How to enable CORS in Grails 3.0.1

So, if you got here using grails 3.2.+ you can use the default way.

Go to your application.yml and add:

grails:
    cors:
        enabled: true

It will add Access-Control-Allow-Origin '*'. If you want something different, look this page

We used a normal servlet filter with an entry in resources.groovy to solve this problem:

public class CorsFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest req, HttpServletResponse resp, FilterChain chain)
            throws ServletException, IOException {

        String origin = req.getHeader("Origin");

        boolean options = "OPTIONS".equals(req.getMethod());
        if (options) {
            if (origin == null) return;
            resp.addHeader("Access-Control-Allow-Headers", "origin, authorization, accept, content-type, x-requested-with");
            resp.addHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, DELETE, TRACE, OPTIONS");
            resp.addHeader("Access-Control-Max-Age", "3600");
        }

        resp.addHeader("Access-Control-Allow-Origin", origin == null ? "*" : origin);
        resp.addHeader("Access-Control-Allow-Credentials", "true");

        if (!options) chain.doFilter(req, resp);
    }
}

resources.groovy:

beans = {
    corsFilter(CorsFilter)
}

This works with CORS requests using basic authentication. I wrote the Grails 2.x plugin and this seemed easier than getting it to work with Grails 3.