How to connect Angular 2 with Spring boot application?

Question

I used HttpModule to send post request to send login credentials to a Spring framework application but the request is getting filtered out by spring security.Angular application is not sending a post request but sending some "Options" request.

What does the below code do?

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;

        response.setHeader("Access-Control-Allow-Origin", "http://localhost:4200");
        response.setHeader("Access-Control-Allow-Methods", "POST, PUT, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Credentials", "true");

        if (!(request.getMethod().equalsIgnoreCase("OPTIONS"))) {
            try {
                chain.doFilter(req, res);
            } catch(Exception e) {
                e.printStackTrace();
            }
        } else {
            System.out.println("Pre-flight");
            response.setHeader("Access-Control-Allow-Methods", "POST,GET,DELETE");
            response.setHeader("Access-Control-Max-Age", "3600");
            response.setHeader("Access-Control-Allow-Headers", "authorization, content-type," +
                    "access-control-request-headers,access-control-request-method,accept,origin,authorization,x-requested-with");
            response.setStatus(HttpServletResponse.SC_OK);
        }

    }

Answer 1

Your CORS configuration allows traffic only from

 response.setHeader("Access-Control-Allow-Origin", "http://localhost:4200");

Make sure that your Angular client is running on that specific host & port.

A browser initially makes an HTTP OPTIONS (CORS pre-flight) request to verify if the client host/port match in the response of the server (ie the value of the Access-Control-Allow-Origin response header that you set)