Add local WSGI server authorizer

[NadimAsad]

No documentation string, tests or styling have been provided with initial commit. I'm currently looking for maintainer feedback for the proposed addition of new local WSGI server based authorizer class.

[LilSpazJoekp]

What I've found so far. I think this would be better suited as an example instead of being part of prawcore.

Regardless, how would one use this? Could you provide a working example?

[NadimAsad]

The state was supposed to be user specified, I forgot to fix this while I was creating the class. The example for the flow can be found in the updated obtain_refresh_token.py. The old code to obtain refresh token was replaced to use the new proposed class.

[NadimAsad]

Example for flow

#!/usr/bin/env python

"""This example demonstrates the flow for retrieving a refresh token.

In order for this example to work your application's redirect URI must be set
to http://localhost:65010/auth_callback.

This tool can be used to conveniently create refresh tokens for later use with
your web application OAuth2 credentials.

"""
import os
import sys
import uuid

import prawcore


def main():
    """Provide the program's entry point when directly executed."""
    if len(sys.argv) < 2:
        print(f"Usage: {sys.argv[0]} SCOPE...")
        return 1

    authorizer = prawcore.LocalWSGIServerAuthorizer(
        prawcore.TrustedAuthenticator(
            prawcore.Requestor("prawcore_refresh_token_example"),
            os.environ["PRAWCORE_CLIENT_ID"],
            os.environ["PRAWCORE_CLIENT_SECRET"],
            "http://localhost:65010/auth_callback",
        ),
        sys.argv[1:],
        duration="permanent",
    )
    authorizer.authorize_local_server(state=str(uuid.uuid4()))
    print(f"Refresh token: {authorizer.refresh_token}")


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

[NadimAsad]

Using custom praw Reddit client

praw.ini

[eXRCWebAppClient]
client_id=<WEB-APP-CLIENT-ID>
client_secret=<WEB-APP-CLIENT-SECRET>
local_client_scopes=read identity
redirect_uri=http://localhost:65010/auth_callback

Python Interpreter Output

>>> from praw import Reddit
>>> reddit = Reddit("eXRCWebAppClient", user_agent="eXRCWebAppClient_test")
>>> print(reddit.user.me())
eXMirrorBot
>>> print(reddit.auth._reddit._core._authorizer.refresh_token)
<VALID-USER-REFRESH-TOKEN>

This basically can be used as a first time authorizer to get a refreshable token directly from praw. The refresh token can be later assigned to a different domain in the config file.

[bboe]

Overall, something about the code this PR introduces doesn't quite feel right. Even in PRAW (this one more so) I'd argue provided code does more than it should. In a production environment where someone wishes to obtain access tokens for users I wouldn't recommend they use this Authorizer, and instead manually leverage one of the existing ones within their existing web application. For personal use, I'm curious what the short comings are for the existing example -- or why we couldn't provide a simpler example which leverages the wsgiref code.

What do you think?

[bboe]

I didn't know this was in the standard library. Very cool.

[NadimAsad]

My main intention for creating this PR was because the tutorial given in the docs to obtain a refreshable token looked too complex for my liking and is IMO not end-user friendly to easily obtain a refresh token for PRAW. I don't like entering my Reddit username / password / 2FA code through terminal to use the password flow and would like to avoid using this if possible. Even if this PR is not accepted, I personally will be maintaining a fork with the proposed authorizer for my own personal use. If there is any changes that needed to make this suitable for production environment, feel free to let me know. Otherwise, feel free to close this PR.