refactor(缓存): 优化缩略图生成和缓存文件命名逻辑

- 修改缓存元文件名使用 uniqidhex 替代 uniqid 以保持一致性
- 重构 createThumbnail 函数，使其返回缩略图路径并改进参数处理
- 移除冗余的缩略图文件存在性检查，改为统一在函数内处理
- 改进缩略图尺寸检查逻辑，增加有效性验证
- 优化缩略图 ETag 生成方式，优先使用 thumb.uniqid

source.js

@@ -85,7 +85,6 @@ setInterval(() => {
     for (const key in pathIndex) {
         if (currentTime - pathIndex[key].timestamp > CACHE_EXPIRY_MS) {
             delete pathIndex[key];
-            // Consider deleting actual cache files as well if not managed elsewhere
         }
     }
 }, CACHE_CLEANUP_INTERVAL_MS);
@@ -144,7 +143,7 @@ async function processSuccessfulApiData(apiData, uniqidhex, reqPath, token, sign
     const data = { realUrl, cloudtype, expiration: expiration * 1000, path: apiPath, headers, uniqid, thumb };
 
     pathIndex[uniqidhex] = { uniqid: data.uniqid, timestamp: Date.now() };
-    const cacheMetaFile = pathModule.join(cacheDir, `${data.uniqid}.meta`);
+    const cacheMetaFile = pathModule.join(cacheDir, `${uniqidhex}.meta`);
     const cacheContentFile = pathModule.join(cacheDir, `${data.uniqid}.content`);
     const tempCacheContentFile = pathModule.join(cacheDir, `${data.uniqid}_${crypto.randomBytes(16).toString('hex')}.temp`);
 
@@ -172,7 +171,7 @@ async function processSuccessfulApiData(apiData, uniqidhex, reqPath, token, sign
 
 async function tryServeFromStaleCacheOrError(uniqidhex, res, errorMessage) {
     if (pathIndex[uniqidhex]) {
-        const cacheMetaFile = pathModule.join(cacheDir, `${pathIndex[uniqidhex].uniqid}.meta`);
+        const cacheMetaFile = pathModule.join(cacheDir, `${uniqidhex}.meta`);
         const cacheContentFile = pathModule.join(cacheDir, `${pathIndex[uniqidhex].uniqid}.content`);
         if (fs.existsSync(cacheMetaFile) && fs.existsSync(cacheContentFile)) {
             console.warn(`API call failed or returned non-200. Serving stale cache for ${uniqidhex}`);
@@ -215,7 +214,7 @@ async function handleMainRequest(req, res) {
     let cacheContentFile = '';
 
     if (pathIndex[uniqidhex]) {
-        cacheMetaFile = pathModule.join(cacheDir, `${pathIndex[uniqidhex].uniqid}.meta`);
+        cacheMetaFile = pathModule.join(cacheDir, `${uniqidhex}.meta`);
         cacheContentFile = pathModule.join(cacheDir, `${pathIndex[uniqidhex].uniqid}.content`);
     }
 
@@ -377,22 +376,19 @@ async function fetchApiData(reqPath, token, sign) {
 }
 
 // createThumbnail
-function createThumbnail(data, cacheContentFile, thumbCacheFile) {
+function createThumbnail(data, cacheContentFile) {
     const { path, thumb } = data;
+
+    const thumbCacheFile = pathModule.join(cacheDir, `thumb_${thumb.uniqid}.jpeg`);
+    if (fs.existsSync(thumbCacheFile)) return thumbCacheFile;
+
     const isVideo = path && typeof path === 'string' && path.includes('.mp4');
     if (isVideo || !thumb) return;
-    if (fs.existsSync(thumbCacheFile)) return;
-    const width = thumb.width;
-    const height = thumb.height;
-    sharp(cacheContentFile)
-        .resize(width, height)
-        .toFile(thumbCacheFile, (err, info) => {
-            if (err) {
-                console.error(`Error creating thumbnail for ${cacheContentFile}:`, err);
-                return;
-            }
-        });
-
+    const width = thumb.width && thumb.width > 0 ? thumb.width : undefined;
+    const height = thumb.height && thumb.height > 0 ? thumb.height : undefined;
+    if (!width) return;
+    sharp(cacheContentFile).resize(width, height).toFile(thumbCacheFile);
+    return thumbCacheFile;
 }
 
 
@@ -461,13 +457,9 @@ const fetchAndServe = (data, tempCacheContentFile, cacheContentFile, cacheMetaFi
                         fs.renameSync(tempCacheContentFile, cacheContentFile);
                         console.log(`Successfully cached: ${cacheContentFile}`);
 
-
+                        // 生成缩略图
                         if (data.thumb) {
-                            const thumbCacheFile = pathModule.join(cacheDir, `${data.uniqid}_thumb.jpg`);
-                            if (!fs.existsSync(thumbCacheFile)) {
-                                // 创建缩略图
-                                createThumbnail(data, cacheContentFile, thumbCacheFile);
-                            }
+                            createThumbnail(data, cacheContentFile);
                         }
                     } catch (renameError) {
                         console.error(`Error renaming temp cache file ${tempCacheContentFile} to ${cacheContentFile}:`, renameError);
@@ -514,21 +506,19 @@ function serveFromCache(cacheData, cacheContentFile, cacheMetaFile, res) {
         'Last-Modified': (cacheData.headers && cacheData.headers['last-modified']) || new Date(fs.statSync(cacheMetaFile).mtime).toUTCString(),
     };
     if (cacheData.thumb) {
-        const thumbCacheFile = pathModule.join(cacheDir, `${cacheData.uniqid}_thumb.jpg`);
-        if (fs.existsSync(thumbCacheFile)) {
+        var thumbCacheFile = createThumbnail(cacheData, cacheContentFile)
+        if (thumbCacheFile && fs.existsSync(thumbCacheFile)) {
             cacheData.headers['content-length'] = fs.statSync(thumbCacheFile).size;
             const responseHeaders = {
                 ...baseHeaders,
                 ...(cacheData.headers || {}),
-                'ETag': (cacheData.uniqid || '') + '_thumb',
+                'ETag': (cacheData.thumb.uniqid || cacheData.uniqid) + '_thumb',
                 'Content-Type': 'image/jpeg',
             };
             res.writeHead(HTTP_STATUS.OK, responseHeaders);
             const thumbStream = fs.createReadStream(thumbCacheFile);
             thumbStream.pipe(res);
             return;
-        } else {
-            createThumbnail(cacheData, cacheContentFile, thumbCacheFile)
         }
     }