in reply to Question: how to check remote image property

use LWP::Simple qw( get );

my $image = get("http://example.com/images/file.jpg");
defined($image)
   or die("Unable to fetch image\n");

my $image = GD::Image->new($image);

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Re^2: Question: how to check remote image property
by samtregar (Abbot) on Apr 07, 2008 at 20:40 UTC
    Looks right to me, but beware that this loads the whole image into memory. If this URL is being supplied by untrusted users you'll need to do something to prevent being crashed by someone pointing you to a gigantic image. Even trusted users can do this - I once had users uploading 200MB+ uncompressed images into Krang so they could include them on web-pages (shrunk via HTML width/height attributes, of course!).

    Anybody know how you tell LWP to stop if it gets to X bytes? Some kind of read-callback, yes?

    -sam

[reply]

      Can't do it with LWP::Simple (natch), but yes if you use $ua->get( $url, :content_cb => ... ) you can pass a callback which dies after the requisite number of bytes have been received. 

      #!/opt/local/bin/perl

use strict;
use LWP::UserAgent ();

my $ua = LWP::UserAgent->new();
$ua->env_proxy;

my $rcvd = 0;
my $buf = '';
my $resp = $ua->get( 'http://www.google.com/',
                     ':content_cb' => sub { $buf .= $_[0]; die "NO MOR
+\n" if ( $rcvd += length $_[0] ) > 512; });

print "content:\n", $buf, "\n\n";

print "headers:\n", $resp->as_string, "\n";
exit 0;

__END__

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      If the callback gets too much your response object will have an X-Died header (if you care if it did or not).

      The cake is a lie.
      The cake is a lie.
      The cake is a lie.

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