Compress –Zip– Multiple Files And Download with PHP

With PHP’s  build-in ZipArchive Class we can archive multiple files into one bundle ,  compressed as Zip file-format . If you have read my previous article ” How To Make Files Downloadable with PHP ” then you already know that PHP can “send-out”  raw HTTP headers to instruct the browser to behave accordingly ( redirection , authentication , catching , downloading ) . The magical function to do so is the header() function . This function allows us to define raw HTTP headers as a string (most of these header parameters are pretty self explanatory) . The script will then execute those headers and force the browser to render the page accordingly .

We have to bundle multiple files into one ZipArchive and instruct the browser the file-type it will receive  . Compressing is accomplished in four steps :

1. Instantiating a new ZipArchive Class (Creating a new object)
2. Opening and assigning a name to the object .
3. Adding files into the object (most likely with a loop )
4. Closing the object

The final step is to “read ” the compressed object readfile(“Compressed-File-Name”) , which will be delivered to the browser .  Of course some extra steps has to be  implemented like — sanitizing all data received by the browser , redirecting empty requests (no $_POST data , for example if the user links directly to the script ) —- . I haven’t included an important step , download count limit . This step is left as home work to the reader 🙂 .

The code is divided into two files : the user-interface (index.php)  where the user selects which files he would like to download . The second file “download.php” , receives the request and returns a compressed file .

Source code for Index.php :

<h2 style="color:blue;text-align:center"> Select which files you want to include in the zip-file
<form action="download.php"" method="post"></pre>
<p style="height: <span class=;">100px; overflow: auto; border: 5px solid #eee; background: #eee; color: #000; margin-bottom: 1.5em;width:250px"></p>

<pre>
<label><input type="checkbox" name="items[]" value="pic7.jpg" checked="checked"/> Thumb-image </label>

<label><input type="checkbox" name="items[]" value="test.pdf"/> A test PDF file</label>

<label><input type="checkbox" name="items[]" value="test.txt"/> A simple text file</label>

<label><input type="checkbox" name="items[]" value="test.swf"/>A Flash animation</label>
<label><br />
<input type="checkbox" name="items[]" value="pic1.png"/> Small icon for webdesign 

<label><input type="checkbox" name="items[]" value="pic2.png" /> Small icon for webdesign </label>

<label><input type="checkbox" name="items[]" value="pic3.png" checked="checked" /> Small icon for webdesign </label>

<label><input type="checkbox" name="items[]" value="pic4.png"/>Small icon for webdesign </label>

<label><input type="checkbox" name="items[]" value="pic5.png"/> Small icon for webdesign</label>

<label><input type="checkbox" name="items[]" value="pic6.png"/> Small icon for webdesign</label>

</label><br />
</p>
<input type="submit" name="formSubmit" value="Download" >
</form>

Source code for download.php

<?php

function zipFilesAndDownload($file_names,$archive_file_name,$file_path){
	$zip = new ZipArchive();
	//create the file and throw the error if unsuccessful
	if ($zip->open($archive_file_name, ZIPARCHIVE::CREATE )!==TRUE) {
    	exit("cannot open <$archive_file_name>\n");
	}
	//add each files of $file_name array to archive
	foreach($file_names as $files)	{
  		$zip->addFile($file_path.$files,$files);		
	}
	$zip->close();
$zipped_size = filesize($archive_file_name);
header("Content-Description: File Transfer");
header("Content-type: application/zip"); 
header("Content-Type: application/force-download");// some browsers need this
header("Content-Disposition: attachment; filename=$archive_file_name");
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header("Content-Length:". " $zipped_size");
ob_clean();
flush();
readfile("$archive_file_name");
unlink("$archive_file_name"); // Now delete the temp file (some servers need this option)
    exit;	
  }
if(isset($_POST['formSubmit'])) {
//$file_names=$_POST['items'];// Always sanitize your submitted data!!!!!!
//$file_names = filter_var_array($_POST['items']);//works but it's the wrong method
$filter = filter_input_array(INPUT_POST, FILTER_SANITIZE_SPECIAL_CHARS) ;
$file_names = $filter['items'] ; 
//Archive name
$archive_file_name='DEMO-archive.zip';
//Download Files path
$file_path= getcwd(). '/content/';
//cal the function
zipFilesAndDownload($file_names,$archive_file_name,$file_path);
} else {

header("Refresh: 5; url= ./index.php ");
print '<h1 style="text-align:center">You you shouldn\'t be here ......</pre>
<p style="color: red;"><strong>redirection in 5 seconds</strong></p>
<pre>';
exit;
}

Download the source code