Minimal Plack app that interacts with query params

query-plack.cgi

#!/usr/bin/env plackup

use strict;
use warnings;
use Data::Dumper;
use Plack::Request;
use Plack::Response;

my $app = sub {

    my $req = Plack::Request->new( shift );
    my $query = $req->parameters;

    my $res = Plack::Response->new( 200 );
    $res->body( '<pre>' . Dumper( $query ) . '</pre>' );
    $res->finalize;
};