note 84824 modified in function.flock by danbrown

Here's a handy class to allow retrying a write with flock a set number of times. If it can't flock, it will sleep for a brief random interval and try again. If you have a lot of concurrent writes going on, you can use it to avoid data corruption. <?php class SafeWriter { // suggested mode 'a' for writing to the end of the file public static function writeData($path, $mode, $data) { $fp = fopen($path, $mode); $retries = 0; $max_retries = 100; if (!$fp) { // failure return false; } // keep trying to get a lock as long as possible do { if ($retries > 0) { usleep(rand(1, 10000)); } $retries += 1; } while (!flock($fp, LOCK_EX) and $retries <= $max_retries); // couldn't get the lock, give up if ($retries == $max_retries) { // failure return false; } // got the lock, write the data fwrite($fp, "$data\n"); // release the lock flock($fp, LOCK_UN); fclose($fp); // success return true; } } ?> --was-- Here's a handy class to allow retrying a write with flock a set number of times. If it can't flock, it will sleep for a brief random interval and try again. If you have a lot of concurrent writes going on, you can use it to avoid data corruption. class SafeWriter { // suggested mode 'a' for writing to the end of the file public static function writeData($path, $mode, $data) { $fp = fopen($path, $mode); $retries = 0; $max_retries = 100; if (!$fp) { // failure return false; } // keep trying to get a lock as long as possible do { if ($retries > 0) { usleep(rand(1, 10000)); } $retries += 1; } while (!flock($fp, LOCK_EX) and $retries <= $max_retries); // couldn't get the lock, give up if ($retries == $max_retries) { // failure return false; } // got the lock, write the data fwrite($fp, "$data\n"); // release the lock flock($fp, LOCK_UN); fclose($fp); // success return true; } } http://php.net/manual/en/function.flock.php