monitoring the inspector backend class

inspector.js

var dispatch = InspectorBackendClass.Connection.prototype.dispatch;
InspectorBackendClass.Connection.prototype.dispatch = function() {
    if (arguments && arguments.length > 0) {
        var message = arguments[0];
        var object = message ? JSON.parse(message) : {};
        console.log.apply(console,['events', object]);
    }
    dispatch.apply(this, arguments);
}

jason... had a request..

I'd love to recommend using this instead of the protocol sniffing technique i doc'd here:
https://developer.chrome.com/devtools/docs/debugger-protocol#sniffing-the protocol

• I was looking at InspectorBackendClass.Connection and it appears there are some dump and wrap functions that looked to be built for this sort of thing.
• can you try out logging both directions. Maybe a unicode arrow in front of each log to indication which way it was going?
• also i think it should strip out things like id and empty message payloads.

This doesn't seem to be working anymore (at least in canary). Script is trying to JSON.parse an object.

Following the logic in the source of dispatch which this patch calls; I was able to get it working with the following:

var dispatch = InspectorBackendClass.Connection.prototype.dispatch;
InspectorBackendClass.Connection.prototype.dispatch = function() {
    if (arguments && arguments.length > 0) {
        var message = arguments[0];
        var object = ((typeof message === "string") ? JSON.parse(message) : message);
        console.log.apply(console,['events', object]);
    }
    dispatch.apply(this, arguments);
}

I also had success removing object altogether and passing message to dispatch, but wasn't sure of the stability of it.

@jasonLaster et al.. two things:

native dumpInspectorProtocolMessages

Instead of using this logging snippet, you can set InspectorBackendClass.Options.dumpInspectorProtocolMessages = true to log all messages to the console. It will log the JSON.stringify'd messages.

IMO, stringified is a bit messy, so I have a patch to clean it up and match this logging snippet's output: https://codereview.chromium.org/1606303003.

Updated protocol logging snippet:

As mentioned above, the snippet at the top of the gist is broken. I've evolved what @talitore did above and also instrumented the sendMessage method, which is key.

// This will log all protocol traffic to the console

const mainConnection = WebInspector.targetManager.mainTarget()._connection

const _dispatch = mainConnection.__proto__.dispatch;
const _sendMessage = mainConnection.__proto__.sendMessage;


mainConnection.__proto__.dispatch = function(message) {
    console.log('received: ', typeof message === "string" ? JSON.parse(message) : message);
    _dispatch.apply(this, arguments);
}

mainConnection.__proto__.sendMessage = function(message) {
    console.log('sending : ', message);
    _sendMessage.apply(this, arguments);
}

This is worth using until https://codereview.chromium.org/1606303003 has landed.

cheers

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updated again in july 2016.

Update: see https://gist.github.com/paulirish/127aebeb18788e3babc2b194c2f7ad0a#logging-protocol-activity