(php) download remote file with curl

gistfile1.txt

<?php

	function download_remote_file_with_curl($file_url, $save_to) {
		$ch = curl_init();
		curl_setopt($ch, CURLOPT_POST, 0); 
		curl_setopt($ch, CURLOPT_URL, $file_url);
		curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36');
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
		$file_content = curl_exec($ch);
		curl_close($ch);

		$downloaded_file = fopen($save_to, 'w');
		fwrite($downloaded_file, $file_content);
		fclose($downloaded_file);
 
	}

    download_remote_file_with_curl('https://example.com/example.txt', realpath("./") . '/btc.json');