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team-api/internal/middleware/idempotency.go
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package middleware
import (
"fmt"
"net/http"
"time"
"github.com/gogf/gf/v2/frame/g"
"github.com/gogf/gf/v2/net/ghttp"
"github.com/gogf/gf/v2/os/gtime"
"github.com/qianfree/team-api/internal/dao"
do "github.com/qianfree/team-api/internal/model/do"
"github.com/qianfree/team-api/internal/response"
)
const (
IdempotencyHeader = "Idempotency-Key"
// maxCachedBodyLen limits the response body size stored for idempotent replay.
// Responses larger than this will still be deduplicated but won't cache the body.
maxCachedBodyLen = 64 * 1024 // 64 KB
// idempotencyTTL is how long an idempotency record is retained before it can be cleaned up.
idempotencyTTL = 24 * time.Hour
)
// Idempotency ensures that requests with the same Idempotency-Key
// are processed only once. Subsequent requests with the same key
// return the cached response.
//
// 幂等键按认证主体(userType + tenantID + userID)隔离:不同租户/用户即便复用同一
// 客户端 Idempotency-Key,也各自独立,避免命中彼此缓存的响应体(跨租户数据泄漏)
// 或彼此误触 409。因此本中间件必须挂载在认证中间件(如 TenantAuth)之后。
func Idempotency(r *ghttp.Request) {
clientKey := r.GetHeader(IdempotencyHeader)
if clientKey == "" {
r.Middleware.Next()
return
}
ctx := r.Context()
// 组合出按主体隔离的存储键(仍是单一字符串,不改表结构)
tenantID := r.GetCtxVar(CtxKeyTenantID).Int64()
userID := r.GetCtxVar(CtxKeyUserID).Int64()
userType := r.GetCtxVar(CtxKeyUserType).String()
// 开放平台不走 TenantAuth,身份存在 OpenPlatformAuth 注入的 typed context key 里,
// 上面三个 CtxVar 全是零值。若不单独取,所有应用会共用同一个 ":0:0:" 前缀 ——
// 不同租户复用同一个 Idempotency-Key 就会读到彼此缓存的响应体(跨租户数据泄漏)。
// 主体取「应用」而非「用户」:开放平台请求由应用发起,重试也以应用为单位。
if appID := GetOpenAppID(r.Context()); appID > 0 {
userType = "open"
tenantID = GetOpenTenantID(r.Context())
userID = appID
}
idempotencyKey := buildIdempotencyKey(userType, tenantID, userID, clientKey)
// Check if this key has been processed before
var record struct {
Id int64 `json:"id" orm:"id"`
Status string `json:"status" orm:"status"`
ResponseBody string `json:"response_body" orm:"response_body"`
}
err := dao.SysIdempotencyRecords.Ctx(ctx).
Where("idempotency_key", idempotencyKey).
Where("expires_at > NOW()").
Scan(&record)
if err != nil {
// DB error: fail-closed to prevent duplicate processing
response.ErrorMsg(r, 500, "系统繁忙,请稍后重试")
return
}
if record.Id > 0 {
if record.Status == "completed" && record.ResponseBody != "" {
// 重放缓存响应。本中间件只挂载在 /api/* 统一响应端点上:成功响应恒为
// HTTP 200 + JSON(response.Success 使用 WriteJson),业务错误为 HTTP 422
// 且会被标记为 failed 而不进入此重放分支。因此固定回写 200 + JSON Content-Type,
// 避免复用未初始化的 r.Response.Status(默认 0)以及丢失 Content-Type。
r.Response.Header().Set("Content-Type", "application/json; charset=utf-8")
r.Response.WriteStatus(http.StatusOK)
r.Response.Write([]byte(record.ResponseBody))
r.Exit()
return
}
if record.Status == "processing" {
writeConflictResponse(r)
return
}
}
// Insert processing record
_, err = dao.SysIdempotencyRecords.Ctx(ctx).Data(do.SysIdempotencyRecords{
IdempotencyKey: idempotencyKey,
Status: "processing",
ExpiresAt: gtime.Now().Add(idempotencyTTL),
}).Insert()
if err != nil {
// If insert fails (duplicate key), another request is already processing
writeConflictResponse(r)
return
}
// Capture the response
r.Middleware.Next()
// After processing, update the record with cached body
status := "completed"
statusCode := r.Response.Status
if statusCode >= 400 {
status = "failed"
}
var responseBody string
if buf := r.Response.Buffer(); len(buf) > 0 && len(buf) <= maxCachedBodyLen {
responseBody = string(buf)
}
// Update the record
dao.SysIdempotencyRecords.Ctx(ctx).
Where("idempotency_key", idempotencyKey).
Data(do.SysIdempotencyRecords{
Status: status,
ResponseBody: responseBody,
}).Update()
}
// buildIdempotencyKey 组合出按认证主体隔离的幂等存储键。
// 加入 userType/tenantID/userID 前缀,使不同主体即便复用同一客户端 key 也互不干扰,
// 杜绝跨租户命中彼此缓存响应体(数据泄漏)或误触 409。
func buildIdempotencyKey(userType string, tenantID, userID int64, clientKey string) string {
return fmt.Sprintf("%s:%d:%d:%s", userType, tenantID, userID, clientKey)
}
// writeConflictResponse writes a 409 Conflict response for duplicate idempotency keys.
func writeConflictResponse(r *ghttp.Request) {
r.Response.WriteStatus(409)
r.Response.WriteJson(g.Map{
"error": g.Map{
"type": "conflict",
"message": "请求正在处理中,请勿重复提交",
"code": "409",
},
})
r.Exit()
}