如何使用php锁定打开的文本文件[重复]

Question

我创建了一个脚本来生成由数字和字母组成的序列，如 A-0045-20170502。我的问题是如何锁定文件，以便在同时使用该文件时，只有一个用户可以在其他用户之前编辑.

函数序列(){ $字母 = ['A','B','C','D','E','F','G','H','I','J','K','L ','M','N','O','P','Q','R','S','T','U','V','W','X', 'Y','Z'];

    $content = file_get_contents("seq_file");
    $content = file_get_contents("seq_file") + 1 ;
    $letter_number = file_get_contents("letter_number");

    if ($content ==9999){

        file_put_contents("seq_file",0);
        $content = 0 ;
        $letter_number = $letter_number + 1 ;
        file_put_contents("letter_number",$letter_number);
    }
    file_put_contents("seq_file",$content);

       return   sprintf("%s-%05d-%s",$letter[$letter_number],$content,date("Ymd",strtotime("now"))); // A-00522-20170205
}



if(file_exists("seq_file") &&  file_exists("letter_number")){
    $seq = sequence();
} else {
    file_put_contents("letter_number",0);
    file_put_contents("seq_file",0);
    $seq = sequence();

}

Answer 1

您可以为此使用flock 函数。完成读/写后，请确保使用flock($file_handle, LOCK_UN) 释放锁定。

来自 PHP 网站的示例：

<?php

$fp = fopen("/tmp/lock.txt", "r+");

if (flock($fp, LOCK_EX)) {  // acquire an exclusive lock
    ftruncate($fp, 0);      // truncate file
    fwrite($fp, "Write something here\n");
    fflush($fp);            // flush output before releasing the lock
    flock($fp, LOCK_UN);    // release the lock
} else {
    echo "Couldn't get the lock!";
}

fclose($fp);

?>