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ajaxWDwx.js Limit to number of Updates of Clientraw data.

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TNETWeather:
After adding Ajax to my pages, I noted a large increase in traffic in the logs...

The traffic increase was the updates of clientraw data for the Ajax code.  Since I have it set to update once every 30 seconds, anyone that camped out on a page with it, would make 120 downloads of the clientraw data per hour.

Not a real big deal as the bandwidth is relatively low (~660 bytes x 120 = 80k an hour).

However, I did start noticing that some "visitors" were camped out for hours even days at a time.  Most likely sitting in a tab they are not viewing (many of them sitting on my Scripts page for example).  One visitor appears to have been there now for 4 days...

So I thought about adding update limits to the Ajax code.  WDL has the same type of restriction ability and most that use it are much more restrictive than 2 hours.

I added at the top of the ajaxWDwx.js file...

var updates = 0;      // Start counter
var maxupdates = 240;   // Maxium Number of updates allowed

This setup two variable... updates which would be incremented each time an update took place, and maxupdates.  I set it initially to 5 so I could test it without waiting two hours... but now have it at 240 which is 2 hours using my update rate of once very 30 seconds.

Next I modified the line which checked if a valid clientraw was found... to:

// If we have a valid clientraw file AND updates is < maxupdates
if(clientraw[0] == '12345' && wdpattern.test(x.responseText) && updates < maxupdates ) {
     updates ++;

This basically says that if updates is < maxupdates go ahead if the other conditions are met... followed by an increment of the updates variable if it did get past the if statement.

Lastly, I changed the following lines:

setTimeout("reset_ajax_color('')",flashtime); // change text back to default color
setTimeout("ajaxLoader(clientrawFile + '?' + new Date().getTime())", reloadTime); // get new data after 5 secs

to:

if (updates < maxupdates) {
   setTimeout("reset_ajax_color('')",flashtime); // change text back to default color
   setTimeout("ajaxLoader(clientrawFile + '?' + new Date().getTime())", reloadTime); // get new data after 5 secs
}

This prevents any update of the timeouts if the updates are now larger than the maxupdates.

Ideally, I would do some more like:

o Allow for 0 maxupdates to mean no limit
o If paused, update somewhere where it indicates that the data is now frozen.

saratogaWX:
I'm doing a new release of the WD/AJAX/PHP sample set, and the ajaxWDwx.js V2.09 will include this nifty feature, along with the 0=no limit, and a replacement for the ajaxindicator text with 'Updates paused - reload page to start',

and a bunch of other enhancements too.. Should be ready for release tomorrow :-)

Thanks for the idea and demo code, Kevin!

Best regards,
Ken

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