How can I remove a property from a object - go

Question

I have a User struct:
type User struct {
gorm.Model
Email string
Password string
AccountType int
CompanyId int
FirstName string
LastName string
PhoneNumber string
RecoveryEmail string
Contractor bool `gorm:"sql:'not null' default:'false'"`
}
I'm using this struct to get a row from the database using gorm:
// Get a specific user from the database.
func getUser(id uint) (*User, error) {
var user User
if err := database.Connection.Select("id, created_at, email, account_type, company_id, first_name, last_name").Where("id = ? ", id).First(&user).Error; err != nil {
return nil, err
}
fmt.Println(&user)
return &user, nil
}
My Gin hanlder:
// #Summary Attempts to get a existing user by id
// #tags users
// #Router /api/users/getUserById [get]
func HandleGetUserById(c *gin.Context) {
// Were using delete params as it shares the same interface.
var json deleteParams
if err := c.Bind(&json); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"message": "No user ID found, please try again."})
return
}
outcome, err := getUser(json.Id)
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{"message": "Something went wrong while trying to process that, please try again.", "error": err.Error()})
log.Println(err)
return
}
c.JSON(http.StatusOK, gin.H{
"message": "Successfully found user",
"user": outcome,
})
}
It returns back everything fine, but when I return &user the fields not selected are returned back with default values:
{
"message": "Successfully found user",
"user": {
"ID": 53,
"CreatedAt": "2018-06-24T00:05:49.761736+01:00",
"UpdatedAt": "0001-01-01T00:00:00Z",
"DeletedAt": null,
"Email": "jack#jackner.com",
"Password": "",
"AccountType": 0,
"CompanyId": 2,
"FirstName": "",
"LastName": "",
"PhoneNumber": "",
"RecoveryEmail": "",
"Contractor": false
}
}
Is there a way in go to remove empty or null properties from an object? Or will I have to send back an object instead with the values mapped to said new object? If there's a simple way of doing the former with a helper function I'd like to know how.

Answer 1

You can specify the omitempty tag in your object's fields definitions.
Example:
Email string `json:",omitempty"`
If you define the fields that way, empty values will not be present in the JSON output:
https://golang.org/pkg/encoding/json/#Marshal
The "omitempty" option specifies that the field should be omitted from the encoding if the field has an empty value, defined as false, 0, a nil pointer, a nil interface value, and any empty array, slice, map, or string.