Error when making call with content type application/xml

[LucasAndersson]

Hi

I'm building a gateway that will receive XML, map it to JSON, call an underlying external service using said JSON and then return a XML response to the gateway caller. I've set up a simple route that modifies the path, request and response bodies. When I call my gateway I get this response back:

{ "timestamp": "2018-11-12T15:43:22.621+0000", "path": "/v1/reserve", "status": 500, "error": "Internal Server Error", "message": "Content type 'application/xml' not supported" }

Does Spring Cloud Gateway not support XML? How do you propose that I deal with this problem?

[spencergibb]

There's nothing specific in gateway for any content type. Can you explain how to reproduce the problem? What versions are you using? What is your configuration?

[LucasAndersson]

Thank you for the quick response Spencer!
I created a public github repo with a minimal example:

https://github.com/LucasAndersson/spring-cloud-gateway-xml-demo

curl -X POST "http://localhost:8080/post" -H "content-type:application/xml" -d '<foo>bar</foo>'
{"timestamp":"2018-11-13T09:35:22.496+0000","path":"/post","status":500,"error":"Internal Server Error","message":"Content type 'application/xml' not supported"}

I also tried serializing to a json string using jackson like this:

.modifyRequestBody(GatewayRequest.class, String.class, (s, g) ->
                                {
                                    DownstreamRequest downstreamRequest = new DownstreamRequest();
                                    downstreamRequest.setBar(g.getFoo());

                                    try
                                    {
                                        return Mono.just(new ObjectMapper().writeValueAsString(downstreamRequest));
                                    } catch (JsonProcessingException e)
                                    {
                                        return Mono.error(e);
                                    }
                                }

With that approach I get a slightly different error:

curl -X POST "http://localhost:8080/post" -H "content-type:application/xml" -d '<foo>bar</foo>'
{"timestamp":"2018-11-13T09:40:53.745+0000","path":"/post","status":415,"error":"Unsupported Media Type","message":"Content type 'application/xml' not supported"}

I created my project using Spring Initializr, however I had to downgrade to Finchley.RELEASE version of Spring Cloud and 2.0.6.RELEASE version of Spring Boot because of the issue described here: #577

What I'm trying to achieve is to receive an XML payload in my gateway, map it to a different model and pass it downstream as JSON, map the response from the downstream service (which is also JSON) to a different model and return it to the gateway caller as XML. In my example I've only added a filter to modify the request body, I never seem to reach the downstream service so I thought it would be irrelevant to include a filter to modify the response.

There will be 4 different models involved, the gateway request/response (which should be (de)serialized as XML) and the downstream service request/response (which should be (de)serialized as JSON).