[core] Add support for multipart/ mediatype and encoding params

[zhemant]

The PR will add support for

• proper parsing of multiple parameters in request body e.g multipart/related.
• add parsing for encoding parameters from specifications
• add flags to handle multipart
• add test yaml for multipart
• add test for verifying flags and parameters
• handling body and form params in response
• add test for verifying flags and parameters in reponse

Multipart Requests: https://swagger.io/docs/specification/describing-request-body/multipart-requests/
Encoding: https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.3.md#encoding-object

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[zhemant]

@wing328 I have added the PR again for support of multipart and encoding. I will add tests for these additions

[zhemant]

Added test yaml file and test function to verify required flag for body in formparams, multipart related contenttype and its flags, encoding objects for multipart

[zhemant]

@wing328 the PR is complete from my side. Please check

[wing328]

cc @OpenAPITools/generator-core-team

[zhemant]

A conflict was generated. I fixed the conflict. Any other comments or suggestions on the PR?

[zhemant]

@wing328 there are no comments on the PR, can it be merged, please?

[zhemant]

@wing328 any inputs, please?

[wing328]

Sorry didn't have time to review yet. Will try to get it done before 5.x release.

[zhemant]

no problem. Take your time. I will solve conflicts once you check it. Whenever I solve conflicts there are new merge requests which again generate conflicts.

[zhemant]

@wing328 any updates on this?

[lucjross]

@wing328 i've run into this issue as well. updates?

[zhemant]

@wing328 Could we please try to get this merged? I will fix the conflicts if we can merge.

[ryana]

Seems like wanting to upload different content-types within a multipart upload is table stakes for an API. Is there another way we should be doing this?

If not, what are the changes this gets merged?

[adabuleanu]

Hello. Any updates on how to add encoding to multipart requests or is there a workaround available? Seems this PR is abandoned, but the issue is still present. In my case I want to send an integer on the request.
Here is my openapi spec:

paths:
  /files:
    post:
      operationId: createFile
      requestBody:
        required: true
        content:
          multipart/form-data:
            schema:
              $ref: "#/components/schemas/CreateFile"
            encoding:
              retention:
                contentType: application/json

components:
  schemas:
    CreateFile:
      type: object
      required:
        - file
      properties:
        retention:
          type: integer
          description: Retention time in seconds.
          format: int64
          minimum: 0
          default: 1
        file:
          type: string
          description: The document file.
          format: binary

And the failure is:

request body has an error: doesn't match schema #/components/schemas/CreateFile: Error at "/retention": value must be an integer

I am using the python generated client with v7.7.0 openapi generator version.

Also, I can reproduce the same behavior using curl:

# this fails because there is no type defined for retention param
$ curl -X 'POST 'http://localhost:8080/api/v1/files'   -H 'accept: application/json'   -H 'Content-Type: multipart/form-data'   -F 'file=@file.xml;type=text/xml'  -F 'retention=1'
request body has an error: doesn't match schema #/components/schemas/CreateFile: Error at "/retention": value must be an integer

# this passes because the enconding is application/json for the retention param
$ curl -X 'POST 'http://localhost:8080/api/v1/files'   -H 'accept: application/json'   -H 'Content-Type: multipart/form-data'   -F 'file=@file.xml;type=text/xml'  -F 'retention=1;type=application/json'

I want to achieve the same with the python generated client.

[zhemant]

From the latest code, I see there is some support for encoding, I am not sure. But if multipart/related is still interesting for response, then I would be happy to create another clean PR with the changes.