Laravel presenters for JSON responses - php

Question

I’ve recently discovered that presenters (like this one) implement the decorator pattern and are a great way to add fields and logic to existing Laravel models. Take the following example for my question below:
// Tack on a new readable timestamp field.
public function timeago()
{
return $this->object->created_at->whenForHumans();
}
// Wrap an existing field with some formatting logic
public function created_at()
{
return $this->object->created_at->format('Y-m-d');
}
I can then use these presenter fields in my view:
{{ $object->timeago }}
{{ $object->created_at }}
How would you implement the decorator pattern for an API that returns JSON responses rather than Blade views? In all the Laravel/JSON articles I have read, objects are immediately returned without undergoing any transformation / presenter logic. e.g.:
// converting a model to JSON
return User::find($id)->toJson();
// returning a model directly will be converted to JSON
return User::all();
// return associated models
return User::find($id)->load('comments')->get();
How can I implement presenter fields in my JSON response?
$object->timeago
$object->created_at

Answer 1

As you mentioned, User::all returns JSON, so do something like:
Some function to get data and return a decorated response:
public function index()
{
$news = News::all();
return $this->respond([
'data' => $this->newsTransformer->transformCollection($news->toArray())
]
);
}
The above function will call Transformer::transformCollection:
<?php namespace Blah\Transformers;
abstract class Transformer {
public function transformCollection(array $items)
{
return array_map([$this, 'transform'], $items);
}
public abstract function transform($item);
}
which in turn will call NewsTransformer::transform():
public function transform($news)
{
return [
'title' => $news['title'],
'body' => $news['body'],
'active' => (boolean) $news['some_bool'],
'timeago' => // Human readable
'created_at' => // Y-m-d
];
}
The end result being JSON with the format you require, in this case:
{
data: {
title: "Some title",
body: "Some body...",
active: true,
timeago: "On Saturday, 1st of March",
created_at: "2014-03-01"
}
}
By the way, Laracasts has an excellent series on building APIs -- hope that helps!
For clarity, the respond function in the first code snippet just wraps the data with a status code, and any headers, something like:
return Response::json($data, 200);