Registering body decoder for wildard */* content-type

[EmilLaursen]

This is similar to #473

except I want to accept any content-type:

/api/v1/srv/upload/kbl:
    post:
      tags:
        - srv
      summary: Upload xml file to process it.
      operationId: upload.file
      requestBody:
        content:
          multipart/form-data:
            schema:
              required:
                - file
              type: object
              properties:
                file:
                  type: string
                  format: binary
            encoding:
              file:
                contentType: "*/*"

If I use a request with content-type application/pdf in the file form field, I get the content type not supported "application/pdf" error. Registering a specific RegisterBodyDecoder for application/pdf will work, but I would like to register one on the wildcard */*

	openapi3filter.RegisterBodyDecoder("*/*", noopDecoder)

which accepts application/pdf and all other unknown media-types! Is this possible? I do not know which content-types I receive in advance, so I can not register a decoder for each one.

[fenollp]

This won't work today: the header content-type matching logic for registered body decoders does not handle wildcards yet.

kin-openapi/openapi3filter/req_resp_decoder.go

Lines 825 to 826 in d54840d

	decoder, ok := bodyDecoders[mediaType]
	if !ok {

You should be able to achieve what you want by adding some code there. Something akin to:

	// ...
	decoder, ok := bodyDecoders[mediaType]
	catchAllDecoder, canCatchAll := bodyDecoders[mediaType]
	if !ok {
		if canCatchAll {
			decoder = catchAllDecoder
		} else {
	// ...

[EmilLaursen]

I can take a stab at this when I have some free time