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

Hello Monks,

I am start to learn CGI Program.

When I execute the following coding I get the following Error Message: 

Can't use an undefined value as a symbol reference at C:/Apache2/cgi-b
+in/de.cgi line 50.

[download]

Please guide where I made mistake

HTML File Contains

<html>
<body>

<form action="/cgi-bin/de.cgi" method="post" enctype="multipart/form-d
+ata">
    <p>Please Select a file to upload:</p>
    <input type="file" name="file"><br><br>
    <input type="text" name="filename"><br><br><br>
    <input type="submit">
</form>

</body></html>

[download]

CGI File Contains

#!d:/perl/bin/perl

use strict;
use CGI;
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use Fcntl qw( :DEFAULT :flock );

use constant UPLOAD_DIR     => 'c:/uploads';
use constant BUFFER_SIZE    => 16_384;
use constant MAX_FILE_SIZE  => 1_048_576;       # Limit each upload to
+ 1 MB
use constant MAX_DIR_SIZE   => 100 * 1_048_576; # Limit total uploads 
+to 100 MB
use constant MAX_OPEN_TRIES => 100;

$CGI::DISABLE_UPLOADS   = 0;
$CGI::POST_MAX          = MAX_FILE_SIZE;

my $q = new CGI;
$q->cgi_error and error( $q, "Error transferring file: " . $q->cgi_err
+or );

my $file      = $q->param( "file" )     || error( $q, "No file receive
+d." );
my $filename  = $q->param( "filename" ) || error( $q, "No filename ent
+ered." );
my $fh        = $q->upload( $file );
my $buffer    = "";

if ( dir_size( UPLOAD_DIR ) + $ENV{CONTENT_LENGTH} > MAX_DIR_SIZE ) {
    error( $q, "Upload directory is full." );
}

# Allow letters, digits, periods, underscores, dashes
# Convert anything else to an underscore
$filename =~ s/[^\w.-]/_/g;
if ( $filename =~ /^(\w[\w.-]*)/ ) {
    $filename = $1;
}
else {
    error( $q, "Invalid file name; files must start with a letter or n
+umber." );
}

# Open output file, making sure the name is unique
until ( sysopen OUTPUT, UPLOAD_DIR . $filename, O_CREAT | O_EXCL ) {
    $filename =~ s/(\d*)(\.\w+)$/($1||0) + 1 . $2/e;
    $1 >= MAX_OPEN_TRIES and error( $q, "Unable to save your file." );
}

binmode $fh;
binmode OUTPUT;

# Write contents to output file
while ( read( $fh, $buffer, BUFFER_SIZE ) ) {
    print OUTPUT $buffer;
}

close OUTPUT;


sub dir_size {
    my $dir = shift;
    my $dir_size = 0;
    
    # Loop through files and sum the sizes; doesn't descend down subdi
+rs
    opendir DIR, $dir or die "Unable to open $dir: $!";
    while ( readdir DIR ) {
        $dir_size += -s "$dir/$_";
    }
    return $dir_size;
}


sub error {
    my( $q, $reason ) = @_;
    
    print $q->header( "text/html" ),
          $q->start_html( "Error" ),
          $q->h1( "Error" ),
          $q->p( "Your upload was not procesed because the following e
+rror ",
                 "occured: " ),
          $q->p( $q->i( $reason ) ),
          $q->end_html;
    exit;
}

[download]

Replies are listed 'Best First'.
Re: CGI Error
by davidrw (Prior) on Sep 27, 2005 at 12:52 UTC
    I think if you change: 
    my $fh        = $q->upload( $file );

    [download]
    to: 
    my $fh        = $q->upload( 'file' );

    [download]
    You should be good ... For reference, here's a very quick and dirty (but working) simple upload form example:
    Read more... (1165 Bytes)
[reply]
[d/l]
[select]
Re: CGI Error
by izut (Chaplain) on Sep 27, 2005 at 11:11 UTC

    Change, in the line 50, OUTPUT by STDOUT.

    Update: Misread question.

    It seems that $fh is not defined when you use it in open OUTPUT $buffer, check it. The code below reproduces the error:

    use Fcntl qw(:DEFAULT :flock);
sysopen(OUTPUT, "output.bin", O_CREAT|O_EXCL|O_WRONLY) or die $!;
binmode OUTPUT;
while (read(my $fh, my $buffer, 4096)) {
        print OUTPUT $buffer;
}
close OUTPUT or die $!;

    [download]

    Igor S. Lopes - izut
    surrender to perl. your code, your rules.
[reply]
[d/l]
[select]

      Also there are an error in this code: my $fh = $q->upload( $file ); It should be like this (according to CGI.pm): my $fh = $q->upload( 'my_upload_field_from_form' );

      From CGI.pm:

      To be safe, use the upload() function (new in version 2.47). When called with the name of an upload field, upload() returns a filehandle, or undef if the parameter is not a valid filehandle. 
                  $fh = upload("uploaded_file");
            while (<$fh>) {
                  print;
            }

      [download]

      Igor S. Lopes - izut
      surrender to perl. your code, your rules.
[reply]
[d/l]
[select]

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