WebFlux Multipart File Upload not possible with annotations @RouterOperations and @RequestBody. Enpoints defined as 'RouterFunction'

[FrantisekSchneider]

For an endpoint using Spring WebFlux to upload a file, the Swagger UI documentation is not generated properly. It doesn't allow to choose a file and send it as a multipart request.

                    method = "POST",
                    operationId = "uploadExcelfile",
                     requestBody = RequestBody(
                        required = true,
                        description = "Excel file",
                        content = [
                            Content(
                                schema = Schema(
                                    description = "Excel file",
                                    type = "object",
                                    name = "excelfile",
                                ),
                                mediaType = MediaType.MULTIPART_FORM_DATA_VALUE,
                                encoding = [Encoding(
                                    name = "excelfile",
                                    contentType = MediaType.APPLICATION_OCTET_STREAM_VALUE
                                )]
                            )
                        ]
                    )```

 "/api/files/smart-matching": {
  "post": {
    "operationId": "uploadExcelfile",
    "requestBody": {
      "content": {
        "multipart/form-data": {
          "encoding": {
            "excelfile": {
              "contentType": "application/octet-stream"
            }
          },
          "schema": {
            "description": "Excel file",
            "type": "object"
          }
        }
      },
      "description": "Excel file",
      "required": true
    },

--- 
* Environment + Language *
Spring Boot : 2.2.4
Kotlin: 1.3.7
org.springdoc:springdoc-openapi-webflux-ui:1.4.1

---
**Possible solution?**
I guess I need the properties support like in issue mentioned in https://stackoverflow.com/questions/14455408/how-to-post-files-in-swagger-openapi
`
 "paramType": "body",
 "dataType": "file",
`

[bnasslahsen]

@FrantisekSchneider,

This is not directly a springdoc-openapi issue.
But this is related to missing properties from the swagger-annotations: springdoc-openapi is built on top of swagger-core and swagger-annotations.

This is the link to the existing swagger-core issue:

• @Schema does not provide a property for: Properties[] properties  swagger-api/swagger-core#3433

You can log you comments here, for the support, or directly propose a PR on the swagger-core project.

You can correct this behaviour with springdoc-openapi: For example, you can declare minimal informations on using @RouterOperation.

@RouterOperation(method = RequestMethod.POST,
		operation = @Operation(operationId = "uploadExcelfile",
				requestBody = @RequestBody(required = true, description = "Excel file"),
				responses = @ApiResponse()))

And then enhance it using OpenApiCustomiser:

@Bean
OpenApiCustomiser openApiCustomiser() {
	return openApi ->
			openApi.getPaths().values().stream().flatMap(pathItem -> pathItem.readOperations().stream())
					.forEach(operation -> {
						if ("uploadExcelfile".equals(operation.getOperationId())) {
							RequestBody requestBody = operation.getRequestBody();
							requestBody.setContent(new Content().addMediaType(MediaType.APPLICATION_FORM_URLENCODED_VALUE,
									new io.swagger.v3.oas.models.media.MediaType().schema(new ObjectSchema().addProperties("excelfile", new FileSchema()))));
						}
					});
}

[FrantisekSchneider]

thank you very much -> closed