52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
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package id
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import (
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"crypto/rand"
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"math/big"
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"time"
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"github.com/oklog/ulid"
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)
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const randomRange = 631152381 // ~20 years in seconds
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// NewULID returns a new ULID string using the current time, or an error if something goes wrong.
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func NewULID() (string, error) {
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newUlid, err := ulid.New(ulid.Timestamp(time.Now()), rand.Reader)
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if err != nil {
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return "", err
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}
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return newUlid.String(), nil
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}
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// NewULIDFromTime returns a new ULID string using the given time, or an error if something goes wrong.
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func NewULIDFromTime(t time.Time) (string, error) {
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newUlid, err := ulid.New(ulid.Timestamp(t), rand.Reader)
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if err != nil {
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return "", err
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}
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return newUlid.String(), nil
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}
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// NewRandomULID returns a new ULID string using a random time in an ~80 year range around the current datetime, or an error if something goes wrong.
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func NewRandomULID() (string, error) {
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b1, err := rand.Int(rand.Reader, big.NewInt(randomRange))
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if err != nil {
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return "", err
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}
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r1 := time.Duration(int(b1.Int64()))
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b2, err := rand.Int(rand.Reader, big.NewInt(randomRange))
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if err != nil {
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return "", err
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}
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r2 := -time.Duration(int(b2.Int64()))
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arbitraryTime := time.Now().Add(r1 * time.Second).Add(r2 * time.Second)
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newUlid, err := ulid.New(ulid.Timestamp(arbitraryTime), rand.Reader)
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if err != nil {
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return "", err
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}
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return newUlid.String(), nil
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}
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