Go getValueFromPath()

개요

Go getValueFromPath()

package main

import (
	"fmt"
	"reflect"
	"strings"
)

type User struct {
	Name    string
	Profile Profile
}

type Profile struct {
	Email string
	Phone string
}

func main() {
	user := User{
		Name: "John Doe",
		Profile: Profile{
			Email: "john.doe@example.com",
			Phone: "123-456-7890",
		},
	}

	fmt.Println(getValueFromPath(user, ".X"))             // <nil>
	fmt.Println(getValueFromPath(user, ".Name"))          // "John Doe"
	fmt.Println(getValueFromPath(user, ".Profile"))       // {john.doe@example.com 123-456-7890}
	fmt.Println(getValueFromPath(user, ".Profile.Email")) // "john.doe@example.com"
	fmt.Println(getValueFromPath(user, ".Profile.Phone")) // "123-456-7890"
}

func getValueFromPath(v interface{}, path string) interface{} {
	fields := strings.Split(path[1:], ".")
	rv := reflect.ValueOf(v)
	for _, field := range fields {
		rv = rv.FieldByName(field)
		if !rv.IsValid() {
			return nil
		}
	}
	return rv.Interface()
}

package main

import (
	"fmt"
	"reflect"
	"strings"
)

type User struct {
	Name    string  `json:"name"`
	Profile Profile `json:"profile"`
}

type Profile struct {
	Email string `json:"email"`
	Phone string `json:"phone"`
}

func main() {
	user := User{
		Name: "John Doe",
		Profile: Profile{
			Email: "john.doe@example.com",
			Phone: "123-456-7890",
		},
	}

	fmt.Println(getValueFromPath(user, "x"))             // <nil>
	fmt.Println(getValueFromPath(user, "name"))          // "John Doe"
	fmt.Println(getValueFromPath(user, "profile"))       // {john.doe@example.com 123-456-7890}
	fmt.Println(getValueFromPath(user, "profile.email")) // "john.doe@example.com"
	fmt.Println(getValueFromPath(user, "profile.phone")) // "123-456-7890"
}

func getValueFromPath(v interface{}, path string) interface{} {
	fields := strings.Split(path, ".")
	rv := reflect.ValueOf(v)

	for _, field := range fields {
		rv = reflect.Indirect(rv)

		switch rv.Kind() {
		case reflect.Struct:
			rv = rv.FieldByNameFunc(func(name string) bool {
				fieldType, _ := rv.Type().FieldByName(name)
				jsonTag := fieldType.Tag.Get("json")
				return jsonTag == field || strings.EqualFold(name, field)
			})

		default:
			return nil
		}

		if !rv.IsValid() {
			return nil
		}
	}

	return rv.Interface()
}