[RESOLVED] Perplexing PHP Problem

daltman1967

I'm using the following code:

if(ini_get('zlib.output_compression'))
  ini_set('zlib.output_compression', 'Off');
$file_extension = strtolower(substr(strrchr($file,"."),1));
$mime_types=array();
...
...
$mime_types['mp3']   = 'audio/mpeg';
...
...
$mime_types['wma']   = 'audio/x-ms-wma';

$ext=strtolower(substr(strrchr($file,'.'),1));
$mime=$mime_types[$ext];

header('Pragma: public');   // required
header('Expires: 0');       // no cache
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Last-Modified: '.gmdate ('D, d M Y H:i:s', filemtime ($file)).' GMT');
header('Cache-Control: private',false);
header('Content-Type: '.$mime);
header('Content-Length: '.filesize($file)); // provide file size
header('Content-Disposition: attachment; filename="'.basename($file).'"');
header('Content-Transfer-Encoding: binary');
header('Connection: close');
readfile($file);    // push it out

$file contains both the directory and the filename, i.e.,

../Image/audio/My-Redeemer-LivesHS.mp3

The script opens the save as dialog box, with the proper file size, and allows me to save the file.

However: Some files work properly, others do not.
When loaded into Media Player, it says it cannot play the content. Real Player will handle some, but fail on others. Real Player couldn't handle the .wma file I tried, but handled ALL of the .mp3's; Media Player couldn't handle ANY of them.

The original files, if simply copied off the server into the directory via FTP, work fine. There's some sort of problem with the download script. It must be changing the internal structure of the files somehow.

I have provided a MYSQL database of the files available. The user chooses the file name, then clicks a button to download. This should pop up the 'save as/open' dialog box. Once the file has arrived, it should play... just as the original.

Since the original file isn't the problem, and the copy on the server side isn't the problem, ergo, the problem MUST be in the script. But... I'm stumped. I REALLY need this to work all the time, every time, with both audio and video file formats. I've tried several 'force download' scripts, but the end result is the same.

Anybody have any ideas? 😕

Shrike

Have you checked the headers of each file to ensure they are sent correctly?

halojoy

What I would have a look at
is the
header('Content-Transfer-Encoding: binary');
and the
header('Content-Type: '.$mime);

It might be that some file formats would need some special Content-Transfer-Encoding
in order to reduce chances of corrupt file.
If you can not play, then I say it is probably a file that got corrupted in TRANSFER.
🙂

daltman1967

The $mime type has to be correct... 'audio/mpeg' is .mp3. As far as 'Content-Transfer-Encoding: binary', I have no idea what else to put. I have another mp3 file that transfers just fine. Both have the Artist Name, Album Name, etc. in the file. But this one particular file transfers badly every time, same as the WMA. It's too bad you can't have a "save as" box and then do the transfer via FTP...

Weedpacket

Well, you can have a "save as" box... The Content-Type "application/octet-stream" is the mime type for a generic binary file; if you don't say that it's an audio file the client won't have a reason to treat it like one.

If the file transferred via the script (using application/octet-stream) is still corrupt, then you'll still have the downloaded file, and can start comparing it with what you should have received (the copy you fetched via ftp). File size is the easiest property to compare. My mind is a blank right now when it comes to programs that provide detailed comparisons of binary files, but I expect they're out there.

It's perhaps noteworthy that some applications can read some results, but not others. It may be that different applications have different approaches to error correction (MP3 files have very little integrity protection beyond the header: it's possible to convert all the "\n" in such a file to "\r\n" (an ftp transfer using ASCII mode can do that), and the result will still play; the output will be garbled, but it will still play.

It's still true that if the file after transfer is different from the file before transfer then it's the transfer script that's changing it. If I may make a request:

Please post a minimal version of the offending script. Most of the code can no doubt be removed and leave something that still corrupts files (for example, it only needs to transfer one given file, so it doesn't need to do a lot of work identifying file name and type). Also, attach a small file that the script corrupts - twice: "before" and "after" versions.

daltman1967

Ok, here's the short version of the code:

<?
$file="../Images/audio/My-Redeemer-LivesHS.mp3";
if(ini_get('zlib.output_compression'))
ini_set('zlib.output_compression', 'Off');

header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Content-Type: application/octet-stream");
header('Content-Length: '.filesize($file));
header("Content-Disposition: attachment; filename=".basename($file));
header('Content-Transfer-Encoding: binary');
readfile($file);
exit();
?>

Both the original file on my hard drive and its corresponding copy on the server play fine. Only the downloaded version fails to play.

The original is called 'My-Redeemer-LivesHS.mp3' and the copy is 'My-Redeemer-LivesHSa.mp3' -- however, the 'Manage Attachments' function of this page would not upload my zip file(s). The files are 5619kb each. I'd be happy to e-mail them, though...
Any help is GREATLY appreciated.

daltman1967

Since I can't post the songs by attachment, I've zipped them and made them available on my server at http://www.refugeministries.info/songs.zip. I've tested the zip download, and all is as it should be.

.wma songs don't work at all; I'm guessing this is a .mime type issue as well as a header issue. The problem HAS to be in the headers.... but where??