Got Oauth2 working on a python webserver

.gitignore

@@ -127,3 +127,6 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+config.json
+.idea/

web/Oauth2.py

@@ -0,0 +1,112 @@
+import os, json
+from flask import Flask, g, session, redirect, request, url_for, jsonify, make_response, render_template
+from requests_oauthlib import OAuth2Session
+
+with open("config.json", "r") as f:
+    config = json.load(f)
+
+OAUTH2_CLIENT_ID = config["OAUTH2_CLIENT_ID"]
+OAUTH2_CLIENT_SECRET = config["OAUTH2_CLIENT_SECRET"]
+OAUTH2_REDIRECT_URI = config["OAUTH2_REDIRECT_URI"]
+
+API_BASE_URL = os.environ.get('API_BASE_URL', 'https://discordapp.com/api')
+AUTHORIZATION_BASE_URL = API_BASE_URL + '/oauth2/authorize'
+TOKEN_URL = API_BASE_URL + '/oauth2/token'
+
+app = Flask(__name__, template_folder=config['HTML_TEMPLATES'])
+app.debug = True
+app.config['SECRET_KEY'] = OAUTH2_CLIENT_SECRET
+
+base_url = "http://127.0.0.1:47670"
+
+token_transfer = []
+
+if 'http://' in OAUTH2_REDIRECT_URI:
+    os.environ['OAUTHLIB_INSECURE_TRANSPORT'] = 'true'
+
+
+def token_updater(token):
+    session['oauth2_token'] = token
+
+
+def local_redirect(address):
+    return base_url + address
+
+
+def make_session(token=None, state=None, scope=None):
+    return OAuth2Session(
+        client_id=OAUTH2_CLIENT_ID,
+        token=token,
+        state=state,
+        scope=scope,
+        redirect_uri=OAUTH2_REDIRECT_URI,
+        auto_refresh_kwargs={
+            'client_id': OAUTH2_CLIENT_ID,
+            'client_secret': OAUTH2_CLIENT_SECRET,
+        },
+        auto_refresh_url=TOKEN_URL,
+        token_updater=token_updater)
+
+
+@app.route('/')
+def main():
+    print(session)
+    if "userInfo" in session:
+        print("User has previous session")
+        return redirect(local_redirect("/home"), 302)
+    else:
+        print("User does not have previous session")
+        return redirect(local_redirect("/link"), 302)
+
+
+@app.route('/home')
+def home():
+    try:
+        return render_template('home.html', user=session["userInfo"]["username"])
+    except KeyError:
+        print("User's previous session is invalid")
+        return redirect(local_redirect("/link"), 302)
+
+
+@app.route('/link')
+def link():
+    scope = request.args.get(
+        'scope',
+        'identify guilds')
+    discord = make_session(scope=scope.split(' '))
+    authorization_url, state = discord.authorization_url(AUTHORIZATION_BASE_URL)
+    session['oauth2_state'] = state
+    print(session)
+    return redirect(authorization_url, 302)
+
+
+@app.route('/callback')
+def callback():
+    global token_transfer
+    if request.values.get('error'):
+        return request.values['error']
+    discord = make_session(state=session.get('oauth2_state'))
+    token = discord.fetch_token(
+        TOKEN_URL,
+        client_secret=OAUTH2_CLIENT_SECRET,
+        authorization_response=request.url)
+    token_transfer = token
+    print(session)
+    return redirect(local_redirect("/me"), 302)
+
+
+@app.route('/me/')
+def me():
+    session['oauth2_token'] = token_transfer
+    discord = make_session(token=session.get('oauth2_token'))
+    user = discord.get(API_BASE_URL + '/users/@me').json()
+    guilds = discord.get(API_BASE_URL + '/users/@me/guilds').json()
+
+    session['userInfo'] = user
+    session['guildInfo'] = guilds
+
+    return redirect(local_redirect("/"), 302)
+
+
+if __name__ == '__main__':
+    app.run(port=47670)