medium_ad/app/utils/rand.go

package utils

import (
	crand "crypto/rand"
	"fmt"
	"math/big"
	"math/rand"
	"time"
)

func RandString(l int, c ...string) string {
	var (
		chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
		str   string
		num   *big.Int
	)
	if len(c) > 0 {
		chars = c[0]
	}
	chrLen := int64(len(chars))
	for len(str) < l {
		num, _ = crand.Int(crand.Reader, big.NewInt(chrLen))
		str += string(chars[num.Int64()])
	}
	return str
}

func RandNum() string {
	seed := time.Now().UnixNano() + rand.Int63()
	return fmt.Sprintf("%05v", rand.New(rand.NewSource(seed)).Int31n(1000000))
}