Files
smartmate/backend/middleware/idempotency.go
LoveLosita cf9a3c79e4 Version: 0.2.3.dev.260211
fix: 🐛 修复刷新 Token 接口错误返回问题

- 当 token 本身存在问题时,改为返回 400 业务错误
- 不再错误地返回 500 服务端异常状态码 

feat: 🔁 新增基于 X-Idempotency-Key 与 Redis 的通用幂等中间件

- 基于 X-Idempotency-Key 实现请求幂等控制 🧩
- 记录 UUID 及对应返回结果至 Redis
- 当相同 UUID 重复请求时,直接返回缓存结果 
- 应用于所有涉及增删改操作的接口
- 解决部分接口未实现幂等性的问题 🔒
2026-02-11 16:16:07 +08:00

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package middleware
import (
"bytes"
"encoding/json"
"fmt"
"log"
"net/http"
"time"
"github.com/LoveLosita/smartflow/backend/dao"
"github.com/LoveLosita/smartflow/backend/respond"
"github.com/gin-gonic/gin"
)
type IdempotencyValue struct {
Status int `json:"status"` // HTTP 状态码
Body string `json:"body"` // JSON 响应体
}
type responseRecorder struct {
gin.ResponseWriter
body *bytes.Buffer
}
func (r *responseRecorder) Write(b []byte) (int, error) {
r.body.Write(b) // 录制到缓冲区
return r.ResponseWriter.Write(b) // 正常发送给前端
}
func IdempotencyMiddleware(cache *dao.CacheDAO) gin.HandlerFunc {
return func(c *gin.Context) {
// 1. 获取 IKey
ikey := c.GetHeader("X-Idempotency-Key")
if ikey == "" {
c.JSON(http.StatusBadRequest, respond.MissingIdempotencyKey) // 400 错误,缺少 IKey
c.Abort()
return
}
userID := c.GetInt("user_id") // 假设 JWT 已存入
redisKey := fmt.Sprintf("idempotency:%d:%s", userID, ikey)
// 2. 查 Redis 缓存
cachedData, err := cache.GetRecord(c, redisKey)
if err != nil { // 💡 Fail-OpenRedis 挂了也别卡住用户,记个日志继续走
log.Printf("[Idempotency] Redis Get error: %v", err)
} else if cachedData != "" {
// 命中缓存,直接回放录像
var val IdempotencyValue
json.Unmarshal([]byte(cachedData), &val)
c.Data(val.Status, "application/json", []byte(val.Body))
c.Abort()
return
}
// 3. 分布式锁:防止微秒级的并发碰撞 (SetNX)
// 锁 10 秒,防止请求卡死导致 key 永久锁定
lockKey := redisKey + ":lock"
success, err := cache.AcquireLock(c, lockKey, 10*time.Second)
if err != nil { // 如果加锁报错,为了保险我们依然放行,让底层的数据库唯一索引去兜底
log.Printf("[Idempotency] Redis Lock error: %v", err)
} else if !success {
c.JSON(http.StatusConflict, respond.RequestIsProcessing)
c.Abort()
return
}
// 💡 只有在加锁成功时才需要 defer 删锁
if err == nil && success {
defer cache.ReleaseLock(c, lockKey)
}
// 4. 装饰 ResponseWriter 开始录制
recorder := &responseRecorder{
ResponseWriter: c.Writer,
body: bytes.NewBufferString(""),
}
c.Writer = recorder
// 5. 执行后续 Handler (你的 Service 逻辑)
c.Next()
// 6. 录制完成,存入 Redis (缓存 24 小时)
// 只有状态码 < 500 时才存入 Redis这样如果是服务器临时抽风用户重试依然有机会成功
if c.Writer.Status() < 500 {
respVal := IdempotencyValue{
Status: c.Writer.Status(),
Body: recorder.body.String(),
}
data, _ := json.Marshal(respVal)
if err := cache.SaveRecord(c, redisKey, string(data), 24*time.Hour); err != nil {
log.Printf("[Idempotency] Redis Save error: %v", err)
}
}
}
}