Update cloudflare.js

docker/cloudflare.js

@@ -2,19 +2,60 @@ addEventListener('fetch', event => {
   event.respondWith(handleRequest(event.request))
 })
 
-  // This data source from: https://raw.githubusercontent.com/Websoft9/doc.websoft9.com/refs/heads/main/docs/reference/_include/dockerhub-proxy.md
-  const backends = []
-  async function handleRequest(request) {
-    // 随机选择一个后端服务器
-    const backend = backends[Math.floor(Math.random() * backends.length)]
+var backends = [];
 
-    // 构建新的请求 URL
-    const url = new URL(request.url)
-    url.hostname = new URL(backend).hostname
+async function checkHealth() {
+  const healthChecks = backends.map(async url => {
+      const start = Date.now();
+      try {
+          const response = await fetch(url, { method: 'HEAD' });
+          const end = Date.now();
+          return {
+              url,
+              healthy: response.ok,
+              responseTime: response.ok ? end - start : Infinity
+          };
+      } catch (error) {
+          return {
+              url,
+              healthy: false,
+              responseTime: Infinity
+          };
+      }
+  });
 
-    // 转发请求到选定的后端服务器
-    const modifiedRequest = new Request(url, request)
-    const response = await fetch(modifiedRequest)
-    return response
+  return await Promise.all(healthChecks);
 }
 
+async function handleRequest(request) {
+  // 检查健康状态
+  const healthResults = await checkHealth();
+
+  // 过滤出健康的后端服务器
+  const healthyBackends = healthResults.filter(result => result.healthy);
+
+  if (healthyBackends.length === 0) {
+      return new Response('All backend servers are down', { status: 503 });
+  }
+
+  // 按响应时间排序健康的后端服务器
+  healthyBackends.sort((a, b) => a.responseTime - b.responseTime);
+
+  // 尝试按顺序转发请求到健康的后端服务器
+  for (const backend of healthyBackends) {
+      try {
+          const url = new URL(request.url);
+          url.hostname = new URL(backend.url).hostname;
+          const modifiedRequest = new Request(url, request);
+          const response = await fetch(modifiedRequest);
+          if (response.ok) {
+              return response;
+          }
+      } catch (error) {
+          console.error(`Failed to fetch from ${backend.url}: ${error}`);
+      }
+  }
+
+  // 如果所有后端服务器都失败
+  return new Response('Failed to fetch from all backends', { status: 502 });
+}