md5sums of downloaded files are wrong Options

[larry78723]

I'm having a problem that files downloaded from my site don't have the same md5sum as the original file. Here's an example:

md5sum of original file: a00bd61088cf4f4a0138d51f24e554f0

md5sum of downloaded file: 6f23af927c0a3348345ed1415fb89e36

I suspect that something is inserting bits into the downloads. I've scrubbed the code for hidden spaces but found none.

Here's the code I'm using:

CODE

<?php

function mydloader($filename=NULL)  {
    if( isset( $filename ) ) {        
        $ext = pathinfo($filename, PATHINFO_EXTENSION);
            {
            if ($ext == '.iso')
                header('Content-Type: application/x-cd-image');
            elseif ($ext =='.gz')
                header('Content-Type: application/zip');
            else
                header('Content-Type: octet-stream');
            }
        header('Content-Length: ' .filesize($filename));
        header("Content-Disposition: attachment; filename={$filename}");
        header('Pragma: no-cache');
        header('Expires: 0');        
        readfile($filename);
                  
      }
        
    else {
        echo "isset failed";
        }  
}
mydloader($_GET["f"]);   //passed from calling script

I'd appreciate some help on this.

[larry78723]

Won't allow me to edit last post but new info.

Comparison of Sizes:
original size: 5674712
download size: 5674783

I also xxd’d both files and compared them in Meld. It appears that the filename is being pre-pended to the downloaded file.

[larry78723]

I'm having a problem that files downloaded from my site don't have the same md5sum as the original file. Here's an example:

I've studied the hex code for both the original file and the downloaded file. I found that the file name is being prepended to the downloaded file in the code I posted. I've checked for blank spaces and found none.

Does anyone have any ideas about what may be causing this?

Thanks in advance.

[Christian J]

No experience with this, but I didn't understand this part:

CODE

function mydloader($filename=NULL)  {

Doesn't the above make $filename null? On the other hand, right after comes:

CODE

    if( isset( $filename ) ) {    

which should return false if $filename really was null.

BTW, these curly braces look a bit misplaced:

CODE

            {
            if ($ext == '.iso')
                header('Content-Type: application/x-cd-image');
            elseif ($ext =='.gz')
                header('Content-Type: application/zip');
            else
                header('Content-Type: octet-stream');
            }

[larry78723]

BTW, these curly braces look a bit misplaced:

CODE

            {
            if ($ext == '.iso')
                header('Content-Type: application/x-cd-image');
            elseif ($ext =='.gz')
                header('Content-Type: application/zip');
            else
                header('Content-Type: octet-stream');
            }

I used the curly braces to offset the if-elseif-else statements from the rest of the headers. It all works, but somehow the filename is being injected into the start of the downloaded file.

[Christian J]

Comparison of Sizes:
original size: 5674712
download size: 5674783

somehow the filename is being injected into the start of the downloaded file.

Maybe it's done by readfile(), or even when the file was first uploaded (say by the FTP program)? This should be possible to test, seems readfile() returns the number of bytes read from the file on success. You could also try running filesize() on various places in the script.

[larry78723]

I've got everything working now. Thanks to all that replied.

[Christian J]

What was the cause?