[Qtwebengine] How to tell when DOM resources finishes downloading?

[Kevin Truong]

Hi Kai and community,

I patched QWebEngineUrlRequestInterceptor so that it emits a signal when
the DOM resource is finished downloading (or if it failed, or if it
aborted). I'd like to help contribute to the Qt Web Engine project, so I
was wondering if I can submit my patch for a code review to the repository.
Maybe other people might find this feature useful.

What is the process for me to submit my patch?

Best,
Kevin


On Wed, Nov 25, 2015 at 12:14 AM, Koehne Kai <Kai.Koehne at theqtcompany.com>
wrote:

> > -----Original Message-----
> > From: Kevin Truong [mailto:knt261 at gmail.com]
> > Sent: Tuesday, November 24, 2015 7:15 PM
> > To: Koehne Kai <Kai.Koehne at theqtcompany.com>
> > Cc: qtwebengine at qt-project.org
> > Subject: Re: [Qtwebengine] How to tell when DOM resources finishes
> > downloading?
> >
> > Sure Kai -- here's my use case: I have a page that loads ajax data into
> the
> > document. The ajax gets loaded into the DOM much later than when the
> > DomContentLoaded and the Load event is triggered (the red and blue
> vertical
> > lines in the picture under "Network Panel Overview"
> > https://developer.chrome.com/devtools/docs/network). If I understood
> > correctly, it means the ajax is loaded much later than when
> loadFinished() is
> > signaled as well. The amount of time we have to wait before the ajax is
> loaded
> > into the document is variable -- it can take 50ms, or it can take up to
> 10 seconds.
> > I would like to know exactly when the ajax is loaded into the DOM (or if
> that's
> > not possible, exactly when the render finish downloading the ajax) before
> > serializing/downloading the HTML of the page and doing tests on the
> HTML. This
> > is because the HTML changes after the ajax is loaded into the DOM, and
> the
> > tests need to be run on the updated HTML, not the initial HTML.
>
> I see. If you know the HTML/AJAX of the specific page, you might be able
> to hook up
> a JS handler that is called when the AJAX request is done, and then signal
> this to the
> C++ world , e.g. via QWebChannel.
>
> > I'd like this to be generalized as well (not just ajax, but any other
> DOM resource),
> > because I have test pages where the exact same thing happens, but with
> iframes
> > instead of ajax, or with certain very specific plug-ins (like the
> facebook posts
> > that load below an article page). These resources load independently of
> > DomContentLoaded and the Load event. However, I can identify them either
> via
> > the URL or the content type -- I just need to figure out how I can tell
> the render
> > to serialize only right after these resources are loaded.
>
> I'm afraid that's not possible right now in the general case. In Qt 5.6
> we'll add
> QWebEngineUrlRequestInterceptor:
>
> http://doc-snapshots.qt.io/qt5-5.6/qwebengineurlrequestinterceptor.html
>
> But that is called _before_ the request hits the networking stack.
>
> But even if you would have a way to get notified when the network request
> is
> done, it doesn't mean that the page is re-rendered/the DOM being updated.
>
> Regards
>
> Kai
>
>
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