create handler to add cors headers to response

handle/handle.go

@@ -109,6 +109,15 @@ func IgnoreIndex(serve http.HandlerFunc) http.HandlerFunc {
 	}
 }
 
+func AddCorsHeaders(serve http.HandlerFunc) http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		writer.Header().Set("Access-Control-Allow-Origin", "*")
+		writer.Header().Set("Access-Control-Allow-Headers", "*")
+
+		serve(writer, request)
+	}
+}
+
 // Listening function for serving the handler function.
 func Listening() ListenerFunc {
 	return func(binding string, handler http.HandlerFunc) error {

handle/handle_test.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path"
 	"testing"
+	"strings"
 )
 
 var (
@@ -458,3 +459,32 @@ func TestValidReferrer(t *testing.T) {
 		})
 	}
 }
+
+func TestAddsCorsHeaders(t *testing.T) {
+	testCases := []struct {
+		name     string
+		header   string
+		value    string
+	}{
+		{"Add Access-Control-Allow-Origin header", "Access-Control-Allow-Origin", "*"},
+		{"Add Access-Control-Allow-Headers header", "Access-Control-Allow-Headers", "*"},
+	}
+
+	for _, serveFile := range serveFileFuncs {
+		handler := AddCorsHeaders(Basic(serveFile, baseDir))
+		for _, tc := range testCases {
+			t.Run(tc.name, func(t *testing.T) {
+				req := httptest.NewRequest("GET", "http://localhost/", nil)
+				w := httptest.NewRecorder()
+
+				handler(w, req)
+
+				resp := w.Result()
+				headerValue := strings.Join(resp.Header[tc.header], ", ")
+				if headerValue != tc.value {
+					t.Errorf("Response header %q = %q, want %q", tc.header, headerValue, tc.value)
+				}
+			})
+		}
+	}
+}