Context Path with Webflux

Question

I\'ve been trying to find a way to set the context path for a webflux application. I know I can configure it using

server.servlet.context-path

Answer 1

For use cases where WebFlux application is behind load balancer/proxy you can use dedicated class - ForwardedHeaderTransformer that will extract path context from X-Forwarded-Prefix and will add it to ServerHttpRequest.

Doing so you won't need to modify global context-path (which does not make sense in WebFlux)

More about it here: https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#webflux-web-handler-api

Answer 2

You can use web filter to make WebFlux support contextPath

@Bean
public WebFilter contextPathWebFilter() {
    String contextPath = serverProperties.getServlet().getContextPath();
    return (exchange, chain) -> {
        ServerHttpRequest request = exchange.getRequest();
        if (request.getURI().getPath().startsWith(contextPath)) {
            return chain.filter(
                exchange.mutate()
                .request(request.mutate().contextPath(contextPath).build())
                .build());
        }
        return chain.filter(exchange);
    };
}

Answer 3

For Undertow I managed to add a context path by creating a customized UndertowReactiveWebServerFactory:

 @Bean
public UndertowReactiveWebServerFactory undertowReactiveWebServerFactory(
        @Value("${server.servlet.context-path}") String contextPath) {
    return new UndertowReactiveWebServerFactory() {
        @Override
        public WebServer getWebServer(HttpHandler httpHandler) {
            Map<String, HttpHandler> handlerMap = new HashMap<>();
            handlerMap.put(contextPath, httpHandler);
            return super.getWebServer(new ContextPathCompositeHandler(handlerMap));
        }
    };
}