so ... it looks really like the exposed API is completely useless as it is
```js
webkit.messageHandlers.gjs.postMessage('hello');
```
Returns a
[boxed instance proxy GIName:WebKit2.JavascriptResult jsobj@0x7fa08c2e4160
native@0x7fa052081d80]
and if you try to get its value it goes bananas with a message like:
Gjs-WARNING **: JS ERROR: Error: Unable to find module implementing foreign
type JavaScriptCore.Value
What's the purpose of register_script_message_handler at all? What am I
missing?
On Wed, Nov 1, 2017 at 11:02 AM, Andrea Giammarchi <
andrea.giammar...@gmail.com> wrote:
> I've quickly provided a proof of concept but you could have a JSONChannel
> class singleton on the client side that queue each info and wait for the
> GJS side to receive one before sending another.
>
> I might try a real implementation though and see how it works.
>
> however, this is just a work around for the fact you can send messages
> without any content (... and I wonder how that can be useful in any way ...)
>
> Regards
>
> On Wed, Nov 1, 2017 at 10:50 AM, Sam Jansen <sam.jan...@starleaf.com>
> wrote:
>
>>
>>
>> On 1 November 2017 at 11:55, Andrea Giammarchi <
>> andrea.giammar...@gmail.com> wrote:
>>
>>> Actually the `notify::title` with a prefixed "secret-channel" and
>>> serialized JSON looks like the best of them all, for the time being, as it
>>> makes it straight forward for both client and server to communicate.
>>>
>>> ```js
>>> // listen to each response
>>> new MutationObserver(m => {
>>> if (/^secret:response=/.test(document.title)) {
>>> const data = JSON.parse(document.title.slice(RegExp['$&'].length));
>>> document.title = '';
>>> console.log(data);
>>> }
>>> }).observe(
>>> document.querySelector('title'),
>>> {childList: true}
>>> );
>>>
>>> // send info using client or simulate server sending in responses
>>> document.title = 'secret:response=' + JSON.stringify({some: 'value'});
>>> ```
>>>
>>> with a proper class/wrap to handle events and send data transparently it
>>> might be a great way to exchange info
>>>
>>>
>> I've just come to the opposite conclusion, though I don't disagree as
>> such...
>>
>> My concern is that setting document.title, and having notify::title
>> called is asynchronous (I believe). So in your JS, if one had:
>>
>> ```
>> document.title = '1'
>> document.title = '2'
>> ```
>>
>> Then by the time notify::title is called, and you inspect your
>> "webkit.title" property, I'd expect you'd only see the '2' value, and
>> (likely) not the '1'.
>>
>> It's possible to solve this by ensuring the GJS side has picked up a
>> message, and e.g. reset the title, I suppose. This feels like an awkward
>> solution to me though.
>>
>>
>>>
>>>
>>> On Wed, Nov 1, 2017 at 5:53 AM, Sam Jansen <sam.jan...@starleaf.com>
>>> wrote:
>>>
>>>>
>>>>
>>>> On 1 November 2017 at 05:43, <philip.chime...@gmail.com> wrote:
>>>>
>>>>> On Thu, Oct 12, 2017 at 5:23 AM Andrea Giammarchi <
>>>>> andrea.giammar...@gmail.com> wrote:
>>>>>
>>>>>> FWIW I've used the location with a private channel as protocol to
>>>>>> intercept calls to/from the page and GJS.
>>>>>>
>>>>>> https://github.com/WebReflection/jsgtk-twitter/blob/master/a
>>>>>> pp#L162-L175
>>>>>>
>>>>>> The channel is a random string: https://github.com/Web
>>>>>> Reflection/jsgtk-twitter/blob/master/app#L59
>>>>>>
>>>>>> From the page, which is aware of the "secret" channel, I call GJS
>>>>>> actions via location.href = `secret1234:method(${encodeURI
>>>>>> Component(JSON.stringify(value))})`;
>>>>>>
>>>>>> The protocol secret1234 is intercepted and the
>>>>>> `controller.method(JSON.parse(decodeURIComponent(restOfURI)))`
>>>>>> invoked.
>>>>>>
>>>>>> To signal the page everything is fine I use
>>>>>> this.webView.runJavaScript https://github.com/WebReflect
>>>>>> ion/jsgtk-twitter/blob/master/app#L377
>>>>>>
>>>>>> The page has a listener for the `secret1234` event on the main
>>>>>> window, and such listener is instrumented to react accordingly with the
>>>>>> CustomEvent .detail payload/info.
>>>>>>
>>>>>> This might look a bit convoluted, and it has JSON serialization as
>>>>>> limitation for the kind of data you want to pass (i.e. I use base64
>>>>>> encoded
>>>>>> images as source from remotely fetched files enabling somehow CORS for
>>>>>> whatever I want) but it worked well, circumventing the missing
>>>>>> communication channel available in Qt.
>>>>>>
>>>>>> Maybe today there are better ways for doing a similar thing and if
>>>>>> that's the case, please share.
>>>>>>
>>>>>
>>>>> Here is another, fairly new, way to do it. Start out by registering a
>>>>> "script message handler":
>>>>> http://devdocs.baznga.org/webkit240~4.0_api/webkit2.usercont
>>>>> entmanager#method-register_script_message_handler
>>>>>
>>>>> To send a message to the page, use the same thing that Andrea uses:
>>>>> http://devdocs.baznga.org/webkit240~4.0_api/webkit2.webview#
>>>>> method-run_javascript
>>>>>
>>>>> To send a message from the page to the GJS program, use the
>>>>> postMessage() method mentioned in the documentation, and connect to this
>>>>> signal in your GJS program to receive the message:
>>>>> http://devdocs.baznga.org/webkit240~4.0_api/webkit2.usercont
>>>>> entmanager#signal-script-message-received
>>>>>
>>>>>
>>>> Excellent - I had not noticed this. My first attempt at communicating
>>>> between WebKit2 and GJS was via setting "document.title" and having GJS
>>>> connect to the "notify::title" signal! Not a great approach, this looks
>>>> much better.
>>>>
>>>>
>>>>> Although I just realized that unfortunately the values won't be able
>>>>> to be marshalled into GJS since you need to use the JavaScriptCore API to
>>>>> get at them. This is a really nice method in C, but in JS you can only use
>>>>> it to send a message without any content. That is annoying. I should
>>>>> probably open up an issue about this.
>>>>>
>>>>>
>>>> I just hit upon this problem myself. In researching it, I found it is
>>>> solved (at least well enough for my use-case) with this open source
>>>> library:
>>>>
>>>> https://github.com/saifulbkhan/wkjscore-result
>>>>
>>>> It's awkward having another dependency for me, especially one that
>>>> isn't in a normal Ubuntu/Fedora/etc. package, but otherwise this approach
>>>> worked fine for me.
>>>>
>>>>
>>>>> On Wed, Oct 11, 2017 at 12:57 PM, Adriano Patrizio <
>>>>>> adriano.patri...@hotmail.com> wrote:
>>>>>>
>>>>>>> Thank you for response, this is my problem: have necessity to
>>>>>>> implement methods into my web application webkit2 based and comunicate
>>>>>>> with
>>>>>>> GJS script (example: filesystem functions to read and write files or
>>>>>>> window
>>>>>>> managment).
>>>>>>>
>>>>>>
>>>>> Regards,
>>>>> Philip C
>>>>>
>>>>> _______________________________________________
>>>>> javascript-list mailing list
>>>>> javascript-list@gnome.org
>>>>> https://mail.gnome.org/mailman/listinfo/javascript-list
>>>>>
>>>>>
>>>>
>>>
>>
>
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