Use cUrl with Chrome remote debugging

Question

I'm trying to connect to Chrome remote debuging with cUrl, however, responses from Chrome return "200 OK" but no data.

I set up chrome using:

chrome.exe --headless --remote-debugging-port=12345

I can successfully get a list of pages with:

>curl -i "http://localhost:12345/json"

HTTP/1.1 200 OK
Content-Length:612
Content-Type:application/json; charset=UTF-8
[ {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:12345/devtools/page/19d24d3a-25b7-4ee8-a5cf-4f3d17778575",
  ...
   "webSocketDebuggerUrl": "ws://localhost:12345/devtools/page/19d24d3a-25b7-4ee8-a5cf-4f3d17778575"
} ]

However, I can only get empty successful response from debugger URLs:

>echo {"id":0,"method":"Page.navigate","params":{"url":"https://stackoverflow.com/"}}|curl -i "http://localhost:12345/devtools/page/19d24d3a-25b7-4ee8-a5cf-4f3d17778575" -H "Content-Type: application/json" -d -

HTTP/1.1 200 OK
Content-Length:0
Content-Type:text/plain

Commands like Page.navigate and also misformed requests return 200 OK but nothing is performed.

What I'm I missing???

Answer 1

You need to use websockets to manage chrome like that. Quoting chromedevtools.github.io:

Your application can discover available pages by requesting: http://localhost:9222/json and getting a JSON object with information about inspectable pages along with the WebSocket addresses that you could use in order to start instrumenting them

This is how it would work (at least on my Mac):

Run Chrome

docker pull deepsweet/chromium-headless-remote:69
docker run -it --rm -p 9222:9222 deepsweet/chromium-headless-remote:69

Fetching WebSocket addresses

curl -i "http://localhost:9222/json"
HTTP/1.1 200 OK
Content-Length:361
Content-Type:application/json; charset=UTF-8

[ {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/DC33B65CA373BE2770F2A1031C3B4CBF",
   "id": "DC33B65CA373BE2770F2A1031C3B4CBF",
   "title": "about:blank",
   "type": "page",
   "url": "about:blank",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/DC33B65CA373BE2770F2A1031C3B4CBF"
} ]

Sending your command

echo '{ "id":2, "method":"Page.navigate", "params":{"url": "http://www.stackoverflow.com"} }' | websocat -t - ws://localhost:9222/devtools/page/DC33B65CA373BE2770F2A1031C3B4CBF

websocat is used in the example. You can also write a simple script to do it like here

Make sure the page is opened

curl -i "http://localhost:9222/json"
HTTP/1.1 200 OK
Content-Length:432
Content-Type:application/json; charset=UTF-8

[ {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/DC33B65CA373BE2770F2A1031C3B4CBF",
   "id": "DC33B65CA373BE2770F2A1031C3B4CBF",
   "title": "Stack Overflow - Where Developers Learn, Share, & Build Careers",
   "type": "page",
   "url": "https://stackoverflow.com/",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/DC33B65CA373BE2770F2A1031C3B4CBF"
} ]