[Sugar-devel] web-activity: env.getEnvironment dependency with Python code

[Daniel Narvaez]

My summary email is still valid but for completeness... I'm not sure it's
possible even from inside webkit to implement a non-racy
window-object-cleared signal.

On Wednesday, 27 November 2013, Daniel Narvaez wrote:

> It might be a good idea to send an email to the webkitgtk mailing list by
> the way.
>
> I wonder if it would make sense to add a window-object-cleared signal to
> WebkKitView (webkitgtk1 has it). They provide a way to run javascript code
> from the view and it seems being able to run it before any other js code
> has been executed would be a very common use case, one you wouldn't want
> people to write an extension for...
>
> On Wednesday, 27 November 2013, Daniel Narvaez wrote:
>
>> This makes me wonder if the current approach is actually racy by the
>> way... I'm not sure the window object is guaranteed to be ready even on the
>> load_finished event. Network and javascript context might be completely
>> independent from this point of view (they are in separate processes after
>> all).
>>
>> I feel the best approach here is the webkit extension really, even if it
>> requires a little bit of C code.
>>
>> On Wednesday, 27 November 2013, Daniel Narvaez wrote:
>>
>>> Hi,
>>>
>>> did you try to implement it and see if it works? I probably tried this
>>> when I first implemented getEnvironment but I might have done it wrong or
>>> something. My worry is that the javascript context might not be ready yet
>>> at that time, so either the python js code would fail or affect the old
>>> view.
>>>
>>> By the way, if you are determined to solve this and the loaded_started
>>> approach doesn't work, I know it would be possible to make it work using
>>> this
>>>
>>> http://webkitgtk.org/reference/webkit2gtk/unstable/WebKitScriptWorld.html
>>>
>>> It runs in the web process, so it tells you exactly when a new window
>>> object is created. Though using that API requires an extension written in C
>>> :/ If despite that you are interested in working on that I can give you
>>> some more pointers.
>>>
>>> On Wednesday, 27 November 2013, Rogelio Mita wrote:
>>>
>>>> I noticed existence of a WebKitWebView event which is emitted before
>>>> what any resource be loaded, called webkit_loaded_started<http://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#WEBKIT-LOAD-STARTED:CAPS>
>>>>
>>>>> WEBKIT_LOAD_STARTED: A new load request has been made. No data has
>>>>> been received yet, empty structures have been allocated to perform the
>>>>> load; the load may still fail due to transport issues such as not being
>>>>> able to resolve a name, or connect to a port.
>>>>
>>>> I did a concept proof on sugar-toolkit-gtk3 to show this behaviour and
>>>> the result was:
>>>>
>>>> [image: Imágenes integradas 1]
>>>>
>>>> I think that this behaviour can solve the issue with env.getEnvironment
>>>> and your hard dependency with sugar var provided by python code.
>>>>
>>>> This log also show how load_event_finished is executed between
>>>> successive requests, then there is no doubt about the current problem
>>>> existence.
>>>>
>>>> You think this may be a solution?, change the script so that it is now
>>>> run in this event (load_event_started) and rewrite getEnvironment
>>>> disregarding the possibility that there is no environment variable provided
>>>> by the Python code, in others words ever when activity is in sugar mode,
>>>> window.sugar.environment will be present
>>>>
>>>>
>>>> --
>>>> Roger
>>>>
>>>> Activity Central <http://activitycentral.com/>
>>>>
>>>
>>>
>>> --
>>> Daniel Narvaez
>>>
>>>
>>
>> --
>> Daniel Narvaez
>>
>>
>
> --
> Daniel Narvaez
>
>

-- 
Daniel Narvaez
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