multipart/form-data should support custom content-type selection.

Content & configuration

Swagger/OpenAPI definition:

paths:
 /analysis/api/stores:
   post:
     responses:
       '201':
         $ref: '#/components/responses/CONTINUE'
     requestBody:
       required: true
       content:
         multipart/form-data:
           schema:
             $ref: '#/components/schemas/Child'
           encoding: # The same level as schema
             test: # Property name (see schema)
               contentType: application/json
             test2: # Property name (see schema)
               contentType: application/xml
     tags:
       - Learning
info:
 title: test api
 version: v1
tags:
 - name: Feature Request
   description: respect multipart child content-type
openapi: 3.0.2
components:
 schemas:
   Error:
     type: object
     properties:
       message:
         type: string
         description: Error message
       errors:
         type: object
         description: Errors
       status:
         type: string
         description: Error name
       code:
         type: integer
         format: int32
         description: Error code
   Base:
     type: object
     properties:
       company:
         type: string
   Child:
     type: object
     properties:
       test:
         type: array
         items:
           $ref: '#/components/schemas/Base'
       test2:
         type: array
         items:
           $ref: '#/components/schemas/Base'
 responses:
   CONTINUE:
     description: Continue
     content:
       application/json:
         schema:
           type: object
           properties:
             error:
               type: string

Is your feature request related to a problem?

It is currently not possible to define specific Content-Type for a request part via encoding/{property-name}/contentType.

Describe the solution you'd like

• Each request part should have a ContentType Component on top of it to select the content-type.
• The contentTypes prop would be the encoding/{property-name}/contentType splitted and trimmed via seperator char , for multiple content-type possibilities.
• Curlify needs to be adjusted.
• Introduced with #6461 the sample generation for multipart could then use the selected conten-type for generation.
• By default, the Content-Type of individual request parts is set automatically according to the type of the schema properties that describe the request parts:

Start by tracing multipart request handling through src/core/components/content-type.jsx, src/core/curlify.js, and src/core/json-schema-components.jsx. Check how encoding/{property-name}/contentType is parsed and passed into request-part rendering and curl generation. Done means custom content types are selectable, used for multipart samples, and reflected in generated curl commands.