업로드 이미지 WebP 최적화 1차 적용

backend/src/routes/auth.js

@@ -1,5 +1,4 @@
 const express = require('express')
-const path = require('path')
 const bcrypt = require('bcryptjs')
 const { z } = require('zod')
 const { nanoid } = require('nanoid')
@@ -12,15 +11,10 @@ const {
   updateUserProfile,
 } = require('../db')
 const { requireAuth } = require('../middleware/auth')
+const { createMemoryUpload, writeOptimizedImage } = require('../lib/image-storage')
 
 const router = express.Router()
 
-function buildUploadFilename(file) {
-  const ext = path.extname(file.originalname || '').toLowerCase()
-  const safeExt = ext && /^[.a-z0-9]+$/.test(ext) ? ext : ''
-  return `${Date.now()}-${nanoid()}${safeExt}`
-}
-
 const signupSchema = z.object({
   email: z.string().email(),
   password: z.string().min(6),
@@ -45,7 +39,6 @@ router.post('/signup', async (req, res) => {
 
   req.session.userId = user.id
   req.session.isAdmin = !!user.isAdmin
-  // 세션을 응답 전에 명시적으로 저장해 Set-Cookie가 확실히 내려오도록 보강
   req.session.save((err) => {
     if (err) return res.status(500).json({ error: 'session_save_failed' })
     res.json(user)
@@ -94,13 +87,7 @@ router.get('/meta', async (req, res) => {
   res.json({ hasUsers: (await countUsers()) > 0 })
 })
 
-const upload = multer({
-  storage: multer.diskStorage({
-    destination: (req, file, cb) => cb(null, path.join(__dirname, '..', '..', 'uploads', 'avatars')),
-    filename: (req, file, cb) => cb(null, buildUploadFilename(file)),
-  }),
-  limits: { fileSize: 3 * 1024 * 1024 },
-})
+const upload = createMemoryUpload(multer, { fileSize: 4 * 1024 * 1024 })
 
 router.post('/profile', requireAuth, upload.single('avatar'), async (req, res) => {
   const parsed = profileSchema.safeParse(req.body)
@@ -109,12 +96,19 @@ router.post('/profile', requireAuth, upload.single('avatar'), async (req, res) =
   const user = await findUserById(req.session.userId)
   if (!user) return res.status(404).json({ error: 'not_found' })
 
+  const optimized = req.file
+    ? await writeOptimizedImage({
+        file: req.file,
+        directory: 'avatars',
+        width: 512,
+        height: 512,
+        fit: 'cover',
+        quality: 82,
+      })
+    : null
+
   const shouldRemoveAvatar = parsed.data.removeAvatar === '1'
-  const nextAvatarSrc = shouldRemoveAvatar
-    ? ''
-    : req.file
-      ? `/uploads/avatars/${req.file.filename}`
-      : user.avatarSrc || ''
+  const nextAvatarSrc = shouldRemoveAvatar ? '' : optimized?.src || user.avatarSrc || ''
   const updated = await updateUserProfile({
     id: user.id,
     nickname: parsed.data.nickname,