chore: update common utils (#1908)

common/util/util.go

@@ -0,0 +1,60 @@
+package util
+
+import (
+	"crypto/rand"
+	"math/big"
+	"net/mail"
+	"strings"
+
+	"github.com/google/uuid"
+)
+
+// HasPrefixes returns true if the string s has any of the given prefixes.
+func HasPrefixes(src string, prefixes ...string) bool {
+	for _, prefix := range prefixes {
+		if strings.HasPrefix(src, prefix) {
+			return true
+		}
+	}
+	return false
+}
+
+// ValidateEmail validates the email.
+func ValidateEmail(email string) bool {
+	if _, err := mail.ParseAddress(email); err != nil {
+		return false
+	}
+	return true
+}
+
+func GenUUID() string {
+	return uuid.New().String()
+}
+
+func Min(x, y int) int {
+	if x < y {
+		return x
+	}
+	return y
+}
+
+var letters = []rune("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+// RandomString returns a random string with length n.
+func RandomString(n int) (string, error) {
+	var sb strings.Builder
+	sb.Grow(n)
+	for i := 0; i < n; i++ {
+		// The reason for using crypto/rand instead of math/rand is that
+		// the former relies on hardware to generate random numbers and
+		// thus has a stronger source of random numbers.
+		randNum, err := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
+		if err != nil {
+			return "", err
+		}
+		if _, err := sb.WriteRune(letters[randNum.Uint64()]); err != nil {
+			return "", err
+		}
+	}
+	return sb.String(), nil
+}