error_handling.go

package error_handling

import (
	"errors"
	"reflect"
)

// ---------------
// variables Error
// ---------------
var (
	ErrArgs = errors.New("args error")
)

func WebCall2() error {
	return ErrArgs
}

// ---------------
// default Error
// ---------------
func WebCall1() error {
	return errors.New("default error")
}

// ---------------
// Type as context, Custom Error
// ---------------
type UnmarshalTypeError struct {
	Value string       // description of JSON value
	Type  reflect.Type // type of Go value it could not be assigned to
}

func (e *UnmarshalTypeError) Error() string {
	return "json: cannot unmarshal " + e.Value + " into Go value of type " + e.Type.String()
}

type InvalidUnmarshalError struct {
	Type reflect.Type
}

func (e *InvalidUnmarshalError) Error() string {
	if e.Type.Kind() != reflect.Ptr {
		return "json: Unmarshal(non-pointer " + e.Type.String() + ")"
	}
	return "json: Unmarshal(nil " + e.Type.String() + ")"
}
func Unmarshal(data []byte, v interface{}) error {
	rv := reflect.ValueOf(v)
	if rv.Kind() != reflect.Ptr || rv.IsNil() {
		return &InvalidUnmarshalError{reflect.TypeOf(v)}
	}

	return &UnmarshalTypeError{"string", reflect.TypeOf(v)}
}