Reactive Spring does not support HttpServletRequest as parameter in REST endpoint?

Question

I created a RestController which look like this :

@RestController public class GreetingController {      @RequestMapping(value = "/greetings", method = RequestMethod.GET)     public Mono<Greeting> greeting(HttpServletRequest request) {          return Mono.just(new Greeting("Hello..." + request.toString()));     } } 

Unfortunately when I try to hit the "greetings" endpoint I get an exception :

java.lang.IllegalStateException: No resolver for argument [0] of type [org.apache.catalina.servlet4preview.http.HttpServletRequest]

I am using

compile('org.springframework.boot.experimental:spring-boot-starter-web-reactive') 

How to fix this ?

Link to full stack-trace. Link to build.gradle

----------EDIT----------

Using the interface. Now getting :

java.lang.IllegalStateException: No resolver for argument [0] of type [javax.servlet.http.HttpServletRequest] on method (rest is same)

Answer 1

You should never use the Servlet API in a Spring Reactive Web application. This is not supported and this is making your app container-dependent, whereas Spring Web Reactive can work with non-Servlet runtimes such as Netty.

Instead you should use the HTTP API provided by Spring; here's your code sample with a few changes:

import org.springframework.http.server.reactive.ServletServerHttpRequest;  @RestController public class GreetingController {      @GetMapping("/greetings")     public Mono<Greeting> greeting(ServerHttpRequest request) {          return Mono.just(new Greeting("Hello..." + request.getURI().toString()));     } } 

You can inject either ServerWebExchange or directly ServerHttpRequest / ServerHttpResponse.