Fixing 401 Error with CORS Preflights (with Spring boot)

              

When the web application runs on a different domain and the server runs on another domain,  we have to deal with cross origin requests. But, if we don't know the mechanism of cross origin resource sharing (CORS), we will end up with errors like 401.

Error in brief

    My Angular web application runs on port 4200, and my spring boot application runs on server on port 8080. I could not enable CORS in my backend, so, I got an error when sending a request from my application like this.

 

  

Reason

       My pre-flight request is not responded with status OK(200).

Solution

        I enabled CORS in my backend. To do this, there are several methods. Here in my post, I have shown the easiest way to do that. But, if you are interest in knowing other ways, click me )

By using Web Security in Spring Boot,

      You have to create a web security configuration class.  I hope everybody creates that class for backend authentication purposes. 

If you have already created that class, inside configure(HttpSecurity httpSecurity) method ,add this line httpSecurity.cors();

It's that simple !!!