haldis/app/zeus.py

"Script containing everything specific to ZeusWPI"
import typing

from flask import (Blueprint, current_app, flash, redirect, request, session,
                   url_for)
from flask_login import login_user
from flask_oauthlib.client import OAuth, OAuthException
from werkzeug.wrappers import Response

from models import User, db

oauth_bp = Blueprint("oauth_bp", __name__)


def zeus_login():
    "Log in using ZeusWPI"
    return current_app.zeus.authorize(
        callback=url_for("oauth_bp.authorized", _external=True)
    )


@oauth_bp.route("/login/zeus/authorized")
def authorized() -> typing.Any:
    # type is 'typing.Union[str, Response]', but this errors due to
    #   https://github.com/python/mypy/issues/7187
    "Check authorized status"
    resp = current_app.zeus.authorized_response()
    if resp is None:
        return "Access denied: reason=%s error=%s" % (
            request.args["error"],
            request.args["error_description"],
        )
    if isinstance(resp, OAuthException):
        return f"Access denied: {resp.message}<br>{resp.data}"

    session["zeus_token"] = (resp["access_token"], "")
    me = current_app.zeus.get("current_user/")
    username = me.data.get("username", "").lower()

    user = User.query.filter_by(username=username).first()
    # pylint: disable=R1705
    if username and user:
        return login_and_redirect_user(user)
    elif username:
        user = create_user(username)
        return login_and_redirect_user(user)

    flash("You're not allowed to enter, please contact a system administrator")
    return redirect(url_for("general_bp.home"))


def init_oauth(app):
    "Initialize the OAuth for ZeusWPI"
    oauth = OAuth(app)

    zeus = oauth.remote_app(
        "zeus",
        consumer_key=app.config["ZEUS_KEY"],
        consumer_secret=app.config["ZEUS_SECRET"],
        request_token_params={},
        base_url="https://adams.ugent.be/oauth/api/",
        access_token_method="POST",
        access_token_url="https://adams.ugent.be/oauth/oauth2/token/",
        authorize_url="https://adams.ugent.be/oauth/oauth2/authorize/",
    )

    # pylint: disable=W0612
    @zeus.tokengetter
    def get_zeus_oauth_token():
        return session.get("zeus_token")

    return zeus


def login_and_redirect_user(user) -> Response:
    "Log in the user and then redirect them"
    login_user(user)
    return redirect(url_for("general_bp.home"))


def create_user(username) -> User:
    "Create a temporary user if it is needed"
    user = User()
    user.configure(username, False, 1)
    db.session.add(user)
    db.session.commit()
    return user