get certain data from json golang - json

Question

tmpbyte, _ := json.Marshal(vdata["user"])
fmt.Println(string(tmpbyte))
I got this data from mongodb,
[
{
"avatar_image": "https://i6e.jpg",
"display_name": "flash.info",
"image_user": "",
"user_id": "qXGFIa",
"username": "flash.info"
},
{
"avatar_image": "https://847a",
"display_name": "Akhmad Jazuli",
"image_user": "",
"user_id": "mf7EXj",
"username": "akhmad.jazuli"
},
{
"avatar_image": "https://i-stageb10a.jpg",
"display_name": " Alfan Rey",
"image_user": "",
"user_id": "bsiAlG",
"username": "fn.alfan"
}
]
how to get only loop of user_id from this data?
user_id1
user_id2
user_id1

Answer 1

The first step is to create a data structure for your entities about users and then decode the data using MongoDB.
type User struct {
Id primitive.ObjectID `bson="_id"`
AvatarImage string `bson="avatar_image"`
DisplayName string `bson="display_name"`
UserId string `bson="user_id"`
UserName string `bson="username"`
}
func GetUserIds(ctx context.Context) ([]string, error) {
userIds := make([]string, 0)
cur, err := collectionUser.Find(ctx, nil)
if err != nil {
return nil, err
}
for cur.Next(ctx) {
user := new(User)
if err := cur.Decode(user); err != nil {
return nil, err
}
userIds = append(userIds, user.UserId)
}
return userIds, nil
}
}