Presento - Transformer & Presenter Package for PHP

Nahid Bin Azhar — Sat, 21 Sep 2019 18:10:22 +0000

Presento

A data preparing and presenting package for PHP.

Github: https://github.com/nahid/presento

Why Presento?

Presento is a simple but powerful tools for preparing and presenting data.
When we build an API based application, we need to transform the data before present it through the response. This package will make this task easier for you.

Not clear enough?

Don't worry, you'll get better idea from the Usage examples.

Requirements

PHP >= 7.0
ext-json

Installation

Install the package using composer:

composer require nahid/presento

Usage

Presento serves two important purposes. one is Presentation and another is Transformation of the data.

Let's see some examples to understand how to use it.

We'll use the following data set to show the examples. Let's say we've this data set fetched from some data source and need to do some transformation or modifications before sending it to the response.

$response = [
    "id" => 123456,
    "name" => "Nahid Bin Azhar",
    "email" => "talk@nahid.im",
    "type" => 1,
    "is_active" => 1,
    "created_at" => "2018-01-02 02:03:04",
    "updated_at" => "2018-01-02 02:03:04",
    "deleted_at" => "2018-01-02 02:03:04",
    "projects" => [
        [
            "id" => 1,
            "name" => "Laravel Talk",
            "url"   => "https://github.com/nahid/talk",
            "license" => "CC0",
            "created_at" => "2016-02-02 02:03:04"
        ],
        [
            "id" => 2,
            "name" => "JsonQ",
            "url"   => "https://github.com/nahid/jsonq",
            "license" => "MIT",
            "created_at" => "2018-01-02 02:03:04"
        ]
    ]
];

Simple Presentation Example

When sending this data to the API response, we only want to send the id, name, email, type, is_active and projects.

We can simply do that by preparing a Presenter for this like following.

// UserPresenter.php

class UserPresenter extends \Nahid\Presento\Presenter
{
    public function present() : array
    {
        return [
            'id',
            'name',
            'email',
            'type',
            'is_active',
            'projects',
        ];
    }
}

And you might already guessed how to use it, right?

$user = new UserPresenter($response);
dump($user->get());

It'd show something like this:

[
    "id" => 123456,
    "name" => "Nahid Bin Azhar",
    "email" => "talk@nahid.im",
    "type" => 1,
    "is_active" => 1,
    "projects" => [
        [
            "id" => 1,
            "name" => "Laravel Talk",
            "url"   => "https://github.com/nahid/talk",
            "license" => "CC0",
            "created_at" => "2016-02-02 02:03:04"
        ],
        [
            "id" => 2,
            "name" => "JsonQ",
            "url"   => "https://github.com/nahid/jsonq",
            "license" => "MIT",
            "created_at" => "2018-01-02 02:03:04"
        ]
    ]
]

Pretty simple, right?

'key' aliasing in Presentation example

Let's say you want to change some of the 'key' to something different, like the id key to user_id .
How can you do that?

Just do the following.

// UserPresenter.php
class UserPresenter extends \Nahid\Presento\Presenter
{
    public function present() : array
    {
        return [
            'user_id' => 'id',
            'name',
            'email',
            'type',
            'is_active',
        ];
    }
}

This will format the data like following:

[
    "user_id" => 123456,
    "name" => "Nahid Bin Azhar",
    "email" => "talk@nahid.im",
    "type" => 1,
    "is_active" => 1,
]

Deep traversing in Presentation example

You can easily dive deep and get data from a nested level by using . (dot) notation.

Let's say you want to show the name of the first package as the top_package in your data.

This is how you do it.

// UserPresenter.php
class UserPresenter extends \Nahid\Presento\Presenter
{
    public function present() : array
    {
        return [
            'id',
            'name',
            'email',
            'type',
            'is_active',
            'top_package' => 'projects.0.name',
            'projects',
        ];
    }
}

This will format the data like this:

[
    "id" => 123456,
    "name" => "Nahid Bin Azhar",
    "email" => "talk@nahid.im",
    "type" => 1,
    "is_active" => 1,
    "top_package" => "Laravel Talk",
    "projects" => [
        [
            "id" => 1,
            "name" => "Laravel Talk",
            "url"   => "https://github.com/nahid/talk",
            "license" => "CC0",
            "created_at" => "2016-02-02 02:03:04"
        ],
        [
            "id" => 2,
            "name" => "JsonQ",
            "url"   => "https://github.com/nahid/jsonq",
            "license" => "MIT",
            "created_at" => "2018-01-02 02:03:04"
        ]
    ]
]

Notice the top_package key in the data.

Simple Transformer Example

Let's say our UserPresenter is like this:

// UserPresenter.php
class UserPresenter extends \Nahid\Presento\Presenter
{
    public function present() : array
    {
        return [
            'user_id' => 'id',
            'name',
            'email',
            'type',
            'is_active',
        ];
    }
}

And we want to show the user_id as hashed value instead of an incremental integer value as it is in our database. That means we want to transform the user_id.

To do that we need to create a Transformer Class like this:

// UserTransformer.php
class UserTransformer extends \Nahid\Presento\Transformer
{
    public function getUserIdProperty($value)
    {
        return md5($value);
    }
}

Notice that, as we will transform the user_id property, we named our transformer method as getUserIdProperty. So, if you want to transform the name property too, you need to just create another method in this class named getNameProperty and add the transformation logic inside it.

Now, we need to let know the Presenter how to Transform the data before presenting it.

To do that, we need to add the following method in the UserPresenter class.

// UserPresenter.php
public function transformer()
{
    return UserTransformer::class;
}

So, our final output would be:

[
    "user_id" => "e10adc3949ba59abbe56e057f20f883e",
    "name" => "Nahid Bin Azhar",
    "email" => "talk@nahid.im",
    "type" => 1,
    "is_active" => 1,
]

Ain't it easy, mate?

Nested Presenter Example

You might notice that there is a collection of projects in our data set. If each project is a separate resource, you might have a separate Presenter for that. Like this:

// ProjectPresenter.php
class ProjectPresenter extends \Nahid\Presento\Presenter
{
    public function present() : array
    {
        return [
            'id',
            'name',
            'url',
            'license',
            'created_at',
        ];
    }

    public function transformer()
    {
        return ProjectTransformer::class;
    }
}

Can you use this Presenter for each of the projects in the Users data?

Hell Yeah! Just do this:

// UserPresenter.php
public function present() : array
{
    return [
        'user_id' => 'id',
        'name',
        'email',
        'type',
        'is_active',
        'projects' => [ProjectPresenter::class => ['projects']],
    ];
}

Now, each of the project in the list of projects in Users will be presented as defined in the ProjectPresenter.

Base Data format conversion Example

As you have seen that, the data set we have used till now is a plain Array. But some times it might not be the case. You might need to work with something different, like Eloquent Model of Laravel framework.
In that case, you can simply add a method called convert in your Presenter to convert the Base data to an Array format.

Let's see an Example:

// UserPresenter.php
public function convert($data)
{
    if ($data instanceof Model) {
        return $data->toArray();
    }

    return $data;
}

That's it.

DEV Community: Nahid Bin Azhar