auth-api/pkgs/utils/utils.go
2023-05-08 15:29:19 +02:00

51 lines
1.4 KiB
Go

package utils
import (
"math/rand"
"strings"
"time"
"golang.org/x/crypto/bcrypt"
)
const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const (
letterIdxBits = 6 // 6 bits to represent a letter index
letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
)
var src = rand.NewSource(time.Now().UnixNano())
// CheckPasswordHash checks a password hash
func CheckPasswordHash(password, hash string) bool {
err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
return err == nil
}
// HashPassword hashes a password
func HashPassword(password string) (string, error) {
bytes, err := bcrypt.GenerateFromPassword([]byte(password), 14)
return string(bytes), err
}
// RandString generates a random string. Taken from https://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-go (RandStringBytesMaskImprSrcSB())
func RandString(n int) string {
sb := strings.Builder{}
sb.Grow(n)
// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
if remain == 0 {
cache, remain = src.Int63(), letterIdxMax
}
if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
sb.WriteByte(letterBytes[idx])
i--
}
cache >>= letterIdxBits
remain--
}
return sb.String()
}