go-convert 
Convert a value into another type.
go get -u github.com/Eun/go-convert
Usage
package main
import (
"fmt"
"github.com/Eun/go-convert"
)
func main() {
// convert a int to a string
var s string
convert.MustConvert(1, &s)
fmt.Printf("%s\n", s)
// convert a map into a struct
type User struct {
ID int
Name string
}
var u User
convert.MustConvert(map[string]string{
"Name": "Joe",
"ID": "10",
}, &u)
fmt.Printf("%#v\n", u)
// convert Id to int and Groups to []int and keep the rest
m := map[string]interface{}{
"Id": 0,
"Groups": []int{},
}
// convert a map into well defined map
convert.MustConvert(
map[string]interface{}{
"Id": "1",
"Name": "Joe",
"Groups": []string{"3", "6"},
"Country": "US",
},
&m,
)
fmt.Printf("%v\n", m)
// convert a interface slice into well defined interface slice
// making the first one an integer, the second a string and the third an float
sl := []interface{}{0, "", 0.0}
convert.MustConvert([]string{"1", "2", "3"}, &sl)
fmt.Printf("%v\n", sl)
}
Recipe system
go-convert uses a recipe system that defines how and which types should be converted in which type. A lot of recipes are already builtin (see recipes.go), however you can add your own or overwrite the builtin ones.
package main
import (
"fmt"
"strings"
"github.com/Eun/go-convert"
)
type Roles struct {
IsAdmin bool
IsDeveloper bool
}
type User struct {
ID int
Name string
Roles Roles
}
func main() {
// this is the data we want to convert
data := map[string]string{
"id": "10",
"Name": "Joe",
"roles": "AD", // this user is Admin (A) and Developer (D)
}
// create a converter
conv := convert.New(convert.Options{
Recipes: convert.MustMakeRecipes(
// convert string into Roles
func(_ convert.Converter, in string, out *Roles) error {
(*out).IsAdmin = false
(*out).IsDeveloper = false
if strings.Contains(in, "A") {
(*out).IsAdmin = true
}
if strings.Contains(in, "D") {
(*out).IsDeveloper = true
}
return nil
},
),
})
var user User
conv.MustConvert(data, &user)
// user is now an instance of User
fmt.Printf("%#v\n", user)
}
Adding inline recipes
You can also add recipes inline by implementing a ConvertRecipes() []Recipe function.
Example:
package main
import (
"fmt"
"strings"
"github.com/Eun/go-convert"
)
type Roles struct {
IsAdmin bool
IsDeveloper bool
}
type User struct {
ID int
Name string
Roles Roles
}
func (user *User) ConvertRecipes() []convert.Recipe {
return convert.MustMakeRecipes(
// convert string into Roles
func(_ convert.Converter, in string, out *Roles) error {
out.IsAdmin = false
out.IsDeveloper = false
if strings.Contains(in, "A") {
out.IsAdmin = true
}
if strings.Contains(in, "D") {
out.IsDeveloper = true
}
return nil
},
)
}
func main() {
// this is the data we want to convert
data := []map[string]string{
{
"id": "10",
"Name": "Joe",
"roles": "AD", // this user is Admin (A) and Developer (D)
},
{
"id": "21",
"Name": "Alice",
"roles": "D", // this user is Developer (D)
},
}
var users []User
convert.MustConvert(data, &users)
// users is now an instance of []User
fmt.Printf("%#v\n", users)
}
Notice
This library is using reflection so be aware it might be slow in your usecase.
