CODEWITHSUNDEEP
javascriptgoogle-chromegoogle-chrome-devtoolsremote-debugging
Haji
Haji

Reputation: 1775

Chrome Remote Debugging - Getting Page Notifications

I'm remote debugging Chrome, using the --remote-debugging-port switch and running another Chrome instance from which I'm debugging using web sockets. That's a bit different from most examples I see online where the debugging is done using node.js.

I need to navigate to a page, then evaluating some code in it. Both these actions work as expected using this code, that I run in a page in the 2nd Chrome instance:

var socket = new WebSocket(url);
function debug(action, data){
    var msg;
    switch (action) {
        case 'NAVIGATE':
            msg = {'id':1001, 'method':'Page.navigate', 'params':{'url':data.urlToNavigate}};
            break;
        case 'EVALUATE':
            msg = {'id':1002, 'method':'Runtime.evaluate', 'params':{'expression':data.jsCodeToEvaluate}};
            break;
    }
    socket.send(JSON.stringify(msg));
}

The problem I have is with getting notifications. I want to evaluate the code only after navigation has completed (let's say, after the document has loaded). I get messages on the socket in the following way, but as I understand the return message of the Page.navigate method is received when the navigation command has been started/received by the debugged page, not when the navigation completes.

socket.onmessage = function (event) {
    var data = JSON.parse(event.data);
    switch (data.id) {
        case 1001:
            //A navigation command to app page has been received but not yet navigated
            break;
    }
};

How can I use notifications to create a flow such as: Navigate > Wait for navigation to complete > Evaluate some code? I couldn't get any notifications.

Upvotes: 1

Views: 461

Answers (1)

Haji
Haji

Reputation: 1775

The problem was that notifications weren't enabled. To enable notifications:

socket.send(JSON.stringify({'id':12345, 'method':'Page.enable'}));

Then, notifications are received this way:

socket.onmessage = function (event) {
    var data = JSON.parse(event.data);
    switch (data.method) {
        case 'Page.frameNavigated':
            console.log('Navigation completed');
            break;
        //....  
    }
}

Same goes for runtime notifications (Runtime.enable), network notifications and so on...

Upvotes: 1

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