What is the nil/zero value of bson.ObjectId

Question

I was creating unary tests when I got stuck on the following situation:

I have an object that has a foreign key. For some reason, I need to switch the ID and it works. However, sometimes, I need to remove this ID. If I have an ID, I realise a certain action and if I don't, then nothing happens.

However, I can't find the way to set my bson.ObjectId as nil or zero.

Does anyone knows how to do or a work around?

This is like &string("Hello"). It's invalid. But you can store the `bson.ObjectIdHex(id)` value to some `tmp` variable and then assign `&tmp` it to the `*bson.ObjectID` variable. — dom, Dec 16 '18 at 01:27
Maybe there is a better way to implement it, but I would have to see the code snippet. — dom, Dec 16 '18 at 01:32

score 10 · Accepted Answer · answered Nov 28 '19 at 15:57

10

Or you can use the primitive.NilObjectID

NilObjectID is the zero value for ObjectID.

answered Nov 28 '19 at 15:57

Bastien

994
11
25

I switch the answer from my response to yours, i feel that your approach is more logic :) – Emixam23 Jun 22 '21 at 08:34

score 2 · Answer 2 · answered Dec 16 '18 at 07:22

2

bson.ObjectId is an alias for string , therefore the zero value is an empty string ""

answered Dec 16 '18 at 07:22

Mostafa Solati

1,235
2
13
33

score 2 · Answer 3 · answered Dec 19 '18 at 15:41

Based on @dom answer (in the comments), there is the workaround I am now using:

package your_package

import "github.com/globalsign/mgo/bson"

func GenerateNewGuidHelper() *bson.ObjectId {
    id := bson.NewObjectId()
    return &id
}

func IsStringIdValid(id string) bool {
    return id != "" && bson.IsObjectIdHex(id)
}

func ConvertStringIdToObjectId(id string) *bson.ObjectId {
    if id != "" && bson.IsObjectIdHex(id){
        bsonObjectId := bson.ObjectIdHex(id)
        return &bsonObjectId
    }
    return nil
}

func ConvertStringIdsToObjectIds(ids []string) []*bson.ObjectId {
    var _ids []*bson.ObjectId
    for _, id := range ids {
        _ids = append(_ids, ConvertStringIdToObjectId(id))
    }
    return _ids
}

func IsObjectIdValid(id *bson.ObjectId) bool {
    return id.Hex() != "" && bson.IsObjectIdHex(id.Hex())
}

func ConvertObjectIdToStringId(id *bson.ObjectId) string  {
    if id != nil {
        return id.Hex()
    }
    return ""
}

func ConvertObjectIdsToStringIds(ids []*bson.ObjectId) []string {
    var _ids []string
    for _, id := range ids {
        _ids = append(_ids, ConvertObjectIdToStringId(id))
    }
    return _ids
}

Also, as said @dom, I am now saving my mongoDB ID as *bson.ObjectId instead of bson.ObjectId. Example:

package datamodels

import (
    "github.com/globalsign/mgo/bson"
)

type User struct {
    ID *bson.ObjectId `protobuf:"bytes,1,opt,name=id,proto3" json:"_id,omitempty" bson:"_id,omitempty"`
}

I hope it helps !

What is the nil/zero value of bson.ObjectId

3 Answers3