Data Transfer Object

Want to deserialize an object with data on the fly? Go for it by using the From trait.

How is this package any different from spaties popular data-transfer-object, you may ask? Well, it's not meant to be a replacement by any means. But while using it I've often come across some things I've missed since I knew them from serde, like renaming and ignoring properties, something that spatie's data-transfer-object might not get in the near future. So there it is, my own little DTO package :) I hope it helps someone, as it helps me in my daily work. Feel free to open issues or pull requests - any help is greatly appreciated!

Requirements

This package is designed for PHP ≥ 8.0 only since it's using PHP 8.0 Attributes.

Attributes

Name

You get a parameter which is not named as the parameter in your class? #[Name(...)] to the rescue - just specify the name from the Request:

use Dgame\DataTransferObject\Annotation\Name;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;

    public int $offset;
    #[Name('size')]
    public int $limit;
}

Now the key size will be mapped to the property $limit - but keep in mind: the name limit is no longer known since you overwrote it with size. If that is not your intention, take a look at the Alias Attribute.

Alias

You get a parameter which is not always named as the parameter in your class? #[Alias(...)] can help you - just specify the alias from the Request:

use Dgame\DataTransferObject\Annotation\Alias;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;

    public int $offset;
    #[Alias('size')]
    public int $limit;
}

Now the keys size and limit will be mapped to the property $limit. You can mix #[Name(...)] and #[Alias(...)] as you want:

use Dgame\DataTransferObject\Annotation\Alias;
use Dgame\DataTransferObject\Annotation\Name;
use Dgame\DataTransferObject\DataTransfer;

final class Foo
{
    use DataTransfer;

    #[Name('a')]
    #[Alias('z')]
    public int $id;
}

The keys a and z are mapped to the property id - but not the key id since you overwrote it with a. But the following

use Dgame\DataTransferObject\Annotation\Alias;
use Dgame\DataTransferObject\DataTransfer;

final class Foo
{
    use DataTransfer;

    #[Alias('a')]
    #[Alias('z')]
    public int $id;
}

will accept the keys a, z and id.

Transformations

If you want to transform a value before it is assigned to the property, you can use Transformations. You just need to implement the Transformation interface.

Cast

Cast is currently the only built-in Transformation and let you apply a Type-Cast before the value is assigned to the property:

If not told otherwise, a simple type-cast is performed. In the example below it would just call something like $this->id = (int) $id:

use Dgame\DataTransferObject\Annotation\Cast;

final class Foo
{
    use DataTransfer;

    #[Cast]
    public int $id;
}

But that would be tried for any input. If you want to limit this to certain types, you can use types:

use Dgame\DataTransferObject\Annotation\Cast;

final class Foo
{
    use DataTransfer;

    #[Cast(types: ['string', 'float', 'bool'])]
    public int $id;
}

Here the cast would only be performed if the incoming value is either an int, string, float or bool.

If you want more control, you can use a static method inside of the class:

use Dgame\DataTransferObject\Annotation\Cast;

final class Foo
{
    use DataTransfer;

    #[Cast(method: 'toInt', class: self::class)]
    public int $id;

    public static function toInt(string|int|float|bool $value): int
    {
        return (int) $value;
    }
}

or a function:

use Dgame\DataTransferObject\Annotation\Cast;

function toInt(string|int|float|bool $value): int
{
    return (int) $value;
}

final class Foo
{
    use DataTransfer;

    #[Cast(method: 'toInt')]
    public int $id;
}

If a class is given but not a method, by default __invoke will be used:

use Dgame\DataTransferObject\Annotation\Cast;

final class Foo
{
    use DataTransfer;

    #[Cast(class: self::class)]
    public int $id;

    public function __invoke(string|int|float|bool $value): int
    {
        return (int) $value;
    }
}

Validation

You want to validate the value before it is assigned? We can do that. There are a few pre-defined validations prepared, but you can easily write your own by implementing the Validation-interface.

Min

use Dgame\DataTransferObject\Annotation\Min;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;
    
    #[Min(0)]
    public int $offset;
    #[Min(0)]
    public int $limit;
}

Both $offset and $limit must be at least have the value 0 (so they must be positive-integers). If not, an exception is thrown. You can configure the message of the exception by specifying the message parameter:

use Dgame\DataTransferObject\Annotation\Min;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;
    
    #[Min(0, message: 'Offset must be positive!')]
    public int $offset;
    #[Min(0, message: 'Limit must be positive!')]
    public int $limit;
}

Max

use Dgame\DataTransferObject\Annotation\Max;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;
    
    #[Max(1000)]
    public int $offset;
    #[Max(1000)]
    public int $limit;
}

Both $offset and $limit may not exceed 1000. If they do, an exception is thrown. You can configure the message of the exception by specifying the message parameter:

use Dgame\DataTransferObject\Annotation\Max;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;
    
    #[Max(1000, message: 'Offset may not be larger than 1000')]
    public int $offset;
    #[Max(1000, message: 'Limit may not be larger than 1000')]
    public int $limit;
}

Instance

Do you want to make sure that a property is an instance of a certain class or that each item in an array is an instance of that said class?

use Dgame\DataTransferObject\Annotation\Instance;

final class Collection
{
    #[Instance(class: Entity::class, message: 'We need an array of Entities!')]
    private array $entities;
}

Type

If you are trying to cover objects or other class instances, you should probably take a look at Instance.

As long as you specify a type for your properties, the Type validation is automatically added to ensure that the specified values can be assigned to the specified types. If not, a validation exception will be thrown. Without this validation, a TypeError would be thrown, which may not be desirable.

So this code

final class Foo
{
    private ?int $id;
}

is actually seen as this:

use Dgame\DataTransferObject\Annotation\Type;

final class Foo
{
    #[Type(name: '?int')]
    private ?int $id;
}

The following snippets are equivalent to the snippet above:

use Dgame\DataTransferObject\Annotation\Type;

final class Foo
{
    #[Type(name: 'int|null')]
    private ?int $id;
}

use Dgame\DataTransferObject\Annotation\Type;

final class Foo
{
    #[Type(name: 'int', allowsNull: true)]
    private ?int $id;
}

If you want to change the exception message, you can do so using the message parameter:

use Dgame\DataTransferObject\Annotation\Type;

final class Foo
{
    #[Type(name: '?int', message: 'id is expected to be int or null')]
    private ?int $id;
}

Custom

Do you want your own Validation? Just implement the Validation-interface:

use Dgame\DataTransferObject\Annotation\Validation;
use Dgame\DataTransferObject\DataTransfer;

#[Attribute(Attribute::TARGET_PROPERTY)]
final class NumberBetween implements Validation
{
    public function __construct(private int|float $min, private int|float $max)
    {
    }

    public function validate(mixed $value): void
    {
        if (!is_numeric($value)) {
            throw new InvalidArgumentException(var_export($value, true) . ' must be a numeric value');
        }

        if ($value < $this->min) {
            throw new InvalidArgumentException(var_export($value, true) . ' must be >= ' . $this->min);
        }

        if ($value > $this->max) {
            throw new InvalidArgumentException(var_export($value, true) . ' must be <= ' . $this->max);
        }
    }
}

final class ValidationStub
{
    use DataTransfer;

    #[NumberBetween(18, 125)]
    private int $age;

    public function getAge(): int
    {
        return $this->age;
    }
}

Ignore

You don't want a specific key-value to override your property? Just ignore it:

use Dgame\DataTransferObject\Annotation\Ignore;
use Dgame\DataTransferObject\DataTransfer;

final class Foo
{
    use DataTransfer;

    #[Ignore]
    public string $uuid = 'abc';
    public int $id = 0;
}

$foo = Foo::from(['uuid' => 'xyz', 'id' => 42]);
echo $foo->id; // 42
echo $foo->uuid; // abc

Reject

You want to go one step further than simply ignoring a value? Then Reject it:

use Dgame\DataTransferObject\Annotation\Reject;
use Dgame\DataTransferObject\DataTransfer;

final class Foo
{
    use DataTransfer;

    #[Reject(reason: 'The attribute "uuid" is not supposed to be set')]
    public string $uuid = 'abc';
}

$foo = Foo::from(['id' => 42]); // Works fine
echo $foo->id; // 42
echo $foo->uuid; // abc

$foo = Foo::from(['uuid' => 'xyz', 'id' => 42]); // throws 'The attribute "uuid" is not supposed to be set'

Required

Normally, a nullable-property or a property with a provided default value is treated with said default-value or null if the property cannot be assigned from the provided data. If no default-value is provided and the property is not nullable, an error is thrown in case the property was not found. But in some cases you might want to specify the reason, why the property is required or even want to require an otherwise default-able property. You can do that by using Required:

use Dgame\DataTransferObject\Annotation\Required;
use Dgame\DataTransferObject\DataTransfer;

final class Foo
{
    use DataTransfer;

    #[Required(reason: 'We need an "id"')]
    public ?int $id;
    
    #[Required(reason: 'We need a "name"')]
    public string $name;
}

Foo::from(['id' => 42, 'name' => 'abc']); // Works
Foo::from(['name' => 'abc']); // Fails but would work without the `Required`-Attribute since $id is nullable
Foo::from(['id' => 42]); // Fails and would fail regardless of the `Required`-Attribute since $name is not nullable and has no default-value - but the reason why it is required is now more clear.

Optional

The counterpart of Required. If you don't want to or can't provide a default/nullable value, Optional will assign the default value of the property-type in case of a missing value:

final class Foo
{
    use DataTransfer;
    
    #[Optional]
    public int $id;
}

$foo = Foo::from([]);
assert($foo->id === 0);

Of course you can specify which value should be used if no data is provided:

final class Foo
{
    use DataTransfer;
    
    #[Optional(value: 42)]
    public int $id;
}

$foo = Foo::from([]);
assert($foo->id === 42);

In case you're using Optional together with a provided default-value, the default-value has always priority:

final class Foo
{
    use DataTransfer;
    
    #[Optional(value: 42)]
    public int $id = 23;
}

$foo = Foo::from([]);
assert($foo->id === 23);

Numeric

You have int or float properties but aren't sure if those aren't delivered as e.g. string? Numeric to the rescue! It will translate the value to a numeric representation (to int or float):

use Dgame\DataTransferObject\Annotation\Numeric;

final class Foo
{
    use DataTransfer;
    
    #[Numeric(message: 'id must be numeric')]
    public int $id;
}

$foo = Foo::from(['id' => '23']);
assert($foo->id === 23);

Boolean

You have bool properties but aren't sure if those aren't delivered as string or int? Boolean can help you with that!

use Dgame\DataTransferObject\Annotation\Boolean;

final class Foo
{
    use DataTransfer;
    
    #[Boolean(message: 'checked must be a bool')]
    public bool $checked;
    #[Boolean(message: 'verified must be a bool')]
    public bool $verified;
}

$foo = Foo::from(['checked' => 'yes', 'verified' => 0]);
assert($foo->checked === true);
assert($foo->verified === false);

Date

You want a DateTime but got a string? No problem:

use Dgame\DataTransferObject\Annotation\Date;
use \DateTime;

final class Foo
{
    use DataTransfer;
    
    #[Date(format: 'd.m.Y', message: 'Your birthday must be a date')]
    public DateTime $birthday;
}

$foo = Foo::from(['birthday' => '19.09.1979']);
assert($foo->birthday === DateTime::createFromFormat('d.m.Y', '19.09.1979'));

In

Your value must be one of a specific range or enumeration? You can ensure that with In:

use Dgame\DataTransferObject\Annotation\In;

final class Foo
{
    use DataTransfer;
    
    #[In(values: ['beginner', 'advanced', 'difficult'], message: 'Must be either "beginner", "advanced" or "difficult"')]
    public string $difficulty;
}

Foo::from(['difficulty' => 'foo']); // will throw a error, since difficulty is not in the provided values
$foo = Foo::from(['difficulty' => 'advanced']);
assert($foo->difficulty === 'advanced');

NotIn

Your value must not be one of a specific range or enumeration? You can ensure that with NotIn:

use Dgame\DataTransferObject\Annotation\NotIn;

final class Foo
{
    use DataTransfer;
    
    #[NotIn(values: ['holy', 'shit', 'wtf'], message: 'Must not be a swear word')]
    public string $word;
}

Matches

You must be sure that your values match a specific pattern? You can do that for all scalar values by using Matches:

use Dgame\DataTransferObject\Annotation\Matches;

final class Foo
{
    use DataTransfer;
    
    #[Matches(pattern: '/^[a-z]+\w*/', message: 'Your name must start with a-z')]
    public string $name;
    
    #[Matches(pattern: '/[1-9][0-9]+/', message: 'products must be at least 10')]
    public int $products;
}

Foo::from(['name' => '_', 'products' => 99]); // will throw a error, since name does not start with a-z
Foo::from(['name' => 'John', 'products' => 9]); // will throw a error, since products must be at least 10

Trim

You have to make sure, that string values are trimmed? No worries, we have Trim:

use Dgame\DataTransferObject\Annotation\Trim;

final class Foo
{
    use DataTransfer;
    
    #[Trim]
    public string $name;
}

$foo = Foo::from(['name' => ' John   ']);
assert($foo->name === 'John');

Path

Did you ever wanted to extract a value from a provided array? Path to the rescue:

final class Person
{
    use DataTransfer;

    #[Path('person.name')]
    public string $name;
}

It helps while with JSON's special $value attribute

final class Person
{
    use DataTransfer;

    #[Path('married.$value')]
    public bool $married;
}

and with XML's #text.

final class Person
{
    use DataTransfer;

    #[Path('first.name.#text')]
    public string $firstname;
}

But we can do even more. You can choose which parts of the field are taken

final class Person
{
    use DataTransfer;

    #[Path('child.{born, age}')]
    public array $firstChild = [];
}

and can even assign them directly to an object:

final class Person
{
    use DataTransfer;
    
    public int $id;
    public string $name;
    public ?int $age = null;

    #[Path('ancestor.{id, name}')]
    public ?self $parent = null;
}

SelfValidation

In addition to the customary validations you can specify a class-wide validation after all assignments are done:

#[SelfValidation(method: 'validate')]
final class SelfValidationStub
{
    use DataTransfer;

    public function __construct(public int $id)
    {
    }

    public function validate(): void
    {
        assert($this->id > 0);
    }
}

ValidationStrategy

The default validation strategy is fail-fast which means an Exception is thrown as soon as an error is detected. But that might not desirable, so you can configure this with a ValidationStrategy:

#[ValidationStrategy(failFast: false)]
final class Foo
{
    use DataTransfer;

    #[Min(3)]
    public string $name;
    #[Min(0)]
    public int $id;
}

Foo::from(['name' => 'a', 'id' => -1]);

The example above would throw a combined exception that name is not long enough and id must be at least 0. You can configure this as well by extending the ValidationStrategy and provide a FailureHandler and/or a FailureCollection.

Property promotion

In the above examples, property promotion is not always used because it is more readable that way, but property promotion is supported. So the following example

use Dgame\DataTransferObject\Annotation\Min;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;
    
    #[Min(0)]
    public int $offset;
    #[Min(0)]
    public int $limit;
}

can be rewritten as shown below

use Dgame\DataTransferObject\Annotation\Min;
use Dgame\DataTransferObject\DataTransfer;

final class Limit
{
    use DataTransfer;

    public function __construct(
        #[Min(0)] public int $offset,
        #[Min(0)] public int $limit
    ) { }
}

and it still works.

Nested object detection

You have nested objects and want to deserialize them all at once? That is a given:

use Dgame\DataTransferObject\DataTransfer;

final class Bar
{
    public int $id;
}

final class Foo
{
    use DataTransfer;
    
    public Bar $bar;
}

$foo = Foo::from(['bar' => ['id' => 42]]);
echo $foo->bar->id; // 42

Have you noticed the missing From in Bar? From is just a little wrapper for the actual DTO. So your nested classes don't need to use it at all.

There is no limit to the depth of nesting, the responsibility is yours! :)

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README.md

README.md

Data Transfer Object

Requirements

Attributes

Name

Alias

Transformations

Cast

Validation

Min

Max

Instance

Type

Custom

Ignore

Reject

Required

Optional

Numeric

Boolean

Date

In

NotIn

Matches

Trim

Path

SelfValidation

ValidationStrategy

Property promotion

Nested object detection

Files

README.md

Latest commit

History

README.md

File metadata and controls

Data Transfer Object

Requirements

Attributes

Name

Alias

Transformations

Cast

Validation

Min

Max

Instance

Type

Custom

Ignore

Reject

Required

Optional

Numeric

Boolean

Date

In

NotIn

Matches

Trim

Path

SelfValidation

ValidationStrategy

Property promotion

Nested object detection