Hey all,

I wouldn't consider myself a perl 'expert' by any stretch of the imagination, but I can't figure out what's wrong with my implementation of this code. Specifically, I was trying to use Ovid's code to implement a file upload utility for my site.

I can't get it to work, though. It gets to the sysopen command, but when it tries to write data, it either freezes, or writes nothing to the file and closes, leaving a zero-length file. What am I doing wrong? The "meat" of the code should be the same as Ovid's source.

Anyways, here's the code. I've put in some extra print statements for debugging purposes.

#!/usr/bin/perl -w

use strict;
use CGI;
use Fcntl;

use constant BUFFER_SIZE   => 16_384;       # Amount of upload file to
+ read at one time
use constant MAX_FILE_SIZE => 1_048_576;    # This is the filesize upl
+oad limit
use constant UPLOAD_DIR    => "/data/www/inverse.org/html/muckraker/te
+mp/";

$CGI::DISABLE_UPLOADS      = 0;             # Temporarily reenable upl
+oads
$CGI::POST_MAX             = MAX_FILE_SIZE; # This will stop someone f
+rom uploading
                                            # a fifty meg file to your
+ system
my $req      = CGI->new; 
my $theext   = "gif";
my $donepage = "up2.html";

my %upload_path = ('personal'   => 'temp_a/',
                   'impersonal' => 'temp_b/');

my $path = 'personal'; # my $path = $req->param('path');

if (! exists $upload_path{$path}) {
    # Oops!  It's not in our hash.  Someone was being naughty!
    print $req->redirect("some_error_page.html");
    exit;
}
$path = $upload_path{$path};

print "Content-type: text/html\n\n";

UPLOAD_FILE:
{
    for my $onnum (1..10) {
        my $file = $req->param("FILE$onnum") or next UPLOAD_FILE;
        if ($file) {
            my $buffer;
            my $file_handle = $req->upload( $file );
            my $format = $req->uploadInfo($file)->{'Content-Type'};
            print "format is '$format'\n";
        
            # In the following regex, we're getting the image type of 
+the MIME type.
            # This is better than checking the extension because if th
+ey upload from
            # a system that doesn't use extensions - or if the user's 
+redefined their
            # extensions, we'd have problems.
            $format    =~ s!^image/([a-zA-Z]+)$!$1!;
            if ($format !~ /$theext/o) {
                print "skipping to next\n";
                next UPLOAD_FILE;
            }
        
            my $fileName = "";
            
            # Create a random filename.  Keep running the loop if the 
+filename exists,
            # or if $fileName is false.
            while (! $fileName or -e UPLOAD_DIR.$path.$fileName) {
                $fileName = "";
                my @myarray=('a'..'z','A'..'Z','1'..'9');
                for (1..8) {
                    $fileName .= $myarray[rand(@myarray)];
                }
                $fileName .= ".$theext";
            }
            
            print "creating new file '" . UPLOAD_DIR . " :: $path :: $
+fileName'\n";
            # This will create the new file
            sysopen OUTFILE, UPLOAD_DIR . $path . $fileName, O_CREAT o
+r die "Can't open UPLOAD_DIR$path$fileName: $!";
            
            print "sysopen done\n";
#            print OUTFILE $file_handle;
            while ( read( $file_handle, $buffer, BUFFER_SIZE ) ) { 
                print "buffering... ";
                print OUTFILE $buffer; 
            }

            print "printing done\n";
            close (OUTFILE); 
            print "closing file\n";
        }
    }
}

print "program done\n";
[download]

Sample output:

format is 'image/gif' creating new file '/data/www/inverse.org/html/muckraker/temp/ :: temp_a/ :: Q1ywz4Nt.gif' sysopen done printing done closing file program done</B>

Commented out lines are ones I tried; whenever I used the single unbuffered print command, I got the zero-width file, but the program would freeze when I used the buffered write procedure shown.

I don't know how to debug using the built in tools since I can't 'fake' the GIF file I'm trying to send. I've tried many different .GIF files, all created in Photoshop.

I've tried other code snippets, both from this site and from the CGI.pm documentation, but they all seem to fail at the same point - the writing of the GIF file. I'm uploading from the same HTML file that Ovid referred to, using MSIE 5.5 (though I've tried in Netscape 4.74 and a few other browsers too). Any help on this would be very much appreciated!

Andre Germain