For Github webhook payload URL

app.psgi

use strict;
use warnings;
use utf8;
use Plack::Request;
use HTTP::Entity::Parser;
use Hash::MultiValue;
use JSON;
use Data::Dumper;

my $parser = HTTP::Entity::Parser->new;
$parser->register('application/x-www-form-urlencoded','HTTP::Entity::Parser::UrlEncoded');

sub {
    my $env = shift;
    my ( $params, $uploads) = $parser->parse($env);

    my $body_parameters = Hash::MultiValue->new(@$params);
    my $data = JSON::decode_json($body_parameters->{payload} );
    #return ["200", ["Content-Type" => "text/plain"], [Dumper($data)]];

    my $ret = sprintf("name: %s, PR number: %d, Base branch:%s, merged_at: %s",
        $data->{repository}->{name},
        $data->{pull_request}->{number},
        $data->{pull_request}->{base}->{ref},
        $data->{pull_request}->{merged_at}
    );

    return ["200", ["Content-Type" => "text/plain"], [$ret]];
};