我有一個(gè)像下面這樣的結(jié)構(gòu)字段。我還將相同結(jié)構(gòu)的原始 protobuf 存儲(chǔ)在 db 中?，F(xiàn)在每次都將數(shù)據(jù)獲取或保存到 mongo。ReallyBigRaw當(dāng)我想保存到數(shù)據(jù)庫時(shí)，我必須從 proto更新，而當(dāng)我必須解組ReallyBigRaw以ReallyBigObj給出響應(yīng)時(shí)，我必須解組。有沒有辦法我可以實(shí)現(xiàn)一些接口或提供一些回調(diào)函數(shù)，以便 mongo 驅(qū)動(dòng)程序在保存或從 DB 獲取數(shù)據(jù)之前自動(dòng)執(zhí)行此操作。另外，我沒有使用官方的 golang mongo 驅(qū)動(dòng)程序mgo，我已經(jīng)閱讀了一些可以在mgogolang 庫中完成的答案。import ( "github.com/golang/protobuf/jsonpb" "go.mongodb.org/mongo-driver/bson" "go.mongodb.org/mongo-driver/bson/primitive" proto "github.com/dinesh/api/go")type ReallyBig struct { ID string `bson:"_id,omitempty"` DraftID string `bson:"draft_id,omitempty"`// Marshaled ReallyBigObj proto to map[string]interface{} stored in DB ReallyBigRaw map[string]interface{} `bson:"raw,omitempty"` ReallyBigObj *proto.ReallyBig `bson:"-"` CreatedAt primitive.DateTime `bson:"created_at,omitempty"` UpdatedAt primitive.DateTime `bson:"updated_at,omitempty"`}func (r *ReallyBig) GetProto() (*proto.ReallyBig, error) { if r.ReallyBigObj != nil { return r.ReallyBigObj, nil } Obj, err := getProto(r.ReallyBigRaw) if err != nil { return nil, err } r.ReallyBigObj = Obj return r.ReallyBigObj, nil}func getRaw(r *proto.ReallyBig) (map[string]interface{}, error) { m := jsonpb.Marshaler{} b := bytes.NewBuffer([]byte{}) // marshals proto to json format err := m.Marshal(b, r) if err != nil { return nil, err } var raw map[string]interface{} // unmarshal the raw data to an interface err = json.Unmarshal(b.Bytes(), &raw) if err != nil { return nil, err } return raw, nil}func getProto(raw map[string]interface{}) (*proto.ReallyBig, error) { b, err := json.Marshal(raw) if err != nil { return nil, err } u := jsonpb.Unmarshaler{} var reallyBigProto proto.ReallyBig err = u.Unmarshal(bytes.NewReader(b), &recipeProto) if err != nil { return nil, err } return &reallyBigProto, nil}
1 回答
繁星coding
TA貢獻(xiàn)1797條經(jīng)驗(yàn) 獲得超4個(gè)贊
我實(shí)現(xiàn)了MarshalerandUnmarshaler接口。由于 mongo 驅(qū)動(dòng)程序調(diào)用MarshalBSON并且UnmarshalBSON如果類型實(shí)現(xiàn)Marshaler并且Unmarshaler我們也最終陷入無限循環(huán)。為了避免這種情況，我們創(chuàng)建了type. 別名Golang僅繼承字段而不是方法，因此我們最終調(diào)用正常bson.Marshal和bson.Unmarshal
func (r *ReallyBig) MarshalBSON() ([]byte, error) {
type ReallyBigAlias ReallyBig
reallyBigRaw, err := getRaw(r.ReallyBigObj)
if err != nil {
return nil, err
}
r.ReallyBigRaw = reallyBigRaw
return bson.Marshal((*ReallyBigAlias)(r))
}
func (r *ReallyBig) UnmarshalBSON(data []byte) error {
type ReallyBigAlias ReallyBig
err := bson.Unmarshal(data, (*ReallyBigAlias)(r))
if err != nil {
return err
}
reallyBigProto, err := getProto(r.ReallyBigRaw)
if err != nil {
return err
}
r.ReallyBigObj = reallyBigProto
return nil
}
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