chromedp-proxy is a simple command-line tool to proxy and log Chrome DevTools Protocol sessions sent from a CDP client to a CDP browser session. chromedp-proxy captures and (by default) logs all of the WebSocket messages sent during a CDP session between a remote and local endpoint, and can be used to expose a CDP browser listening on localhost to a remote endpoint.

chromedp-proxy is mainly used to capture and debug the wireline protocol sent from DevTools/Selenium/Puppeteer to Chrome/Chromium/headless_shell/etc. It was originally written for debugging wireline problems/issues with the chromedp project.

Install in the usual Go way:

$ go get -u github.com/chromedp/chromedp-proxy

By default, chromedp-proxy listens on localhost:9223 and proxies requests to/from localhost:9222:

$ chromedp-proxy

chromedp-proxy can also be used to expose a local Chrome instance on an external address/port:

$ chromedp-proxy -l 192.168.1.10:9222

By default, chromedp-proxy logs to both stdout and to $PWD/logs/cdp-<id>.log, but that can be changed through flags:

# only log to stdout
$ chromedp-proxy -n
# or only log to stdout by specifying an empty log name
$ chromedp-proxy -log ''
# log to /var/log/cdp/session-<id>.log
$ chromedp-proxy -log '/var/log/cdp/session-%s.log'

$ ./chromedp-proxy -help
Usage of ./chromedp-proxy:
  -l string
    	listen address (default "localhost:9223")
  -log string
    	log file mask (default "logs/cdp-%s.log")
  -n	disable logging to file
  -r string
    	remote address (default "localhost:9222")