Find unused CSS selectors across a list of URLs

find-unused-css-selectors.pl

#!/usr/bin/env perl
#
# Find unused CSS selectors by crawling a list of URLs
# (--url, even more than one) and matching all elements in
# a page to find out which selectors are never used across
# all given URLs
#
# Usage:
# ./find-unused-css-selectors.pl --css file.css --url http://some.url [--url http://some.other.url ...]
#
# Cosimo, 26/7/2012

use 5.010; use strict; use warnings; use autodie;

use CSS::Tiny       ();
use Getopt::Long    ();
use Mojo::UserAgent ();

Getopt::Long::GetOptions(
    'css=s' => \my $css_file,
    'url=s' => \my @url,
);

my $css = CSS::Tiny->read($css_file);
my $mojo = Mojo::UserAgent->new->max_redirects(4);

my $total = scalar keys %{ $css };
say "Found $total total CSS selectors";

for my $url (@url) {

    say "- Loading URL $url...";
    my $dom = $mojo->get($url)->res->dom;

    for my $selector (keys %{$css}) {
        next unless $dom->at($selector);
        delete $css->{$selector};
    }

}

my $remaining = scalar keys %{ $css };
printf "%d/%d unused selectors:\n", $remaining, $total;
say "- $_" for sort keys %{ $css };