How to offer binary files for download via CGI ?

vivapl has asked for the wisdom of the Perl Monks concerning the following question:

In need of wisdom

Could someone please give me an example on how to download binary files(gzipped)?

Currently by clicking on a button on my webpage, I'm getting back a file of size 0. However when I intercept the content and save it into my temp dir, it's good. I'm just about clueless at this moment.

Here is my code:(I call &dl_user($somefile))

sub read_binary
{
  local($fname) = @_;
  
  open(FILE, "<$fname") || return '';
  while(<FILE>){ $spcontent .= $_; }
  close(FILE);

  $spcontent;
}

sub dl_user
{
  ($loc)=@_;

  $filename = $loc;
  $filename =~ s/.+\/([^\/]+)$/$1/;
  $filename =~ s/.+\\([^\\]+)$/$1/;
  print "Content-Type: application/x-binary\n";
print"Content-Disposition:attachment;filename=$filename\n\n";
  &read_binary($loc);
}
[download]

Thanks in advance!

Edit by tye, title, remove extra P tags

Comment on How to offer binary files for download via CGI ? Download Code

Replies are listed 'Best First'.
Re: How to offer binary files for download via CGI ? by JamesNC (Chaplain) on Jul 22, 2003 at 21:51 UTC
did you try binmode? `sub read_binary { local($fname) = @_; open(FILE, "<$fname") \|\| return ''; binmode FILE; while(<FILE>){ $spcontent .= $_; } close(FILE); $spcontent; }` [download] JamesNC	[reply] [d/l]
Re: How to offer binary files for download via CGI ? by sgifford (Prior) on Jul 22, 2003 at 21:48 UTC
The sample code you've posted doesn't do anything with the file's contents; it just reads them, puts them in a variable, then returns it as the result of `dl_user`. Perhaps it's printed elsewhere, but if not that's part of your problem. The usual content type for arbitrary binary data is `application/octet-stream`, although I don't think that's part of your current problem. It can also be awkward to read binary files with the diamond operator `<FILE>`, since line breaks don't occur in any particular place. It's usually best to use `read`, but again I don't think this is causing the problem you're seeing.	[reply] [d/l] [select]
Re: Re: How to offer binary files for download via CGI ? by waswas-fng (Curate) on Jul 22, 2003 at 23:53 UTC
<> Do the Right Thing with bin slurps -- although read is better. octet-stream seems to have some issues with random browsers showing the file instead of saving. I will have to go back and look what type i used after doing a ton of tests with many browsers -- I just hvae it stuck in my mind that octet-stream failed a bunch of download tests last time I did this. -Waswas	[reply]
Re: How to offer binary files for download via CGI ? by Zaxo (Archbishop) on Jul 22, 2003 at 20:51 UTC
I think you should look into LWP::UserAgent. That will handle most of the details. All you need to do is tell it what you want. There is a unified interface for several protocols, including http and ftp. After Compline, Zaxo	[reply]
Re: Re: How to offer binary files for download via CGI ? by bobn (Chaplain) on Jul 22, 2003 at 23:49 UTC
LWP::UserAgent is for being an http client. When was the last time a client used CGI or needed to `print "Content-Type: application/x-binary\n";`? --Bob Niederman, http://bob-n.com	[reply] [d/l]