Reggie Thomson’s Diary

I have had several requests for the PHP code for forcing downloads of specific file types. Here it is:

<?php

function download_file ($file)
{
	//First, see if the file exists
	if (!is_file ($file))
	{
		die ('<b>404 File not found!</b>') ;
	}

	$file_length = filesize ($file) ;
	$filename = basename ($file) ;
	$file_extension = strtolower (substr (strrchr ($filename, '.'), 1)) ;
	$file_modified = filemtime ($file) ;

	//This will set the Content-Type to the appropriate setting for the file
	switch ($file_extension)
	{
	case 'kmz':
		$content_type = 'application/vnd.google-earth.kmz' ;
		break ;
	case 'kml':
		$content_type = 'application/vnd.google-earth.kml+xml' ;
		break ;
	case 'pdf':
		$content_type = 'application/pdf' ;
		break ;
	case 'exe':
		$content_type = 'application/octet-stream' ;
		break ;
	case 'zip':
		$content_type = 'application/zip' ;
		break ;
	case 'doc':
		$content_type = 'application/msword' ;
		break ;
	case 'xls':
		$content_type = 'application/vnd.ms-excel' ;
		break ;
	case 'ppt':
		$content_type = 'application/vnd.ms-powerpoint' ;
		break ;
	case 'gif':
		$content_type = 'image/gif' ;
		break ;
	case 'png':
		$content_type = 'image/png' ;
		break ;
	case 'jpeg':
	case 'jpg':
		$content_type = 'image/jpg' ;
		break ;
	case 'mp3':
		$content_type = 'audio/mpeg' ;
		break ;
	case 'wav':
		$content_type = 'audio/x-wav' ;
		break ;
	case 'mpeg':
	case 'mpg':
	case 'mpe':
		$content_type = 'video/mpeg' ;
		break ;
	case 'mov':
		$content_type = 'video/quicktime' ;
		break ;
	case 'avi':
		$content_type = 'video/x-msvideo' ;
		break ;

	//The following are for extensions that shouldn't be downloaded (sensitive stuff, like php files)
	case 'php':
	case 'htm':
	case 'html':
	case 'txt':
		die ('<b>Cannot be used for '. $file_extension .' files!</b>') ;
		break;
	default:
		$content_type = 'application/force-download' ;
	}


	switch ($file_extension)
	{
	case 'kmz':
	case 'kml':
		header ('Last-Modified: ' . gmdate ('D, d M Y H:i:s \G\M\T', $file_modified));
		header ('Content-Length: ' . $file_length) ;
		header ('Content-Type: ' . $content_type) ;
		break ;

	default:
		//Begin writing headers
		header ('Pragma: public') ;
		header ('Expires: 0') ;
		header ('Cache-Control: must-revalidate, post-check=0, pre-check=0') ;
		header ('Cache-Control: public') ;
		header ('Content-Description: File Transfer') ;

		//Use the switch-generated Content-Type
		header ('Content-Type: ' . $content_type) ;

		//Force the download - set the headers
		header ('Content-Disposition: attachment; filename=' . $filename . ';') ;
		header ('Content-Transfer-Encoding: binary') ;
		header ('Content-Length: ' . $file_length) ;
	}

	//Now read the file and exit
	@readfile ($file) ;
	exit ;
}

// Put the file in a directory on your website and change the information below
// replacing "/directory/to/" with your directory
// and "filename.ext" with the filename and its extension

$file = '/directory/to/filename.ext' ;
download_file ($file) ;

?>

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