如何在WebFlux中正确实现CORS？

Question

我想创建一个简单的Spring Boot / Webflux服务器作为REST API。我正在尝试在本地进行测试。 Webflux服务器在端口8080上运行，并且我有另一台服务器在端口3000上运行html（React.js）。我想从网站向服务器发出CORS请求。为此，我使用方法addCorsMappings创建了一个Java类，并添加了@Configuration注释。我想知道是否通过添加注释神奇地使Spring知道被注释的类，但是根据这个article，我还需要在org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.mypackage.CORSHandler中添加spring.factories file属性。但是，我仍然看到addCorsMappings甚至没有被调用（我看不到日志消息）。作为Spring Boot的新手，我还缺少其他配置吗？

这是我的主要课程：

package com.mypackage;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import reactor.ipc.netty.http.server.HttpServer;
import org.springframework.http.HttpMethod;
import org.springframework.http.server.reactive.HttpHandler;
import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerResponse;

import static org.springframework.http.HttpStatus.UNAUTHORIZED;
import static org.springframework.http.MediaType.APPLICATION_JSON;
import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
import static org.springframework.web.reactive.function.server.RequestPredicates.POST;
import static org.springframework.web.reactive.function.server.RequestPredicates.accept;
import static org.springframework.web.reactive.function.server.RequestPredicates.contentType;
import static org.springframework.web.reactive.function.server.RequestPredicates.method;
import static org.springframework.web.reactive.function.server.RequestPredicates.path;
import static org.springframework.web.reactive.function.server.RouterFunctions.nest;
import static org.springframework.web.reactive.function.server.RouterFunctions.route;
import static org.springframework.web.reactive.function.server.RouterFunctions.toHttpHandler;

public class Server {
    private static final Logger log = LogManager.getLogger(Server.class);
    public static final String HOST = "localhost";
    public static final int PORT = 8080;

    public static void main(String[] args) throws Exception {
        Server server = new Server();
        server.startReactorServer();

        System.out.println("Press ENTER to exit.");
        System.in.read();
    }

    public RouterFunction<ServerResponse> routingFunction() {
        PersonRepository repository = new DummyPersonRepository();
        PersonHandler handler = new PersonHandler(repository);

        return nest(path("/person"),
                nest(accept(APPLICATION_JSON),
                        route(GET("/{id}"), handler::getPerson)
                                .andRoute(method(HttpMethod.GET), handler::listPeople)
                ).andRoute(POST("/").and(contentType(APPLICATION_JSON)), handler::createPerson));
    }

    public void startReactorServer() {
        RouterFunction<ServerResponse> route = routingFunction().filter((request, next) -> {
            log.warn(request.path());

            if (request.path().contains("person")) {
                log.warn("calling next()");
                return next.handle(request);
            } else {
                return ServerResponse.status(UNAUTHORIZED).build();
            }
        });

        HttpHandler httpHandler = toHttpHandler(route);

        ReactorHttpHandlerAdapter adapter = new ReactorHttpHandlerAdapter(httpHandler);
        HttpServer server = HttpServer.create(HOST, PORT);
        server.newHandler(adapter).block();

    }
}

这是我的CORSHandler课：

package com.mypackage;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.web.reactive.config.CorsRegistry;
import org.springframework.web.reactive.config.EnableWebFlux;
import org.springframework.web.reactive.config.WebFluxConfigurer;
import org.springframework.web.reactive.function.server.HandlerFunction;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;

@Configuration
public class CORSHandler implements WebFluxConfigurer {
    private static final Logger log = LogManager.getLogger(CORSHandler.class);

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        log.warn("from addCorsMappings!!");
        registry.addMapping("*")
                .allowedOrigins("*")
                .allowedMethods("*")
                .allowedHeaders("Content-Type", "Access-Control-Allow-Headers", "Authorization",
                        "X-Requested-With", "mode")
                .allowCredentials(true);
    }
}

Answer 1

我目前发现的解决方案是，包含配置方法的类需要作为AnnotationConfigApplicationContext上下文的参数给出。需要将上下文作为WebHttpHandlerBuilder.webHandler(RouterFunctions.toWebHandler(route)).applicationContext(context)的参数。所以主类看起来像这样：

package com.mypackage;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.web.reactive.function.server.RouterFunctions;
import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
import reactor.ipc.netty.http.server.HttpServer;
import org.springframework.http.HttpMethod;
import org.springframework.http.server.reactive.HttpHandler;
import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerResponse;

import static org.springframework.http.HttpStatus.UNAUTHORIZED;
import static org.springframework.http.MediaType.APPLICATION_JSON;
import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
import static org.springframework.web.reactive.function.server.RequestPredicates.POST;
import static org.springframework.web.reactive.function.server.RequestPredicates.accept;
import static org.springframework.web.reactive.function.server.RequestPredicates.contentType;
import static org.springframework.web.reactive.function.server.RequestPredicates.method;
import static org.springframework.web.reactive.function.server.RequestPredicates.path;
import static org.springframework.web.reactive.function.server.RouterFunctions.nest;
import static org.springframework.web.reactive.function.server.RouterFunctions.route;
import static org.springframework.web.reactive.function.server.RouterFunctions.toHttpHandler;

@SpringBootApplication
public class Server {
    private static final Logger log = LogManager.getLogger(Server.class);
    public static final String HOST = "localhost";
    public static final int PORT = 8080;

    public static void main(String[] args) throws Exception {
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(CorsConfiguration.class);
        Server server = new Server();
        server.startReactorServer(ctx);

        System.out.println("Press ENTER to exit.");
        System.in.read();
    }

    public RouterFunction<ServerResponse> routingFunction() {
        PersonRepository repository = new DummyPersonRepository();
        PersonHandler handler = new PersonHandler(repository);

        return nest(path("/person"),
                nest(accept(APPLICATION_JSON),
                        route(GET("/{id}"), handler::getPerson)
                                .andRoute(method(HttpMethod.GET), handler::listPeople)
                ).andRoute(POST("/").and(contentType(APPLICATION_JSON)), handler::createPerson));
    }

    public void startReactorServer(AnnotationConfigApplicationContext ctx) {
        RouterFunction<ServerResponse> route = this.routingFunction().filter((request, next) -> {
            log.warn(request.path());

            if (request.path().contains("person")) {
                log.warn("calling next()");
                return next.handle(request);
            } else {
                return ServerResponse.status(UNAUTHORIZED).build();
            }
        });

        HttpHandler httpHandler = WebHttpHandlerBuilder.webHandler(RouterFunctions.toWebHandler(route))
        .applicationContext(ctx).build();

        ReactorHttpHandlerAdapter adapter = new ReactorHttpHandlerAdapter(httpHandler);
        HttpServer server = HttpServer.create(HOST, PORT);
        server.newHandler(adapter).block();
    }
}

和CorsConfiguration类看起来像这样：

package com.mypackage;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.cors.reactive.CorsUtils;
import org.springframework.web.reactive.config.EnableWebFlux;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;
import reactor.core.publisher.Mono;

@Configuration
@EnableWebFlux
public class CorsConfiguration {

    private static final Logger log = LogManager.getLogger(CorsConfiguration.class);

    private static final String ALLOWED_HEADERS = "x-requested-with, authorization, Content-Type, Authorization, credential, X-XSRF-TOKEN, mode";
    private static final String ALLOWED_METHODS = "GET, PUT, POST, DELETE, OPTIONS";
    private static final String ALLOWED_ORIGIN = "*";
    private static final String MAX_AGE = "3600";

    @Bean
    public WebFilter corsFilter() {
        log.warn("from CorsConfiguration!!!");
        return (ServerWebExchange ctx, WebFilterChain chain) -> {
            ServerHttpRequest request = ctx.getRequest();
            log.warn("after ServerHttpRequest");
            if (CorsUtils.isCorsRequest(request)) {
                log.warn("inside isCorsRequest");
                ServerHttpResponse response = ctx.getResponse();
                HttpHeaders headers = response.getHeaders();
                headers.add("Access-Control-Allow-Origin", ALLOWED_ORIGIN);
                headers.add("Access-Control-Allow-Methods", ALLOWED_METHODS);
                headers.add("Access-Control-Max-Age", MAX_AGE);
                headers.add("Access-Control-Allow-Headers", ALLOWED_HEADERS);
                if (request.getMethod() == HttpMethod.OPTIONS) {
                    response.setStatusCode(HttpStatus.OK);
                    return Mono.empty();
                }
            }
            return chain.filter(ctx);
        };
    }
}

在此代码中，corsFilter被调用并设置CORS标头，但路由却不起作用（返回404状态）。