Improve/clean some code

public/auth.php

 <?php
-session_start();
+require '../spotify/spotify.php';
 
-require '../vendor/autoload.php';
-require '../config.php';
-
-$session = new SpotifyWebAPI\Session(
-    $CLIENT_ID,
-    $CLIENT_SECRET,
-    $REDIRECT_URI
-);
+$session = new SpotifyWebAPI\Session($CLIENT_ID, $CLIENT_SECRET, $REDIRECT_URI);
 
 $state = $session->generateState();
 
 $_SESSION['state'] = $state;
 
 $options = [
-    'scope' => [
-        'playlist-read-private',
-        'playlist-modify-private',
-        'playlist-modify-public',
-        'user-read-private',
-    ],
+    'scope' => $SPOTIFY_REQUIRED_SCOPES,
     'state' => $state,
 ];
 

public/callback.php

 <?php
-session_start();
+require '../spotify/spotify.php';
 
-require '../vendor/autoload.php';
-require '../config.php';
-
-$session = new SpotifyWebAPI\Session(
-    $CLIENT_ID,
-    $CLIENT_SECRET,
-    $REDIRECT_URI
-);
+$session = new SpotifyWebAPI\Session($CLIENT_ID, $CLIENT_SECRET, $REDIRECT_URI);
 
 $storedState = $_SESSION['state'];
 $state = $_GET['state'];

public/index.php

 <?php
-session_start();
-
-require '../vendor/autoload.php';
-require '../config.php';
+require '../spotify/spotify.php';
 
 if (isset($_GET['logout'])) {
     $_SESSION['accessToken'] = '';
     $_SESSION['refreshToken'] = '';
 }
 
-$accessToken = '';
-if (isset($_SESSION['accessToken'])) {
-    $accessToken = $_SESSION['accessToken'];
-}
-$refreshToken = '';
-if (isset($_SESSION['refreshToken'])) {
-    $refreshToken = $_SESSION['refreshToken'];
-}
+$_SESSION['accessToken'] = isset($_SESSION['accessToken']) ? $_SESSION['accessToken'] : '';
+$_SESSION['refreshToken'] = isset($_SESSION['refreshToken']) ? $_SESSION['refreshToken'] : '';
 
-if (!$accessToken) {
+if (!$_SESSION['accessToken']) {
     header('Location: auth.php');
     die();
 }
 
-$session = new SpotifyWebAPI\Session(
-    $CLIENT_ID,
-    $CLIENT_SECRET,
-    $REDIRECT_URI
-);
+$session = new SpotifyWebAPI\Session($CLIENT_ID, $CLIENT_SECRET, $REDIRECT_URI);
 
 // Use previously requested tokens fetched from session
-if ($accessToken) {
-    $session->setAccessToken($accessToken);
-    $session->setRefreshToken($refreshToken);
+if ($_SESSION['accessToken']) {
+    $session->setAccessToken($_SESSION['accessToken']);
+    $session->setRefreshToken($_SESSION['refreshToken']);
 } else {
     // Or request a new access token
-    $session->refreshAccessToken($refreshToken);
+    $session->refreshAccessToken($_SESSION['refreshToken']);
 }
 
 $options = [
-  'scope' => [
-      'playlist-read-private',
-      'playlist-modify-private',
-      'playlist-modify-public',
-      'user-read-private',
-  ],
+  'scope' => $SPOTIFY_REQUIRED_SCOPES,
   'auto_refresh' => true,
 ];
 
@@ -58,23 +40,19 @@ $_SESSION['refreshToken'] = $session->getRefreshToken();
 
 $user = $api->me();
 
-$templateData = [];
-$templateData['user'] = $user;
-$templateData['userImageUrl'] = '';
-if ($user->images[0]) {
-    $templateData['userImageUrl'] = $user->images[0]->url;
-}
+$templateData = [
+  'user' => $user,
+  'playlists' => [],
 
-$templateData['infos'] = [];
-$templateData['errors'] = [];
+  'infos' => [],
+  'errors' => [],
+];
 
 $selectedPlaylistId = '';
 if (isset($_GET['playlist'])) {
     $selectedPlaylistId = $_GET['playlist'];
 }
 
-$templateData['playlists'] = [];
-
 if ($selectedPlaylistId) {
     $playlist = $api->getPlaylist($selectedPlaylistId);
     error_log('Will create new playlist from tracks in playlist '.$selectedPlaylistId.' "'.$playlist->name.'".');

config.php → spotify/spotify.php

 <?php
+session_start();
 
-$parametersFile = __DIR__.'/parameters.php';
+require '../vendor/autoload.php';
+
+$parametersFile = realpath(__DIR__.'/../parameters.php');
 if (!is_file($parametersFile)) {
   die('Missing parameters file: '.$parametersFile);
 }
 
 require $parametersFile;
+
+$SPOTIFY_REQUIRED_SCOPES = [
+    'playlist-read-private',
+    'playlist-modify-private',
+    'playlist-modify-public',
+    'user-read-private',
+];

template.php

@@ -16,7 +16,9 @@
     <div class="col-md-2">
 
       <div class="card">
-        <img src="<?php echo $templateData['userImageUrl']; ?>" class="card-img-top" alt="<?php echo $templateData['user']->display_name; ?>">
+        <?php if (count($templateData['user']->images)) { ?>
+        <img src="<?php echo $templateData['user']->images[0]->url; ?>" class="card-img-top" alt="<?php echo $templateData['user']->display_name; ?>">
+        <?php } ?>
         <div class="card-body">
           <h5 class="card-title"><?php echo $templateData['user']->display_name; ?></h5>
           <a href="<?php echo $templateData['user']->external_urls->spotify; ?>" class="btn btn-primary">View profile</a>