How can I serve an image with a Perl CGI script?

Question

My Google fu is failing me. How do I use Perl to serve up an already generated image?

Example:

<html><body><img src="getimage.pl"></body></html>

What goes in getimage.pl?

score 7 · Accepted Answer · edited May 21 '19 at 08:23

7

Here you go:

#!/usr/bin/perl -w
my $file = "inner-nav.gif";

## my $length = (stat($file)) [10];
## (stat($file)) [10]; is the inode change time in seconds since  00:00 January 1, 1970 GMT. 
my $length = (stat($file)) [7];
print "Content-type: image/gif\n";
print "Content-length: $length \n\n";
binmode STDOUT;
open (FH,'<', $file) || die "Could not open $file: $!";
my $buffer = "";
while (read(FH, $buffer, 10240)) {
    print $buffer;
}
close(FH);

edited May 21 '19 at 08:23

Karl Skartveit

3
2

answered May 02 '09 at 22:03

RichieHindle

272,464
47
358
399

1

Sorry - my Perl is extremely rusty. That was a (tested) example I found on the net. – RichieHindle May 06 '09 at 14:22
Is there something missing? - as my browser indicates it is still in the busy loading state (denoted by animated loading symbol) even after the image is displayed in the browser. Should there be something added to end of the response sent back to the client, to indicate loading complete? – therobyouknow Aug 09 '10 at 09:49

score 6 · Answer 2 · answered May 02 '09 at 22:03

6

Something like this ...

#!/usr/bin/perl

use strict;
use warnings;
use CGI;

my $gfx='';
$gfx = makeImage();
print CGI::header( type=>'image/png',
                   expires=>'+1m',
                   content_length=>length($gfx)});
print $gfx;

answered May 02 '09 at 22:03

This assumes n can only handle png images. The query is not that specific, so gotta accommodate for all... – Jarett Lloyd Sep 06 '18 at 08:24

score 3 · Answer 3 · answered Aug 22 '13 at 15:54

A small correction to the code -- the stat command provided did not return the length of the file. Some browsers did not care, but others would fail to load the image. (stat($file))[10] is 'ctime', not the length of the file.

#!/usr/bin/perl -w
my $file = "inner-nav.gif";
my $length = -s $file;
print "Content-type: image/gif\n";
print "Content-length: $length \n\n";
binmode STDOUT;
open (FH,'<', $file) || die "Could not open $file: $!";
my $buffer = "";
while (read(FH, $buffer, 10240)) {
    print $buffer;
}

score 2 · Answer 4 · edited May 07 '09 at 04:48

2

WWW FAQs: "How do I output images from a Perl/CGI or PHP script" should get you going in the right direction. You will have to forgive me for not answering your question directly as I haven't touched Perl in about 5 years.

edited May 07 '09 at 04:48

brian d foy

129,424
31
207
592

answered May 02 '09 at 21:56

Jordan S. Jones

13,703
5
44
49

score 0 · Answer 5 · edited Apr 19 '13 at 10:40

A simple solution that handles png or jpg files. Lookup the latest version of GD if you want to do more filetypes.

http://www.perlmonks.org/?node_id=18565

#

sub serveImage
{
    use GD;

    my ( $localPath ) = @_;

    if( $localPath =~ /\.png/i )
    {
        print "Content-type: image/png\n\n";
        binmode STDOUT;
        my $image = GD::Image->newFromPng( $localPath );
        print $image->png;
    }
    else
    {
        print "Content-type: image/jpeg\n\n";
        binmode STDOUT;
        my $image = GD::Image->newFromJpeg( $localPath );
        print $image->jpeg(100);
    }


}

score 0 · Answer 6 · edited Jun 05 '17 at 15:48

One user asked if there was something missing. I think so. exit 1; is missing at the end of the script. Here's my revised version (lol I only added in the exit 1;)

#!/usr/bin/perl -w
my $file = "inner-nav.gif";
my $length = (stat($file)) [10];
print "Content-type: image/gif\n";
print "Content-length: $length \n\n";
binmode STDOUT;
open (FH,'<', $file) || die "Could not open $file: $!";
my $buffer = "";
while (read(FH, $buffer, 10240)) {
    print $buffer;
}
close(FH);
exit 1;

A better way, I think anyway, is to do this:

#!/usr/bin/perl

# must haves!
use strict;
use warnings;

use CGI;
my $cgi = new CGI; # used in 'getParam($)' for getting URL paramaters

use lib "pm"; # my own perl modules library
use user; # my user related functions
use dir; # my directory handling functions

# these will be used for $fn if $fn not found, read error, or no user
my $file_not_found = "/img_srvr/error-file-not-found.jpg";
my $read_error = "/img_srvr/error-reading-image.jpg";
my $no_such_user = "/img_srvr/error-no-such-user.jpg";

# the premise of the following is to capture all input into separate vars
# verify that each element is correct, and then spit out the image.

 # for my site.  remove it if you like.  see below for getParam($) definition
my $uid = getParam("uid");
if (not userExists($uid)) { printImage($no_such_user); exit 1; }

my $folder = "/img_srvr/$uid"; # the folder where the images are stored

my $fn = getParam("img"); # see below for definition
my $path = "$folder/$fn"; # this, too, _is_ better

if (not fileExists($path))
  { printImage($file_not_found); exit 1; } else
  { printImage($path); }

exit 1;


#########################################################################


######################
sub printImage($) {
  # be sure to do your error checking BEFORE calling this. it'll just
  # blindly rip along.
  my $fn = $_[0];
  my $type = getType($fn); # see sub below
  my $buffer = "";

  print "content-type: image/$type\n"; # these are awful, but ok for now
  print "\n"; # separate just in case we want to add more to the header.

  binmode STDOUT;

  open my $FH, "<", $fn or die "$!";
  while (read ($FH, $buffer, 10240)) {
    print $buffer; # prefer NOT to print as I read...
  }
  close $FH;

  # return $OUTPUT; # this would be better, no?
}

######################
# there's gotta be a better way, spock!
sub getType($) {
  my $f = $_[0];

  if ($f =~ /\.gif$/i) { return "gif"; }
  if ($f =~ /\.jpg|\.jpeg$/i) { return "jpeg"; }
  if ($f =~ /\.png$/i) { return "png"; }

  return "bmp";
}

sub getParam($) {
  return $cgi->param($_[0]);
}

Oh! And this might be a useful link (mime types!):

====

Finally, using the above printImage function I made, is it possible to 'resize' the image? If so, how? I do not want to install another package, or anything like that. It has to be simple.

How can I serve an image with a Perl CGI script?

6 Answers6

Linked