用于提供文件最新版本的PHP脚本

Question

My PHP's rusty and I'm hoping that someone can help me with a quick script - I don't really know where to start with it!

I have a folder containing zipped archives of various versions of a software product:

• Product_1.00.zip
• Product_1.05.zip
• Product_2.00.zip

etc.

Now, on my web site I have a button to download the product. However, I'd like that button to always download the latest version.

It seems to me that a nice solution would be to link to a PHP script that would scan the folder for the latest version and deliver that file to the user as if they have pointed the browser directly at the file.

Can anyone provide me with a starting point?

Answer 1

I think it's the easiest to read the files from the directory into an array. Then natsort the array and pop off the last entry.

Here is an example:

<?php
function getLatestVersion() {
    $dir = dir('.');
    $files = array();

    while (($file = $dir->read()) !== false) {
        $files[] = $file;
    }
    $dir->close();

    natsort($files);
    return array_pop($files);
}

Outputs

array(6) {
  [0]=>
  string(1) "."
  [1]=>
  string(2) ".."
  [2]=>
  string(16) "Product_1.00.zip"
  [3]=>
  string(16) "Product_1.05.zip"
  [5]=>
  string(16) "Product_2.00.zip"
  [4]=>
  string(17) "Product_10.00.zip"
}

How to download the latest version of the zip file?

EDIT

Like @j_mcnally pointed out in his comment below it's more efficient to let the webserver handle the serving of static files. Possible ways are direct links or redirecting the request from the PHP file to the right location using a 301.

But if you still want to let PHP do the work. Here is an example.

---

Grabbed the example below from http://perishablepress.com/http-headers-file-downloads and altered it a bit.

<?php // HTTP Headers for ZIP File Downloads
// http://perishablepress.com/press/2010/11/17/http-headers-file-downloads/

// set example variables

// Only this line is altered
$filename = getLatestVersion();

$filepath = "/var/www/domain/httpdocs/download/path/";

// http headers for zip downloads
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");
header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"".$filename."\"");
header("Content-Transfer-Encoding: binary");
header("Content-Length: ".filesize($filepath.$filename));
ob_end_flush();
@readfile($filepath.$filename);
?>