struct.go

// Copyright 2021 Wayback Archiver. All rights reserved.
// Use of this source code is governed by the MIT
// license that can be found in the LICENSE file.

package helper // import "github.com/wabarc/helper"

import (
	"fmt"
	"reflect"
)

// SetField sets field of v with given name to given value.
func SetField(v interface{}, name string, value string) error {
	// v must be a pointer to a struct
	rv := reflect.ValueOf(v)
	if rv.Kind() != reflect.Ptr || rv.Elem().Kind() != reflect.Struct {
		return fmt.Errorf("v must be pointer to struct")
	}

	// Dereference pointer
	rv = rv.Elem()

	// Lookup field by name
	fv := rv.FieldByName(name)
	if !fv.IsValid() {
		return fmt.Errorf("not a field name: %s", name)
	}

	// Field must be exported
	if !fv.CanSet() {
		return fmt.Errorf("cannot set field %s", name)
	}

	// We expect a string field
	if fv.Kind() != reflect.String {
		return fmt.Errorf("%s is not a string field", name)
	}
	fv.SetString(value)

	return nil
}