Restoring document state

Dave,

                Could it be that the submission is being sent but not completed before the unload. I’ve worked with it before and found that it was intermittently successful. In the end we went for warning the user their unsaved changes would be lost when they left the page and it was unsaved

Unfortunately there aren’t any ways to test the page as your leaving it

Just my 2c

Ryan

In our application we've implemented a feature whereby if a user navigates away without saving while they're editing a document through Orbeon Forms, the document's unsaved changes will be restored if they reopen the document for editing at some later time.  We've been doing this since before the eXist state persistence mechanism was added, so what we did was to use an onbeforeunload event to dispatch a custom event to the model which in turn triggered a submission of the instance we want to restore later.

I'm now trying to update to a more recent version of Orbeon and I'm finding that the mechanism is no longer working.  If I dispatch the custom event manually (by adding a trigger for debugging) then the submission is fired, but when the event is dispatched within an onbeforeunload event handler, the submission is not fired.  I've tried adding an alert within the onbeforeunload handler and that gets hit.  On the other hand, I've tried putting an xxforms:script containing an alert in the model which responds to the custom event, and that does not gets hit when the custom event is dispatched by the onbeforeunload handler (but is hit when the custom event is dispatched by the debugging trigger, of course).

So, I have two questions.

* Is there something I need to do to be able to still use an onbeforeunload handler to dispatch custom events to the model to trigger a submission?
* Is there a way that I could instead use Orbeon's state persistence to save and later restore the state of the document?

The latter approach is appealing but is not easy: we wouldn't want to restore the entire user state, just the state of one instance document, and we'd need some way to identify whether the same user was editing the same document as before or a different document which happens to be based on the same form.  From what I can understand from the documentation, Orbeon can recognise when a user has returned to a page via the browser history, but we need to be able to say that a new request is for the same underlying document as some previous request.

Any thoughts?

Dave

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Dave,

                I see, nice workaround I’ll be sure to remember that next time I’m using onbeforeunload.

Is it possible that some of the unload has already begun in IE and its not firing any new javascript events?

Thanks

Ryan

Ryan,

Thanks for that, but I don't think that's the problem: we're not hitting a break point in the code that the submission invokes, so the submission is not even starting, let alone completing. 

We worked around the problem you mention by having both an onbeforeunload event (which fires the submission to back up the document) and an onunload event (which blocks for a while if the submission hasn't completed).

I've managed to get things working reliably in Firefox by removing a call to ORBEON.xforms.Server.executeNextRequest(true);.  However, I'm still struggling to get it to work in IE.

Dave

Ryan Puddephatt wrote:

Dave,

                Could it be that the submission is being sent but not completed before the unload. I’ve worked with it before and found that it was intermittently successful. In the end we went for warning the user their unsaved changes would be lost when they left the page and it was unsaved

Unfortunately there aren’t any ways to test the page as your leaving it

Just my 2c

Ryan

In our application we've implemented a feature whereby if a user navigates away without saving while they're editing a document through Orbeon Forms, the document's unsaved changes will be restored if they reopen the document for editing at some later time.  We've been doing this since before the eXist state persistence mechanism was added, so what we did was to use an onbeforeunload event to dispatch a custom event to the model which in turn triggered a submission of the instance we want to restore later.

I'm now trying to update to a more recent version of Orbeon and I'm finding that the mechanism is no longer working.  If I dispatch the custom event manually (by adding a trigger for debugging) then the submission is fired, but when the event is dispatched within an onbeforeunload event handler, the submission is not fired.  I've tried adding an alert within the onbeforeunload handler and that gets hit.  On the other hand, I've tried putting an xxforms:script containing an alert in the model which responds to the custom event, and that does not gets hit when the custom event is dispatched by the onbeforeunload handler (but is hit when the custom event is dispatched by the debugging trigger, of course).

So, I have two questions.

* Is there something I need to do to be able to still use an onbeforeunload handler to dispatch custom events to the model to trigger a submission?
* Is there a way that I could instead use Orbeon's state persistence to save and later restore the state of the document?

The latter approach is appealing but is not easy: we wouldn't want to restore the entire user state, just the state of one instance document, and we'd need some way to identify whether the same user was editing the same document as before or a different document which happens to be based on the same form.  From what I can understand from the documentation, Orbeon can recognise when a user has returned to a page via the browser history, but we need to be able to say that a new request is for the same underlying document as some previous request.

Any thoughts?

Dave

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