How to handle HTTP OPTIONS requests in Spring Boot 2 with webflux?

spring boot options request
what is spring webflux
spring webflux webclient
spring 5 cors
webflux vs mvc
spring webflux logging
spring webflux functional endpoints
spring webflux crud example

I configured cors as following:

@Bean
WebFluxConfigurer corsConfigurer() {
    return new WebFluxConfigurerComposite() {

        @Override
        public void addCorsMappings(CorsRegistry registry) {
            registry.addMapping("/**").allowedOrigins("*")
                    .allowedMethods("*");
        }
    };
}

and my POST is like that:

@Bean
RouterFunction<ServerResponse> routes() {
    return route(POST("/create")
                          .and(accept(APPLICATION_JSON))
                          .and(contentType(APPLICATION_JSON)), serverRequest 
                                 -> create(serverRequest);
}

anyway my angular application cannot make any request until I add OPTIONS route like this:

@Bean
RouterFunction<ServerResponse> routes() {
    return route(POST("/create")
                          .and(accept(APPLICATION_JSON))
                          .and(contentType(APPLICATION_JSON)), serverRequest 
                                 -> create(serverRequest)
         .andRoute(OPTIONS("/create"), serverRequest -> ServerResponse.ok().build());
}

Is that necessary? Is there any way to remove this OPTIONS handling?

I don't think this is supported with WebFlux functional endpoints. The Spring Framework reference documentation points to the CorsWebFilter instead.

You can define a CorsWebFilter @Bean and configure it with a custom CorsConfiguration to achieve the same thing.

2. Enabling CORS on Annotated Elements. Spring provides the @CrossOrigin annotation to enable CORS requests on controller classes and/or handler methods. headers; All HTTP methods mapped by the handler method are allowed As a result, we are enabling cross-origin request handling for that  Learn to handle the HTTP OPTIONS requests specific to REST resource in Spring webmvc applications by adding specific handler method for RequestMethod.OPTIONS. 1. HTTP OPTIONS Method. The HTTP OPTIONS method is used to describe the communication options for the target resource. This method allows the client to determine the options and/or

It's depend on.

If your back end and front end build on the same server and using same port, there is no need to support OPTIONS.

If not, you must support OPTIONS, because it is used to identify which methods is allowed on your server to prevent/allow CORS (cross origin resource sharing).

All latest modern browser are implemented CORS by sending HTTP OPTIONS to check it. If your sever refuse or deny it, the browser will banned your request.

There are also HTTP method specific shortcut variants of which, by default, matches to all HTTP methods. but does not match "/projects/spring/boot/​versions" [a-z]+}") public void handle(@PathVariable String version, Spring WebFlux also supports custom request mapping attributes  Spring WebClient is a non-blocking, reactive client to perform HTTP requests, a part of Spring WebFlux framework In this tutorial, you will learn how to use WebClient and take a look at the difference between its exchange() and retrieve() methods What you'll need JDK 8+ or OpenJDK 8+ Maven 3+

OPTIONS requests are pre-flight requests in Cross-origin resource sharing (CORS) and they are required to making request across different origins.

This pre-flight request is made by some browsers as a safety measure to ensure that the request being done is trusted by the server that server understand method, origin and headers being sent on the request are safe.

this is how process works:

  1. client send request to server with OPTIONS
  2. if OPTIONS Request is OK then client send actual request to server.

you might also need to expose headers.

@Bean
    WebFluxConfigurer corsConfigurer() {
        return new WebFluxConfigurerComposite() {

            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/**").allowedOrigins("*")
                        .allowedMethods("*")
                .exposedHeaders("*");
            }
        };
    }

HTTP/2. 2. WebClient. 2.1. Retrieve; 2.2. Exchange; 2.3. Request body The reactive stack, web framework, Spring WebFlux, was added later in version 5.0. or if using Spring Boot, check the Spring Boot configuration options for each HttpHandler — basic, common API for HTTP request handling with  4. Spring Boot WebFlux Example. In this Spring boot 2 application, I am creating employee management system. I chosen it because, while learning, you can compare it with traditional MVC style application. To make it fully non-blocking, I am using mongodb as back-end database. 4.1. Maven dependencies

I had the same issue with adding CORS by "addCorsMappings" (like you did) Seems like OPTIONS route isn't supported with the above config. only by this.

@Bean
CorsWebFilter corsFilter() {
    CorsConfiguration config = new CorsConfiguration();
    config.setAllowCredentials(true);
    config.addAllowedOrigin("http://domain1.com");
    config.addAllowedHeader("*");
    config.addAllowedMethod("*");

    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    source.registerCorsConfiguration("/**", config);

    return new CorsWebFilter(source);
}

If security is enabled, preflight requests are currently answered with 401. This is a working together to host and review code, manage projects, and build software together. GET' -H 'Origin:localhost' -X OPTIONS http://localhost:8080/ @​rwinch I created a new Spring Boot 2 project and had the following  timeTaken: the time taken to handle the request; We can adapt this response to our needs if we feel it's too verbose. We can tell Spring what fields we want to be returned by specifying them in the management.trace.http.include property of our application.properties: management.trace.http.include=RESPONSE_HEADERS

"Access to fetch at 'http://localhost:8080/api/webcontent/en/menu' Spring webflux… Support for routing cross-origin OPTIONS requests #830 We have several Spring Boot Services embedded in one Big Spring Boot Service. of my gateway is org.springframework.cloud.spring-cloud-gateway.2.2.2. Spring WebFlux framework is part of Spring 5 and provides reactive programming support for web applications. In this tutorial, we'll be creating a small reactive REST application using the reactive web components RestController and WebClient. We will also be looking at how to secure our reactive endpoints using Spring Security.

Spring WebFlux Tutorials By default an HTTP OPTIONS request is handled by setting the Note that we have upgraded our Spring dependency to version 4.3.​2. Spring Boot - Web Application Testing With Embedded Server And TestRestTemplate · Java - How to find Available Runtime Memory? In this quick tutorial, we're going to present a way of performing HTTP requests in Java — by using the built-in Java class HttpUrlConnection. Explore the new Java 9's HttpClient API which provides a lot of flexibility and powerful features. A quick list of the available web and application servers in Java.

Handling responses 2. To use WebClient api, we must have spring-boot-starter​-webflux module imported in the project. For example, sending a HTTP POST request involves following steps. If we are only interested in response body entity the using methods retrieve() and then bodyToFlux() and bodyToMono() will​  Spring Boot 2.2.2 and Spring Boot 1.5.22; keytool; Keytool is a certificate management utility provided together with the JDK, so if you have the JDK installed, you should already have keytool available. To check it, try running the command keytool --help from your Terminal prompt.

Comments
  • As mentioned below WebFluxConfigurer doesn't work with functional endpoints, CorsWebFilter does. Explicit OPTIONS handling as suggested above not required, but do remember the OPTIONS request will need to include Origin and Access-Control-Request-Method headers - caught me out in testing as I wasn't adding the later.
  • It worked, thank you! Still I don't get the difference. I will post another question for it.
  • Thank you for response. But, shouldn't webCluxConfigurer with corsMapping be enough? I already allowed all reauests with all methods, so why bother to creating another route with options?
  • docs.spring.io/spring/docs/5.0.2.RELEASE/…, to config cors with functional endpoint.
  • Thank you for response. But, shouldn't webCluxConfigurer with corsMapping be enough? I already allowed all reauests with all methods, so why bother to creating another route with options?