fix: force OSS direct download even when traffic quota is enabled

backend/database.js

@@ -365,6 +365,21 @@ function initDatabase() {
     )
   `);
 
+  // 下载流量日统计表（用于用户侧报表）
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS user_download_traffic_daily (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      user_id INTEGER NOT NULL,
+      date_key TEXT NOT NULL, -- YYYY-MM-DD（本地时区）
+      bytes_used INTEGER NOT NULL DEFAULT 0,
+      download_count INTEGER NOT NULL DEFAULT 0,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+      updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+      UNIQUE(user_id, date_key),
+      FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
+    )
+  `);
+
   // 日志表索引
   db.exec(`
     CREATE INDEX IF NOT EXISTS idx_logs_created_at ON system_logs(created_at);
@@ -377,6 +392,9 @@ function initDatabase() {
     -- 优势：快速查询用户最近的活动记录，支持时间范围过滤
     -- 使用场景：用户活动历史、审计日志查询
     CREATE INDEX IF NOT EXISTS idx_logs_user_created ON system_logs(user_id, created_at);
+
+    -- 下载流量报表索引（按用户+日期查询）
+    CREATE INDEX IF NOT EXISTS idx_download_traffic_user_date ON user_download_traffic_daily(user_id, date_key);
   `);
 
   console.log('[数据库性能优化] ✓ 日志表复合索引已创建');
@@ -1421,6 +1439,104 @@ function migrateDownloadTrafficFields() {
   }
 }
 
+// 下载流量报表（按天聚合）
+const DownloadTrafficReportDB = {
+  normalizeDays(days, defaultDays = 30, maxDays = 365) {
+    const parsed = Number(days);
+    if (!Number.isFinite(parsed) || parsed <= 0) {
+      return defaultDays;
+    }
+    return Math.min(maxDays, Math.max(1, Math.floor(parsed)));
+  },
+
+  formatDateKey(date = new Date()) {
+    const target = date instanceof Date ? date : new Date(date);
+    if (Number.isNaN(target.getTime())) {
+      return null;
+    }
+    const year = target.getFullYear();
+    const month = String(target.getMonth() + 1).padStart(2, '0');
+    const day = String(target.getDate()).padStart(2, '0');
+    return `${year}-${month}-${day}`;
+  },
+
+  addUsage(userId, bytesUsed, downloadCount = 1, date = new Date()) {
+    const uid = Number(userId);
+    const bytes = Math.floor(Number(bytesUsed));
+    const count = Math.floor(Number(downloadCount));
+    const dateKey = this.formatDateKey(date);
+
+    if (!Number.isFinite(uid) || uid <= 0 || !Number.isFinite(bytes) || bytes <= 0 || !dateKey) {
+      return null;
+    }
+
+    const normalizedCount = Number.isFinite(count) && count > 0 ? count : 1;
+
+    return db.prepare(`
+      INSERT INTO user_download_traffic_daily (user_id, date_key, bytes_used, download_count, created_at, updated_at)
+      VALUES (?, ?, ?, ?, datetime('now', 'localtime'), datetime('now', 'localtime'))
+      ON CONFLICT(user_id, date_key)
+      DO UPDATE SET
+        bytes_used = user_download_traffic_daily.bytes_used + excluded.bytes_used,
+        download_count = user_download_traffic_daily.download_count + excluded.download_count,
+        updated_at = datetime('now', 'localtime')
+    `).run(uid, dateKey, bytes, normalizedCount);
+  },
+
+  getDailyUsage(userId, days = 30) {
+    const uid = Number(userId);
+    if (!Number.isFinite(uid) || uid <= 0) {
+      return [];
+    }
+
+    const safeDays = this.normalizeDays(days);
+    const offset = `-${safeDays - 1} days`;
+
+    return db.prepare(`
+      SELECT
+        date_key,
+        bytes_used,
+        download_count
+      FROM user_download_traffic_daily
+      WHERE user_id = ?
+        AND date_key >= date('now', 'localtime', ?)
+      ORDER BY date_key ASC
+    `).all(uid, offset);
+  },
+
+  getPeriodSummary(userId, days = null) {
+    const uid = Number(userId);
+    if (!Number.isFinite(uid) || uid <= 0) {
+      return { bytes_used: 0, download_count: 0 };
+    }
+
+    if (days === null || days === undefined) {
+      const row = db.prepare(`
+        SELECT
+          COALESCE(SUM(bytes_used), 0) AS bytes_used,
+          COALESCE(SUM(download_count), 0) AS download_count
+        FROM user_download_traffic_daily
+        WHERE user_id = ?
+      `).get(uid);
+      return row || { bytes_used: 0, download_count: 0 };
+    }
+
+    const safeDays = this.normalizeDays(days);
+    const offset = `-${safeDays - 1} days`;
+
+    const row = db.prepare(`
+      SELECT
+        COALESCE(SUM(bytes_used), 0) AS bytes_used,
+        COALESCE(SUM(download_count), 0) AS download_count
+      FROM user_download_traffic_daily
+      WHERE user_id = ?
+        AND date_key >= date('now', 'localtime', ?)
+    `).get(uid, offset);
+
+    return row || { bytes_used: 0, download_count: 0 };
+  }
+};
+
 // 系统日志操作
 const SystemLogDB = {
   // 日志级别常量
@@ -1616,6 +1732,7 @@ module.exports = {
   SettingsDB,
   VerificationDB,
   PasswordResetTokenDB,
+  DownloadTrafficReportDB,
   SystemLogDB,
   TransactionDB,
   WalManager

backend/server.js

@@ -62,7 +62,7 @@ function clearOssUsageCache(userId) {
   console.log(`[OSS缓存] 已清除: 用户 ${userId}`);
 }
 
-const { db, UserDB, ShareDB, SettingsDB, VerificationDB, PasswordResetTokenDB, SystemLogDB, TransactionDB, WalManager } = require('./database');
+const { db, UserDB, ShareDB, SettingsDB, VerificationDB, PasswordResetTokenDB, DownloadTrafficReportDB, SystemLogDB, TransactionDB, WalManager } = require('./database');
 const StorageUsageCache = require('./utils/storage-cache');
 const { JWT_SECRET, generateToken, generateRefreshToken, refreshAccessToken, authMiddleware, adminMiddleware, isJwtSecretSecure } = require('./auth');
 const { StorageInterface, LocalStorageClient, OssStorageClient, formatFileSize, formatOssError } = require('./storage');
@@ -691,6 +691,31 @@ function formatDateTimeForSqlite(date = new Date()) {
   return `${year}-${month}-${day} ${hours}:${minutes}:${seconds}`;
 }
 
+function getDateKeyFromDate(date = new Date()) {
+  const target = date instanceof Date ? date : new Date(date);
+  if (Number.isNaN(target.getTime())) {
+    return null;
+  }
+  const year = target.getFullYear();
+  const month = String(target.getMonth() + 1).padStart(2, '0');
+  const day = String(target.getDate()).padStart(2, '0');
+  return `${year}-${month}-${day}`;
+}
+
+function getRecentDateKeys(days = 30, now = new Date()) {
+  const safeDays = Math.max(1, Math.floor(Number(days) || 30));
+  const keys = [];
+  for (let i = safeDays - 1; i >= 0; i -= 1) {
+    const date = new Date(now.getTime());
+    date.setDate(date.getDate() - i);
+    const key = getDateKeyFromDate(date);
+    if (key) {
+      keys.push(key);
+    }
+  }
+  return keys;
+}
+
 function getNextDownloadResetTime(lastResetAt, resetCycle) {
   const baseDate = parseDateTimeValue(lastResetAt);
   if (!baseDate) {
@@ -847,11 +872,16 @@ const applyDownloadTrafficUsageTransaction = db.transaction((userId, bytesToAdd)
 
   UserDB.update(userId, { download_traffic_used: nextUsed });
 
+  const addedBytes = Math.max(0, nextUsed - trafficState.used);
+  if (addedBytes > 0) {
+    DownloadTrafficReportDB.addUsage(userId, addedBytes, 1, new Date());
+  }
+
   return {
     quota: trafficState.quota,
     usedBefore: trafficState.used,
     usedAfter: nextUsed,
-    added: Math.max(0, nextUsed - trafficState.used)
+    added: addedBytes
   };
 });
 
@@ -863,6 +893,63 @@ function applyDownloadTrafficUsage(userId, bytesToAdd) {
   return applyDownloadTrafficUsageTransaction(userId, Math.floor(parsedBytes));
 }
 
+const reserveDirectDownloadTrafficTransaction = db.transaction((userId, bytesToReserve) => {
+  const policyState = enforceDownloadTrafficPolicyTransaction(userId, 'direct_download_reserve');
+  const user = policyState?.user || UserDB.findById(userId);
+  if (!user) {
+    return { ok: false, reason: 'user_not_found' };
+  }
+
+  const reserveBytes = Math.floor(Number(bytesToReserve));
+  if (!Number.isFinite(reserveBytes) || reserveBytes <= 0) {
+    return {
+      ok: true,
+      quota: normalizeDownloadTrafficQuota(user.download_traffic_quota),
+      usedBefore: normalizeDownloadTrafficUsed(user.download_traffic_used, normalizeDownloadTrafficQuota(user.download_traffic_quota)),
+      usedAfter: normalizeDownloadTrafficUsed(user.download_traffic_used, normalizeDownloadTrafficQuota(user.download_traffic_quota)),
+      reserved: 0
+    };
+  }
+
+  const trafficState = getDownloadTrafficState(user);
+  if (!trafficState.isUnlimited && reserveBytes > trafficState.remaining) {
+    return {
+      ok: false,
+      reason: 'insufficient',
+      quota: trafficState.quota,
+      usedBefore: trafficState.used,
+      remaining: trafficState.remaining
+    };
+  }
+
+  const nextUsed = trafficState.used + reserveBytes;
+  UserDB.update(userId, { download_traffic_used: nextUsed });
+  DownloadTrafficReportDB.addUsage(userId, reserveBytes, 1, new Date());
+
+  return {
+    ok: true,
+    quota: trafficState.quota,
+    usedBefore: trafficState.used,
+    usedAfter: nextUsed,
+    reserved: reserveBytes
+  };
+});
+
+function reserveDirectDownloadTraffic(userId, bytesToReserve) {
+  const parsedBytes = Number(bytesToReserve);
+  if (!Number.isFinite(parsedBytes) || parsedBytes <= 0) {
+    return {
+      ok: true,
+      quota: 0,
+      usedBefore: 0,
+      usedAfter: 0,
+      reserved: 0
+    };
+  }
+
+  return reserveDirectDownloadTrafficTransaction(userId, Math.floor(parsedBytes));
+}
+
 function runDownloadTrafficPolicySweep(trigger = 'scheduled') {
   try {
     const users = UserDB.getAll();
@@ -2526,6 +2613,112 @@ app.get('/api/user/profile', authMiddleware, (req, res) => {
   });
 });
 
+// 获取用户下载流量额度与报表
+app.get('/api/user/download-traffic-report', authMiddleware, (req, res) => {
+  try {
+    const days = DownloadTrafficReportDB.normalizeDays(req.query.days, 30, 365);
+
+    const policyState = enforceDownloadTrafficPolicy(req.user.id, 'traffic_report');
+    const latestUser = policyState?.user || UserDB.findById(req.user.id);
+    if (!latestUser) {
+      return res.status(404).json({
+        success: false,
+        message: '用户不存在'
+      });
+    }
+
+    const trafficState = getDownloadTrafficState(latestUser);
+    const dailyRows = DownloadTrafficReportDB.getDailyUsage(latestUser.id, days);
+    const dailyRowMap = new Map(
+      dailyRows.map(row => [row.date_key, row])
+    );
+    const dateKeys = getRecentDateKeys(days, new Date());
+    const dailySeries = dateKeys.map(dateKey => {
+      const row = dailyRowMap.get(dateKey);
+      const bytesUsed = Number(row?.bytes_used || 0);
+      const downloadCount = Number(row?.download_count || 0);
+      return {
+        date: dateKey,
+        bytes_used: Number.isFinite(bytesUsed) && bytesUsed > 0 ? Math.floor(bytesUsed) : 0,
+        download_count: Number.isFinite(downloadCount) && downloadCount > 0 ? Math.floor(downloadCount) : 0
+      };
+    });
+
+    const selectedSummary = DownloadTrafficReportDB.getPeriodSummary(latestUser.id, days);
+    const todaySummary = DownloadTrafficReportDB.getPeriodSummary(latestUser.id, 1);
+    const sevenDaySummary = DownloadTrafficReportDB.getPeriodSummary(latestUser.id, 7);
+    const thirtyDaySummary = DownloadTrafficReportDB.getPeriodSummary(latestUser.id, 30);
+    const allSummary = DownloadTrafficReportDB.getPeriodSummary(latestUser.id, null);
+
+    const peakDay = dailySeries.reduce((peak, current) => {
+      if (!peak || current.bytes_used > peak.bytes_used) {
+        return current;
+      }
+      return peak;
+    }, null);
+
+    const safeQuota = trafficState.quota > 0 ? trafficState.quota : 0;
+    const remainingBytes = safeQuota > 0 ? Math.max(0, safeQuota - trafficState.used) : null;
+    const usagePercentage = safeQuota > 0
+      ? Math.min(100, Math.round((trafficState.used / safeQuota) * 100))
+      : null;
+
+    res.json({
+      success: true,
+      quota: {
+        quota: safeQuota,
+        used: trafficState.used,
+        remaining: remainingBytes,
+        usage_percentage: usagePercentage,
+        is_unlimited: trafficState.isUnlimited,
+        reset_cycle: latestUser.download_traffic_reset_cycle || 'none',
+        expires_at: latestUser.download_traffic_quota_expires_at || null,
+        last_reset_at: latestUser.download_traffic_last_reset_at || null
+      },
+      report: {
+        days,
+        daily: dailySeries,
+        summary: {
+          today: {
+            bytes_used: Number(todaySummary?.bytes_used || 0),
+            download_count: Number(todaySummary?.download_count || 0)
+          },
+          last_7_days: {
+            bytes_used: Number(sevenDaySummary?.bytes_used || 0),
+            download_count: Number(sevenDaySummary?.download_count || 0)
+          },
+          last_30_days: {
+            bytes_used: Number(thirtyDaySummary?.bytes_used || 0),
+            download_count: Number(thirtyDaySummary?.download_count || 0)
+          },
+          selected_range: {
+            bytes_used: Number(selectedSummary?.bytes_used || 0),
+            download_count: Number(selectedSummary?.download_count || 0),
+            average_daily_bytes: Math.round(Number(selectedSummary?.bytes_used || 0) / Math.max(1, days))
+          },
+          all_time: {
+            bytes_used: Number(allSummary?.bytes_used || 0),
+            download_count: Number(allSummary?.download_count || 0)
+          },
+          peak_day: peakDay
+            ? {
+                date: peakDay.date,
+                bytes_used: peakDay.bytes_used,
+                download_count: peakDay.download_count
+              }
+            : null
+        }
+      }
+    });
+  } catch (error) {
+    console.error('获取下载流量报表失败:', error);
+    res.status(500).json({
+      success: false,
+      message: '获取下载流量报表失败'
+    });
+  }
+});
+
 // 获取用户主题偏好（包含全局默认主题）
 app.get('/api/user/theme', authMiddleware, (req, res) => {
   try {
@@ -3932,7 +4125,6 @@ app.get('/api/files/download-url', authMiddleware, async (req, res) => {
     });
   }
 
-  // 开启下载流量配额后，禁止发放直连 URL（避免绕过后端计量）
   const policyState = enforceDownloadTrafficPolicy(req.user.id, 'download_url');
   const latestUser = policyState?.user || UserDB.findById(req.user.id);
   if (!latestUser) {
@@ -3943,12 +4135,6 @@ app.get('/api/files/download-url', authMiddleware, async (req, res) => {
   }
 
   const trafficState = getDownloadTrafficState(latestUser);
-  if (!trafficState.isUnlimited) {
-    return res.status(403).json({
-      success: false,
-      message: '当前账号已启用下载流量限制，请使用系统下载入口'
-    });
-  }
 
   // 检查用户是否配置了 OSS（包括个人配置和系统级统一配置）
   const hasUnifiedConfig = SettingsDB.hasUnifiedOssConfig();
@@ -3960,11 +4146,44 @@ app.get('/api/files/download-url', authMiddleware, async (req, res) => {
   }
 
   try {
-    const { GetObjectCommand } = require('@aws-sdk/client-s3');
+    const { GetObjectCommand, HeadObjectCommand } = require('@aws-sdk/client-s3');
     const { getSignedUrl } = require('@aws-sdk/s3-request-presigner');
 
-    const { client, bucket, ossClient } = createS3ClientContextForUser(req.user);
+    const { client, bucket, ossClient } = createS3ClientContextForUser(latestUser);
     const objectKey = ossClient.getObjectKey(normalizedPath);
+    let fileSize = 0;
+
+    // 启用下载流量限制时，签发前先校验文件大小与剩余额度
+    if (!trafficState.isUnlimited) {
+      let headResponse;
+      try {
+        headResponse = await client.send(new HeadObjectCommand({
+          Bucket: bucket,
+          Key: objectKey
+        }));
+      } catch (headError) {
+        const statusCode = headError?.$metadata?.httpStatusCode;
+        if (headError?.name === 'NotFound' || headError?.name === 'NoSuchKey' || statusCode === 404) {
+          return res.status(404).json({
+            success: false,
+            message: '文件不存在'
+          });
+        }
+        throw headError;
+      }
+
+      const contentLength = Number(headResponse?.ContentLength || 0);
+      fileSize = Number.isFinite(contentLength) && contentLength > 0
+        ? Math.floor(contentLength)
+        : 0;
+
+      if (fileSize > trafficState.remaining) {
+        return res.status(403).json({
+          success: false,
+          message: `下载流量不足：文件 ${formatFileSize(fileSize)}，剩余 ${formatFileSize(trafficState.remaining)}`
+        });
+      }
+    }
 
     // 创建 GetObject 命令
     const command = new GetObjectCommand({
@@ -3976,10 +4195,24 @@ app.get('/api/files/download-url', authMiddleware, async (req, res) => {
     // 生成签名 URL（1小时有效）
     const signedUrl = await getSignedUrl(client, command, { expiresIn: 3600 });
 
+    // 直连模式下无法精确获知真实下载字节；限流时在签发前预扣文件大小
+    if (!trafficState.isUnlimited && fileSize > 0) {
+      const reserveResult = reserveDirectDownloadTraffic(latestUser.id, fileSize);
+      if (!reserveResult?.ok) {
+        const remaining = Number(reserveResult?.remaining || 0);
+        return res.status(403).json({
+          success: false,
+          message: `下载流量不足：文件 ${formatFileSize(fileSize)}，剩余 ${formatFileSize(remaining)}`
+        });
+      }
+    }
+
     res.json({
       success: true,
       downloadUrl: signedUrl,
-      expiresIn: 3600
+      expiresIn: 3600,
+      direct: true,
+      quotaLimited: !trafficState.isUnlimited
     });
   } catch (error) {
     console.error('[OSS签名] 生成下载签名失败:', error);
@@ -5235,8 +5468,8 @@ app.post('/api/share/:code/download-url', shareRateLimitMiddleware, async (req,
     const storageType = share.storage_type || 'oss';
     const ownerTrafficState = getDownloadTrafficState(shareOwner);
 
-    // 本地存储，或分享者启用了下载流量上限：统一走后端下载（便于计量）
-    if (storageType !== 'oss' || !ownerTrafficState.isUnlimited) {
+    // 本地存储：继续走后端下载
+    if (storageType !== 'oss') {
       let downloadUrl = `${getSecureBaseUrl(req)}/api/share/${code}/download-file?path=${encodeURIComponent(normalizedFilePath)}`;
 
       if (share.share_password) {
@@ -5265,11 +5498,43 @@ app.post('/api/share/:code/download-url', shareRateLimitMiddleware, async (req,
       });
     }
 
-    const { GetObjectCommand } = require('@aws-sdk/client-s3');
+    const { GetObjectCommand, HeadObjectCommand } = require('@aws-sdk/client-s3');
     const { getSignedUrl } = require('@aws-sdk/s3-request-presigner');
 
     const { client, bucket, ossClient } = createS3ClientContextForUser(shareOwner);
     const objectKey = ossClient.getObjectKey(normalizedFilePath);
+    let fileSize = 0;
+
+    if (!ownerTrafficState.isUnlimited) {
+      let headResponse;
+      try {
+        headResponse = await client.send(new HeadObjectCommand({
+          Bucket: bucket,
+          Key: objectKey
+        }));
+      } catch (headError) {
+        const statusCode = headError?.$metadata?.httpStatusCode;
+        if (headError?.name === 'NotFound' || headError?.name === 'NoSuchKey' || statusCode === 404) {
+          return res.status(404).json({
+            success: false,
+            message: '文件不存在'
+          });
+        }
+        throw headError;
+      }
+
+      const contentLength = Number(headResponse?.ContentLength || 0);
+      fileSize = Number.isFinite(contentLength) && contentLength > 0
+        ? Math.floor(contentLength)
+        : 0;
+
+      if (fileSize > ownerTrafficState.remaining) {
+        return res.status(403).json({
+          success: false,
+          message: `下载流量不足：文件 ${formatFileSize(fileSize)}，剩余 ${formatFileSize(ownerTrafficState.remaining)}`
+        });
+      }
+    }
 
     // 创建 GetObject 命令
     const command = new GetObjectCommand({
@@ -5281,10 +5546,22 @@ app.post('/api/share/:code/download-url', shareRateLimitMiddleware, async (req,
     // 生成签名 URL（1小时有效）
     const signedUrl = await getSignedUrl(client, command, { expiresIn: 3600 });
 
+    if (!ownerTrafficState.isUnlimited && fileSize > 0) {
+      const reserveResult = reserveDirectDownloadTraffic(shareOwner.id, fileSize);
+      if (!reserveResult?.ok) {
+        const remaining = Number(reserveResult?.remaining || 0);
+        return res.status(403).json({
+          success: false,
+          message: `下载流量不足：文件 ${formatFileSize(fileSize)}，剩余 ${formatFileSize(remaining)}`
+        });
+      }
+    }
+
     res.json({
       success: true,
       downloadUrl: signedUrl,
       direct: true,
+      quotaLimited: !ownerTrafficState.isUnlimited,
       expiresIn: 3600
     });
 

frontend/app.html

@@ -2331,6 +2331,163 @@
           </div>
         </div>
 
+        <!-- 下载流量额度与统计 -->
+        <div v-if="user && !user.is_admin" class="settings-section settings-download-traffic" style="margin-bottom: 40px;">
+          <h3 class="settings-section-title" style="margin-bottom: 20px;">
+            <i class="fas fa-tachometer-alt"></i> 下载流量额度与统计
+          </h3>
+          <div class="settings-panel" style="background: var(--bg-card); border: 1px solid var(--glass-border); border-radius: 12px; padding: 18px;">
+            <div style="display: flex; justify-content: space-between; gap: 10px; align-items: center; flex-wrap: wrap; margin-bottom: 12px;">
+              <div style="font-size: 13px; color: var(--text-secondary);">
+                管理员设置的下载流量限制会在这里实时展示，单位自动按 B/KB/MB/GB/TB 切换
+              </div>
+              <div style="display: flex; gap: 8px; align-items: center; flex-wrap: wrap;">
+                <button
+                  class="btn btn-secondary"
+                  style="padding: 5px 10px; font-size: 12px;"
+                  :class="{ 'btn-primary': downloadTrafficReport.days === 7 }"
+                  @click="setDownloadTrafficReportDays(7)">
+                  近7天
+                </button>
+                <button
+                  class="btn btn-secondary"
+                  style="padding: 5px 10px; font-size: 12px;"
+                  :class="{ 'btn-primary': downloadTrafficReport.days === 30 }"
+                  @click="setDownloadTrafficReportDays(30)">
+                  近30天
+                </button>
+                <button
+                  class="btn btn-secondary"
+                  style="padding: 5px 10px; font-size: 12px;"
+                  :class="{ 'btn-primary': downloadTrafficReport.days === 90 }"
+                  @click="setDownloadTrafficReportDays(90)">
+                  近90天
+                </button>
+                <button
+                  class="btn btn-secondary"
+                  style="padding: 5px 10px; font-size: 12px;"
+                  :class="{ 'btn-primary': downloadTrafficReport.days === 180 }"
+                  @click="setDownloadTrafficReportDays(180)">
+                  近180天
+                </button>
+                <button class="btn btn-secondary" style="padding: 5px 10px; font-size: 12px;" @click="loadDownloadTrafficReport(downloadTrafficReport.days)" :disabled="downloadTrafficReport.loading">
+                  <i :class="downloadTrafficReport.loading ? 'fas fa-sync-alt fa-spin' : 'fas fa-sync-alt'"></i>
+                  {{ downloadTrafficReport.loading ? '加载中...' : '刷新' }}
+                </button>
+              </div>
+            </div>
+
+            <div v-if="downloadTrafficReport.error" style="margin-bottom: 10px; padding: 10px 12px; border-radius: 8px; background: rgba(239,68,68,0.1); color: #ef4444; font-size: 13px;">
+              <i class="fas fa-exclamation-triangle"></i> {{ downloadTrafficReport.error }}
+            </div>
+
+            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 10px; margin-bottom: 12px;">
+              <div style="padding: 12px; border-radius: 10px; background: rgba(59,130,246,0.1); border: 1px solid rgba(59,130,246,0.25);">
+                <div style="font-size: 12px; color: var(--text-muted); margin-bottom: 6px;">当前限制</div>
+                <div style="font-size: 18px; font-weight: 700; color: #3b82f6;">
+                  {{ downloadTrafficIsUnlimited ? '不限' : formatBytes(downloadTrafficQuotaBytes) }}
+                </div>
+              </div>
+              <div style="padding: 12px; border-radius: 10px; background: rgba(245,158,11,0.1); border: 1px solid rgba(245,158,11,0.28);">
+                <div style="font-size: 12px; color: var(--text-muted); margin-bottom: 6px;">已使用</div>
+                <div style="font-size: 18px; font-weight: 700; color: #f59e0b;">
+                  {{ formatBytes(downloadTrafficUsedBytes) }}
+                </div>
+              </div>
+              <div style="padding: 12px; border-radius: 10px; background: rgba(16,185,129,0.1); border: 1px solid rgba(16,185,129,0.26);">
+                <div style="font-size: 12px; color: var(--text-muted); margin-bottom: 6px;">剩余可用</div>
+                <div style="font-size: 18px; font-weight: 700; color: #10b981;">
+                  {{ downloadTrafficIsUnlimited ? '不限' : formatBytes(downloadTrafficRemainingBytes || 0) }}
+                </div>
+              </div>
+              <div style="padding: 12px; border-radius: 10px; background: rgba(99,102,241,0.12); border: 1px solid rgba(99,102,241,0.28);">
+                <div style="font-size: 12px; color: var(--text-muted); margin-bottom: 6px;">策略</div>
+                <div style="font-size: 14px; font-weight: 700; color: #6366f1;">
+                  {{ getDownloadResetCycleText(downloadTrafficResetCycle) }}
+                </div>
+                <div style="font-size: 12px; color: var(--text-secondary); margin-top: 4px;">
+                  到期: {{ downloadTrafficExpiresAt ? formatDate(downloadTrafficExpiresAt) : '无' }}
+                </div>
+              </div>
+            </div>
+
+            <div v-if="!downloadTrafficIsUnlimited" style="margin-bottom: 12px;">
+              <div style="display: flex; justify-content: space-between; font-size: 12px; color: var(--text-secondary); margin-bottom: 6px;">
+                <span>额度使用率</span>
+                <span>{{ downloadTrafficUsagePercentage }}%</span>
+              </div>
+              <div style="height: 10px; background: rgba(148,163,184,0.24); border-radius: 999px; overflow: hidden;">
+                <div :style="{ width: downloadTrafficUsagePercentage + '%', height: '100%', background: downloadTrafficUsagePercentage > 90 ? '#ef4444' : (downloadTrafficUsagePercentage > 75 ? '#f59e0b' : '#22c55e') }"></div>
+              </div>
+            </div>
+
+            <div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 10px; margin-bottom: 12px;">
+              <div style="padding: 10px; border-radius: 8px; background: var(--bg-secondary); border: 1px solid var(--glass-border);">
+                <div style="font-size: 12px; color: var(--text-muted);">今天使用</div>
+                <div style="font-weight: 700; color: var(--text-primary); margin-top: 4px;">
+                  {{ formatBytes(downloadTrafficReport.summary?.today?.bytes_used || 0) }}
+                </div>
+              </div>
+              <div style="padding: 10px; border-radius: 8px; background: var(--bg-secondary); border: 1px solid var(--glass-border);">
+                <div style="font-size: 12px; color: var(--text-muted);">近7天</div>
+                <div style="font-weight: 700; color: var(--text-primary); margin-top: 4px;">
+                  {{ formatBytes(downloadTrafficReport.summary?.last_7_days?.bytes_used || 0) }}
+                </div>
+              </div>
+              <div style="padding: 10px; border-radius: 8px; background: var(--bg-secondary); border: 1px solid var(--glass-border);">
+                <div style="font-size: 12px; color: var(--text-muted);">近30天</div>
+                <div style="font-weight: 700; color: var(--text-primary); margin-top: 4px;">
+                  {{ formatBytes(downloadTrafficReport.summary?.last_30_days?.bytes_used || 0) }}
+                </div>
+              </div>
+              <div style="padding: 10px; border-radius: 8px; background: var(--bg-secondary); border: 1px solid var(--glass-border);">
+                <div style="font-size: 12px; color: var(--text-muted);">所选区间</div>
+                <div style="font-weight: 700; color: var(--text-primary); margin-top: 4px;">
+                  {{ formatBytes(downloadTrafficReport.summary?.selected_range?.bytes_used || 0) }}
+                </div>
+              </div>
+              <div style="padding: 10px; border-radius: 8px; background: var(--bg-secondary); border: 1px solid var(--glass-border);">
+                <div style="font-size: 12px; color: var(--text-muted);">历史累计</div>
+                <div style="font-weight: 700; color: var(--text-primary); margin-top: 4px;">
+                  {{ formatBytes(downloadTrafficReport.summary?.all_time?.bytes_used || 0) }}
+                </div>
+              </div>
+            </div>
+
+            <div style="border: 1px solid var(--glass-border); border-radius: 10px; overflow: hidden;">
+              <div style="padding: 10px 12px; background: var(--bg-secondary); border-bottom: 1px solid var(--glass-border); font-size: 13px; color: var(--text-secondary); display: flex; justify-content: space-between; align-items: center;">
+                <span>按天用量明细（最近 {{ downloadTrafficReport.days }} 天）</span>
+                <span v-if="downloadTrafficReport.summary?.peak_day">峰值: {{ formatReportDateLabel(downloadTrafficReport.summary.peak_day.date) }} / {{ formatBytes(downloadTrafficReport.summary.peak_day.bytes_used || 0) }}</span>
+              </div>
+
+              <div v-if="downloadTrafficReport.loading && downloadTrafficDailyRowsDesc.length === 0" style="padding: 16px; text-align: center; color: var(--text-muted);">
+                <i class="fas fa-spinner fa-spin"></i> 报表加载中...
+              </div>
+              <div v-else-if="downloadTrafficDailyRowsDesc.length === 0" style="padding: 16px; text-align: center; color: var(--text-muted);">
+                暂无下载流量记录
+              </div>
+              <div v-else style="max-height: 280px; overflow: auto;">
+                <table style="width: 100%; border-collapse: collapse;">
+                  <thead>
+                    <tr style="background: rgba(148,163,184,0.12);">
+                      <th style="padding: 10px; text-align: left; font-size: 12px; color: var(--text-secondary);">日期</th>
+                      <th style="padding: 10px; text-align: right; font-size: 12px; color: var(--text-secondary);">下载流量</th>
+                      <th style="padding: 10px; text-align: right; font-size: 12px; color: var(--text-secondary);">下载次数</th>
+                    </tr>
+                  </thead>
+                  <tbody>
+                    <tr v-for="row in downloadTrafficDailyRowsDesc" :key="row.date" style="border-top: 1px solid var(--glass-border);">
+                      <td style="padding: 9px 10px; color: var(--text-primary); font-size: 13px;">{{ formatReportDateLabel(row.date) }}</td>
+                      <td style="padding: 9px 10px; text-align: right; color: var(--text-primary); font-size: 13px; font-weight: 600;">{{ formatBytes(row.bytes_used || 0) }}</td>
+                      <td style="padding: 9px 10px; text-align: right; color: var(--text-secondary); font-size: 13px;">{{ row.download_count || 0 }}</td>
+                    </tr>
+                  </tbody>
+                </table>
+              </div>
+            </div>
+          </div>
+        </div>
+        
         <!-- 界面设置 -->
         <h3 class="settings-section-title settings-section-gap" style="margin: 40px 0 20px 0;"><i class="fas fa-palette"></i> 界面设置</h3>
         <div class="settings-panel settings-theme-panel" style="background: var(--bg-card); padding: 20px; border-radius: 12px; border: 1px solid var(--glass-border); margin-bottom: 30px;">

frontend/app.js

@@ -311,6 +311,17 @@ createApp({
       ossUsageLoading: false,
       ossUsageError: null,
 
+      // 下载流量报表
+      downloadTrafficReport: {
+        days: 30,
+        loading: false,
+        error: null,
+        quota: null,
+        daily: [],
+        summary: null,
+        lastUpdatedAt: null
+      },
+
       // 主题设置
       currentTheme: 'dark', // 当前生效的主题: 'dark' 或 'light'
       globalTheme: 'dark', // 全局默认主题（管理员设置）
@@ -374,6 +385,80 @@ createApp({
       return Math.min(100, Math.round((this.ossUsedBytes / this.ossQuotaBytes) * 100));
     },
 
+    downloadTrafficQuotaBytes() {
+      const reportQuota = Number(this.downloadTrafficReport?.quota?.quota);
+      if (Number.isFinite(reportQuota) && reportQuota >= 0) {
+        return reportQuota;
+      }
+      const userQuota = Number(this.user?.download_traffic_quota || 0);
+      return Number.isFinite(userQuota) && userQuota > 0 ? Math.floor(userQuota) : 0;
+    },
+
+    downloadTrafficUsedBytes() {
+      const reportUsed = Number(this.downloadTrafficReport?.quota?.used);
+      if (Number.isFinite(reportUsed) && reportUsed >= 0) {
+        return Math.floor(reportUsed);
+      }
+      const userUsed = Number(this.user?.download_traffic_used || 0);
+      return Number.isFinite(userUsed) && userUsed > 0 ? Math.floor(userUsed) : 0;
+    },
+
+    downloadTrafficIsUnlimited() {
+      if (this.downloadTrafficReport?.quota?.is_unlimited === true) {
+        return true;
+      }
+      return this.downloadTrafficQuotaBytes <= 0;
+    },
+
+    downloadTrafficRemainingBytes() {
+      if (this.downloadTrafficIsUnlimited) {
+        return null;
+      }
+
+      const reportRemaining = Number(this.downloadTrafficReport?.quota?.remaining);
+      if (Number.isFinite(reportRemaining) && reportRemaining >= 0) {
+        return Math.floor(reportRemaining);
+      }
+
+      return Math.max(0, this.downloadTrafficQuotaBytes - this.downloadTrafficUsedBytes);
+    },
+
+    downloadTrafficUsagePercentage() {
+      if (this.downloadTrafficIsUnlimited) {
+        return 0;
+      }
+
+      const reportPercentage = Number(this.downloadTrafficReport?.quota?.usage_percentage);
+      if (Number.isFinite(reportPercentage) && reportPercentage >= 0) {
+        return Math.min(100, Math.round(reportPercentage));
+      }
+
+      if (this.downloadTrafficQuotaBytes <= 0) {
+        return 0;
+      }
+
+      return Math.min(100, Math.round((this.downloadTrafficUsedBytes / this.downloadTrafficQuotaBytes) * 100));
+    },
+
+    downloadTrafficResetCycle() {
+      return this.downloadTrafficReport?.quota?.reset_cycle
+        || this.user?.download_traffic_reset_cycle
+        || 'none';
+    },
+
+    downloadTrafficExpiresAt() {
+      return this.downloadTrafficReport?.quota?.expires_at
+        || this.user?.download_traffic_quota_expires_at
+        || null;
+    },
+
+    downloadTrafficDailyRowsDesc() {
+      const rows = Array.isArray(this.downloadTrafficReport?.daily)
+        ? this.downloadTrafficReport.daily
+        : [];
+      return [...rows].reverse();
+    },
+
     // 存储类型显示文本
     storageTypeText() {
       return this.storageType === 'local' ? '本地存储' : 'OSS存储';
@@ -1460,17 +1545,48 @@ handleDragLeave(e) {
       this.loadFiles(newPath);
     },
 
-    downloadFile(file) {
+    async downloadFile(file) {
       // 构建文件路径
       const filePath = this.currentPath === '/' ? `/${file.name}` : `${this.currentPath}/${file.name}`;
 
-      // 统一走后端下载接口，确保下载流量可精确计量
+      const canDirectOssDownload = this.storageType === 'oss'
+        && this.user?.oss_config_source !== 'none';
+
+      // OSS 下载优先使用直连（避免服务器中转导致带宽与费用双重损耗）
+      if (canDirectOssDownload) {
+        const directResult = await this.downloadFromOSS(filePath);
+        if (directResult) {
+          return;
+        }
+      }
+
+      // 其他场景走后端下载接口（支持下载流量计量/权限控制）
       this.downloadFromLocal(filePath);
     },
 
-    // 保留方法名兼容旧调用，内部统一转发到后端下载
-    downloadFromOSS(filePath) {
-      this.downloadFromLocal(filePath);
+    async downloadFromOSS(filePath) {
+      try {
+        const response = await axios.get(`${this.apiBase}/api/files/download-url`, {
+          params: { path: filePath }
+        });
+
+        if (!response.data?.success || !response.data?.downloadUrl) {
+          return false;
+        }
+
+        const link = document.createElement('a');
+        link.href = response.data.downloadUrl;
+        link.setAttribute('download', '');
+        link.rel = 'noopener noreferrer';
+        link.target = '_blank';
+        document.body.appendChild(link);
+        link.click();
+        document.body.removeChild(link);
+        return true;
+      } catch (error) {
+        console.error('OSS直连下载失败，将回退到后端下载:', error);
+        return false;
+      }
     },
 
     // 本地存储下载
@@ -2731,6 +2847,67 @@ handleDragLeave(e) {
       }
     },
 
+    async loadDownloadTrafficReport(days = this.downloadTrafficReport.days) {
+      if (!this.isLoggedIn || !this.user || this.user.is_admin) {
+        return;
+      }
+
+      const allowedDays = [7, 30, 90, 180];
+      const normalizedDays = allowedDays.includes(Number(days)) ? Number(days) : 30;
+
+      this.downloadTrafficReport.days = normalizedDays;
+      this.downloadTrafficReport.loading = true;
+      this.downloadTrafficReport.error = null;
+
+      try {
+        const response = await axios.get(
+          `${this.apiBase}/api/user/download-traffic-report?days=${normalizedDays}`,
+        );
+
+        if (response.data.success) {
+          const quota = response.data.quota || null;
+          const report = response.data.report || {};
+          this.downloadTrafficReport.quota = quota;
+          this.downloadTrafficReport.daily = Array.isArray(report.daily) ? report.daily : [];
+          this.downloadTrafficReport.summary = report.summary || null;
+          this.downloadTrafficReport.lastUpdatedAt = new Date().toISOString();
+
+          // 同步到 user 对象，保证文件页/设置页显示一致
+          if (this.user && quota) {
+            this.user.download_traffic_quota = Number(quota.quota || 0);
+            this.user.download_traffic_used = Number(quota.used || 0);
+            this.user.download_traffic_reset_cycle = quota.reset_cycle || 'none';
+            this.user.download_traffic_quota_expires_at = quota.expires_at || null;
+            this.user.download_traffic_last_reset_at = quota.last_reset_at || null;
+          }
+        } else {
+          this.downloadTrafficReport.error = response.data.message || '获取报表失败';
+        }
+      } catch (error) {
+        console.error('获取下载流量报表失败:', error);
+        this.downloadTrafficReport.error = error.response?.data?.message || '获取报表失败';
+      } finally {
+        this.downloadTrafficReport.loading = false;
+      }
+    },
+
+    setDownloadTrafficReportDays(days) {
+      const nextDays = Number(days);
+      if (this.downloadTrafficReport.loading || nextDays === this.downloadTrafficReport.days) {
+        return;
+      }
+      this.loadDownloadTrafficReport(nextDays);
+    },
+
+    formatReportDateLabel(dateKey) {
+      if (!dateKey) return '-';
+      const match = String(dateKey).match(/^(\d{4})-(\d{2})-(\d{2})$/);
+      if (match) {
+        return `${match[2]}-${match[3]}`;
+      }
+      return dateKey;
+    },
+
     // 刷新存储空间使用统计（根据当前存储类型）
     async refreshStorageUsage() {
       if (this.storageType === 'oss' && this.user?.oss_config_source !== 'none') {
@@ -2894,7 +3071,9 @@ handleDragLeave(e) {
           }
           break;
         case 'settings':
-          // 设置页面不需要额外加载数据
+          if (this.user && !this.user.is_admin) {
+            this.loadDownloadTrafficReport();
+          }
           break;
       }
     },
@@ -3612,6 +3791,7 @@ handleDragLeave(e) {
       } else if (newView === 'settings' && this.user && !this.user.is_admin) {
         // 普通用户进入设置页面时加载OSS配置
         this.loadOssConfig();
+        this.loadDownloadTrafficReport();
       }
 
       // 记住最后停留的视图（需合法且已登录）