84 lines
2.3 KiB
Go
84 lines
2.3 KiB
Go
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// uniqueid
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// 的设计是用于生成全局唯一的 ID，避免重复。
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// 此库不考虑分布式，仅通过数据库主键索引来实现。
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// 当 id 重复时，由业务端抛出错误即可
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package uniqueid
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import (
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"context"
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"crypto/rand"
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"log/slog"
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"math/big"
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"time"
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"git.lnton.com/lnton/pkg/orm"
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"github.com/ixugo/goddd/pkg/hook"
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)
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const (
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// 删除 o 和 i 的字符集，避免视觉混淆
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LetterBytes36NoOI = "abcdefghjklmnpqrstuvwxyz0123456789"
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LetterBytes72 = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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LetterBytes36 = "abcdefghijklmnopqrstuvwxyz0123456789" // default
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LetterBytes36Upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
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)
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type IDManager struct {
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store UniqueIDStorer
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// TODO: 可以初始化时读取数据库内的数量，判断重复因子，从而减少尝试或更换策略
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letterBytes string // 随机字符串字符集
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}
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func NewIDManager(store UniqueIDStorer) *IDManager {
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return &IDManager{
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store: store,
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letterBytes: LetterBytes36,
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}
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}
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// SetLetterBytes 设置随机字符串字符集
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func (m *IDManager) SetLetterBytes(letterBytes string) {
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m.letterBytes = letterBytes
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}
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// UniqueID 获取唯一 id
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func (m *IDManager) UniqueID(prefix string, length int) string {
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cost := hook.UseTiming(time.Second)
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defer cost()
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// 如果在最低长度中，碰撞比较频繁，增加 1 位长度再试一次
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for i := range 10 {
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// 生成自定义长度随机数，通过数据库主键来防止碰撞，碰撞后再次尝试
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for range 36 {
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id := prefix + GenerateRandomString(m.letterBytes, length+i)
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if err := m.store.Add(context.Background(), &UniqueID{ID: id}); err != nil {
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slog.Error("UniqueID", "err", err)
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continue
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}
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return id
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}
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}
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slog.Error("UniqueID", "err", "超过最大循环次数，未获取到唯一 id")
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return "unknown"
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}
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// UndoUniqueID 删除唯一 id
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func (m *IDManager) UndoUniqueID(id string) error {
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var uni UniqueID
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return m.store.Del(context.Background(), &uni, orm.Where("id=?", id))
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}
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// GenerateRandomString 生成随机字符串
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func GenerateRandomString(letterBytes string, length int) string {
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lettersLength := big.NewInt(int64(len(letterBytes)))
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result := make([]byte, length)
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for i := 0; i < length; i++ {
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idx, _ := rand.Int(rand.Reader, lettersLength)
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result[i] = letterBytes[idx.Int64()]
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}
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return string(result)
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}
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