Is it Possible to "Interrupt" an Interactive Report Refresh

Question

We have a particular Interactive Report for which we want to enforce two column filters as mandatory. We've already figured out how to examine the current filters and determine if they are set.
What we need now is some mechanism by which if the user changes the filter criteria (for example deleting one of these mandatory filters), we can stop the APEX refresh and produce an error message. For example, could some such logic be placed in the Before Refresh event?
Does anyone have any ideas how this might be done?
-Joe

Answer 1

I've looked at this for a bit but I don't think there is any even remotely fair way to deal with this. The ajax calls for IRs do not use jQuery.ajax calls (unfortunate) but use a call to htmldb_Get.getAsync. An XmlHttpRequest object is created there but is of course never exposed, thus not allowing interaction on it, and is probably too deeprooted in the apex javascript to change. If it was using jQuery you could've tried to use the ajaxSetup, such as described in javascript - Abort Ajax requests using jQuery - Stack Overflow or Stop all active ajax requests in jQuery - Stack Overflow (and all variations when looking for ajax aborting).
There is nothing you can do from say the before refresh event since canceling that is only canceling the before refresh event, not the actual refresh.
I believe that simply overriding some function on the gReport object might serve you best. Keeping in mind it is best not fiddled with and is unsupported etc etc - I suppose you know the drill by now.
There are a couple of candidates for this. "gReport.action" for example: you could simply block of any ajax action on the report before it happens: remove filters, add filters, search, pull - without having to worry about xmlhttprequests. I explored some other routes but honestly they became too complex for what it was.
//first store the original _Get function. We can't lose this because we still need it.
var old_Get = gReport._Get;
//now override the existing function with our own implementation. Preserve the signature so that the params can
//be passed on
gReport._Get = function(p_widget_mod,p_widget_action,p_widget_action_mod,p_id,p_value,p_x05,p_x06,p_x07,p_x08,p_x09,p_x10){
  //lets do some arbitrary check in here
  if(p_widget_mod == "PULL"){
     //now nothing will happen when you want to pull the report
     return false;
  //and dont forget to at least execute the original function !
  old_Get(p_widget_mod,p_widget_action,p_widget_action_mod,p_id,p_value,p_x05,p_x06,p_x07,p_x08,p_x09,p_x10);
Now when executing
gReport.pull()
nothing will happen.
You'll need to modify this to suit your needs though. If this is taking it too far for you then you may have hit a brick wall though, I can't see any other option personally and so far.