byte_slice.go

package nulls

import (
	"database/sql"
	"database/sql/driver"
	"encoding/base64"
	"encoding/json"
)

// ByteSlice adds an implementation for []byte
// that supports proper JSON encoding/decoding.
type ByteSlice struct {
	ByteSlice []byte
	Valid     bool // Valid is true if ByteSlice is not NULL
}

// Interface implements the nullable interface. It returns nil if
// the byte slice is not valid, otherwise it returns the byte slice value.
func (ns ByteSlice) Interface() interface{} {
	if !ns.Valid {
		return nil
	}
	return ns.ByteSlice
}

// NewByteSlice returns a new, properly instantiated
// ByteSlice object.
func NewByteSlice(b []byte) ByteSlice {
	return ByteSlice{ByteSlice: b, Valid: true}
}

// Scan implements the Scanner interface.
func (ns *ByteSlice) Scan(value interface{}) error {
	n := sql.NullString{String: base64.StdEncoding.EncodeToString(ns.ByteSlice)}
	err := n.Scan(value)
	if err != nil {
		return err
	}
	//ns.Float32, ns.Valid = float32(n.Float64), n.Valid
	ns.ByteSlice, err = base64.StdEncoding.DecodeString(n.String)
	ns.Valid = n.Valid
	return err
}

// Value implements the driver Valuer interface.
func (ns ByteSlice) Value() (driver.Value, error) {
	if !ns.Valid {
		return nil, nil
	}
	return base64.StdEncoding.EncodeToString(ns.ByteSlice), nil
}

// MarshalJSON marshals the underlying value to a
// proper JSON representation.
func (ns ByteSlice) MarshalJSON() ([]byte, error) {
	if ns.Valid {
		return json.Marshal(ns.ByteSlice)
	}
	return json.Marshal(nil)
}

// UnmarshalJSON will unmarshal a JSON value into
// the propert representation of that value.
func (ns *ByteSlice) UnmarshalJSON(text []byte) error {
	ns.Valid = false
	if string(text) == "null" {
		return nil
	}

	ns.ByteSlice = text
	ns.Valid = true
	return nil
}

// UnmarshalText will unmarshal text value into
// the propert representation of that value.
func (ns *ByteSlice) UnmarshalText(text []byte) error {
	return ns.UnmarshalJSON(text)
}