Hydrator

Lightweight hydrators, usable for various hydration purposes. Hydrate away!

Installation

Install with composer:

composer require stratadox/hydrator

What is this?

The Hydrator package exists in the context of object deserialization. It is useful when loading objects from a data source.

To hydrate an object, means to assign values to its properties.

A Hydrator populates the fields of other objects.

Hydration generally works in tandem with Instantiation; the process of creating empty objects.

How to use this?

Basic Objects

The most basic usage looks like this:

<?php
use Stratadox\Hydrator\ObjectHydrator;

$hydrator = ObjectHydrator::default();
$thing = new Thing();

$hydrator->writeTo($thing, [
    'foo'      => 'Bar.',
    'property' => 'value',
]);

assert($thing->foo === 'Bar.');
assert($thing->getProperty() === 'value');

The default hydrator requires the hydrated object to have access to all of its own properties.

When that's not the case, for instance when some properties are private to the parent, a reflective hydrator is available:

<?php
use Stratadox\Hydrator\ReflectiveHydrator;

$hydrator = ReflectiveHydrator::default();

Collection Objects

To hydrate collection objects, the Hydrator package provides either a MutableCollectionHydrator, suitable for most collection classes:

<?php
use Stratadox\Hydrator\MutableCollectionHydrator;

$hydrator = MutableCollectionHydrator::default();
$collection = new SplFixedArray;

$hydrator->writeTo($collection, ['foo', 'bar']);

assert(2 === count($collection));

The MutableCollectionHydrator hydrates by mutating the collection object. Naturally, this will not work when your collections are immutable, in which case the ImmutableCollectionHydrator should be used instead.

What else can it do?

The hydrators can be decorated to extend their capabilities.

Mapping

To transform the input data with hydration mapping, the Mapping decorator can be used:

<?php
use Stratadox\HydrationMapping\IntegerValue;
use Stratadox\HydrationMapping\StringValue;
use Stratadox\Hydrator\MappedHydrator;
use Stratadox\Hydrator\ObjectHydrator;

$hydrator = MappedHydrator::using(
    ObjectHydrator::default(), 
    StringValue::inProperty('title'),
    IntegerValue::inProperty('rating'),
    StringValue::inPropertyWithDifferentKey('isbn', 'id')
);

$book = new Book;
$hydrator->writeTo($book, [
    'title'  => 'This is a book.',
    'rating' => 3,
    'isbn'   => '0000000001'
]);

Observing

The hydration process can be observed in two ways: before or after hydrating.

To observe the hydration process right before hydration begins, use:

use Stratadox\Hydrator\ObjectHydrator;
use Stratadox\Hydrator\ObserveBefore;

$hydrator = ObserveBefore::hydrating(ObjectHydrator::default(), new MyCustomObserver());

To observe the hydration process right after hydration is done, use:

use Stratadox\Hydrator\ObjectHydrator;
use Stratadox\Hydrator\ObserveAfter;

$hydrator = ObserveAfter::hydrating(ObjectHydrator::default(), new MyCustomObserver());

The observer must be a HydrationObserver. It will receive both the object instance and the input data.

Stratadox/Hydrator