Azure Functions OpenApi extensions File Upload POST request

Question

Is there a way of decorating a function so that the generated swagger UI will allow the user to select a file for upload

I have a new function app with the code necessary to upload a file and store that file away, but I can't figure out how to get the OpenAPI extensions to correctly document that API in the generated swagger UI.

Thanks.

Answer 1

Here is one of the workarounds that you can try

For instance I have considered file my response to be an image/png and here is my function OpenAPI Function

    
        [FunctionName(nameof(SampleFunction.Run))]
        [OpenApiOperation(operationId: "run", tags: new[] { "multipartformdata" }, Summary = "Transfer image through multipart/formdata", Description = "This transfers an image through multipart/formdata.", Visibility = OpenApiVisibilityType.Advanced)]
        [OpenApiSecurity("function_key", SecuritySchemeType.ApiKey, Name = "code", In = OpenApiSecurityLocationType.Query)]
        [OpenApiRequestBody(contentType: "multipart/form-data", bodyType: typeof(MultiPartFormDataModel), Required = true, Description = "Image data")]
        [OpenApiResponseWithBody(statusCode: HttpStatusCode.OK, contentType: "image/png", bodyType: typeof(byte[]), Summary = "Image data", Description = "This returns the image", Deprecated = false)]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "POST", Route = "form/multipart")] HttpRequest req,
            ILogger log)
        {
            var files = req.Form.Files;
            var file = files[0];

            var content = default(byte[]);
            using (var ms = new MemoryStream())
            {
                await file.CopyToAsync(ms).ConfigureAwait(false);
                content = ms.ToArray();
            }

            var result = new FileContentResult(content, "image/png");

            return result;
        }

Its Model

public class MultiPartFormDataModel
    {
        public byte[] FileUpload { get; set; }
    }

Here is the output for Image file :

Here is the output for Text file :

REFERENCES: Azure Functions Binary Data Transfer via Swagger UI