What are the differences between using HTTP and FTP protocols in PHP when accessing files on a server, and what are the potential pitfalls of each?

When accessing files on a server in PHP, the main differences between using HTTP and FTP protocols lie in the methods of file transfer and authentication required. HTTP is typically used for transferring files over the web, while FTP is commonly used for accessing files on a remote server. Potential pitfalls of using HTTP include limited access control and slower transfer speeds, while FTP may require additional authentication and security measures.

// Using HTTP to access a file on a server
$file_url = 'http://www.example.com/file.txt';
$file_content = file_get_contents($file_url);
echo $file_content;
```

```php
// Using FTP to access a file on a server
$ftp_server = 'ftp.example.com';
$ftp_user = 'username';
$ftp_pass = 'password';
$ftp_connection = ftp_connect($ftp_server);
ftp_login($ftp_connection, $ftp_user, $ftp_pass);
$file_path = '/path/to/file.txt';
$file_content = ftp_get($ftp_connection, 'php://output', $file_path, FTP_BINARY);
echo $file_content;
ftp_close($ftp_connection);