How can PHP scripts be structured to prevent user-created content from being overwritten during file operations?

To prevent user-created content from being overwritten during file operations in PHP, you can use file locking mechanisms to ensure that only one process can write to the file at a time. This can be achieved by using the `flock()` function to acquire an exclusive lock on the file before writing to it, and releasing the lock after the operation is completed. 

$filename = 'user_content.txt';

$fp = fopen($filename, 'a+');
if (flock($fp, LOCK_EX)) {
    fwrite($fp, "User content goes here\n");
    flock($fp, LOCK_UN);
} else {
    echo "Could not lock file!";
}

fclose($fp);

Keywords

PHP file operations file locking concurrency race condition

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