[FIXED] Angular 6 + Spring Boot: Error: "from origin 'http://localhost:4200' has been blocked by CORS policy"

Issue

I am trying to connect angular 6 project with spring boot application. When I run angular project, it constantly gives this error, although I have installed all the dependencies and imports.

I have used following line of code in controller class.

@CrossOrigin(origins = "http://localhost:4200/", maxAge = 3600)

I have also included this SimpleCORSFilter.java file in java folder:

package com.oms;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

@Component
public class SimpleCORSFilter implements Filter {

private final Logger log = LoggerFactory.getLogger(SimpleCORSFilter.class);

public SimpleCORSFilter() {
    log.info("SimpleCORSFilter init");
}

@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {

    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;

    response.setHeader("Access-Control-Allow-Origin", "*");
    response.setHeader("Access-Control-Allow-Credentials", "true");
    response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
    response.setHeader("Access-Control-Max-Age", "3600");
    response.setHeader("Access-Control-Allow-Headers", "Content-Type, Accept, X-Requested-With, remember-me");

    chain.doFilter(req, res);
}

@Override
public void init(FilterConfig filterConfig) {
}

@Override
public void destroy() {
}

}

Also I have created proxy.conf.json file in angular project:

{
    "/api": {
      "target": "http://localhost:8080",
      "secure": false
    }
  }

This file is included like this in angular.json:

"start": "ng serve --proxy-config proxy.conf.json",

Still I am getting this error:

Access to XMLHttpRequest at 'http://localhost:8080/fetchAll' from origin 'http://localhost:4200' has been blocked by CORS policy: Request header field authorization is not allowed by Access-Control-Allow-Headers in preflight response.**

I referred such type of queries, but could not get the exact solution.

I am really confused, if there is any error in code? What steps should be taken to resolve this issue?

Solution

When you are using Spring Boot, I would suggest you to add a CorsFilter bean in your configurations instead of introducing a CORS filter. Let me know if this helps.

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

Happy Coding :)

Answered By - Pratik Ambani
Answer Checked By - Katrina (JavaFixing Volunteer)