swagger-ui: Encoding attribute is not respected on the request

Q&A

• OS: macOS
• Browser: chrome
• Version: 74
• Method of installation: composer
• Swagger-UI version: 3.10.0
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Example Swagger/OpenAPI definition:

openapi: 3.0.0
info:
  title: 'Test Swagger'
  description: 'Test Swagger'
  contact:
    email: test@swagger.com
  version: '1'
paths:
  /api/v1/profile:
    post:
      tags:
        - Profile
      summary: 'profile of the user user'
      requestBody:
        description: 'Profile that needs to be stored'
        content:
          multipart/mixed:
            schema:
              properties:
                avatar_image:
                  description: avatar_image
                  type: file
                profile:
                  type: object
                  $ref: '#/components/schemas/Profile'
              type: object
            encoding:
              profile:
                contentType: application/json
      responses:
        201:
          description: 'Profile that was registered.'
          content:
            application/json:
              schema:
                type: object
        422:
          description: 'Unprocessable Entity.'
          content:
            application/json:
              schema:
                type: object
      security:
        -
          passport:
            - '*'
components:
  schemas:
    Profile:
      title: Profile
      description: 'profile model'
      required:
        - email
        - telephone
      properties:
        email:
          schema: Profile
          description: 'Email of the profile'
          type: string
        name:
          schema: Profile
          description: 'Name of the profile'
          type: string
      type: object
  securitySchemes:
    passport:
      type: oauth2
      description: 'Laravel passport oauth2 security.'
      in: header
      scheme: http
      flows:
        password:
          authorizationUrl: 'http://swagger.test/oauth/authorize'
          tokenUrl: 'http://swagger.test/oauth/token'
          refreshUrl: 'http://swagger.test/token/refresh'
          scopes: {  }
tags:
  -
    name: Profile
    description: 'Operations for the user profile'

Describe the bug you’re encountering

To reproduce…

Steps to reproduce the behavior:

1. Fill the blanks for the /api/v1/profile request
2. Make the request
3. The requests sends the following payload:

------WebKitFormBoundaryaSzepCtBw5Aiaiue
Content-Disposition: form-data; name="avatar_image"; filename="the-avatar_image.png"
Content-Type: image/png


------WebKitFormBoundaryaSzepCtBw5Aiaiue
Content-Disposition: form-data; name="profile"

{
  "email": "myemail@test.com",
  "name": "my name"
}
------WebKitFormBoundaryaSzepCtBw5Aiaiue-- 

Expected behavior

The payload should be

------WebKitFormBoundaryaSzepCtBw5Aiaiue
Content-Disposition: form-data; name="avatar_image"; filename="the-avatar_image.png"
Content-Type: image/png


------WebKitFormBoundaryaSzepCtBw5Aiaiue
Content-Disposition: form-data; name="profile"
Content-Type: application/json
{
  "email": "myemail@test.com",
  "name": "my name"
}
------WebKitFormBoundaryaSzepCtBw5Aiaiue-- 

Check that the profile attribute contains it’s content-type as “application/json”.