Best Practices

Keeping Dry

Writing the same thing in multiple places goes against the concept of keeping your code DRY (don’t repeat yourself).

Here’s a suggestion on how to organize your “core” functionality.

The Karma example

Let’s take our fictional “Karma” addon that lets you assign points to users.

We want to be able to output a user’s points from a tag, as well as allowing other addons to get a user’s points. With this in mind, we can see that retrieving points will be a duplicated effort. We’ll want to move that somewhere reusable.

Here’s our addon directory:

Karma/
|-- KarmaAPI.php
|-- KarmaTags.php
└── Scorekeeper.php

Here we have our API and event listener classes, as well as our own Scorekeeper class that’ll – you guessed it – keep score.

Now here’s the API:

<?php

namespace Statamic\Addons\Karma;

use Statamic\Extend\API;

class KarmaAPI extends API
{
    private $scorekeeper;

    protected function __construct(ScoreKeeper $scorekeeper)
    {
        $this->scorekeeper = $scorekeeper;
    }

    public function getPoints($user)
    {
        return $this->scorekeeper->getPoints($user);
    }
}

And the tags:

<?php

namespace Statamic\Addons\Karma;

use Statamic\Extend\Tags;

class KarmaTags extends Tags
{
    private $scorekeeper;

    protected function __construct(ScoreKeeper $scorekeeper)
    {
        $this->scorekeeper = $scorekeeper;
    }

    public function getPoints($user)
    {
        return $this->scorekeeper->getPoints($user);
    }
}

Finally, the scorekeeper class:

<?php

namespace Statamic\Addons\Karma;

use Statamic\API\User;

class ScoreKeeper
{
    public function getPoints($user)
    {
        return User::get($user)['points'];
    }
}

As you can see, both addon aspects simply pass the work onto a common class.

If you’d like to use addon helper methods in your extra classes (eg. the ScoreKeeper class), you can use the Statamic\Extend\Extensible trait.