login and logout with telegram

telegram.php

@@ -18,4 +18,46 @@ function getTelegramUserData() {
 		return $auth_data;
 	}
 	return false;
-}
+}
+/** 
+ * Check if data is from telegram
+ * 
+ * This checks if the data provides is from telegram. It includes a Fix for firefox
+ * 
+ * @param mixed $auth_data The Authentication Data
+ * 
+ * @return $auth_data
+ * 
+*/
+function checkTelegramAuthorization($auth_data) {
+	$check_hash = $auth_data['hash'];
+	unset($auth_data['hash']);
+	$data_check_arr = [];
+	foreach ($auth_data as $key => $value) {
+	 // $data_check_arr[] = $key . '=' . $value;
+	  $data_check_arr[] = $key . '=' . str_replace('https:/t', 'https://t', $value);
+	}
+	sort($data_check_arr);
+	$data_check_string = implode("\n", $data_check_arr);
+	$secret_key = hash('sha256', TG_BOT_API_TOKEN, true);
+	$hash = hash_hmac('sha256', $data_check_string, $secret_key);
+	if (strcmp($hash, $check_hash) !== 0) {
+	  throw new Exception('Data is NOT from Telegram');
+	}
+	if ((time() - $auth_data['auth_date']) > 86400) {
+	  throw new Exception('Data is outdated');
+	}
+	return $auth_data;
+  }
+
+
+/**
+ * Save telegram userdata
+ * 
+ * Save the telegram user data in a cookie
+ *  @return void
+ */  
+function saveTelegramUserData($auth_data) {
+	$auth_data_json = json_encode($auth_data);
+	setcookie('tg_user', $auth_data_json);
+  }