From f136442c2d9e579ac78d1e9d4a4f21a231a867aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Bruckert?= <stephane.bruckert@gmail.com>
Date: Sun, 26 Jul 2020 20:46:35 +0100
Subject: [PATCH] Fix Flask example app (#539)

---
 examples/app.py | 39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/examples/app.py b/examples/app.py
index fb1d804..583d415 100644
--- a/examples/app.py
+++ b/examples/app.py
@@ -3,9 +3,11 @@ Prerequisites
 
     pip3 install spotipy Flask Flask-Session
 
+    // from your [app settings](https://developer.spotify.com/dashboard/applications)
     export SPOTIPY_CLIENT_ID=client_id_here
     export SPOTIPY_CLIENT_SECRET=client_secret_here
-    export SPOTIPY_REDIRECT_URI='http://127.0.0.1:8080' // added to your [app settings](https://developer.spotify.com/dashboard/applications)
+    export SPOTIPY_REDIRECT_URI='http://127.0.0.1:8080' // must contain a port
+
     // on Windows, use `SET` instead of `export`
 
 Run app.py
@@ -17,27 +19,38 @@ import os
 from flask import Flask, session, request, redirect
 from flask_session import Session
 import spotipy
+import uuid
 
 app = Flask(__name__)
 app.config['SECRET_KEY'] = os.urandom(64)
 app.config['SESSION_TYPE'] = 'filesystem'
-
+app.config['SESSION_FILE_DIR'] = './.flask_session/'
 Session(app)
 
-auth_manager = spotipy.oauth2.SpotifyOAuth()
-spotify = spotipy.Spotify(auth_manager=auth_manager)
+caches_folder = './.spotify_caches/'
+if not os.path.exists(caches_folder):
+    os.makedirs(caches_folder)
 
 
 @app.route('/')
 def index():
+    if not session.get('uuid'):
+        # Step 1. Visitor is unknown, give random ID
+        session['uuid'] = str(uuid.uuid4())
+
+    auth_manager = spotipy.oauth2.SpotifyOAuth(cache_path=session_cache_path(), show_dialog=True)
     if request.args.get("code"):
-        session['token_info'] = auth_manager.get_access_token(request.args["code"])
+        # Step 3. Being redirected from Spotify auth page
+        auth_manager.get_access_token(request.args.get("code"))
         return redirect('/')
 
-    if not session.get('token_info'):
+    if not auth_manager.get_cached_token():
+        # Step 2. Display sign in link when no token
         auth_url = auth_manager.get_authorize_url()
         return f'<h2><a href="{auth_url}">Sign in</a></h2>'
 
+    # Step 4. Signed in, display data
+    spotify = spotipy.Spotify(auth_manager=auth_manager)
     return f'<h2>Hi {spotify.me()["display_name"]}, ' \
            f'<small><a href="/sign_out">[sign out]<a/></small></h2>' \
            f'<a href="/playlists">my playlists</a>'
@@ -45,13 +58,21 @@ def index():
 
 @app.route('/sign_out')
 def sign_out():
+    os.remove(session_cache_path())
     session.clear()
     return redirect('/')
 
 
 @app.route('/playlists')
 def playlists():
-    if not session.get('token_info'):
+    auth_manager = spotipy.oauth2.SpotifyOAuth(cache_path=session_cache_path())
+
+    if not auth_manager.get_cached_token():
         return redirect('/')
-    else:
-        return spotify.current_user_playlists()
+
+    spotify = spotipy.Spotify(auth_manager=auth_manager)
+    return spotify.current_user_playlists()
+
+
+def session_cache_path():
+    return caches_folder + session.get('uuid')
\ No newline at end of file