Built-in Model

The go mongox library provides a built-in Model struct, which includes three fields: ID, CreatedAt, and UpdatedAt.

type Model struct {
	ID        primitive.ObjectID `bson:"_id,omitempty"`
	CreatedAt time.Time          `bson:"created_at"`
	UpdatedAt time.Time          `bson:"updated_at"`
}

func (m *Model) DefaultId() primitive.ObjectID {
	if m.ID.IsZero() {
		m.ID = primitive.NewObjectID()
	}
	return m.ID
}

func (m *Model) DefaultCreatedAt() time.Time {
	if m.CreatedAt.IsZero() {
		m.CreatedAt = time.Now().Local()
	}
	return m.CreatedAt
}

func (m *Model) DefaultUpdatedAt() time.Time {
	m.UpdatedAt = time.Now().Local()
	return m.UpdatedAt
}

This struct implements the DefaultModel interface, and if the EnableDefaultFieldHook option is set to true during plugin initialization (for details, refer to Enable Built-in Plugin - Hook), the go mongox library will automatically handle the assignment of the ID and time fields during document creation and update operations.

Specifically:

• When creating documents (InsertOne, InsertMany), the DefaultId() and DefaultCreatedAt() methods are called to initialize the ID and CreatedAt fields.
• When updating documents (UpdateOne, UpdateMany), the DefaultUpdatedAt() method is called to set and retrieve the UpdatedAt value, updating the updated_at field accordingly.
• During the Upsert operation, all three methods are called to ensure all relevant fields are properly initialized or updated.

You can embed it into your own custom struct as shown below:

type User struct {
	mongox.Model `bson:",inline"`
	Name         string `bson:"name"`
	Age          int    `bson:"age"`
}

CustomModel Interface

The go mongox library provides the CustomModel interface, allowing developers to customize the names and values of the ID, CreatedAt, and UpdatedAt fields. This is particularly useful when handling custom field names or formats.

The CustomModel interface is defined as follows:

type CustomModel interface {
	// CustomID is used to set and retrieve the custom ID field name and value
	CustomID() (string, any)
	// CustomCreatedAt is used to set and retrieve the custom CreatedAt field name and value
	CustomCreatedAt() (string, any)
	// CustomUpdatedAt is used to set and retrieve the custom UpdatedAt field name and value
	CustomUpdatedAt() (string, any)
}

Example of a Custom Implementation:

type CustomModel struct {
	ID        string `bson:"_id"`
	CreatedAt int64  `bson:"createdAt"`
	UpdatedAt int64  `bson:"updatedAt"`
}

func (m *CustomModel) CustomID() (string, any) {
	if m.ID == "" {
		m.ID = primitive.NewObjectID().Hex()
	}
	return "_id", m.ID
}

func (m *CustomModel) CustomCreatedAt() (string, any) {
	if m.CreatedAt == 0 {
		m.CreatedAt = time.Now().Local().Unix()
	}
	return "createdAt", m.CreatedAt
}

func (m *CustomModel) CustomUpdatedAt() (string, any) {
	m.UpdatedAt = time.Now().Local().Unix()
	return "updatedAt", m.UpdatedAt
}