Using Google Chrome remote debugging protocol - google-chrome

Question

I need to get the network events from Chrome. I've found this:
https://developer.chrome.com/devtools/docs/debugger-protocol
https://developer.chrome.com/devtools/docs/protocol/1.1/network#command-enable
It seems that Chrome uses a port to get messages, answer and send events, for remote debugging. It says it uses JSON, so I decided to try it.
So, I wrote some simple java code that opens the port that chrome is listening on (ofcourse i've started it by using google-chrome --remote-debugging-port=9222 on my ubuntu machine). I have a thread that writes to stdout anything coming from this port, and then the code writes this to the outputstream of the socket using this line (a sample method from the protocol):
out.println("{\"id\": 1,\"method\": \"Network.enable\"}");
I would expect some answer (according to the protocol) in the input stream but nothing happens.
Does anyone ever done something like this? I can't find anything on the net.

Answer 1

Finally I've got it. Credit goes to https://www.igvita.com/2012/04/09/driving-google-chrome-via-websocket-api/.
First I send an HTTP request to http://localhost:9222/json. This returns a JSON list of open tabs in Chrome, for each I also get a WebSocket uri (webSocketDebuggerUrl):
[
{
"description": "",
"devtoolsFrontendUrl": "/devtools/devtools.html?ws=localhost:9222/devtools/page/C014A09F-BD0A-40BA-B23C-7B18B84942CD",
"faviconUrl": "http://cdn.sstatic.net/stackoverflow/img/favicon.ico?v=00a326f96f68",
"id": "C014A09F-BD0A-40BA-B23C-7B18B84942CD",
"title": "Using Google Chrome remote debugging protocol - Stack Overflow",
"type": "page",
"url": "https://stackoverflow.com/questions/28430479/using-google-chrome-remote-debugging-protocol",
"webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/C014A09F-BD0A-40BA-B23C-7B18B84942CD"
}
]
Then I can use WebSocket to send messages for debugging a specific tab, using this URI. I also found this for using Jetty implementation of WebSocket: javax.websocket client simple example.