Opening downloaded zip file creates cpgz file?

Question

If I make the url for a zip file the href of a link and click the link, my zip file gets downloaded and opening it gets the contents as I expect.

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Answer 1

The answer in my case was that there was an empty line being output before readfile().

So i added:

ob_end_clean();

readfile($filename);

But you should probably search for the place where this line is being output in your code.

Answer 2

Ok, I answered my own question.

The main problem, which I originally didn't make clear, was that the file was not located on my application server. It was in a Amazon AWS s3 bucket. That is why I had used a full url in my question, http://mysite... and not just a file path on the server. As it turns out fopen() can open urls (all s3 bucket "objects", a.k.a. files, have urls) so that is what I did.

Here's my final code:

$zip= "http://mysite.com/uploads/my-archive.zip"; // my Amazon AWS s3 url
header("Content-Type: archive/zip"); // works with "application/zip" too
header("Content-Disposition: attachment; filename='my-archive.zip"); // what you want to call the downloaded zip file, can be different from what is in the s3 bucket   
$zip = fopen($zip,"r"); // open the zip file
echo fpassthru($zip); // deliver the zip file
exit(); //non-essential

Answer 3

You're passing the URL to readfile() like:

$archive = 'https://mysite.com/uploads/my-archive.zip';

While you should pass the path on the server, for example:

$archive = '/uploads/my-archive.zip';

Assuming the file is located in the upload folder.

Additionally try the following headers:

header("Content-type: application/octet-stream"); 
header("Content-disposition: attachment; filename=file.zip");  

Answer 4

Another possible answer, I found After much searching, I found that the two possible reasons for a *.zip "unzipping" to a *.zip.cpgz are:

1. the *.zip file is corrupted
2. the "unzip" tool being used can't handle >2GB files

Being a Mac user, the second reason was the cause for my problem unzipping the file: the standard Mac OS tool is Archive Utility, and it apparently can't handle >2GB files. (The file in question for me was a zipped 4GB raspbian disk image.)

What I ended up doing was to use a Debian virtual machine, already existing in Virtual Box on my Mac. unzip 6.0 on Debian 8.2 had no problem unzipping the archive.

Answer 5

In my case, I was trying to create the file in a directory above public_html and the rules of the hosting didn't allow it.

Answer 6

The PHP documentation for readfile says that it will output the contents of a file and return an int.

So your code, echo readfile("$archive");, will echo $archive (btw, the double quotes are meaningless here; you should remove them), and THEN output the int that is being returned. That is, your line should be: readfile($archive);

Also, you should be using a local path (not an http:// link) to the archive.

Altogether:

if($yesCanDownload){
    $archive='/path/to/my-archive.zip';
    header("Content-Type: application/zip");
    header("Content-Disposition: attachment; filename=".basename($archive));
    header("Content-Length: ".filesize($archive));
    ob_clean();
    flush();
    readfile($archive);
}

Lastly, if that does not work, make sure filesize($archive) is returning the accurate length of the file.