[FIXED] Spring Boot Data Rest + CORS not being enabled properly for OPTIONS/DELETE

Issue

I've got an extremely simple example that I can't get to work.

I have my domain that models my database, and my Repository.

public interface MyTestRepository extends CrudRepository<MyTest, Integer> {
}

I used http://resttesttest.com/ to test it. For GET Method's it returns me the JSON REST information without any issue.

I can query the endpoint http://localhost:8080/mytest/1 and I get back the information for id=1 from the database.

However, the problem comes in when I try to use the DELETE option. If I run a DELETE on http://localhost:8080/mytest/1 I get

Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://resttesttest.com' is therefore not allowed access. The response had HTTP status code 403.

I initially tried the following, but found out that I can't use it because I'm using Spring-data-Rest. https://jira.spring.io/browse/DATAREST-573

@Override
public void addCorsMappings(CorsRegistry registry) {
    registry.addMapping("/**")
        .allowedOrigins("*")
        .allowedMethods("*")
        .allowedHeaders("*")
        .allowCredentials(true).maxAge(3600);
}

I googled around and found this.

How to configure CORS in a Spring Boot + Spring Security application?

So I added

@Bean
public FilterRegistrationBean corsFilter() {
    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    CorsConfiguration config = new CorsConfiguration();
    config.setAllowCredentials(true);
    config.addAllowedOrigin("*");
    config.addAllowedHeader("*");
    config.addAllowedMethod("*");
    source.registerCorsConfiguration("/**", config);
    FilterRegistrationBean bean = new FilterRegistrationBean(new CorsFilter(source));
    bean.setOrder(0);
    return bean;
}

I also found this thread.

Spring Data Rest and Cors

and tried the following code as well, but no luck.

@Bean
public FilterRegistrationBean corsFilter() {
    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    CorsConfiguration config = new CorsConfiguration();
    config.setAllowCredentials(true);
    config.addAllowedOrigin("*");
    config.addAllowedHeader("*");
    config.addAllowedMethod("OPTIONS");
    config.addAllowedMethod("HEAD");
    config.addAllowedMethod("GET");
    config.addAllowedMethod("PUT");
    config.addAllowedMethod("POST");
    config.addAllowedMethod("DELETE");
    config.addAllowedMethod("PATCH");
    source.registerCorsConfiguration("/**", config);
    // return new CorsFilter(source);
    final FilterRegistrationBean bean = new FilterRegistrationBean(new CorsFilter(source));
    bean.setOrder(0);
    return bean;
}

I added a catch all to test which should allow everything CORS wise to pass, however I still keep getting the No 'Access-Control-Allow-Origin' even though I have "*".

At this point I have no idea what I am missing on why the preflight request doesn't pass access control check.

curl has no problem issuing the delete.

Edit:

Ended up finding the exact solution. I'm not sure of the differences between what I have and this method, but this seems to work.

import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * Note this is a very simple CORS filter that is wide open.
 * This would need to be locked down.
 * Source: https://stackoverflow.com/questions/39565438/no-access-control-allow-origin-error-with-spring-restful-hosted-in-pivotal-web
 */
@Component
public class CORSFilter implements Filter {

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        chain.doFilter(req, res);
    }

    public void init(FilterConfig filterConfig) {}

    public void destroy() {}

}

Solution

This is what I use as a permit all CORS servlet filter:

public class PermissiveCORSFilter implements Filter {

    private static final Logger LOGGER = LoggerFactory.getLogger(PermissiveCORSFilter.class);
    private static final Pattern PATTERN = Pattern.compile("^[a-zA-Z0-9 ,-_]*$");

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;

        String origin;
        String credentialFlag;
        if (request.getHeader("Origin") == null) {
            origin = "*";
            credentialFlag = "false";
         } else {
            origin = request.getHeader("Origin");
            credentialFlag = "true";
         }

        // need to do origin.toString() to avoid findbugs error about response splitting        
        response.addHeader("Access-Control-Allow-Origin", origin.toString());
        response.setHeader("Access-Control-Allow-Credentials", credentialFlag);
        if ("OPTIONS".equals(request.getMethod())) {
            LOGGER.info("Received OPTIONS request from origin:" + request.getHeader("Origin"));
            response.setHeader("Access-Control-Allow-Methods", "GET,POST,HEAD,OPTIONS,PUT,DELETE");
            response.setHeader("Access-Control-Max-Age", "3600");
            String headers = StringUtils.trimToEmpty(request.getHeader("Access-Control-Request-Headers"));
            if (!PATTERN.matcher(headers).matches()) {
                throw new ServletException("Invalid value provided for 'Access-Control-Request-Headers' header");
            }
            response.setHeader("Access-Control-Allow-Headers", headers); // allow any headers
        }
        chain.doFilter(req, res);
    }

    @Override
    public void init(FilterConfig filterConfig) {
        // Do nothing
    }

    @Override
    public void destroy() {
        // Do nothing
    }

Answered By - Pete