What are the best practices for handling file downloads from a remote domain in PHP?

When handling file downloads from a remote domain in PHP, it is important to ensure that the file is downloaded securely and efficiently. One common approach is to use the `file_get_contents()` function along with `file_put_contents()` to download the file from the remote domain and save it locally. Additionally, it is recommended to validate the file type and size before downloading to prevent any security vulnerabilities.

$remoteFile = 'http://example.com/file.zip';
$localFile = 'downloads/file.zip';

// Download the file from the remote domain and save it locally
if (filter_var($remoteFile, FILTER_VALIDATE_URL)) {
    $fileContent = file_get_contents($remoteFile);
    if ($fileContent !== false) {
        file_put_contents($localFile, $fileContent);
        echo 'File downloaded successfully.';
    } else {
        echo 'Failed to download file.';
    }
} else {
    echo 'Invalid URL.';
}