Fixed web socket endpoint for Chrome CDP (Chrome DevTools Protocol)

Question

I use Chrome CDP for some tasks automation.

One have to first start the chrome with CDP:

chromium-browser --remote-debugging-port=9222

and it reports something like

DevTools listening on ws://127.0.0.1:9222/devtools/browser/3e3152c6-20fc-4cea-a9d2-60e4e6b8ad70

I have to copy the ws://... URL to my config file manually to be able to proceed with my task. I probably can work around this using python's subprocess.Popen to do this instead and extract the URL but isn't there a way how to make this URL configurable or at least fixed?

Answer 1

Thanks to wOxxOm! It really can be read from http://127.0.0.1:9222/json/version (Documentation)

As an alternative, I wrote Python script to launch it and get the endpoint as well:

from subprocess import Popen, PIPE


class Browser:
    BANNER = "DevTools listening on "

    def __init__(self, path="/usr/bin/chromium-browser",
            port=9222, ignore_tls_errors=False):

        cmd = [path, f"--remote-debugging-port={port}"]
        if ignore_tls_errors:
            cmd.append("--ignore-certificate-errors")

        self.process = Popen(cmd, stdout=PIPE, stderr=PIPE, universal_newlines=True)

        output = ""
        for line in self.process.stderr:
            output += line
            if self.BANNER in output:
                start_pos = output.find(self.BANNER) + len(self.BANNER)
                end_pos = output.find("\n", start_pos)
                self.url = output[start_pos:end_pos]
                break

    def close(self):
        self.process.terminate()


if __name__ == "__main__":
    try:
        b = Browser()
        print("URL:", b.url)
    finally:
        b.close()