Retrieve current chrome open page in html without saving it - selenium

Question

I'm implementing a python script mainly based on pyautogui. One of the things the script does is to open a chrome webpage. After that I would need to access the DOM of this currently open webpage.
Since I've not opened the browser with selenium, I can't use it to analyze the DOM.
However, my question is: is this currently open chrome page available/saved somewhere in the hard drive so that I can access it with selenium? Like an .html file?
I checked many other questions here and users talk about chrome cache, but there are no html files there.
I just need to be able to access the current open page and not all the historical data in the cache.
Opening web browser directly with selenium is not an option either, since most of the websites analyzed have captchas and distil technology.
Thanks.

Answer 1

If you start the original chrome with --remote-debugging-port=PORT_NR argument, and visit localhost:PORT_NR from another browser, you will have access to the full content of the browser, including dev console.
Once you have this, you have multiple ways to go:
You can visit http://localhost:PORT_NR with with any other browser (or even with the same browser), and you should have full access to the content of the original Chrome. With Selenium you should have a relatively easy time to get by.
You can also use the devtools api (the documentation.. is.. well... there is room for improvement. Search for chrome devtools protocol to be amazed by the lack of docs). As an example you can get to http://localhost:PORT_NR/json to get the available debugging URIs. Grab the relevant websocket endpoint (webSocketDebuggerUrl). Open a websocket connection, and issue a command, like {"method": "DOM.getDocument", "id":12}. You can find available DOM related commands here: https://chromedevtools.github.io/devtools-protocol/1-3/DOM

Answer 2

Sice I had to reinvet the wheel I may give some extra info that I coudn't find anywhere:
Start the Browser with remote debugging enabled (see previous posts)
Connect to the given port on localhost and use these HTTP-GET-Requests to geta very limited control on your browser:
https://chromedevtools.github.io/devtools-protocol/#endpoints
Most important:
GET /json/new?{url}
GET /json/activate/{targetId}
GET /json/close/{targetId}
GET /json or /json/list
To gain full control over the browser, you need to use a "websocket" connection. Each Object in the GET /json or /json/list has it's own ID. Use this ID to interact with the tab. Btw: Type "page" are normal tabs, the other stuff are extentions and so on. Once you know which Tab you want to influence, get it's "webSocketDebuggerUrl".
Use this URL and connect with something that can speak the Websocket-protocol.
Once connected, you must craft a valid Json by the following structure:
{
"id":0,
"method":"Page.navigate",
"params":{url:http://google.com}}
}
Notes:
ID is a simple counter (int) that get bigger - not the ID of the tab(!)
Method is the method described in the docs params is also in the docs.
The return values are always JSONs.
From now on you can use the official docs:
https://chromedevtools.github.io/devtools-protocol/tot/Page/#method-navigate
Dunno how other ppl found out about it but it took a few hours to get it working. Probably cause everyone is just using python's selenium to do it.