feature #392, authentication keys, album notification

* On album notification (for a group), sends one distinct email for each user
  with a new authentication key.

* When someone clicks the link with auth=<key> in URL, if the user is not
  already connected, Piwigo will automatically connect the user.

include/config_default.inc.php

@@ -646,6 +646,10 @@ $conf['recent_post_dates'] = array(
 // the author shown in the RSS feed <author> element
 $conf['rss_feed_author'] = 'Piwigo notifier';
 
+// how long does the authentication key stays valid, in seconds. 3 days by
+// default. 0 to disable.
+$conf['auth_key_duration'] = 3*24*60*60;
+
 // +-----------------------------------------------------------------------+
 // | Set admin layout                                                      |
 // +-----------------------------------------------------------------------+

include/constants.php

@@ -81,6 +81,8 @@ if (!defined('USER_FEED_TABLE'))
   define('USER_FEED_TABLE', $prefixeTable.'user_feed');
 if (!defined('RATE_TABLE'))
   define('RATE_TABLE', $prefixeTable.'rate');
+if (!defined('USER_AUTH_KEYS_TABLE'))
+  define('USER_AUTH_KEYS_TABLE', $prefixeTable.'user_auth_keys');
 if (!defined('USER_CACHE_TABLE'))
   define('USER_CACHE_TABLE', $prefixeTable.'user_cache');
 if (!defined('USER_CACHE_CATEGORIES_TABLE'))

include/functions_mail.inc.php

@@ -514,6 +514,8 @@ SELECT DISTINCT language
     // get subset of users in this group for a specific language
     $query = '
 SELECT
+    ui.user_id,
+    ui.status,
     u.'.$conf['user_fields']['username'].' AS name,
     u.'.$conf['user_fields']['email'].' AS email
   FROM '.USER_GROUP_TABLE.' AS ug
@@ -534,13 +536,27 @@ SELECT
 
     switch_lang_to($language);
 
-    $return&= pwg_mail(null,
-      array_merge(
-        $args,
-        array('Bcc' => $users)
-        ),
-      $tpl
-      );
+    foreach ($users as $u)
+    {
+      $authkey = create_user_auth_key($u['user_id'], $u['status']);
+      
+      $user_tpl = $tpl;
+
+      if ($authkey !== false)
+      {
+        $user_tpl['assign']['LINK'] = add_url_params($tpl['assign']['LINK'], array('auth' => $authkey['auth_key']));
+
+        if (isset($user_tpl['assign']['IMG']['link']))
+        {
+          $user_tpl['assign']['IMG']['link'] = add_url_params(
+            $user_tpl['assign']['IMG']['link'],
+            array('auth' => $authkey['auth_key'])
+            );
+        }
+      }
+
+      $return &= pwg_mail($u['email'], $args, $user_tpl);
+    }
 
     switch_lang_back();
   }

include/functions_user.inc.php

@@ -1462,4 +1462,136 @@ function get_recent_photos_sql($db_field)
     .pwg_db_get_recent_period_expression($user['recent_period'])
     .','.pwg_db_get_recent_period_expression(1,$user['last_photo_date']).')';
 }
+
+/**
+ * Performs auto-connection if authentication key is valid.
+ *
+ * @since 2.8
+ *
+ * @return bool
+ */
+function auth_key_login($auth_key)
+{
+  global $conf, $user;
+
+  if ($user['id'] != $conf['guest_id'])
+  {
+    return false;
+  }
+  
+  if (!preg_match('/^[a-z0-9]{30}$/i', $auth_key))
+  {
+    return false;
+  }
+
+  $query = '
+SELECT
+    *,
+    '.$conf['user_fields']['username'].' AS username,
+    NOW() AS dbnow
+  FROM '.USER_AUTH_KEYS_TABLE.' AS uak
+    JOIN '.USER_INFOS_TABLE.' AS ui ON uak.user_id = ui.user_id
+    JOIN '.USERS_TABLE.' AS u ON u.'.$conf['user_fields']['id'].' = ui.user_id
+  WHERE auth_key = \''.$auth_key.'\'
+;';
+  $keys = query2array($query);
+
+  if (count($keys) == 0)
+  {
+    return false;
+  }
+  
+  $key = $keys[0];
+
+  // is the key still valid?
+  if (strtotime($key['expired_on']) < strtotime($key['dbnow']))
+  {
+    return false;
+  }
+
+  // admin/webmaster/guest can't get connected with authentication keys
+  if (!in_array($key['status'], array('normal','generic')))
+  {
+    return false;
+  }
+
+  $user['id'] = $key['user_id'];
+  log_user($user['id'], false);
+  trigger_notify('login_success', stripslashes($key['username']));
+
+  return true;
+}
+
+/**
+ * Creates an authentication key.
+ *
+ * @since 2.8
+ * @param int $user_id
+ * @return array
+ */
+function create_user_auth_key($user_id, $user_status=null)
+{
+  global $conf;
+
+  if (0 == $conf['auth_key_duration'])
+  {
+    return false;
+  }
+
+  if (!isset($user_status))
+  {
+    // we have to find the user status
+    $query = '
+SELECT
+    status
+  FROM '.USER_INFOS_TABLE.'
+  WHERE user_id = '.$user_id.'
+;';
+    $user_infos = query2array($query);
+
+    if (count($user_infos) == 0)
+    {
+      return false;
+    }
+
+    $user_status = $user_infos[0]['status'];
+  }
+
+  if (!in_array($user_status, array('normal','generic')))
+  {
+    return false;
+  }
+  
+  $candidate = generate_key(30);
+  
+  $query = '
+SELECT
+    COUNT(*),
+    NOW(),
+    ADDDATE(NOW(), INTERVAL '.$conf['auth_key_duration'].' SECOND)
+  FROM '.USER_AUTH_KEYS_TABLE.'
+  WHERE auth_key = \''.$candidate.'\'
+;';
+  list($counter, $now, $expiration) = pwg_db_fetch_row(pwg_query($query));
+  if (0 == $counter)
+  {
+    $key = array(
+      'auth_key' => $candidate,
+      'user_id' => $user_id,
+      'created_on' => $now,
+      'duration' => $conf['auth_key_duration'],
+      'expired_on' => $expiration,
+      );
+    
+    single_insert(USER_AUTH_KEYS_TABLE, $key);
+
+    $key['auth_key_id'] = pwg_db_insert_id();
+    
+    return $key;
+  }
+  else
+  {
+    return create_user_auth_key($user_id);
+  }
+}
 ?>

include/user.inc.php

@@ -65,6 +65,12 @@ if ($conf['apache_authentication'])
   }
 }
 
+// automatic login by authentication key
+if (isset($_GET['auth']))
+{
+  auth_key_login($_GET['auth']);
+}
+
 $user = build_user( $user['id'],
           ( defined('IN_ADMIN') and IN_ADMIN ) ? false : true // use cache ?
          );