cdp.page.DomContentEventFired event listener not catching an event about python-cdp

[HMaker]

It's probably caused by race conditions, the page might be loading too fast between the cdp.page.navigate() command and the async with target_session.wait_for() subscription. We need to subscribe to the event before it be triggered.

[HMaker]

test again with latest version

[TurboKach]

seems working on your new snippet.
will check it later also on a more complex code.

[TurboKach]

problem still exists and not fixed.
tested on latest (for the time of this post) CDP version

Steps to reproduce this bug:

1. update CDP protocol files used for generating cdp folder (you can use my .sh file for one-command execution)
2. Double check that you are NOT using default pycdp lib protocol classes, but generated a fresh ones from pycdp import cdp ---> import cdp

Here is my code that you can use for check:

import asyncio
import sys
import cdp
from pycdp.browser import ChromeLauncher
from pycdp.asyncio import connect_cdp


async def main():
    platform: sys.platform = sys.platform
    chrome_binary_path = '/usr/bin/google-chrome'
    if platform == "darwin":
        chrome_binary_path = (
            "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"  # Mac chrome path
        )
    elif platform in ["linux", "linux2"]:
        chrome_binary_path = "/usr/bin/google-chrome"  # Linux chrome path
    elif platform == "windows":
        chrome_binary_path = "C:\Program Files\Google\Chrome\Application\chrome.exe"  # windows path
    chrome = ChromeLauncher(
        binary=chrome_binary_path,  # linux path
        args=['--remote-debugging-port=9222',]
    )
    # ChromeLauncher.launch() is blocking, run it on a background thread
    await asyncio.get_running_loop().run_in_executor(None, chrome.launch)
    conn = await connect_cdp('http://localhost:9222')
    target_id = await conn.execute(cdp.target.create_target('about:blank'))
    target_session = await conn.connect_session(target_id)
    await target_session.execute(cdp.page.enable())
    # you may use "async for target_session.listen()" to listen multiple events, here we listen just a single event.
    with target_session.safe_wait_for(cdp.page.DomContentEventFired) as navigation:
        await target_session.execute(cdp.page.navigate('https://chromedevtools.github.io/devtools-protocol/'))
        await navigation
    print("EVENT FIRED")
    dom = await target_session.execute(cdp.dom.get_document())
    node = await target_session.execute(cdp.dom.query_selector(dom.node_id, 'p'))
    js_node = await target_session.execute(cdp.dom.resolve_node(node))
    print((await target_session.execute(
        cdp.runtime.call_function_on('function() {return this.innerText;}', js_node.object_id, return_by_value=True)))[
              0].value)
    await target_session.execute(cdp.page.close())
    await conn.close()
    await asyncio.get_running_loop().run_in_executor(None, chrome.kill)


asyncio.run(main())

[HMaker]

I tried to reproduce with your steps but cdp.page.DomContentEventFired is still fired. You can't generate a new, external cdp package, you need to refresh the builtin one:

1. Clone this repository
2. Replace the browser_protocol.json and js_protocol.json files at pycdp/gen folder by the CDP protocol version you wish, then run python pycdp/gen/generate.py, it will refresh builtin cdp wrapper.
3. Run your test script again.

This is the output I got from your test script

NAVIGATION FINISHED
EVENT FIRED
The Chrome DevTools Protocol allows for tools to instrument, inspect, debug and profile Chromium, Chrome and other Blink-based browsers. Many existing projects currently use the protocol. The Chrome DevTools uses this protocol and the team maintains its API.

I just added a new print at the end safe_wait_for() block to show it entered the block. I used Chrome 110 on Ubuntu.

[TurboKach]

Here was a cdpgen-generated package usage misunderstood.
cdpgen generated package cannot be used separate from pycdp due to being a part of it.

#4