52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
package common
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import (
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"crypto/rand"
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"errors"
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"math/big"
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)
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// usernameChars 随机用户名字符集（小写字母 + 数字）
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const usernameChars = "abcdefghijklmnopqrstuvwxyz0123456789"
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const usernameLen = 10
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// UsernameChecker 用户名查重接口（避免 common 反向依赖 repository）
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type UsernameChecker interface {
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ExistsByUsername(username string) (bool, error)
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}
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// GenerateUsername 生成不重复的随机 10 位用户名（小写字母 + 数字）
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// checker 提供去重查询，maxRetry 次重试后仍冲突则返回错误
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func GenerateUsername(checker UsernameChecker, maxRetry int) (string, error) {
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if maxRetry <= 0 {
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maxRetry = 20
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}
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for i := 0; i < maxRetry; i++ {
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username, err := randomUsername(usernameLen)
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if err != nil {
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return "", err
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}
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exists, err := checker.ExistsByUsername(username)
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if err != nil {
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return "", err
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}
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if !exists {
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return username, nil
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}
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}
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return "", errors.New("生成用户名失败，请重试")
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}
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// randomUsername 通过 crypto/rand 生成安全的随机字符串
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func randomUsername(n int) (string, error) {
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b := make([]byte, n)
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for i := range b {
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idx, err := rand.Int(rand.Reader, big.NewInt(int64(len(usernameChars))))
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if err != nil {
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return "", err
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}
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b[i] = usernameChars[idx.Int64()]
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}
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return string(b), nil
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}
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