| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package generalizer |
| |
| import ( |
| "reflect" |
| "sync" |
| ) |
| |
| import ( |
| perrors "github.com/pkg/errors" |
| "google.golang.org/protobuf/encoding/protojson" |
| "google.golang.org/protobuf/proto" |
| ) |
| |
| var ( |
| protobufJsonGeneralizer Generalizer |
| protobufJsonGeneralizerOnce sync.Once |
| ) |
| |
| func GetProtobufJsonGeneralizer() Generalizer { |
| protobufJsonGeneralizerOnce.Do(func() { |
| protobufJsonGeneralizer = &ProtobufJsonGeneralizer{} |
| }) |
| return protobufJsonGeneralizer |
| } |
| |
| // ProtobufJsonGeneralizer generalizes an object to json and realizes an object from json using protobuf. |
| // Currently, ProtobufJsonGeneralizer is disabled temporarily until the triple protocol is ready. |
| type ProtobufJsonGeneralizer struct{} |
| |
| func (g *ProtobufJsonGeneralizer) Generalize(obj interface{}) (interface{}, error) { |
| message, ok := obj.(proto.Message) |
| if !ok { |
| return nil, perrors.Errorf("unexpected type of obj(=%T), wanted is proto.Message", obj) |
| } |
| |
| jsonbytes, err := protojson.Marshal(message) |
| if err != nil { |
| return nil, err |
| } |
| |
| return string(jsonbytes), nil |
| } |
| |
| func (g *ProtobufJsonGeneralizer) Realize(obj interface{}, typ reflect.Type) (interface{}, error) { |
| jsonbytes, ok := obj.(string) |
| if !ok { |
| return nil, perrors.Errorf("unexpected type of obj(=%T), wanted is string", obj) |
| } |
| |
| // typ represents a struct instead of a pointer |
| for typ.Kind() == reflect.Ptr { |
| typ = typ.Elem() |
| } |
| |
| // create the target object |
| ret, ok := reflect.New(typ).Interface().(proto.Message) |
| if !ok { |
| return nil, perrors.Errorf("the type of obj(=%s) should be proto.Message", typ) |
| } |
| |
| // get the values from json |
| err := protojson.Unmarshal([]byte(jsonbytes), ret) |
| if err != nil { |
| return nil, err |
| } |
| |
| return ret, nil |
| } |
| |
| // GetType returns empty string for "protobuf-json" |
| func (g *ProtobufJsonGeneralizer) GetType(_ interface{}) (string, error) { |
| return "", nil |
| } |