Spring CORS No 'Access-Control-Allow-Origin

Question

I am getting the following problem after porting web.xml to java config

No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:63342' is therefore not allowed access.

Based on a few Spring references, the following attempt has been tried:

@Configuration
@ComponentScan(basePackageClasses = AppConfig.class, useDefaultFilters = false, includeFilters = {
        @Filter(org.springframework.stereotype.Controller.class) })
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/*").allowedOrigins("*").allowedMethods("GET", "POST", "OPTIONS", "PUT")
                .allowedHeaders("Content-Type", "X-Requested-With", "accept", "Origin", "Access-Control-Request-Method",
                        "Access-Control-Request-Headers")
                .exposedHeaders("Access-Control-Allow-Origin", "Access-Control-Allow-Credentials")
                .allowCredentials(true).maxAge(3600);
    }

}

The values chosen were taken from a working web.xml filter:

<filter>    
<filter-name>CorsFilter</filter-name>
<filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
<init-param>
    <param-name>cors.allowed.origins</param-name>
    <param-value>*</param-value>
</init-param>
<init-param>
    <param-name>cors.allowed.methods</param-name>
    <param-value>GET,POST,HEAD,OPTIONS,PUT</param-value>
</init-param>
<init-param>
    <param-name>cors.allowed.headers</param-name>
    <param-value>Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers</param-value>
</init-param>
<init-param>
    <param-name>cors.exposed.headers</param-name>
    <param-value>Access-Control-Allow-Origin,Access-Control-Allow-Credentials</param-value>
</init-param>
<init-param>
    <param-name>cors.support.credentials</param-name>
    <param-value>true</param-value>
</init-param>
<init-param>
    <param-name>cors.preflight.maxage</param-name>
    <param-value>10</param-value>
</init-param> </filter> <filter-mapping>

<filter-name>CorsFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

Any ideas why the Spring java config approach is not working like the web.xml file did?

Answer 1

Omkar's answer is quite comprehensive.

But some part of the Global config part has changed.

According to the spring boot 2.0.2.RELEASE reference

As of version 4.2, Spring MVC supports CORS. Using controller method CORS configuration with @CrossOrigin annotations in your Spring Boot application does not require any specific configuration. Global CORS configuration can be defined by registering a WebMvcConfigurer bean with a customized addCorsMappings(CorsRegistry) method, as shown in the following example:

@Configuration
public class MyConfiguration {

    @Bean
    public WebMvcConfigurer corsConfigurer() {
        return new WebMvcConfigurer() {
            @Override
            public void addCorsMappings(CorsRegistry registry) {
                registry.addMapping("/api/**");
            }
        };
    }
}

Most answer in this post using WebMvcConfigurerAdapter, however

The type WebMvcConfigurerAdapter is deprecated

Since Spring 5 you just need to implement the interface WebMvcConfigurer:

public class MvcConfig implements WebMvcConfigurer {

This is because Java 8 introduced default methods on interfaces which cover the functionality of the WebMvcConfigurerAdapter class