Unable to replace a pattern in the same string with Perl

Question

I want to change <a> tags to external links in a HTML text (not a full HTML document). Nevertheless, this Perl program fails to replace a pattern if the pattern occurs multiple times in the same line of string.

Here is a sample program:

use strict;
use warnings;

my $baseURL = "https://example.com";
my $input = <<'END';
<ul>
    <li><a href="https://www.amazon.com">Amazon</a></li>
    <li>
        <!-- Keep it in one line. -->
        <a href="https://www.google.com.tw">Google</a> and <a href="https://tw.yahoo.com">Yahoo</a> and <a href="https://duckduckgo.com">DuckDuckGo</a>
    </li>
</ul>
END

# Replace external links globally.
$input =~ s{<a href=\"([^"]+)\">(.+)</a>}{
    # Skip local URIs.
    substr($1, 0, 4) ne "http" ? "<a href=\"$1\">$2</a>"
    # Skip links in same domain.
    : index($1, "$baseURL") >= 0 ? "<a href=\"$1\">$2</a>"
    # Disable search engines from following links.
    : "<a href=\"$1\" target=\"_blank\" rel=\"noopener nofollow\">$2</a>"}ge;

# Print modified input to STDOUT.
print $input;

UjinT34 · Accepted Answer · 2021-06-22 07:11:42Z

2

(.+) is greedy and captures everything to the last </a>. Try using (.+?) instead.

answered Jun 22, 2021 at 7:11

UjinT34

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