as it might have been to a Domino server say 10 years ago but still – pretty cool idea.

You can abort the ajax request with .abort()

Slowly loading XPage

I created a simple XPage with a before render response page which will take a long time to finish (as you can see below is ~30 seconds)

<xp:this.beforeRenderResponse>
	<![CDATA[#{javascript:
		for (var i=0; i<50000000; i++){
			true;
		}
		return true}
	]]>
</xp:this.beforeRenderResponse>

Aborting the Ajax call

Aborting the call is relatively simple – by assigning a variable to the ajax call we can  then just .abort() it

var temp = $.ajax({
  url: 'http://copper.xomino.com/xomino/jQinX2.nsf/xRunForever.xsp'
}).error(function(){
   console.log('hey what happened')
})

temp.abort()

Running it manually we can see this

But a more practical solution is to set a timeout function to test the ajax value and abort if it is taking too long. How long that is, is entirely up to you……

function dontRunForever(url, time){
    var temp = $.ajax({
      url: url,
    }).error(function(){
       console.log('hey what happened');
    }).success(function(){
       console.log('All Done');
       temp = false
    })

    setTimeout(function(){ //Using function() inside the setTimeout means the function is executed after the "time"
      if(temp){
       console.log('aborting')
       temp.abort()
      } else {
       console.log('ajax call completed in time')
      }
    }, time)
}

dontRunForever(
  'http://copper.xomino.com/xomino/jQinX2.nsf/xRunForever.xsp',
  5000)

So when we run this with a timeout of 5 seconds, we see the abort() trigger

But when we use 50 seconds we see a successful completion and no abort message – and eventually the end of the Timeout success message

This is all well and good – BUT…..

Just because the ajax request is aborted – this does not mean the task stops running on the server – this whole concept improves the user experience and nothing else. This will not stop a never ending task running on the server – only the server settings will truly kill that.

 

Conclusion

When I found this and the fact that it has been around for over 4 years I was somewhat annoyed that I did not know about it earlier, but it is pretty cool still all the same 🙂