Deepcopier
This package is meant to make copying of structs to/from others structs a bit easier.
Installation
go get -u github.com/ulule/deepcopier
Usage
// Deep copy instance1 into instance2
Copy(instance1).To(instance2)
// Deep copy instance1 into instance2 and passes the following context (which
// is basically a map[string]interface{}) as first argument
// to methods of instance2 that defined the struct tag "context".
Copy(instance1).WithContext(map[string]interface{}{"foo": "bar"}).To(instance2)
// Deep copy instance2 into instance1
Copy(instance1).From(instance2)
// Deep copy instance2 into instance1 and passes the following context (which
// is basically a map[string]interface{}) as first argument
// to methods of instance1 that defined the struct tag "context".
Copy(instance1).WithContext(map[string]interface{}{"foo": "bar"}).From(instance2)
Available options for deepcopier struct tag:, Option, Description, ---------, --------------------------------------------------------------------, field, Field or method name in source instance, skip, Ignores the field, context, Takes a map[string]interface{} as first argument (for methods), force, Set the value of a sql.Null* field (instead of copying the struct), Options example:
type Source struct {
Name string
SkipMe string
SQLNullStringToSQLNullString sql.NullString
SQLNullStringToString sql.NullString
}
func (Source) MethodThatTakesContext(c map[string]interface{}) string {
return "whatever"
}
type Destination struct {
FieldWithAnotherNameInSource string `deepcopier:"field:Name"`
SkipMe string `deepcopier:"skip"`
MethodThatTakesContext string `deepcopier:"context"`
SQLNullStringToSQLNullString sql.NullString
SQLNullStringToString string `deepcopier:"force"`
}
Example:
package main
import (
"fmt"
"github.com/ulule/deepcopier"
)
// Model
type User struct {
// Basic string field
Name string
// Deepcopier supports https://golang.org/pkg/database/sql/driver/#Valuer
Email sql.NullString
}
func (u *User) MethodThatTakesContext(ctx map[string]interface{}) string {
// do whatever you want
return "hello from this method"
}
// Resource
type UserResource struct {
DisplayName string `deepcopier:"field:Name"`
SkipMe string `deepcopier:"skip"`
MethodThatTakesContext string `deepcopier:"context"`
Email string `deepcopier:"force"`
}
func main() {
user := &User{
Name: "gilles",
Email: sql.NullString{
Valid: true,
String: "gilles@example.com",
},
}
resource := &UserResource{}
deepcopier.Copy(user).To(resource)
fmt.Println(resource.DisplayName)
fmt.Println(resource.Email)
}
Looking for more information about the usage?
We wrote an introduction article.
Have a look and feel free to give us your feedback.
Contributing
- Ping us on twitter @oibafsellig, @thoas
- Fork the project
- Help us improving and fixing issues
Don't hesitate ;)