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utils/utility/id_helper.go

@@ -0,0 +1,81 @@
+package utility
+
+import (
+	"strings"
+
+	"github.com/rs/xid"
+	"go.uber.org/zap"
+
+	cryptoRand "crypto/rand"
+	"fmt"
+	"math"
+	"math/big"
+	"math/rand"
+	"time"
+
+	log "github.com/go-admin-team/go-admin-core/logger"
+)
+
+const base62Chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
+// GetXid Package xid is a globally unique id generator library
+// 包xid是一个全局唯一的id生成器库
+func GetXid() string {
+	return xid.New().String()
+}
+
+// GetRandIntStr 生成len位的随机数字
+func GetRandIntStr(len int, prefix string) string {
+	rand.Seed(time.Now().UnixNano())
+
+	num := rand.Int31n(int32(math.Pow(10, float64(len))))
+	x := fmt.Sprintf("%s%0*d", prefix, len, num)
+	return x
+}
+
+// GenerateRandString 生成指定位数的字符串
+// 虽然繁琐 但理解之后就觉得很精妙
+func GenerateRandString(length int) string {
+	var chars = []byte(`ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789`) // 长度:(1,256)
+	rand.Seed(time.Now().UnixNano())
+	clen := len(chars)
+	maxRb := 255 - (256 % clen) // [-1,255]  255 - (256%36) = 251  避免模偏倚 为了每个字符被取到的几率相等
+	b := make([]byte, length)
+	r := make([]byte, length+(length/4)) // storage for random bytes. 存储随机字节
+
+	for i := 0; ; {
+		//  将随机的byte值填充到byte数组中 以供使用
+		if _, err := rand.Read(r); err != nil {
+			log.Error(`GenerateRandString`, zap.Error(err))
+			return ``
+		}
+		for _, rb := range r {
+			c := int(rb)
+			if c > maxRb {
+				// Skip this number to avoid modulo bias.跳过这个数字以避免模偏倚
+				continue
+			}
+			b[i] = chars[c%clen]
+			i++
+			if i == length { // 直到取到合适的长度
+				return string(b)
+			}
+		}
+	}
+}
+
+// GenerateBase62Key 生成指定长度的随机 Base62（数字 + 大小写字母）字符串
+func GenerateBase62Key(length int) (string, error) {
+	var b strings.Builder
+	b.Grow(length)
+
+	for i := 0; i < length; i++ {
+		n, err := cryptoRand.Int(cryptoRand.Reader, big.NewInt(int64(len(base62Chars))))
+		if err != nil {
+			return "", err
+		}
+		b.WriteByte(base62Chars[n.Int64()])
+	}
+
+	return b.String(), nil
+}