Enums

swagger-php supports both basic and backed enums out of the box.

Enum as OA\Schema

The simples way of using enums is to annotate them as OA\Schema. This allows you to reference them like any other schema in your spec.

<?php

namespace Openapi\Snippets\Enums\AsSchema;

use OpenApi\Attributes as OA;

#[OA\Schema]
enum Colour
{
    case GREEN;
    case BLUE;
    case RED;
}

#[OA\Schema]
class Product
{
    #[OA\Property]
    public Colour $colour;
}

<?php

namespace Openapi\Snippets\Enums\AsSchema;

use OpenApi\Annotations as OA;

/**
 * @OA\Schema()
 */
enum Colour
{
    case GREEN;
    case BLUE;
    case RED;
}

/**
 * @OA\Schema
 */
class Product
{
    /**
     * @OA\Property
     */
    public Colour $colour;
}

<?php

namespace Openapi\Snippets\Enums\AsSchema;

use OpenApi\Spec as OA;

#[OA\Schema]
enum Colour
{
    case GREEN;
    case BLUE;
    case RED;
}

#[OA\Schema]
class Product
{
    #[OA\Property]
    public Colour $colour;
}

Results in:

openapi: 3.0.0
components:
  schemas:
    Colour:
      type: string
      enum:
        - GREEN
        - BLUE
        - RED
    Product:
      properties:
        colour:
          $ref: '#/components/schemas/Colour'
      type: object

Enum as a type

In hybrid and spec mode, an enum without an OA\Schema still describes the property, parameter or request body it types. It becomes a schema named after the enum, as if it carried OA\Schema, and the type references it.

A backed enum's schema lists the backing values, since that is what the enum serializes to. A bare OA\Schema on the enum lists the case names instead, as below explains.

enum Language: string
{
    case English = 'en';
    case German = 'de';
}

#[OA\Schema]
class Book
{
    #[OA\Property]
    public Language $language;
}

Results in:

openapi: 3.1.0
components:
  schemas:
    Book:
      type: object
      properties:
        language:
          $ref: '#/components/schemas/Language'
      required:
        - language
    Language:
      type: string
      enum:
        - en
        - de

Classic mode leaves the property untyped.

Enum cases

Enum cases can be used as value in an enum list just like a string, integer or any other primitive type.

Basic enum:

<?php

namespace Openapi\Snippets\Enums\Value;

use OpenApi\Attributes as OA;

enum Suit
{
    case Hearts;
    case Diamonds;
    case Clubs;
    case Spades;
}

class Model
{
    #[OA\Property(enum: [Suit::Hearts, Suit::Diamonds])]
    protected array $someSuits;
}

<?php

namespace Openapi\Snippets\Enums\Value;

use OpenApi\Annotations as OA;

enum Suit
{
    case Hearts;
    case Diamonds;
    case Clubs;
    case Spades;
}

class Model
{
    /**
     * @OA\Property(enum={"Suit::Hearts", "Suit::Diamonds"})
     */
    protected array $someSuits;
}

<?php

namespace Openapi\Snippets\Enums\Value;

use OpenApi\Spec as OA;

enum Suit
{
    case Hearts;
    case Diamonds;
    case Clubs;
    case Spades;
}

class Model
{
    #[OA\Property]
    #[OA\Schema(enum: [Suit::Hearts, Suit::Diamonds])]
    protected array $someSuits;
}

Results in:

openapi: 3.0.0
components:
  schemas:
    Model:
      properties:
        someSuits:
          type: array
          enum:
            - Hearts
            - Diamonds
      type: object

Backed enums

If the enum is a backed enum, the case backing value is used instead of the name.

Backed enums

For backed enums there exist two rules that determine whether the name or backing value is used:

1. If no schema type is given, the enum name is used.
2. If a schema type is given, and it matches the backing type, the enum backing value is used.

Default behaviour for backed enums

By default, the name of a backed enum case is used.

Example:

<?php

namespace Openapi\Snippets\Enums\BackedNameAsSchema;

use OpenApi\Attributes as OA;

#[OA\Schema]
enum Colour: int
{
    case GREEN = 1;
    case BLUE = 2;
    case RED = 3;
}

#[OA\Schema]
class Product
{
    #[OA\Property]
    public Colour $colour;
}

<?php

namespace Openapi\Snippets\Enums\BackedNameAsSchema;

use OpenApi\Annotations as OA;

/**
 * @OA\Schema()
 */
enum Colour: int
{
    case GREEN = 1;
    case BLUE = 2;
    case RED = 3;
}

/**
 * @OA\Schema
 */
class Product
{
    /**
     * @OA\Property
     */
    public Colour $colour;
}

<?php

namespace Openapi\Snippets\Enums\BackedNameAsSchema;

use OpenApi\Spec as OA;

#[OA\Schema]
enum Colour: int
{
    case GREEN = 1;
    case BLUE = 2;
    case RED = 3;
}

#[OA\Schema]
class Product
{
    #[OA\Property]
    public Colour $colour;
}

Results in:

openapi: 3.0.0
components:
  schemas:
    Colour:
      type: string
      enum:
        - GREEN
        - BLUE
        - RED
    Product:
      properties:
        colour:
          $ref: '#/components/schemas/Colour'
      type: object

Using the backing value of an enum

To force swagger-php to use the backing value of an enum, you need to set the schema type to match the enum backing type.

Using the backing value (integer:

<?php

namespace Openapi\Snippets\Enums\BackedValueAsSchema;

use OpenApi\Attributes as OA;

#[OA\Schema(type: 'integer')]
enum Colour: int
{
    case GREEN = 1;
    case BLUE = 2;
    case RED = 3;
}

#[OA\Schema]
class Product
{
    #[OA\Property]
    public Colour $colour;
}

<?php

namespace Openapi\Snippets\Enums\BackedValueAsSchema;

use OpenApi\Annotations as OA;

/**
 * @OA\Schema(type="integer")
 */
enum Colour: int
{
    case GREEN = 1;
    case BLUE = 2;
    case RED = 3;
}

/**
 * @OA\Schema
 */
class Product
{
    /**
     * @OA\Property
     */
    public Colour $colour;
}

<?php

namespace Openapi\Snippets\Enums\BackedValueAsSchema;

use OpenApi\Spec as OA;

#[OA\Schema(type: 'integer')]
enum Colour: int
{
    case GREEN = 1;
    case BLUE = 2;
    case RED = 3;
}

#[OA\Schema]
class Product
{
    #[OA\Property]
    public Colour $colour;
}

Results in:

openapi: 3.0.0
components:
  schemas:
    Colour:
      type: integer
      enum:
        - 1
        - 2
        - 3
    Product:
      properties:
        colour:
          $ref: '#/components/schemas/Colour'
      type: object