bServerSide=false w/ajax results in loss of sEcho, server-side errors/warnings

carteriii

My situation can be reproduced using your server_site.html example. Simply change the bServerSide value to false and refresh the page.

You will notice that the table still loads w/ajax just fine, and now local searching also works just fine. However, this generates errors/warnings on the server because sEcho is no longer defined yet is accessed directly when setting $sOutput on line 147. By using Firebug I can see that all the "standard" parameters of dataTables are now missing in the call to server_processing.php.

It is great that we can still use ajax to return the data, yet perform local operations using bServerSide=false, but it seems that the code should still generate the proper information like sEcho when making the server request. I don't think this is urgent, but would you consider fixing that up in a future release?

Thank you.

allan

This isn't quite an expected interaction. When not using server-side processing, all you need to return is the array aaData, as shown in this example: http://datatables.net/examples/data_sources/ajax.html . There is no need to have the server do all of that processing, and it won't be sent any parameters by DataTables, so just a 2D array in aaData will do it.

Allan

carteriii

Great. That would explain why it all works. I ended up in this situation only because I have been using true server-side processing for some complicated initial queries, but for some users the resultset was small so I wanted only local sorting & filtering (to avoid the server hits for every small search or sort). I guess I was either lazy or efficient and kept all the same server-side code, so I started to see the errors on sEcho. I've been able to put an isset() test around it, so I'm good.

May I ask, what does sEcho do? I don't fully understand it, and the one documentation page (http://www.datatables.net/usage/server-side) just says it is for rendering.

Thanks again.

allan

sEcho is basically a tracker for DataTables. Because of the asynchronous nature of the Ajax calls, it is actually possible for them to arrive out of sequence - it's unlikely, but certainly possible if you are rapidly changing pages for example. The sEcho variable allows DataTables to check what response it is expecting and what it has actually got - thus it can throw away old responses which have arrived after a later one!

Making the XHR calls synchronous would address that issue - but hugely slow down the UI responsiveness (although it is possible to do if one wanted...).

Allan

carteriii

That's very well thought out and implemented. Thanks for an awesome bit of work, and your responses here. I think I'll go hit your "Donate" button now, and I encourage everyone else reading this to do the same.

allan

Awesome - thanks :-). Great to hear that DataTables is proving to be useful!

Allan