feat: add rest.WithCustomCors to let caller customize the response (#1274)

rest/internal/cors/handlers_test.go

@@ -62,7 +62,7 @@ func TestCorsHandlerWithOrigins(t *testing.T) {
 				r := httptest.NewRequest(method, "http://localhost", nil)
 				r.Header.Set(originHeader, test.reqOrigin)
 				w := httptest.NewRecorder()
-				handler := NotAllowedHandler(test.origins...)
+				handler := NotAllowedHandler(nil, test.origins...)
 				handler.ServeHTTP(w, r)
 				if method == http.MethodOptions {
 					assert.Equal(t, http.StatusNoContent, w.Result().StatusCode)
@@ -71,6 +71,22 @@ func TestCorsHandlerWithOrigins(t *testing.T) {
 				}
 				assert.Equal(t, test.expect, w.Header().Get(allowOrigin))
 			})
+			t.Run(test.name+"-handler-custom", func(t *testing.T) {
+				r := httptest.NewRequest(method, "http://localhost", nil)
+				r.Header.Set(originHeader, test.reqOrigin)
+				w := httptest.NewRecorder()
+				handler := NotAllowedHandler(func(w http.ResponseWriter) {
+					w.Header().Set("foo", "bar")
+				}, test.origins...)
+				handler.ServeHTTP(w, r)
+				if method == http.MethodOptions {
+					assert.Equal(t, http.StatusNoContent, w.Result().StatusCode)
+				} else {
+					assert.Equal(t, http.StatusNotFound, w.Result().StatusCode)
+				}
+				assert.Equal(t, test.expect, w.Header().Get(allowOrigin))
+				assert.Equal(t, "bar", w.Header().Get("foo"))
+			})
 		}
 	}
 
@@ -81,7 +97,7 @@ func TestCorsHandlerWithOrigins(t *testing.T) {
 				r := httptest.NewRequest(method, "http://localhost", nil)
 				r.Header.Set(originHeader, test.reqOrigin)
 				w := httptest.NewRecorder()
-				handler := Middleware(test.origins...)(func(w http.ResponseWriter, r *http.Request) {
+				handler := Middleware(nil, test.origins...)(func(w http.ResponseWriter, r *http.Request) {
 					w.WriteHeader(http.StatusOK)
 				})
 				handler.ServeHTTP(w, r)
@@ -92,6 +108,24 @@ func TestCorsHandlerWithOrigins(t *testing.T) {
 				}
 				assert.Equal(t, test.expect, w.Header().Get(allowOrigin))
 			})
+			t.Run(test.name+"-middleware-custom", func(t *testing.T) {
+				r := httptest.NewRequest(method, "http://localhost", nil)
+				r.Header.Set(originHeader, test.reqOrigin)
+				w := httptest.NewRecorder()
+				handler := Middleware(func(w http.ResponseWriter) {
+					w.Header().Set("foo", "bar")
+				}, test.origins...)(func(w http.ResponseWriter, r *http.Request) {
+					w.WriteHeader(http.StatusOK)
+				})
+				handler.ServeHTTP(w, r)
+				if method == http.MethodOptions {
+					assert.Equal(t, http.StatusNoContent, w.Result().StatusCode)
+				} else {
+					assert.Equal(t, http.StatusOK, w.Result().StatusCode)
+				}
+				assert.Equal(t, test.expect, w.Header().Get(allowOrigin))
+				assert.Equal(t, "bar", w.Header().Get("foo"))
+			})
 		}
 	}
 }