73 lines
1.9 KiB
Go
73 lines
1.9 KiB
Go
|
package rand
|
||
|
|
|
||
|
|
import (
|
||
|
|
"encoding/hex"
|
||
|
|
"io"
|
||
|
|
)
|
||
|
|
|
||
|
|
const dash byte = '-'
|
||
|
|
|
||
|
|
// UUIDIdempotencyToken provides a utility to get idempotency tokens in the
|
||
|
|
// UUID format.
|
||
|
|
type UUIDIdempotencyToken struct {
|
||
|
|
uuid *UUID
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewUUIDIdempotencyToken returns a idempotency token provider returning
|
||
|
|
// tokens in the UUID random format using the reader provided.
|
||
|
|
func NewUUIDIdempotencyToken(r io.Reader) *UUIDIdempotencyToken {
|
||
|
|
return &UUIDIdempotencyToken{uuid: NewUUID(r)}
|
||
|
|
}
|
||
|
|
|
||
|
|
// GetIdempotencyToken returns a random UUID value for Idempotency token.
|
||
|
|
func (u UUIDIdempotencyToken) GetIdempotencyToken() (string, error) {
|
||
|
|
return u.uuid.GetUUID()
|
||
|
|
}
|
||
|
|
|
||
|
|
// UUID provides computing random UUID version 4 values from a random source
|
||
|
|
// reader.
|
||
|
|
type UUID struct {
|
||
|
|
randSrc io.Reader
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewUUID returns an initialized UUID value that can be used to retrieve
|
||
|
|
// random UUID values.
|
||
|
|
func NewUUID(r io.Reader) *UUID {
|
||
|
|
return &UUID{randSrc: r}
|
||
|
|
}
|
||
|
|
|
||
|
|
// GetUUID returns a UUID random string sourced from the random reader the
|
||
|
|
// UUID was created with. Returns an error if unable to compute the UUID.
|
||
|
|
func (r *UUID) GetUUID() (string, error) {
|
||
|
|
var b [16]byte
|
||
|
|
if _, err := io.ReadFull(r.randSrc, b[:]); err != nil {
|
||
|
|
return "", err
|
||
|
|
}
|
||
|
|
|
||
|
|
return uuidVersion4(b), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// uuidVersion4 returns a random UUID version 4 from the byte slice provided.
|
||
|
|
func uuidVersion4(u [16]byte) string {
|
||
|
|
// https://en.wikipedia.org/wiki/Universally_unique_identifier#Version_4_.28random.29
|
||
|
|
|
||
|
|
// 13th character is "4"
|
||
|
|
u[6] = (u[6] & 0x0f) | 0x40 // Version 4
|
||
|
|
// 17th character is "8", "9", "a", or "b"
|
||
|
|
u[8] = (u[8] & 0x3f) | 0x80 // Variant is 10
|
||
|
|
|
||
|
|
var scratch [36]byte
|
||
|
|
|
||
|
|
hex.Encode(scratch[:8], u[0:4])
|
||
|
|
scratch[8] = dash
|
||
|
|
hex.Encode(scratch[9:13], u[4:6])
|
||
|
|
scratch[13] = dash
|
||
|
|
hex.Encode(scratch[14:18], u[6:8])
|
||
|
|
scratch[18] = dash
|
||
|
|
hex.Encode(scratch[19:23], u[8:10])
|
||
|
|
scratch[23] = dash
|
||
|
|
hex.Encode(scratch[24:], u[10:])
|
||
|
|
|
||
|
|
return string(scratch[:])
|
||
|
|
}
|