protoc-gen-fieldmask插件

message UserInfoRequest {
  string user_id = 1;
  google.protobuf.FieldMask field_mask = 2 [
    (fieldmask.option.Option).in = {gen: true},
    (fieldmask.option.Option).out = {gen: true, message:"UserInfoResponse"}
  ];
}

message Address {
  string country = 1;
  string province = 2;
}

message UserInfoResponse {
  string user_id = 1;
  string name = 2;
  string email = 3;·
  Address address = 4;
}

message NonEmpty {}

service UserInfo {
  rpc GetUserInfo(UserInfoRequest) returns (UserInfoResponse) {}
  rpc UpdateUserInfo(UserInfoRequest) returns (NonEmpty) {}
}

// FieldMask 公共部分代码
// FieldMaskWithMode 根据不同的模式决定不同的使用姿势（Filter 和 Prune）
func (x *UserInfoRequest) FieldMaskWithMode(mode pbfieldmask.MaskMode) *UserInfoRequest_FieldMask {
	fm := &UserInfoRequest_FieldMask{
		maskMode:    mode,
		maskMapping: make(map[string]struct{}, len(x.FieldMask.GetPaths())),
	}

	for _, path := range x.FieldMask.GetPaths() {
		fm.maskMapping[path] = struct{}{}
	}

	return fm
}

// Filter 模式下，包含在 FieldMask 中的字段代表 保留 / 更新。
func (x *UserInfoRequest) FieldMask_Filter() *UserInfoRequest_FieldMask {
	return x.FieldMaskWithMode(pbfieldmask.MaskMode_Filter)
}

// Prune 模式下，包含在 FieldMask 的字段代表需要 去除 / 不更新。
func (x *UserInfoRequest) FieldMask_Prune() *UserInfoRequest_FieldMask {
	return x.FieldMaskWithMode(pbfieldmask.MaskMode_Prune)
}

// UserInfoRequest_FieldMask provide provide helper functions to deal with FieldMask.
type UserInfoRequest_FieldMask struct {
	maskMode    pbfieldmask.MaskMode
	maskMapping map[string]struct{}
}

// 增量更新的服务部分代码 (fieldmask.option.Option).in = {gen: true} 控制生成
func (x *UserInfoRequest) MaskIn_UserId() *UserInfoRequest {}
func (x *UserInfoRequest_FieldMask) MaskedIn_UserId() bool {}

// 响应字段裁剪部分代码 (fieldmask.option.Option).out = {gen: true, message:"UserInfoResponse"} 控制生成
func (x *UserInfoRequest) MaskOut_UserId() *UserInfoRequest {}
func (x *UserInfoRequest) MaskOut_Name() *UserInfoRequest {}
func (x *UserInfoRequest_FieldMask) MaskedOut_UserId() bool {}
func (x *UserInfoRequest_FieldMask) MaskedOut_Name() bool {}
// Mask 根据 FieldMask 和 mode 来裁剪响应字段。
func (x *UserInfoRequest_FieldMask) Mask(m *UserInfoResponse) *UserInfoResponse {
	switch x.maskMode {
	case pbfieldmask.MaskMode_Filter:
		x.filter(m)
	case pbfieldmask.MaskMode_Prune:
		x.prune(m)
	}

	return m
}

func (x *UserInfoRequest_FieldMask) filter(m proto.Message) {
	if len(x.maskMapping) == 0 {
		return
	}

	pr := m.ProtoReflect()
	pr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
		_, ok := x.maskMapping[string(fd.Name())]
		if !ok {
			pr.Clear(fd)
			return true
		}

		return true
	})
}
func (x *UserInfoRequest_FieldMask) prune(m proto.Message) {
	if len(x.maskMapping) == 0 {
		return
	}

	pr := m.ProtoReflect()
	pr.Range(func(fd protoreflect.FieldDescriptor, _ protoreflect.Value) bool {
		_, ok := x.maskMapping[string(fd.Name())]
		if !ok {
			return true
		}

		pr.Clear(fd)
		return true
	})
}

func main() {

    maskedReq := &pb.UserInfoRequest{
        UserId: "1",
    }
    maskedReq.
        MaskOut_Email(). // masking email field in response
        MaskOut_Address() // masking address field in response
}

// 响应裁剪示例
func (u userServer) GetUserInfo(
	ctx context.Context,
	request *pb.UserInfoRequest,
) (*pb.UserInfoResponse, error) {
	// FieldMask_Filter means that the fields are included in the response,
	// otherwise they are omitted.
	// FieldMask_Prune means masked fields are not included in the response,
	// otherwise they are included.
	fm := request.FieldMask_Filter()
	// fm2 := request.FieldMask_Prune()

	fmt.Printf("userServer.GetUserInfo is called: %v\n", request.String())

	resp := &pb.UserInfoResponse{
		UserId:  "69781",
		Name:    "yeqown",
		Email:   "[email protected]",
		Address: nil,
	}

	// judge if the field masked or not, avoid unnecessary call or calculation.
	if fm.MaskedOut_Address() {
		// filter more, so the address field should be included.
		resp.Address = &pb.Address{
			Country:  "China",
			Province: "Sichuan",
		}
	}

	// filter the field masked out.
	_ = fm.Mask(resp)
	return resp, nil
}

// 增量更新示例
func (u userServer) UpdateUserInfo(ctx context.Context, request *pb.UserInfoRequest) (*pb.NonEmpty, error) {
	// FieldMask_Filter means that the fields are expected to update,
	// otherwise they are ignored.
	// FieldMask_Prune means masked fields are ignored to update,
	// otherwise they are expected to update.
	fm := request.FieldMask_Filter()
	// fm2 := request.FieldMask_Prune()

	fmt.Printf("userServer.UpdateUserInfo is called: %v\n", request.String())

	if fm.MaskedIn_UserId() {
		// userId want to be updated, so you should use request.UserId to update.
		fmt.Println("userId want to be updated.")
	}

	return new(pb.NonEmpty), nil
}