CodeIgniter 3 Log extension

MY_Log.php

<?php
/**
 * CodeIgniter core extension
 *
 * @package    CodeIgniter
 * @author     Louis Linehan <[email protected]>
 * @copyright  2017 Louis Linehan
 * @license    https://opensource.org/licenses/MIT MIT
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * MY Log
 *
 * This adds HTTP_REFERER, REQUEST_URI, REMOTE_ADDR to the end of the log message.
 *
 * @package CodeIgniter\application\core
 * @author  Louis Linehan <[email protected]>
 */
class MY_Log extends CI_Log {

	/**
	 * Class constructor
	 *
	 * @return void
	 */
	public function __construct()
	{
		parent::__construct();
	}

	/**
	 * Write Log File
	 *
	 * Generally this function will be called using the global log_message() function
	 *
	 * @param string $level The error level: 'error', 'debug', 'info' or 'all'
	 * @param string $msg   The error message
	 *
	 * @return boolean
	 */
	public function write_log($level, $msg)
	{
		if ($this->_enabled === FALSE)
		{
			return FALSE;
		}

		$level = strtoupper($level);

		if (( ! isset($this->_levels[$level]) OR ($this->_levels[$level] > $this->_threshold))
			&& ! isset($this->_threshold_array[$this->_levels[$level]]))
		{
			return FALSE;
		}

		$filepath = $this->_log_path . 'log-' . date('Y-m-d') . '.' . $this->_file_ext;
		$message  = '';

		if ( ! file_exists($filepath))
		{
			$newfile = TRUE;
			// Only add protection to php files
			if ($this->_file_ext === 'php')
			{
				$message .= "<?php defined('BASEPATH') OR exit('No direct script access allowed'); ?>\n\n";
			}
		}

		if ( ! $fp = @fopen($filepath, 'ab'))
		{
			return FALSE;
		}

		flock($fp, LOCK_EX);

		// Instantiating DateTime with microseconds appended to initial date is needed for proper support of this format
		if (strpos($this->_date_fmt, 'u') !== FALSE)
		{
			$microtime_full  = microtime(TRUE);
			$microtime_short = sprintf('%06d', ($microtime_full - floor($microtime_full)) * 1000000);
			$date            = new DateTime(date('Y-m-d H:i:s.' . $microtime_short, $microtime_full));
			$date            = $date->format($this->_date_fmt);
		}
		else
		{
			$date = date($this->_date_fmt);
		}

		// Changed this to also output the referer and url if found.
		$referer     = ! empty($_SERVER['HTTP_REFERER']) ? ' HTTP_REFERER "' . $_SERVER['HTTP_REFERER'] . '"' : '';
		$request_uri = ! empty($_SERVER['REQUEST_URI']) ? ' REQUEST_URI "' . $_SERVER['REQUEST_URI'] . '"' : '';
		$ip_address  = ! empty($_SERVER['REMOTE_ADDR']) ? ' REMOTE_ADDR "' . $_SERVER['REMOTE_ADDR'] . '"' : '';

		$message .= $this->_format_line($level, $date, $msg . $request_uri . $referer . $ip_address);

		for ($written = 0, $length = self::strlen($message); $written < $length; $written += $result)
		{
			if (($result = fwrite($fp, self::substr($message, $written))) === FALSE)
			{
				break;
			}
		}

		flock($fp, LOCK_UN);
		fclose($fp);

		if (isset($newfile) && $newfile === TRUE)
		{
			chmod($filepath, $this->_file_permissions);
		}

		return is_int($result);
	}
}