Additional `options` directive required for CORS to work

[ksilin]

I have a route for POST requests which should accept frontend requests

Expected behaviour: cors(settings){ route } should be enough to serve CORS requests

Actual behaviour: 405, Method not allowed is returned on the OPTIONS request

Workaround: add a simple options directive to route

  private val methods = List(GET, PUT, POST, PATCH, HEAD, DELETE, OPTIONS)
  val corsSettings: CorsSettings.Default =
    CorsSettings.defaultSettings.copy(allowedMethods = methods)

  val fullRoute = handleRejections(CorsDirectives.corsRejectionHandler) {
    cors(corsSettings) {
      handleRejections(RejectionHandler.default) {
        path("upload") {
//          options {
//            complete(HttpResponse(StatusCodes.OK).withHeaders(`Access-Control-Allow-Methods`(methods: _*)))
//          } ~
          post {
            fileUpload("img") {
              case (fileInfo: FileInfo, fileStream: Source[ByteString, Any]) =>
                logger.info(s"storing ${fileInfo.contentType} / ${fileInfo.fieldName} / ${fileInfo.fileName}")
                complete(StatusCodes.OK)
            }
          }
        }
      }
    }
  }

[lomigmegard]

Hi,

Can you provide the cURL commands you are using to test this route, or at least the complete response that you get back?

It seems the preflight request (required before a POST method) is not interpreted as such. Perhaps a missing Origin or Access-Control-Request-Method header? Both are required to be a valid preflight request.

If you disable the allowGenericHttpRequests setting, you will quickly see if the CORS request is valid.

[ksilin]

@lomigmegard Sorry, the JS code in my form was incorrect. Your code works perfectly without any additional directives.

Thank you for the help and please excuse the inconvenience :)

[lomigmegard]

@ksilin no worries :)