Using regex to extract URLs from plain text with Perl
perl, regex, url
Solution
URI::Find is specifically designed to solve this problem. It will find all URIs and then you can filter them. It has a few heuristics to handle things like trailing punctuation.
UPDATE: Recently updated to handle Unicode.
Problem
How can I use Perl regexps to extract all URLs of a specific domain (with possibly variable subdomains) with a specific extension from plain text? I have tried: ``` my $stuff = 'omg http://fail-o-tron.com/bleh omg omg omg omg omg http://homepage.com/woot.gif dfgdfg http://shomepage.com/woot.gif aaa'; while($stuff =~ m/(http\:\/\/.*?homepage.com\/.*?\.gif)/gmsi) { print $1."\n"; } ``` It fails horribly and gives me: ``` http://fail-o-tron.com/bleh omg omg omg omg omg http://homepage.com/woot.gif http://shomepage.com/woot.gif ``` I thought that wouldn't happen because I am using `.*?`, which ought to be non-greedy and give me the smallest match. Can anyone tell me what I am doing wrong? (I don't want some uber-complex, canned regexp to validate URLs; I want to know what I am doing wrong so I can learn from it.)