增加弹幕本地缓存

2025-12-05 20:05:30 +08:00
parent 40da6ae5b2
commit f8a2964264
5 changed files with 501 additions and 14 deletions
@@ -0,0 +1,330 @@
+// 弹幕缓存工具（IndexedDB）
+
+import type { DanmakuComment } from './types';
+
+// IndexedDB 数据库名称和版本
+const DB_NAME = 'moontvplus_danmaku_cache';
+const DB_VERSION = 1;
+const STORE_NAME = 'danmaku';
+
+// 缓存数据结构
+export interface DanmakuCacheData {
+  episodeId: number;
+  comments: DanmakuComment[];
+  timestamp: number; // 缓存时间戳
+}
+
+// 获取弹幕缓存失效时间（毫秒）
+// 从环境变量读取，默认 3 天（4320 分钟）
+// 设置为 0 表示不缓存
+export function getDanmakuCacheExpireTime(): number {
+  if (typeof window === 'undefined') return 4320 * 60 * 1000; // 3天 = 4320分钟
+
+  const envValue = process.env.NEXT_PUBLIC_DANMAKU_CACHE_EXPIRE_MINUTES;
+  if (envValue) {
+    const minutes = parseInt(envValue, 10);
+    if (!isNaN(minutes)) {
+      // 0 表示不缓存
+      if (minutes === 0) return 0;
+      // 正数表示缓存时间（分钟）
+      if (minutes > 0) return minutes * 60 * 1000;
+    }
+  }
+
+  // 默认 3 天（4320 分钟）
+  return 4320 * 60 * 1000;
+}
+
+// 打开数据库
+async function openDB(): Promise<IDBDatabase> {
+  return new Promise((resolve, reject) => {
+    const request = indexedDB.open(DB_NAME, DB_VERSION);
+
+    request.onerror = () => {
+      reject(new Error('无法打开 IndexedDB'));
+    };
+
+    request.onsuccess = () => {
+      resolve(request.result);
+    };
+
+    request.onupgradeneeded = (event) => {
+      const db = (event.target as IDBOpenDBRequest).result;
+
+      // 创建对象存储（如果不存在）
+      if (!db.objectStoreNames.contains(STORE_NAME)) {
+        const objectStore = db.createObjectStore(STORE_NAME, { keyPath: 'episodeId' });
+        objectStore.createIndex('timestamp', 'timestamp', { unique: false });
+        console.log('IndexedDB 对象存储已创建:', STORE_NAME);
+      }
+    };
+  });
+}
+
+// 保存弹幕到缓存
+export async function saveDanmakuToCache(
+  episodeId: number,
+  comments: DanmakuComment[]
+): Promise<void> {
+  // 如果缓存时间设置为 0，不保存缓存
+  const expireTime = getDanmakuCacheExpireTime();
+  if (expireTime === 0) {
+    console.log('弹幕缓存已禁用，跳过保存');
+    return;
+  }
+
+  try {
+    const db = await openDB();
+    const transaction = db.transaction([STORE_NAME], 'readwrite');
+    const objectStore = transaction.objectStore(STORE_NAME);
+
+    const cacheData: DanmakuCacheData = {
+      episodeId,
+      comments,
+      timestamp: Date.now(),
+    };
+
+    return new Promise((resolve, reject) => {
+      const request = objectStore.put(cacheData);
+
+      request.onsuccess = () => {
+        console.log(`弹幕已缓存: episodeId=${episodeId}, 数量=${comments.length}`);
+        resolve();
+      };
+
+      request.onerror = () => {
+        reject(new Error('保存弹幕缓存失败'));
+      };
+
+      transaction.oncomplete = () => {
+        db.close();
+      };
+    });
+  } catch (error) {
+    console.error('保存弹幕缓存失败:', error);
+    throw error;
+  }
+}
+
+// 从缓存获取弹幕
+export async function getDanmakuFromCache(
+  episodeId: number
+): Promise<DanmakuComment[] | null> {
+  // 如果缓存时间设置为 0，不使用缓存
+  const expireTime = getDanmakuCacheExpireTime();
+  if (expireTime === 0) {
+    console.log('弹幕缓存已禁用，跳过读取');
+    return null;
+  }
+
+  try {
+    const db = await openDB();
+    const transaction = db.transaction([STORE_NAME], 'readonly');
+    const objectStore = transaction.objectStore(STORE_NAME);
+
+    return new Promise((resolve, reject) => {
+      const request = objectStore.get(episodeId);
+
+      request.onsuccess = () => {
+        const result = request.result as DanmakuCacheData | undefined;
+
+        if (!result) {
+          console.log(`弹幕缓存未找到: episodeId=${episodeId}`);
+          resolve(null);
+          return;
+        }
+
+        // 检查缓存是否过期
+        const expireTime = getDanmakuCacheExpireTime();
+        const now = Date.now();
+        const age = now - result.timestamp;
+
+        if (age > expireTime) {
+          const ageMinutes = Math.floor(age / 1000 / 60);
+          console.log(
+            `弹幕缓存已过期: episodeId=${episodeId}, 年龄=${ageMinutes}分钟`
+          );
+          resolve(null);
+          return;
+        }
+
+        const ageMinutes = Math.floor(age / 1000 / 60);
+        console.log(
+          `从缓存获取弹幕: episodeId=${episodeId}, 数量=${result.comments.length}, 年龄=${ageMinutes}分钟`
+        );
+        resolve(result.comments);
+      };
+
+      request.onerror = () => {
+        reject(new Error('获取弹幕缓存失败'));
+      };
+
+      transaction.oncomplete = () => {
+        db.close();
+      };
+    });
+  } catch (error) {
+    console.error('获取弹幕缓存失败:', error);
+    return null;
+  }
+}
+
+// 清除指定弹幕缓存
+export async function clearDanmakuCache(episodeId: number): Promise<void> {
+  try {
+    const db = await openDB();
+    const transaction = db.transaction([STORE_NAME], 'readwrite');
+    const objectStore = transaction.objectStore(STORE_NAME);
+
+    return new Promise((resolve, reject) => {
+      const request = objectStore.delete(episodeId);
+
+      request.onsuccess = () => {
+        console.log(`弹幕缓存已清除: episodeId=${episodeId}`);
+        resolve();
+      };
+
+      request.onerror = () => {
+        reject(new Error('清除弹幕缓存失败'));
+      };
+
+      transaction.oncomplete = () => {
+        db.close();
+      };
+    });
+  } catch (error) {
+    console.error('清除弹幕缓存失败:', error);
+    throw error;
+  }
+}
+
+// 清除所有过期缓存
+export async function clearExpiredDanmakuCache(): Promise<number> {
+  try {
+    const db = await openDB();
+    const transaction = db.transaction([STORE_NAME], 'readwrite');
+    const objectStore = transaction.objectStore(STORE_NAME);
+    const index = objectStore.index('timestamp');
+
+    const expireTime = getDanmakuCacheExpireTime();
+    const now = Date.now();
+    const expireThreshold = now - expireTime;
+
+    return new Promise((resolve, reject) => {
+      const request = index.openCursor();
+      let deletedCount = 0;
+
+      request.onsuccess = (event) => {
+        const cursor = (event.target as IDBRequest<IDBCursorWithValue>).result;
+
+        if (cursor) {
+          const data = cursor.value as DanmakuCacheData;
+
+          if (data.timestamp < expireThreshold) {
+            cursor.delete();
+            deletedCount++;
+          }
+
+          cursor.continue();
+        } else {
+          console.log(`已清除 ${deletedCount} 个过期弹幕缓存`);
+          resolve(deletedCount);
+        }
+      };
+
+      request.onerror = () => {
+        reject(new Error('清除过期弹幕缓存失败'));
+      };
+
+      transaction.oncomplete = () => {
+        db.close();
+      };
+    });
+  } catch (error) {
+    console.error('清除过期弹幕缓存失败:', error);
+    return 0;
+  }
+}
+
+// 清除所有弹幕缓存
+export async function clearAllDanmakuCache(): Promise<void> {
+  try {
+    const db = await openDB();
+    const transaction = db.transaction([STORE_NAME], 'readwrite');
+    const objectStore = transaction.objectStore(STORE_NAME);
+
+    return new Promise((resolve, reject) => {
+      const request = objectStore.clear();
+
+      request.onsuccess = () => {
+        console.log('所有弹幕缓存已清除');
+        resolve();
+      };
+
+      request.onerror = () => {
+        reject(new Error('清除所有弹幕缓存失败'));
+      };
+
+      transaction.oncomplete = () => {
+        db.close();
+      };
+    });
+  } catch (error) {
+    console.error('清除所有弹幕缓存失败:', error);
+    throw error;
+  }
+}
+
+// 获取缓存统计信息
+export async function getDanmakuCacheStats(): Promise<{
+  total: number;
+  expired: number;
+  totalSize: number;
+}> {
+  try {
+    const db = await openDB();
+    const transaction = db.transaction([STORE_NAME], 'readonly');
+    const objectStore = transaction.objectStore(STORE_NAME);
+
+    return new Promise((resolve, reject) => {
+      const request = objectStore.openCursor();
+
+      let total = 0;
+      let expired = 0;
+      let totalSize = 0;
+
+      const expireTime = getDanmakuCacheExpireTime();
+      const now = Date.now();
+      const expireThreshold = now - expireTime;
+
+      request.onsuccess = (event) => {
+        const cursor = (event.target as IDBRequest<IDBCursorWithValue>).result;
+
+        if (cursor) {
+          const data = cursor.value as DanmakuCacheData;
+          total++;
+          totalSize += data.comments.length;
+
+          if (data.timestamp < expireThreshold) {
+            expired++;
+          }
+
+          cursor.continue();
+        } else {
+          resolve({ total, expired, totalSize });
+        }
+      };
+
+      request.onerror = () => {
+        reject(new Error('获取缓存统计信息失败'));
+      };
+
+      transaction.oncomplete = () => {
+        db.close();
+      };
+    });
+  } catch (error) {
+    console.error('获取缓存统计信息失败:', error);
+    return { total: 0, expired: 0, totalSize: 0 };
+  }
+}