authentication.py

#!/usr/bin/env python3
import random, socket, sys, praw

# Obtained from
# https://praw.readthedocs.io/en/stable/tutorials/refresh_token.html#obtaining-refresh-tokens


def main():
    """Provide the program's entry point when directly executed."""

    client_id = input("Client ID: ")
    client_secret = input("Client secret: ")
    reddit = praw.Reddit(
        client_id=client_id,
        client_secret=client_secret,
        redirect_uri="http://localhost:8080",
        user_agent="obtain_refresh_token/v0 by u/bboe",
    )
    state = str(random.randint(0, 65000))
    url = reddit.auth.url(duration="permanent", scopes=("read", "history", "identity"), state=state)
    print(f"Now open this url in your browser:")
    print(f"{url}")

    client = receive_connection()
    data = client.recv(1024).decode("utf-8")
    param_tokens = data.split(" ", 2)[1].split("?", 1)[1].split("&")
    params = {
        key: value for (key, value) in [token.split("=") for token in param_tokens]
    }

    if state != params["state"]:
        send_message(
            client,
            f"State mismatch. Expected: {state} Received: {params['state']}",
        )
        return 1
    elif "error" in params:
        send_message(client, params["error"])
        return 1

    refresh_token = reddit.auth.authorize(params["code"])
    send_message(client, f"Refresh token: {refresh_token}")
    return 0


def receive_connection():
    """Wait for and then return a connected socket..

    Opens a TCP connection on port 8080, and waits for a single client.

    """
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind(("localhost", 8080))
    server.listen(1)
    client = server.accept()[0]
    server.close()
    return client


def send_message(client, message):
    """Send message to client and close the connection."""
    print(message)
    client.send(f"HTTP/1.1 200 OK\r\n\r\n{message}".encode("utf-8"))
    client.close()


if __name__ == "__main__":
    sys.exit(main())