I have a Perl Dancer web application that uses GD to dynamically create images. I am trying to deliver these images to the user as PNG. For example:
package MyApp;
use Dancer ':syntax';
use GD;
...
get '/dynamic_image/:var1/:var2' => sub {
my $im = GD::Image->new(100,100);
my $black = $im->colorAllocate(0,0,0);
my $white = $im->colorAllocate(255,255,255);
$im->rectangle(10,10,90,90,$white);
my $png = $im->png;
return send_file( \$png, content_type => 'image/png', filename => params->{var1}."_".params->{var2}.".png" );
};
However, when accessing the above route, Chrome and Firefox don't seem to know what to do with the image data. If I try to use the route in Lightbox, Chrome complains. For example, when clicking on a link like this:
<a href="/dynamic_image/my/image" rel="lightbox">link</a>
Chrome's console says:
Resource interpreted as Image but transferred with MIME type application/octet-stream: "http://www.example.com/dynamic_image/my/image".
It looks like Dancer is not using content_type correctly. Interestingly, IE8 seems to load the images just fine. Any idea what's going on? I'm currently running it standalone on Windows 7 with Strawberry Perl v5.16.2.
After banging my head against this for awhile, I think I can answer my own question. Firefox actually tipped me off to a bug in my own code. Basically, when accessing the dynamically created image in Firefox, it would display a page with the HTTP request info along with the PNG data. I noticed that some debugging text was displayed on the page. It turns out that I left a print in one of the loops that generated the image data (I had used it to verify the image was being built correctly), and that text somehow made it into the "image" itself--which I assume caused Firefox and Chrome to freak out a bit. So this wasn't a Dancer or application bug, but a PEBKAC issue. Thanks for the input, everybody.