I have fairly simple setup here as described in the code below. But I am not able to get the CORS
to work. I keep getting this error:
XMLHttpRequest cannot load http://localhost:3000/signup. Response to preflight request doesn't pass access control check: No 'Access- Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8000' is therefore not allowed access. The response had HTTP status code 403.
I am sure I am missing something simple here.
Here is the code I have:
package main
import (
"log"
"net/http"
"github.com/gorilla/handlers"
"github.com/gorilla/mux"
"myApp/src/controllers"
)
func main() {
ac := new(controllers.AccountController)
router := mux.NewRouter()
router.HandleFunc("/signup", ac.SignUp).Methods("POST")
router.HandleFunc("/signin", ac.SignIn).Methods("POST")
log.Fatal(http.ListenAndServe(":3000", handlers.CORS()(router)))
}
Please read the link Markus suggested, and also about what triggers CORS pre-flight requests.
Pre-flight requests: You may have a content type like JSON, or some other custom header that's triggering a pre-flight request, which your server may not be handling. Try adding this one, if you're using the ever-common AJAX in your front-end: https://en.wikipedia.org/wiki/List_of_HTTP_header_fields#Requested-With
Gorilla's handlers.CORS()
will set sane defaults to get the basics of CORS working for you; however, you can (and maybe should) take control in a more functional manner.
// Where ORIGIN_ALLOWED is like `scheme://dns[:port]`, or `*` (insecure)
headersOk := handlers.AllowedHeaders([]string{"X-Requested-With"})
originsOk := handlers.AllowedOrigins([]string{os.Getenv("ORIGIN_ALLOWED")})
methodsOk := handlers.AllowedMethods([]string{"GET", "HEAD", "POST", "PUT", "OPTIONS"})
// start server listen
// with error handling
log.Fatal(http.ListenAndServe(":" + os.Getenv("PORT"), handlers.CORS(originsOk, headersOk, methodsOk)(router)))