Hacking Thy Fearful Symmetry

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Playing with Play Perl

February 10, 2013
perl play perl

So, this morning I finally clicked on one of the tweets talking about that new Play Perl thingy. And then I squealed like a little girl. A socially-oriented todo list for my projects is something I had at the back of my head for the longest time -- I was pondering making viewable parts of my Hiveminder tasks, or creating a 'yanick' GitHub project just to have the issue tracker, but this is much better.

But, of course, any new shiny discovery comes with an equal amount of tantalizing unshaved bovine pilosity. Any self-respecting social site must have external widgets. Would it be easy to hack one for Play Perl? Thanks to a very nice API, the answer is 'oh yes':


#!/usr/bin/env perl 

use 5.10.0;

use strict;
use warnings;

use LWP::Simple qw/ get /;
use JSON::XS;
use XML::Writer;

my $username = 'yanick';

my $quests = decode_json get "http://play-perl.org/api/quest?user=$username" ;
my $user = decode_json get "http://play-perl.org/api/user/$username";

my @open_quests = reverse 
    sort { @{$a->{likes}||[]} <=> @{$b->{likes}||[]} }
    grep { $_->{status} eq 'open' } 
        @$quests;

my $w = XML::Writer->new(OUTPUT => \my $output);

$w->startTag('div');
$w->startTag('h1');
$w->dataElement( 
    'a' => ($user->{twitter} ? $user->{twitter}{screen_name} :
        $user->{login}),
    href => "http://play-perl.org/player/$username",
);
$w->endTag;
$w->dataElement( 'div', 'score: ' . $user->{points} );
$w->dataElement( 'h2' => 'three most upvoted quests' );
$w->startTag('ul');
for( @open_quests[0..2] ) {
    $w->startTag('li');
    $w->dataElement( a => $_->{name},
            href => "http://play-perl.org/quest/" . $_->{_id},
            'data-nbr-likes' => $_->{likes} ? scalar @{$_->{likes}} : 0 );
    $w->endTag;
}
$w->endTag;
$w->endTag;

print $output;

Admittedly, it could be more interesting to write the widget straight in JavaScript so that no server-side work is required. And while for the first draft I did use XML::Writer, because it is a heck of a dependable workhorse, the same logic can of course easily be translated to any templating system. With the latter in mind, I had to see what it would like using Template::Caribou, my nascent pet-template project:


package Web::Widget::PlayPerl;

use LWP::Simple qw/ get /;
use JSON::XS;
use Method::Signatures;

use Moose;
use Template::Caribou;
use Template::Caribou::Tags::HTML qw/ :all /,
    ;
use Template::Caribou::Tags::HTML::Extended qw/ anchor /;
use Template::Caribou::Tags
    mytag => { -as => 'widget',     class => 'widget play-perl' },
    mytag => { -as => 'div_quests', class => 'quests' },
    mytag => { -as => 'div_score',  class => 'score' };

with 'Template::Caribou';

has username => (
    is => 'ro',
    isa => 'Str',
    required => 1,
);

has nbr_quests_to_show => (
    is => 'ro',
    isa => 'Int',
    default => 3,
);

has user_data => (
    is => 'ro',
    isa => 'HashRef',
    lazy => 1,
    default => method {
        decode_json get 'http://play-perl.org/api/user/' . $self->username;
    },
);

has open_quests => (
    is => 'ro',
    traits => [ 'Array' ],
    isa => 'ArrayRef',
    lazy => 1,
    default => method {
        my $quests = decode_json get
        'http://play-perl.org/api/quest?status=open;user='.$self->username;

        $_->{likes} ||= [] for @$quests;

        return [
            reverse 
            sort { @{$a->{likes}||[]} <=> @{$b->{likes}||[]} }
            @$quests
        ];
    },
    handles => {
        shift_open_quests => 'shift',
        all_open_quests => 'elements',
    },
);

method user_url      { "http://play-perl.org/player/" . $self->username }
method quest_url($q) { "http://play-perl.org/quest/" . $q->{_id} }

template widget => method {
    widget { 
    h1 { 
        anchor $self->user_url => $self->username  . " at PlayPerl";
    }; 
    div_score { $self->user_data->{points} || '0'; };
    show('quests');
    };
};

template quests => method {
    div_quests {
    h2 { 'top quests' };
    ul {
       for ( grep { $_ }
           ($self->all_open_quests)[0..$self->nbr_quests_to_show] ) {
            li { attr 'data-nbr-likes' => scalar @{ $_->{likes} };
                anchor $self->quest_url($_) => $_->{name};
            } 
        }
    }
};

1;

I'll just leave it there as-is, as a teaser for another, upcoming blog entry. But, as you can see, it does produce a nice base for our desired widget. A little bit of CSS here and there, and we should be ready to go:


$ perl -MWeb::Widget::PlayPerl \
    -E'say Web::Widget::PlayPerl->new( username => "yanick" )->render("widget")'

<div class="widget play-perl">
<h1>
    <a href="http://play-perl.org/player/yanick">yanick at
    PlayPerl</a>
</h1>
<div class="score">0</div>
<div class="quests">
    <h2>top quests</h2>
    <ul>
    <li data-nbr-likes="1">
        <a href="http://play-perl.org/quest/5117cbd7db9ca78259000048">
        Create a PlayPerl widget to put on my blog.</a>
    </li>
    <li data-nbr-likes="1">
        <a href="http://play-perl.org/quest/5117c3c7db9ca78359000031">
        Release Galuga 2, based on Dancer.</a>
    </li>
    <li data-nbr-likes="0">
        <a href="http://play-perl.org/quest/5117c3b7db9ca7825900003e">
        Have a totally self-indulgent blog entry about Caribou and
        its merits.</a>
    </li>
    </ul>
</div>
</div>
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About the author

Yanick Champoux
Perl necrohacker , ACP writer, orchid lover. Slightly bonker all around. he/him/his