feat: enhance API request handling for WebSocket and HTTP protocols

- Added support for WebSocket upgrade requests, converting HTTP/HTTPS to WS/WSS.
- Improved handling of regular HTTP requests by creating a new target URL based on the API base URL.
- Cleaned up request headers to remove potentially problematic headers.
- Enhanced response handling by copying all response headers and setting CORS headers for better cross-origin support.
- Improved error handling to include CORS headers in error responses.

functions/api/index.js

@@ -10,16 +10,35 @@ export async function onRequest(context) {
     return new Response('API_BASEURL environment variable is not set', { status: 500 });
   }
   
-  // 构建目标URL
-  const targetURL = new URL(path, env.API_BASEURL);
+  // 处理 WebSocket 升级请求
+  if (request.headers.get('Upgrade') === 'websocket') {
+    const apiBaseUrl = new URL(env.API_BASEURL);
+    // 将 http/https 转换为 ws/wss
+    const wsBaseUrl = `${apiBaseUrl.protocol === 'https:' ? 'wss:' : 'ws:'}//${apiBaseUrl.host}`;
+    const targetURL = `${wsBaseUrl}${path}${url.search}`;
     
-  // 保留原始查询参数
-  targetURL.search = url.search;
-  
-  // 创建新的请求
-  const newRequest = new Request(targetURL, {
+    return fetch(new Request(targetURL, {
       method: request.method,
       headers: request.headers,
+      body: request.body
+    }));
+  }
+  
+  // 处理普通 HTTP 请求
+  const apiBaseUrl = new URL(env.API_BASEURL);
+  const targetURL = new URL(path, apiBaseUrl.origin);
+  targetURL.search = url.search;
+  
+  // 创建新的请求头，移除可能导致问题的头部
+  const newHeaders = new Headers(request.headers);
+  newHeaders.delete('host');
+  newHeaders.delete('cf-connecting-ip');
+  newHeaders.delete('cf-ipcountry');
+  
+  // 创建新的请求
+  const newRequest = new Request(targetURL.toString(), {
+    method: request.method,
+    headers: newHeaders,
     body: request.body,
   });
   
@@ -27,13 +46,29 @@ export async function onRequest(context) {
     // 转发请求到目标服务器
     const response = await fetch(newRequest);
     
-    // 创建新的响应对象，保留原始响应的状态和头部
-    return new Response(response.body, {
+    // 创建新的响应头，设置 CORS 和其他必要的头部
+    const newResponse = new Response(response.body, {
       status: response.status,
       statusText: response.statusText,
-      headers: response.headers,
     });
+    
+    // 复制所有响应头
+    for (const [key, value] of response.headers.entries()) {
+      newResponse.headers.set(key, value);
+    }
+    
+    // 设置 CORS 头
+    newResponse.headers.set('Access-Control-Allow-Origin', '*');
+    newResponse.headers.set('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
+    newResponse.headers.set('Access-Control-Allow-Headers', '*');
+    
+    return newResponse;
   } catch (error) {
-    return new Response(`Proxy error: ${error.message}`, { status: 500 });
+    return new Response(`Proxy error: ${error.message}`, { 
+      status: 500,
+      headers: {
+        'Access-Control-Allow-Origin': '*'
+      }
+    });
   }
 }