Multiple CORS header ‘Access-Control-Allow-Origin’ not allowed / CORS header ‘Access-Control-Allow-Origin’ missing)

Question

I'm having issues with the CORS headers when sending an HTTP request from my Angular 7 application (hosted on http://localhost:4200) to my Spring-Boot application (hosted on https://localhost:8924) from Firefox.

I have a CORS filter in my Spring-Boot application that is added to my request:

@Component
public class CorsFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(final HttpServletRequest request, final HttpServletResponse response,
                                    final FilterChain filterChain) throws ServletException, IOException {
        response.addHeader("Access-Control-Allow-Origin", "*");
        response.addHeader("Access-Control-Allow-Methods", "GET, POST, DELETE, PUT, PATCH, HEAD");
        response.setHeader("Access-Control-Allow-Headers", "X-Requested-With, Authorization, Content-Type");
        response.addIntHeader("Access-Control-Max-Age", 3600);

        if ("OPTIONS".equalsIgnoreCase(request.getMethod())) 
        {
            response.setStatus(HttpServletResponse.SC_OK);
        } 
        else 
        {
            filterChain.doFilter(request, response);
        }
    }
}

    @Override
    protected void configure(HttpSecurity http) throws Exception 
    {
        http.addFilterBefore(corsFilter(), SessionManagementFilter.class);
        http.csrf().disable().
            authorizeRequests()
                .antMatchers("/api/auth/**","/api/MentorCalendar","/api/user/role/**").permitAll()
                .anyRequest().authenticated()
                .and()
                .exceptionHandling().authenticationEntryPoint(unauthorizedHandler).and()
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);

        http.addFilterBefore(authenticationJwtTokenFilter(), UsernamePasswordAuthenticationFilter.class);
    }

When sending the request, the Firefox console returns this error message:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8924/api/auth/signin. (Reason: Multiple CORS header ‘Access-Control-Allow-Origin’ not allowed).

Commenting out the Access-Control-Allow-Origin:

@Component
public class CorsFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(final HttpServletRequest request, final HttpServletResponse response,
                                    final FilterChain filterChain) throws ServletException, IOException {
//        response.addHeader("Access-Control-Allow-Origin", "*");
        response.addHeader("Access-Control-Allow-Methods", "GET, POST, DELETE, PUT, PATCH, HEAD");
        response.setHeader("Access-Control-Allow-Headers", "X-Requested-With, Authorization, Content-Type");
        response.addIntHeader("Access-Control-Max-Age", 3600);

        if ("OPTIONS".equalsIgnoreCase(request.getMethod())) 
        {
            response.setStatus(HttpServletResponse.SC_OK);
        } 
        else 
        {
            filterChain.doFilter(request, response);
        }
    }
}

Returns this error message:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8924/api/auth/signin. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).

src/app/home/login.component.ts extract

export class LoginComponent {
  constructor(private LoginService: LoginService, private router: Router) {}

  login(inputUsername, inputPassword){
    this.LoginService.login({username: inputUsername, password: inputPassword})
        .subscribe(data => {
        localStorage.setItem("jwtToken", data.accessToken);

src/app/home/login.service.ts

const httpOptions = {
  headers: new HttpHeaders({
    'Content-Type':  'application/json'
  })
};

@Injectable()
export class LoginService {
  loginUrl = "http://localhost:8924/api/auth/signin";

  constructor( private http: HttpClient ) {}

  login(loginCreds: any): Observable<any> {
  return this.http.post<any>(this.loginUrl, loginCreds, httpOptions);
  }
}

How does the response.addHeader("Access-Control-Allow-Origin", "*"); line set multiple headers when included but none when I remove it?

Answer 1

In my case this happens when i set both CORS support in nginx conf file and Django middleware.

Nginx part:

if ($request_method = 'OPTIONS') {
    add_header 'Access-Control-Allow-Origin' '*';
    add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
    add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
    add_header 'Access-Control-Max-Age' 1728000;
    add_header 'Content-Type' 'text/plain; charset=utf-8';
    add_header 'Content-Length' 0;
    return 204;
}
if ($request_method = 'POST') {
    add_header 'Access-Control-Allow-Origin' '*';
    add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
    add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
    add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
}
if ($request_method = 'GET') {
    add_header 'Access-Control-Allow-Origin' '*';
    add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
    add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
    add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
}    

Django part:

MIDDLEWARE = (
    'corsheaders.middleware.CorsMiddleware',

Solution was very simple - i just remove CORS part in nginx and all works perfectly

location / {
    uwsgi_pass  django_upstream;
    include     uwsgi_params;
}

Answer 2

This has solved the issue for me:

if(!response.containsHeader("Access-Control-Allow-Origin"))
{
    response.addHeader("Access-Control-Allow-Origin", "*"); 
}

Not the ideal way to get it to work

Answer 3

Did you try enabling @CrossOrigin() in you springboot controller. Below is the basic snippet.

@CrossOrigin(origins = "http://localhost:9000")
@GetMapping("/greeting")
public Greeting greeting(@RequestParam(required=false, defaultValue="World") String name) {
    System.out.println("==== in greeting ====");
    return new Greeting(counter.incrementAndGet(), String.format(template, name));
}

For more info visit Enabling CORS

I had the same problem. It was solved by above solution. You must not be CORS problem when using Internet Explorer.