Avoid to save blank struct object in db

Question

I am running the below code. When a user saved in db then blank address is saved I have assigned the null struct to address before save. I can not add the omitempty with all the fields for address struct. How I can avoid to save blank address object within users collection

    package main

import (
    "context"
    "fmt"
    "time"

    "go.mongodb.org/mongo-driver/mongo"
    "go.mongodb.org/mongo-driver/mongo/options"
)

type User struct {
    Id          int           `json:"id" bson:"_id,omitempty"`
    FirstName   string        `json:"first_name,omitempty" bson:"first_name,omitempty"`
    LastName    string        `json:"last_name,omitempty" bson:"last_name,omitempty"`
    FullName    string        `json:"full_name,omitempty" bson:"full_name,omitempty"`
    CompanyName string        `json:"company_name" bson:"company_name"`
    Address     AddressStruct `json:"address,omitempty" bson:"address,omitempty"`
}
type AddressStruct struct {
    Address      string `json:"address" bson:"address"`
    City         string `json:"city" bson:"city"`
    State        string `json:"state" bson:"state"`
    Zipcode      string `json:"zipcode" bson:"zipcode"`
    Apt          string `json:"apt" bson:"apt"`
    Default      bool   `json:"default" bson:"default"`
    Status       int8   `json:"status,omitempty" bson:"status,omitempty"`
    Country      string `json:"country,omitempty" bson:"country,omitempty"`
    ShortAddress string `json:"short_address" bson:"short_address"`
}

func main() {
    var user User
    user.FirstName = "Swati"
    user.LastName = "Sharma"
    user.FullName = "Swati Sharma"
    user.Address = AddressStruct{}
    client, ctx := ConnectDbWithNewDriver()
    defer client.Disconnect(ctx)
    a, b := DbInsertOne(client, user)
    fmt.Println("Section1", a, b)
}
func ConnectDbWithNewDriver() (client *mongo.Client, ctx context.Context) {
    ctx = context.Background()
    client, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://127.0.0.1:27017").SetConnectTimeout(5*time.Second))
    if err != nil {
        fmt.Println("CreateSession: ", err)
        client.Disconnect(ctx)
        return
    }
    return
}
func DbInsertOne(client *mongo.Client, data interface{}) (interface{}, error) {
    collection := client.Database("swatitest").Collection("users")
    insertResult, err := collection.InsertOne(context.TODO(), data)
    if err != nil {
        return nil, err
    }
    return insertResult.InsertedID, nil
}

When I run this code then record saved in db like this:

{
    "_id" : ObjectId("61af41b32214b16fe93435a6"),
    "first_name" : "Swati",
    "last_name" : "Sharma",
    "full_name" : "Swati Sharma",
    "company_name" : "",
    "address" : {
        "address" : "",
        "city" : "",
        "state" : "",
        "zipcode" : "",
        "apt" : "",
        "default" : false,
        "short_address" : ""
    }
}

I want to save like:

{
        "_id" : ObjectId("61af41b32214b16fe93435a6"),
        "first_name" : "Swati",
        "last_name" : "Sharma",
        "full_name" : "Swati Sharma",
        "company_name" : ""
}

Answer 1

You may use the omitempty bson tag option, all Go drivers handle it and will not save the field if it's value is the zero value (for primitive types).

So add it to all fields you don't want to get saved as empty string:

type AddressStruct struct {
    Address      string `json:"address" bson:"address,omitempty"`
    City         string `json:"city" bson:"city,omitempty"`
    State        string `json:"state" bson:"state,omitempty"`
    Zipcode      string `json:"zipcode" bson:"zipcode,omitempty"`
    Apt          string `json:"apt" bson:"apt,omitempty"`
    Default      bool   `json:"default" bson:"default,omitempty"`
    Status       int8   `json:"status,omitempty" bson:"status,omitempty"`
    Country      string `json:"country,omitempty" bson:"country,omitempty"`
    ShortAddress string `json:"short_address" bson:"short_address,omitempty"`
}

If you can't modify the struct type, then don't save the struct value. Create your own type (where you add omitempty), copy the struct value into it, and save your own copy.