HTTP status code 401 even though I’m sending credentials in the request

ghz 1years ago ⋅ 1952 views

Question

Recently i have introduced JWT authentication to my Springboot and Angualr2 based App. In There i tried to do a POST request by passing the JWT token as below in my Angualr code

save(jobId: number, taskId: number, note: Note) {

   return this.http.post(environment.APIENDPOINT + '/jobs/' + jobId + '/tasks/' + taskId + '/notes', note, this.setHeaders()).map((response: Response) => response.json());

}


private setHeaders() {
        // create authorization header with jwt token
        let currentUser = JSON.parse(localStorage.getItem('currentUser'));
        console.log("Current token---"+ currentUser.token);
        if (currentUser && currentUser.token) {

  let headers = new Headers();
  headers.append('Content-Type', 'application/json');
  headers.append('authorization','Bearer '+ currentUser.token);
            
   let r = new RequestOptions({ headers: headers })
   return r;

        }
    }

However in the server side it returns status code 401. The issue is in the Springboot side it checks the authorization header as below and it returns null

String authToken = request.getHeader("authorization ");

Then i had a look at the request header and it has the authorization header under Access-Control-Request-Headers as below. But it is not visible to the server side.

enter image description here

Then i read further and found that this could be an issue with CORS configuration. So i have modified my CORS configuration filter to have addExposedHeader as below

@Bean
public CorsFilter corsFilter() {
    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    CorsConfiguration config = new CorsConfiguration();
    config.setAllowCredentials(true);
    config.addAllowedOrigin("*");
    config.addAllowedHeader("*");
    config.addExposedHeader("authorization");
    config.addAllowedMethod("OPTIONS");
    config.addAllowedMethod("GET");
    config.addAllowedMethod("POST");
    config.addAllowedMethod("PUT");
    config.addAllowedMethod("DELETE");

    //config.addExposedHeader("Content-Type");
    source.registerCorsConfiguration("/**", config);
    return new CorsFilter(source);
}

Still the server complains that it can not find the Authorization header. Did i miss any thing here? Appreciate your help

Solution

After reading the sideshowbarker's comment below, i was able to understand the basics behind the issue. In My Project I have a JWT token filter and inside that it always checks the Authorization header. Then i have modified it as below and now it works as expected

protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) throws ServletException, IOException {
try {

    if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {
        response.setStatus(HttpServletResponse.SC_OK);
    }else{
        String authToken = request.getHeader(this.tokenHeader);
        jWTTokenAuthenticationService.parseClaimsFromToken(authToken);
        --
    }
    chain.doFilter(request, response);
}Catch(AuthenticationException authEx){
    SecurityContextHolder.clearContext();
    if (entryPoint != null) {
        entryPoint.commence(request, response, authEx);
    }
}

}

Answer

You need to configure the server to not require authorization for OPTIONS requests (that is, the server the request is being sent to — not the one serving your frontend code).

That’s because what’s happening is this:

  1. Your code tells your browser it wants to send a request with the Authorization header.
  2. Your browser says, OK, requests with the Authorization header require me to do a CORS preflight OPTIONS to ensure the server allows requests with the Authorization header.
  3. Your browser sends the OPTIONS request without theAuthorization header, because the whole purpose of the OPTIONS check is to see if it’s OK to include that header.
  4. Your server sees the OPTIONS request but rejects it with a 401 since it lacks the header.
  5. Your browser expects a 200 or 204 response for the CORS preflight but instead gets that 401. So your browser stops right there and never tries the POST request from your code.

Further details:

The Access-Control-Request-Headers and Access-Control-Request-Method request headers show in the question indicate the browser’s doing a [CORS preflight OPTIONS request](https://developer.mozilla.org/en- US/docs/Web/HTTP/Access_control_CORS#Preflighted_requests).

And the presence of the Authorization and Content-Type: application/json request headers in your request are what trigger your browser do that CORS preflight — by sending an OPTIONS request to the server before trying the POST request in your code. And because that OPTIONS preflight fails, the browser stops right there and never attempts the POST.

So you must figure out what part of the server-side code on the server the request is being sent to causes it to require authorization for OPTIONS requests, and change that so it instead responds to OPTIONS with a 200 or 204 success response without requiring authorization.

For specific help on OPTIONS-enabling a Spring server in particular, see the following answers:

#spring-boot