How to Search and Replace Files on an FTP Server Using PHP

Preparation

Before starting, ensure you have a PHP environment that can connect to an FTP server and that you possess the FTP host, username, password, and port information.

Connecting to FTP Server

Use PHP's FTP extension to establish a connection, authenticate, and switch to passive binary mode.

// Set FTP server connection info
$ftp_server = 'ftp.example.com';
$ftp_user   = 'username';
$ftp_pass   = 'password';
$ftp_port   = 21;

// Establish FTP connection
$ftp_conn = ftp_connect($ftp_server, $ftp_port);
if (! $ftp_conn) {
    die("无法连接到FTP服务器");
}

// Log in to FTP server
if (!ftp_login($ftp_conn, $ftp_user, $ftp_pass)) {
    die("FTP登录失败");
}

// Set transfer mode to binary (passive)
ftp_pasv($ftp_conn, true);

Search and Replace Files

After connecting, list the files in the target directory, download each file to a temporary local copy, replace the desired string, upload the modified file back, and clean up the temporary file.

// Define strings to search and replace
$old_string = 'example.com';
$new_string = 'example.net';

// Target remote directory
$remote_dir = '/path/to/remote/directory';

// List files in the directory
$file_list = ftp_nlist($ftp_conn, $remote_dir);

// Iterate over each file and replace content
foreach ($file_list as $file) {
    // Download file to a temporary local file
    $temp_file = tempnam(sys_get_temp_dir(), 'tempfile');
    ftp_get($ftp_conn, $temp_file, $file, FTP_BINARY);

    // Read file content
    $file_content = file_get_contents($temp_file);

    // Replace the target string
    $new_content = str_replace($old_string, $new_string, $file_content);

    // Write the modified content back to the temporary file
    file_put_contents($temp_file, $new_content);
    ftp_put($ftp_conn, $file, $temp_file, FTP_BINARY);

    // Delete the temporary local file
    unlink($temp_file);
}

// Close the FTP connection
ftp_close($ftp_conn);

Conclusion

The script demonstrates how to programmatically connect to an FTP server using PHP, enumerate files, download them, perform a search-and-replace on their contents, upload the updated files, and finally close the connection, providing a reusable automation pattern for bulk file modifications.