feat:实现项目集功能

utils/cryptil/cryptil.go

@@ -13,6 +13,8 @@ import (
 	"crypto/rand"
 )
 
+var stdChars = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789")
+
 //对称加密与解密之加密【从Beego中提取出来的】
 //@param            value           需要加密的字符串
 //@param            secret          加密密钥
@@ -71,7 +73,6 @@ func Sha1Crypt(str string, salt ...interface{}) (CryptStr string) {
 	return fmt.Sprintf("%x", sha1.Sum([]byte(str)))
 }
 
-
 //生成Guid字串
 func UniqueId() string {
 	b := make([]byte, 48)
@@ -80,4 +81,35 @@ func UniqueId() string {
 		return ""
 	}
 	return Md5Crypt(base64.URLEncoding.EncodeToString(b))
-}
+}
+
+//生成指定长度的字符串.
+func NewRandChars(length int) string {
+	if length == 0 {
+		return ""
+	}
+	clen := len(stdChars)
+	if clen < 2 || clen > 256 {
+		panic("Wrong charset length for NewLenChars()")
+	}
+	maxrb := 255 - (256 % clen)
+	b := make([]byte, length)
+	r := make([]byte, length+(length/4)) // storage for random bytes.
+	i := 0
+	for {
+		if _, err := rand.Read(r); err != nil {
+			panic("Error reading random bytes: " + err.Error())
+		}
+		for _, rb := range r {
+			c := int(rb)
+			if c > maxrb {
+				continue // Skip this number to avoid modulo bias.
+			}
+			b[i] = stdChars[c%clen]
+			i++
+			if i == length {
+				return string(b)
+			}
+		}
+	}
+}