Force File Download version 2.0 with configurable transfer rates

<?php
 
/**
 * This is the Force File Download class of the Skyward Portal
 * @package Skyward_Landing_Page
 * @subpackage Force File Download
 * @filesource
 * @author Matt Ford
 * @version 1.0
 */
 
class com_forcedownload {
 
	/**
	 * This method executes necessary methods based on request data
	 * @access public
	 * @author Matt Ford
	 * @param array $data configuration and request information
	 */
	public function preProcess($data) {
		$data->request["file"] = str_replace(" ", "+", $data->request["file"]);
 
		switch ($data->request["task"]) {
			case "forcefeed":
			default:
				$this->forceFeed($data);
				break;
		}
	}
 
	/**
	 * This method determines if the file path is good and executes the necessary method
	 * @access private
	 * @author Matt Ford
	 * @param array $data configuration and request information
	 */
	private function forceFeed ($data) {
		global $controller, $controller_config;
 
		$file = $controller_config->downloadRootDir . $controller->decrypt($data->request["file"]);
 
		if (file_exists($file) === true && is_file($file) === true && is_readable($file) === true) {
			$this->performDownload($file);
		}
		else {
			$this->invalidFile($file);
		}
	}
 
	/**
	 * This method performs the necessary actions to force the users browser to prompt a download box
	 * @access private
	 * @author Matt Ford
	 * @param string $file path to file
	 */
	private function performDownload($file) {
		$download_rate = 10000; //kbps
		$extension = strtolower(substr(strrchr($file, "."), 1));
 
		switch ($extension) {
 
			case "doc":
			case "docx":
				$mime = "application/msword";
				break;
 
			case "exe":
				$mime = "application/octet-stream";
				break;
 
			case "gif":
				$mime = "image/gif";
				break;
 
			case "jpg":
			case "jpeg":
				$mime = "image/jpeg";
				break;
 
			case "txt":
				$mime = "text/plain";
				break;
 
			case "xls":
			case "xlsx":
				$mime = "application/excel";
				break;
 
			default:
				$mime = "application/octet-stream";
				break;
		}
 
		header ("Content-Description: File Transfer");
		header ("Content-Disposition: attachment; filename=\"" . str_replace(" ", "_", basename($file)) . "\";");
		header ("Content-Type: " . $mime);
		header ("Content-Transfer-Encoding: binary");
		header ("Content-Length: " . filesize($file));
 
		flush();
		ob_flush();
 
		$fp = fopen($file, "r");
 
		while(!feof($fp)) {
			print fread($fp, round($download_rate * 1024));
			flush();
			ob_flush();
			sleep(1);
		}
 
		fclose($fp);
		die();
	}
 
	/**
	 * This method simply echoes an error message of a bad file/path
	 * @access private
	 * @author Matt Ford
	 * @param string $file path to file
	 */
	private function invalidFile($file) {
		global $controller_config;
		//echo "\"" . basename($file) . "\" is either not a valid file or not in the specified path";
		//die();
 
		$this->performDownload($controller_config->path . "/supplementalFiles/img/404_File_Not_Found.jpg");
	}
}
?>