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['$&'].length));
document.title = '';
console.log(data);
}
}).observe(
document.querySelector('title'),
{childList: true}
);
// send info using client or simulate server sending in responses
document.title = 'secret:response=' + JSON.stringify({some: 'value'});
```
with a proper class/wrap to handle events and send data transparently it
might be a great way to exchange info
On Wed, Nov 1, 2017 at 5:53 AM, Sam Jansen <sam.jan...@starleaf.com> wrote:
>
>
> On 1 November 2017 at 05:43, <philip.chime...@gmail.com> wrote:
>
>> On Thu, Oct 12, 2017 at 5:23 AM Andrea Giammarchi <
>> andrea.giammar...@gmail.com> wrote:
>>
>>> FWIW I've used the location with a private channel as protocol to
>>> intercept calls to/from the page and GJS.
>>>
>>> https://github.com/WebReflection/jsgtk-twitter/blob/master/app#L162-L175
>>>
>>> The channel is a random string: https://github.com/Web
>>> Reflection/jsgtk-twitter/blob/master/app#L59
>>>
>>> From the page, which is aware of the "secret" channel, I call GJS
>>> actions via location.href = `secret1234:method(${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/WebReflection/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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