How can I add CORS functionality into my http-gateway (spring-integration-dsl)? - reactjs

Question

I have got a reactjs frontend which sends a request to my api based on spring-integration.
The problem I got is, that I don't know how to bind the CORS functionality in my gateway.
I tried something like this
#Bean
public CrossOrigin cors(){
CrossOrigin c = new CrossOrigin();
c.setOrigin("/**");
return c;
}
#Bean
public IntegrationFlow httpGetTest() {
return IntegrationFlows.from(httpGetGateTest()).channel("http.test.channel").handle("testEndpoint", "hello").get();
}
#Bean
public MessagingGatewaySupport httpGetGateTest() {
HttpRequestHandlingMessagingGateway handler = new HttpRequestHandlingMessagingGateway();
handler.setRequestMapping(createMapping(new HttpMethod[]{HttpMethod.GET}, "/test"));
handler.setCrossOrigin(cors());
handler.setHeaderMapper(headerMapper());
return handler;
}
Request:
axios.get('http://localhost:8080/test')
.then(res=>{console.log(res)})
My endpoint returns "Hello World"
Failed to load resource: the server responded with a status of 415 ()
Access to XMLHttpRequest at 'http://localhost:8080/test' from origin 'http://localhost:3000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Answer 1

First of all, please, be sure that your client really send an Origin HTTP request header.
Otherwise the CORS filtering is not applied to the request: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
Although it sounds like it is there anyway: from origin 'http://localhost:3000'.
Consider to change your setOrigin("/**") to the setOrigin("*"). The Cross-Origin policy is about the whole ULR (domain to be precise), not relative path.
BTW, there is a Java DSL factory in Spring Integration for HTTP components:
#Bean
public IntegrationFlow httpGetTest() {
return IntegrationFlows.from(Http.inboundGateway("/test")
.requestMapping(r -> r.methods(HttpMethod.GET))
.crossOrigin(cors -> cors.origin("*"))
.headerMapper(headerMapper()))
.channel("http.test.channel")
.handle("testEndpoint", "hello")
.get();
}