AutoMapper+

An automapper for PHP inspired by .NET's automapper. Transfers data from one object to another, allowing custom mapping operations.

Installation
Why?
Example usage
In depth
See also
Roadmap

Installation

This library is available on packagist:

$ composer require "mark-gerarts/auto-mapper-plus"

If you're using Symfony, check out the AutoMapper+ bundle.

Why?

When you need to transfer data from one object to another, you'll have to write a lot of boilerplate code. For example when using view models, CommandBus commands, working with API responses, etc.

Automapper+ helps you by automatically transferring properties from one object to another, including private ones. By default, properties with the same name will be transferred. This can be overridden as you like.

Example usage

Suppose you have a class Employee and an associated DTO.

<?php

class Employee
{
    private $id;
    private $firstName;
    private $lastName;
    private $birthYear;
    
    public function __construct($id, $firstName, $lastName, $birthYear)
    {
        $this->id = $id;
        $this->firstName = $firstName;
        $this->lastName = $lastName;
        $this->birthYear = $birthYear;
    }

    public function getId()
    {
        return $this->id;
    }

    // And so on...
}

class EmployeeDto
{
    public $firstName;
    public $lastName;
    public $age;
}

The following snippet provides a quick overview on how the mapper can be configured and used.

<?php

use AutoMapperPlus\Configuration\AutoMapperConfig;
use AutoMapperPlus\AutoMapper;

$config = new AutoMapperConfig();

// Simply registering the mapping is enough to convert properties with the same
// name. Custom actions can be registered for each individual property.
$config
    ->registerMapping(Employee::class, EmployeeDto::class)
    ->forMember('age', function (Employee $source) {
        return date('Y') - $source->getBirthYear();
    })
    ->reverseMap(); // Register the reverse mapping as well.
                            
$mapper = new AutoMapper($config);

// With this configuration we can start converting our objects.
$john = new Employee(10, "John", "Doe", 1980);
$dto = $mapper->map($john, EmployeeDto::class);

echo $dto->firstName; // => "John"
echo $dto->lastName; // => "Doe"
echo $dto->age; // => 37

In depth

Instantiating the AutoMapper

The AutoMapper has to be provided with an AutoMapperConfig, which holds the registered mappings. This can be done in 2 ways:

Passing it to the constructor:

<?php

use AutoMapperPlus\Configuration\AutoMapperConfig;
use AutoMapperPlus\AutoMapper;

$config = new AutoMapperConfig();
$config->registerMapping(Source::class, Destination::class);
$mapper = new AutoMapper($config);

Using the static constructor

<?php

$mapper = AutoMapper::initialize(function (AutoMapperConfig $config) {
    $config->registerMapping(Source::class, Destination::class);
    $config->registerMapping(AnotherSource::class, Destination::class);
    // ...
});

Using the AutoMapper

Once configured, using the AutoMapper is pretty straightforward:

<?php

$john = new Employee("John", "Doe", 1980);

// Map the source object to a new instance of the destination class.
$mapper->map($john, EmployeeDto::class);

// Mapping to an existing object is possible as well.
$mapper->mapToObject($john, new EmployeeDto());

// Map a collection using mapMultiple
$mapper->mapMultiple($employees, EmployeeDto::class);

Registering mappings

Mappings are defined using the AutoMapperConfig's registerMapping() method. Every mapping has to be explicitly defined before you can use it.

A mapping is defined by providing the source class and the destination class. The most basic definition would be as follows:

<?php

$config->registerMapping(Employee::class, EmployeeDto::class);

This will allow objects of the Employee class to be mapped to EmployeeDto instances. Since no extra configuration is provided, the mapping will only transfer properties with the same name.

Custom callbacks

With the forMember() method, you can specify what should happen for the given property of the destination class. When you pass a callback to this method, the return value will be used to set the property.

The callback receives the source object as argument.

<?php

$config->registerMapping(Employee::class, EmployeeDto::class)
    ->forMember('fullName', function (Employee $source) {
        return $source->getFirstName() . ' ' . $source->getLastName();
    });

Operations

Behind the scenes, the callback in the previous example is wrapped in a MapFrom operation. Operations represent the action that should be performed for the given property.

The following operations are provided:

Name	Explanation
MapFrom	Maps the property from the value returned from the provided callback.
Ignore	Ignores the property.
MapTo	Maps the property to another class. Allows for nested mappings. Supports both single values and collections.
FromProperty	Use this to explicitly state the source property name.
DefaultMappingOperation	Simply transfers the property, taking into account the provided naming conventions (if there are any).

You can use them with the same forMember() method. The Operation class can be used for clarity.

<?php

$getName = function() { return 'John'; };

$mapping->forMember('name', $getName);
// The above is a shortcut for the following:
$mapping->forMember('name', Operation::mapFrom($getName));
// Which in turn is equivalent to:
$mapping->forMember('name', new MapFrom($getName));

// Other examples:
// Ignore this property.
$mapping->forMember('id', Operation::ignore());
// Map this property to the given class.
$mapping->forMember('employee', Operation::mapTo(EmployeeDto::class));
// Explicitly state what the property name is of the source object.
$mapping->forMember('name', Operation::fromProperty('unconventially_named_property'));

You can create your own operations by implementing the MappingOperationInterface. Take a look at the provided implementations for some inspiration.

Dealing with nested mappings

Nested mappings can be registered using the MapTo operation. Keep in mind that the mapping for the child class has to be registered as well.

MapTo supports both single entities and collections.

<?php

$config->createMapping(Child::class, ChildDto::class);
$config->createMapping(Parent::class, ParentDto::class)
    ->forMember('child', Operation::mapTo(ChildDto::class));

Naming conventions

By default, a mapping will try to transfer data between properties of the same name. You can, however, specify the naming conventions followed by the source & destination classes. The mapper will take this into account.

For example:

<?php

use AutoMapperPlus\NameConverter\NamingConvention\CamelCaseNamingConvention;
use AutoMapperPlus\NameConverter\NamingConvention\SnakeCaseNamingConvention;

$config->registerMapping(CamelCaseSource::class, SnakeCaseDestination::class)
    ->withNamingConventions(
        new CamelCaseNamingConvention(), // The naming convention of the source class.
        new SnakeCaseNamingConvention() // The naming convention of the destination class.
    );

$source = new CamelCaseSource();
$source->propertyName = 'camel';

$result = $mapper->map($source, SnakeCaseDestination::class);
echo $result->property_name; // => "camel"

The following conventions are provided (more to come):

CamelCaseNamingConvention
PascalCaseNamingConvention
SnakeCaseNamingConvention

You can implement your own by using the NamingConventionInterface.

Explicitly state source property

As mentioned earlier, the operation FromProperty allows you to explicitly state what property of the source object should be used.

<?php

$config->registerMapping(Source::class, Destination::class)
    ->forMember('id', Operation::fromProperty('identifier'));

You should read the previous snippet as follows: "For the property named 'id' on the destination object, use the value of the 'identifier' property of the source object".

FromProperty is Reversible, meaning that when you apply reverseMap(), AutoMapper will know how to map between the two properties. For more info, read the section about reverseMap.

ReverseMap

Since it is a common usecase to map in both directions, the reverseMap() method has been provided. This creates a new mapping in the alternate direction.

reverseMap will keep the registered naming conventions into account, if there are any.

<?php

// reverseMap() returns the new mapping, allowing to continue configuring the 
// new mapping.
$config->registerMapping(Employee::class, EmployeeDto::class)
    ->reverseMap()
    ->forMember('id', Operation::ignore());

$config->hasMappingFor(Employee::class, EmployeeDto::class); // => True
$config->hasMappingFor(EmployeeDto::class, Employee::class); // => True

Note: reverseMap() simply creates a completely new mapping in the reverse direction, using the default options. However, every operation you defined with forMember that implements the Reversible interface, gets defined for the new mapping as well. Currently, only fromProperty supports being reversed.

To make things more clear, take a look at the following example.

<?php

// Source class properties:         Destination class properties:
// - 'some_property',               - 'some_property'
// - 'some_alternative_property'    - 'some_other_property'
// - 'the_last_property'            - 'the_last_property'
//
$config->registerMapping(Source::class, Destination::class)
    ->forMember('some_property', Operation::ignore())
    ->forMember('some_other_property', Operation::fromProperty('some_alternative_property'))
    ->reverseMap();

// When mapping from Source to Destination, the following will happen:
// - some_property gets ignored
// - some_other_property gets mapped by using the value form some_alternative_property
// - the_last_property gets mapped because the names are equal.
//
// Now, when we go in the reverse direction things are different:
// - some_property gets mapped, because Ignore is not reversible
// - some_alternative_property gets mapped because FromProperty is reversible
// - the_last_property gets mapped as well

The Options object

The Options object is a value object containing the possible options for both the AutoMapperConfig and the Mapping instances.

The Options you set for the AutoMapperConfig will act as the default options for every Mapping you register. These options can be overridden for every mapping.

For example:

<?php

$config = new AutoMapperConfig();
$config->getOptions()->setDefaultMappingOperation(Operation::ignore());

$defaultMapping = $config->registerMapping(Source::class, Destination::class);
$overriddenMapping = $config->registerMapping(AnotherSource::class, Destination::class)
    ->withDefaultOperation(new DefaultMappingOperation());

$defaultMapping->getOptions()->getDefaultMappingOperation(); // => Ignore
$overriddenMapping->getOptions()->getDefaultMappingOperation(); // => DefaultMappingOperation

The available options that can be set are:

Name	Default value	Comments
Source naming convention	`null`	The naming convention of the source class (e.g. `CamelCaseNamingConversion`). Also see naming conventions.
Destination naming convention	`null`	See above.
Skip constructor	`true`	whether or not the constructor should be skipped when instantiating a new class. Use `$options->skipConstructor()` and `$options->dontSkipConstructor()` to change.
Property accessor	`PropertyAccessor`	Use this to provide an alternative implementation of the property accessor.
Default mapping operation	`DefaultMappingOperation`	the default operation used when mapping a property. Also see mapping operations

Setting the options

For the AutoMapperConfig

You can set the options for the AutoMapperConfig by retrieving the object:

<?php

$config = new AutoMapperConfig();
$config->getOptions()->dontSkipConstructor();

Alternatively, you can set the options by providing a callback to the constructor. The callback will be passed an instance of the default Options:

<?php

// This will set the options for this specific mapping.
$config = new AutoMapperConfig(function (Options $options) {
    $options->dontSkipConstructor();
    $options->setDefaultMappingOperation(Operation::ignore());
    // ...
});

For the Mappings

A mapping also has the getOptions method available. However, chainable helper methods exist for more convenient overriding of the options:

<?php

$config->registerMapping(Source::class, Destination::class)
    ->skipConstructor()
    ->withDefaultOperation(Operation::ignore());

Setting options via a callable has been provided for mappings as well, using the setDefaults() method:

<?php

$config->registerMapping(Source::class, Destination::class)
    ->setDefaults(function (Options $options) {
        $options->dontSkipConstructor();
        // ...
    });

Mapping with stdClass

As a side note it is worth mentioning that it is possible to map from a stdClass. This is done as you would expect:

<?php

// Register the mapping.
$config->registerMapping(\stdClass::class, Employee::class);
$mapper = new AutoMapper($config);

$employee = new \stdClass();
$employee->firstName = 'John';
$employee->lastName = 'Doe';

$result = $mapper->map($employee, Employee::class);
echo $result->firstName; // => "John"
echo $result->lastName; // => "Doe"

Mapping to a stdClass is not supported (yet).

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automapper-plus's Introduction

AutoMapper+

Table of Contents

Installation

Why?

Example usage

In depth

Instantiating the AutoMapper

Using the AutoMapper

Registering mappings

Custom callbacks

Operations

Dealing with nested mappings

Naming conventions

Explicitly state source property

ReverseMap

The Options object

Setting the options

For the AutoMapperConfig

For the Mappings

Mapping with stdClass

See also

Roadmap

automapper-plus's People

Contributors

Watchers

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