Angie's Techno Stuff

To download a pdf file is very simple, and can be done using a few lines of code such as:

header('Content-disposition: attachment; filename=file1.pdf');
header('Content-type: application/pdf');
readfile('file1.pdf');

This code can be put into a php file, e.g. download.php and used in the webpage as follows:

<a href="download.php">File to download</a>

Recently I needed to download other file types and developed the following code. I use a file object (class) which is instantiated when the fileManager is called.
I found that the files I downloaded were getting corrupted, and fixed the problem with ob_clean() and flush()

Here’s my PHP code for downloading files:

First create a file class:

<?php
/*
 File: File.class.php
 Description: File Management Object to Download Document 
 Author: AS June 2012
 */
class File {

    // File Name 
    private $file;

    //Mime/Type 
    private $type;

    
    // file object Constructor 
    public function File($f_name) {
	    $this->file = $f_name;
        $this->type = $this->setMimeType($f_name);
        $this->download_file();
        return;
    }

	//set mime type
	private function setMimeType($filename){
		$extension = strtolower(substr(strrchr($filename, '.'), 1));
		switch($extension) {
			case "pdf": $type="application/pdf"; break;
			case "pptx": $type="application/vnd.openxmlformats-officedocument.presentationml.presentation"; break;
			case "doc": $type="application/msword"; break;
			case "docx": $type="application/vnd.openxmlformats-officedocument.wordprocessingml.document"; break;
			case "xlsm": $type="application/vnd.ms-excel.sheet.macroEnabled.12"; break;
			
			default: $type=0;
		}
	}
   
     // download the $file 
     private function download_file() {
		 
	   header("Content-Disposition: attachment; filename=".$this->file);
           header("Content-type: ".$this->type);
		
	   // next 2 lines of code required to prevent file corruption
	   ob_clean();
	   flush();

           readfile($this->file);
	   exit;
    }
}
?> 

Create another php file including the following code and call it fileManager.php. It will create the file objects and download them.

require_once( "File.class.php" );
//get values for variables  
$fileName = isset( $_GET["file"] ) ? $_GET["file"] : "";


//download file 
if(is_file($fileName)){
	$download = new File($fileName );
}

Then on web page include a link to your file for downloading e.g.

<a href="fileManager.php?file=filename.pdf">File to download</a>

Don’t forget to upload your file for downloading to the website.

Useful link for other mime types

Tags: downloading files, PHP, preventing file corruption