How to regularly delete old files on an FTP server using PHP

How to use PHP to regularly delete old files on an FTP server

In the modern web development process, many websites need to interact with the FTP server, which may include uploading files, downloading files, or deleting files. Among them, regularly deleting old files is a common requirement. This article will introduce how to use PHP to write a script to regularly delete old files on the FTP server.

1. Understand the FTP server

Before we start writing scripts, we need to understand some basic knowledge about the FTP server. FTP (File Transfer Protocol) is a standard protocol for file transfer on the network. An FTP server is a server hosted on the Internet and used to provide FTP services. The data of the FTP server is stored in a specific directory structure and can be connected and performed file operations through the FTP client.

2. Connect to the FTP server

In PHP, you can use the function ftp_connect() to connect to the FTP server. An example is as follows:

$ftpServer = 'ftp.example.com';
$ftpUsername = 'username';
$ftpPassword = 'password';

$connId = ftp_connect($ftpServer);
$loginResult = ftp_login($connId, $ftpUsername, $ftpPassword);

if($connId && $loginResult) {
    // FTP连接成功，进行后续操作
} else {
    // FTP连接失败，处理错误
}

3. Get the file list in the FTP directory

Use the function ftp_nlist() to get the file list in the specified directory on the FTP server. An example is as follows:

$ftpDirectory = '/path/to/directory/';

$fileList = ftp_nlist($connId, $ftpDirectory);

foreach($fileList as $file) {
    echo $file . '<br>';
}

4. Delete the specified old files

After obtaining the file list, we can traverse the list and decide which files need to be deleted according to our own needs. Use the function ftp_delete() to delete files on the FTP server. An example is as follows:

$ftpDirectory = '/path/to/directory/';
$daysAgo = 30; // 删除30天前的旧文件

$fileList = ftp_nlist($connId, $ftpDirectory);

foreach($fileList as $file) {
    $fileTimestamp = ftp_mdtm($connId, $file);
    $fileTimestamp = date_create_from_format('YmdHis', $fileTimestamp);
    $currentTimestamp = date_create();
    
    $diff = date_diff($currentTimestamp, $fileTimestamp);
    $elapsedDays = $diff->format('%a');
    
    if($elapsedDays > $daysAgo) {
        ftp_delete($connId, $file); // 删除旧文件
        echo '已删除文件：' . $file . '<br>';
    }
}

5. Scheduled execution of scripts

In order to realize the function of regularly deleting old files, we can use Linux's cron scheduled task to execute PHP scripts. Just add a line of rules in the crontab file. The example is as follows:

0 0 * * * php /path/to/script.php

The above example means that the /path/to/script.php script is executed once every morning.

6. Summary

This article introduces the method of using PHP to regularly delete old files on the FTP server. First, we learned the basics of FTP servers. Then, we learned how to connect to the FTP server and obtain the file list in the specified directory. Next, we wrote a code example to delete old files. Finally, we introduced how to execute scripts regularly by setting up scheduled tasks.

I hope this article can help developers who are developing websites to implement the function of regularly deleting old files and improve user experience and efficiency of server resource management.

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