Sebastien Sebastien - 1 year ago 229
reST (reStructuredText) Question

Configuring CORS with Grails 3 and Spring Security REST

I'm trying to figure out how to plug an Angular 2 frontend (running on localhost:4200) into a Grails 3 backend (running on localhost:8080) so I need to enable CORS support in the grails app.

I found this Github project ( that shows how to enable CORS using the grails3-cors-interceptor plugin. I'm running this very application as a test backend and I'm putting a breakpoint in

to check when it's called. And when I do a GET on
, the browser sends an OPTIONS call first that goes through the breakpoint, but the following GET doesn't seem to go there and I can't figure out why. Any idea?

Answer Source

You don't need a plugin (unless you want to use that plugin) to enable CORS here. Well, for your rest endpoints, you can always enable the CORS using the Grails interceptors like below:

class CorsInterceptor {

    CorsInterceptor() {

    boolean before() {
        response.setHeader("Access-Control-Allow-Origin", "http://localhost:4200")
        if (request.method == "OPTIONS") {
            response.setHeader("Access-Control-Allow-Origin", "http://localhost:4200")
            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.status = 200

        return true

    boolean after() { true }

But Grails interceptors cannot intercept the endpoints provided by the Spring Security core/rest plugins since the priority of their interceptors are higher than that of Grails interceptors. So you first need to add a customer filter and then register it before the Spring related filters.

Add a file in src/main/groovy:

package test

import org.springframework.web.filter.OncePerRequestFilter

import javax.servlet.FilterChain
import javax.servlet.ServletException
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse

class CorsFilter extends OncePerRequestFilter {

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

        if (req.getMethod() == "OPTIONS") {
            resp.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
            resp.addHeader("Access-Control-Max-Age", "3600")
            resp.addHeader("Access-Control-Allow-Origin", "http://localhost:4200")
            resp.addHeader("Access-Control-Allow-Credentials", "true")
            resp.status = 200
        } else {
            chain.doFilter(req, resp)

Register it on the resources.groovy:

beans = {

Now, add it to the Spring's filter chain before the security context filter (in Bootstrap.groovy):

    SecurityFilterPosition.SECURITY_CONTEXT_FILTER.order - 1)


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