Detailed explanation of the basic usage method of ftp_site function

gitbox 2025-05-29

In PHP's FTP function library, ftp_site() is a function that is rarely used by beginners but is very powerful. It allows developers to send SITE commands to the FTP server, thus performing some advanced operations supported by the server. This article will explain in detail the basic usage and operation steps of ftp_site() , helping you quickly master it and flexibly use it in FTP projects.

1. What is the ftp_site function?

The ftp_site() function is used to send a SITE command to the FTP server. The SITE command is usually an extended command provided by an FTP server, such as setting file permissions, changing directory properties, or executing custom instructions.

Function prototype

 bool ftp_site ( FTP\Connection $ftp_stream , string $command )

$ftp_stream : The connected FTP resource.
$command : The content of the SITE command you want to send.

The return value is a boolean value: true when successful, false when failed.

2. Preparation before use

Before using ftp_site() , you need to complete the following basic preparation steps:

Connect to the FTP server.
Log in to the FTP server.
Make sure the FTP server supports the SITE commands you want to send.

3. Basic usage examples

Here is a complete example of usage:

 <?php
// 1. Connect toFTPserver
$ftp = ftp_connect("ftp.gitbox.net");
if (!$ftp) {
    die("无法Connect toFTPserver。");
}

// 2. Log in
if (!ftp_login($ftp, "your_username", "your_password")) {
    ftp_close($ftp);
    die("FTPLog in失败。");
}

// 3. Set passive mode（Depends on the situation）
ftp_pasv($ftp, true);

// 4. use SITE Command to set file permissions
$file = "public_html/index.php";
$command = "CHMOD 755 $file";

if (ftp_site($ftp, $command)) {
    echo "File permissions are set successfully。";
} else {
    echo "Failed to set file permissions。";
}

// 5. Disconnect
ftp_close($ftp);
?>

In this example, we use ftp_site() to send the CHMOD 755 command to the FTP server to modify file permissions.

4. Common SITE commands

Different FTP servers support SITE commands differently, and the following are some common examples:

CHMOD : Change permissions for files or directories.
UMASK : Set the default permission mask.
HELP : Lists supported SITE commands.
IDLE : Sets the user idle timeout.

You can try the following command to see which SITE commands the server supports:

 ftp_site($ftp, "HELP");

5. Things to note

Compatibility issues : Not all FTP servers support SITE commands, and the specific command format may also be slightly different.
Permission Requirements : Some SITE commands may require high permissions (such as administrator privileges) to be executed.
Security considerations : The FTP protocol itself is not encrypted, and it is recommended to use SFTP or FTP over TLS (FTPS) when transmitting sensitive information.
Error handling : It is recommended to perform more detailed error handling on the execution results of ftp_site() in production environment.

6. Application scenario expansion

In actual projects, ftp_site() is often used in the following scenarios:

Set file permissions during automated deployment;
Set the default properties directly after creating a directory;
Quickly set up access controls after the user uploads the file;
Use cron scripts to implement regular directory maintenance or file archiving.

7. Summary

Although ftp_site() is not the most commonly used in PHP FTP functions, it is very efficient under specific requirements. As long as you understand the meaning of SITE commands and use them flexibly according to the server support situation, you can greatly improve the automation of FTP management. Once you master it, you will be able to handle advanced operations such as deployment scripts and permission maintenance more easily. I hope this article can help you get started quickly and efficiently use PHP for FTP management!

Detailed explanation of the basic usage method of ftp_site function