Re: Regex to match non image urls

[tobyink]

In these cases it is generally easier to write a regexp which matches only image URLs, and then use the negative match operator !~ instead of the match operator =~.

if ($url !~ m{^.*(jpe?g|gif|xbm|png|bmp)$}) {
  say "$url is not an image";
}

[userdefinable]

Thanks but I'm trying to get the instances of this out of a chunk of text though. Like this:

s~m(\[img\]\s*.*?\.(?:jpe?g|png|svg|gif|bmp)\s*\[/img\])x~Invalid~isg;

but it doesn't work, so I'm clearly not using it correctly.

[tobyink]

Ah, OK. You never said it was part of a s/// operator.

Maybe something along these lines?

use 5.010;
use strict;
use warnings;
my $text = do { local $/ = <DATA> };

my ($start, $end) = map quotemeta, qw([img] [/img]);
$text =~ s{($start(.+?)$end)}{
    my $link = $1;
    my $uri  = $2;
    $uri =~ /\.(?:jpe?g|png|svg|gif|bmp)$/ ? $link : 'Invalid'
}eg;

print $text;

__DATA__
Foo
[img]http://example.com/[/img]
Bar
[img]http://example.com/logo.jpeg[/img]

That said, what you are doing is conceptually broken. It is perfectly valid for an image on the web to have a URL ending with ".cgi", ".php", or even ".html". Whether something is an image or not is decided by its HTTP Content-Type header, not by the last few characters of the URL.

/p

[muba]

That said, what you are doing is conceptually broken. It is perfectly valid for an image on the web to have a URL ending with ".cgi", ".php", or even ".html". Whether something is an image or not is decided by its HTTP Content-Type header, not by the last few characters of the URL.

I couldn't agree more, sir.

That being said, I like the elegance of your code snippet.