Function allowCORS

examples/internal/gateway/handlers.go:35–46

allowCORS allows Cross Origin Resource Sharing from any origin. Don't do this without consideration in production systems.

(h http.Handler)

// allowCORS allows Cross Origin Resource Sharing from any origin.
// Don't do this without consideration in production systems.
func allowCORS(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if origin := r.Header.Get("Origin"); origin != "" {
			w.Header().Set("Access-Control-Allow-Origin", origin)
			if r.Method == "OPTIONS" && r.Header.Get("Access-Control-Request-Method") != "" {
				preflightHandler(w, r)
				return
			}
		}
		h.ServeHTTP(w, r)
	})
}

// preflightHandler adds the necessary headers in order to serve
// CORS from any origin using the methods "GET", "HEAD", "POST", "PUT", "DELETE"