diff --git a/gulpfile.js b/gulpfile.js
index e701708..409e3fb 100755
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -2,6 +2,8 @@ const gulp = require('gulp')
 const del = require('del')
 const $ = require('gulp-load-plugins')()
 
+// for project building
+
 // 编译源代码
 gulp.task('compile-src', function () {
   const project = $.typescript.createProject('tsconfig.json')
diff --git a/src/apis/item/item.middleware.ts b/src/apis/item/item.middleware.ts
index f90e812..f78eb8c 100755
--- a/src/apis/item/item.middleware.ts
+++ b/src/apis/item/item.middleware.ts
@@ -3,6 +3,8 @@ import { Request, Response, NextFunction } from 'express'
 import { ItemFilter } from '@/entities/item.model'
 import itemDao from '@/dao/item.dao'
 import AppError from '@/lib/error'
+import { FileFilter } from '@/entities/file.model'
+import fileDao from '@/dao/file.dao'
 
 /**
  * 验证params中的item是否存在。
@@ -18,3 +20,15 @@ export async function validateItemInParams(req: Request, res: Response, next: Ne
 
   next()
 }
+
+export async function validateAttachmentInParams(req: Request, res: Response, next: NextFunction) {
+  const attachmentId = req.params.attachmentId
+
+  const filter: FileFilter = { _id: attachmentId }
+
+  const [err, attachment] = await callAsync(fileDao.findOne(filter))
+  if (err) return next(err)
+  if (!attachment) return next(new AppError({ message: '没有找到附件', statusCode: 404 }))
+
+  next()
+}