TabContainer: odd behavior in canceling in-flight XHRs

[kpkeerthi]

Please see sample code attached.

What it is? It is a tabcontainer with 3 tabs and one nested tab.

What does it (the code) do? When a tab is clicked, any in-flight XHR pending with the previously selected tab is canceled. This is achieved subscribing to "<tabcontainer-widgetId>-selectChild" topic. We do this to save unnecessary hits from the tabs that are not currently selected.

What is the issue? The code cancels in-flight XHR of a tab (say t1) when a new tab t2 is clicked/selected. When the same tab t1 is selected again, dojo fires a new XHR and loads t1 with its content. This is the expected behavior. But this works only for the tabs that are not nested. Dojo cancels the inflight XHR of a nest tab n1 just fine. But when n1 is selected again, it does not fire new XHR and n1 is stuck at 'Loading...' indefinitely.

[kpkeerthi]

This is an issue with dojo 1.5 as well

[kpkeerthi]

Steps to reproduce:

1. Deploy the attached war file in Tomcat v6 and point your browser (Firefox) to ​http://<host>:<port>/DojoTabs?/index.html

2. Tab-1 will begin loading. Click on Tab-2 and watch Tab-1's XHR getting canceled in Firebug.

3. Click on Tab-1 again and wait until its content load.

4. Now click on the tab 'Nested'. A nested tab Tab-4 will begin loading. Click on tab-3 and watch Tab-4's XHR getting canceled.

5. Click on the tab 'Nested' again. The nested tab Tab-4 will never load again.

[bill]

Sounds like you are talking about dijit, not dojox?

I don't have tomcat installed. Can you attach a test case using a simple HTML file? It can access getResponse.php in dijit/tests.

[kpkeerthi]

Tomcat is optional. All you need is change the href values of the content panes (4 instances) in the attached file inflight-xhr.html.

Save this file to your disk and change the href values and run this file off your disk directly. 'Steps to reproduce' would remain the same except for Step-1.

[bill]

OK, then please change the URL's and reattach the test file. Then we will know we are looking at the exact same test file.

The workaround is to not call cancel().

[kpkeerthi]

inflight-xhr.html modified and reattached

[bill]

TabContainer by itself is working fine. The problem only happens when you manually cancel an in-flight XHR. Manually canceling an in-flight XHR is not supported.

In your test case, when the nested TabContainer is deselected, you are manually calling:

lastSelectedTab.cancel()

on the nested TabContainer's ContentPane. Then, you are expecting the XHR to magically reexecute when the nested TabContainer is selected again. TabContainer doesn't have code to do this. Actually, I don't remember TabContainer having any code to cancel XHR's. I'll attach my test case.

[bill]

working test case because the manual canceling of the XHR is commented out