uuid

Documentation

Overview

Package uuid provides implementations of the Universally Unique Identifier (UUID), as specified in RFC-4122 and DCE 1.1.

RFC-4122[1] provides the specification for versions 1, 3, 4, and 5.

DCE 1.1[2] provides the specification for version 2.

[1] https://tools.ietf.org/html/rfc4122 [2] http://pubs.opengroup.org/onlinepubs/9696989899/chap5.htm#tagcjh_08_02_01_01

Index

• Constants
• Variables
• type NullUUID
  • func (u NullUUID) MarshalJSON() ([]byte, error)
  • func (u *NullUUID) Scan(src interface{}) error
  • func (u *NullUUID) UnmarshalJSON(b []byte) error
  • func (u NullUUID) Value() (driver.Value, error)
• type UUID
  • func FromBytes(input []byte) (UUID, error)
  • func FromBytesOrNil(input []byte) UUID
  • func FromString(input string) (UUID, error)
  • func FromStringOrNil(input string) UUID
  • func Must(u UUID, err error) UUID
  • func NewV3(ns UUID, name string) UUID
  • func NewV4() (UUID, error)
  • func NewV5(ns UUID, name string) UUID
  • func (u UUID) Bytes() []byte
  • func (u UUID) Format(f fmt.State, c rune)
  • func (u UUID) MarshalBinary() ([]byte, error)
  • func (u UUID) MarshalText() ([]byte, error)
  • func (u *UUID) Scan(src interface{}) error
  • func (u *UUID) SetVersion(v byte)
  • func (u UUID) String() string
  • func (u *UUID) UnmarshalBinary(data []byte) error
  • func (u *UUID) UnmarshalText(text []byte) error
  • func (u UUID) Value() (driver.Value, error)
  • func (u UUID) Version() byte

Constants

const (
	V1 byte // Version 1 (date-time and MAC address)
	V2      // Version 2 (date-time and MAC address, DCE security version)
	V3      // Version 3 (namespace name-based)
	V4      // Version 4 (random)
	V5      // Version 5 (namespace name-based)
)

UUID versions.

const Size = 16

Size of a UUID in bytes.

Variables

var Nil = UUID{}

Nil is the nil UUID, as specified in RFC-4122, that has all 128 bits set to zero.

Types

type NullUUID

type NullUUID struct {
	UUID  UUID
	Valid bool
}

NullUUID can be used with the standard sql package to represent a UUID value that can be NULL in the database.

func (NullUUID) MarshalJSON

func (u NullUUID) MarshalJSON() ([]byte, error)

MarshalJSON marshals the NullUUID as null or the nested UUID

func (*NullUUID) Scan

func (u *NullUUID) Scan(src interface{}) error

Scan implements the sql.Scanner interface.

func (*NullUUID) UnmarshalJSON

func (u *NullUUID) UnmarshalJSON(b []byte) error

UnmarshalJSON unmarshals a NullUUID

func (NullUUID) Value

func (u NullUUID) Value() (driver.Value, error)

Value implements the driver.Valuer interface.

type UUID

type UUID [Size]byte

UUID is an array type to represent the value of a UUID, as defined in RFC-4122.

func FromBytes

func FromBytes(input []byte) (UUID, error)

FromBytes returns a UUID generated from the raw byte slice input. It will return an error if the slice isn't 16 bytes long.

func FromBytesOrNil

func FromBytesOrNil(input []byte) UUID

FromBytesOrNil returns a UUID generated from the raw byte slice input. Same behavior as FromBytes(), but returns uuid.Nil instead of an error.

func FromString

func FromString(input string) (UUID, error)

FromString returns a UUID parsed from the input string. Input is expected in a form accepted by UnmarshalText.

func FromStringOrNil

func FromStringOrNil(input string) UUID

FromStringOrNil returns a UUID parsed from the input string. Same behavior as FromString(), but returns uuid.Nil instead of an error.

func Must

func Must(u UUID, err error) UUID

Must is a helper that wraps a call to a function returning (UUID, error) and panics if the error is non-nil. It is intended for use in variable initializations such as

var packageUUID = uuid.Must(uuid.FromString("123e4567-e89b-12d3-a456-426655440000"))

func NewV3

func NewV3(ns UUID, name string) UUID

NewV3 returns a UUID based on the MD5 hash of the namespace UUID and name.

func NewV4

func NewV4() (UUID, error)

NewV4 returns a randomly generated UUID.

func NewV5

func NewV5(ns UUID, name string) UUID

NewV5 returns a UUID based on SHA-1 hash of the namespace UUID and name.

func (UUID) Bytes

func (u UUID) Bytes() []byte

Bytes returns a byte slice representation of the UUID.

func (UUID) Format

func (u UUID) Format(f fmt.State, c rune)

Format implements fmt.Formatter for UUID values.

The behavior is as follows: The 'x' and 'X' verbs output only the hex digits of the UUID, using a-f for 'x' and A-F for 'X'. The 'v', '+v', 's' and 'q' verbs return the canonical RFC-4122 string representation. The 'S' verb returns the RFC-4122 format, but with capital hex digits. The '#v' verb returns the "Go syntax" representation, which is a 16 byte array initializer. All other verbs not handled directly by the fmt package (like '%p') are unsupported and will return "%!verb(uuid.UUID=value)" as recommended by the fmt package.

func (UUID) MarshalBinary

func (u UUID) MarshalBinary() ([]byte, error)

MarshalBinary implements the encoding.BinaryMarshaler interface.

func (UUID) MarshalText

func (u UUID) MarshalText() ([]byte, error)

MarshalText implements the encoding.TextMarshaler interface. The encoding is the same as returned by the String() method.

func (*UUID) Scan

func (u *UUID) Scan(src interface{}) error

Scan implements the sql.Scanner interface. A 16-byte slice will be handled by UnmarshalBinary, while a longer byte slice or a string will be handled by UnmarshalText.

func (*UUID) SetVersion

func (u *UUID) SetVersion(v byte)

setVersion sets the version bits.

func (UUID) String

func (u UUID) String() string

String returns a canonical RFC-4122 string representation of the UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

func (*UUID) UnmarshalBinary

func (u *UUID) UnmarshalBinary(data []byte) error

UnmarshalBinary implements the encoding.BinaryUnmarshaler interface. It will return an error if the slice isn't 16 bytes long.

func (*UUID) UnmarshalText

func (u *UUID) UnmarshalText(text []byte) error

UnmarshalText implements the encoding.TextUnmarshaler interface. Following formats are supported:

"6ba7b810-9dad-11d1-80b4-00c04fd430c8",
"{6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
"urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
"6ba7b8109dad11d180b400c04fd430c8"
"{6ba7b8109dad11d180b400c04fd430c8}",
"urn:uuid:6ba7b8109dad11d180b400c04fd430c8"

ABNF for supported UUID text representation follows:

URN := 'urn'
UUID-NID := 'uuid'

hexdig := '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' |
          'a' | 'b' | 'c' | 'd' | 'e' | 'f' |
          'A' | 'B' | 'C' | 'D' | 'E' | 'F'

hexoct := hexdig hexdig
2hexoct := hexoct hexoct
4hexoct := 2hexoct 2hexoct
6hexoct := 4hexoct 2hexoct
12hexoct := 6hexoct 6hexoct

hashlike := 12hexoct
canonical := 4hexoct '-' 2hexoct '-' 2hexoct '-' 6hexoct

plain := canonical | hashlike
uuid := canonical | hashlike | braced | urn

braced := '{' plain '}' | '{' hashlike  '}'
urn := URN ':' UUID-NID ':' plain

func (UUID) Value

func (u UUID) Value() (driver.Value, error)

Value implements the driver.Valuer interface.

func (UUID) Version

func (u UUID) Version() byte

Version returns the algorithm version used to generate the UUID.