实现SSE心跳机制和非阻塞响应结束

src/routes/geminiRoutes.js

@@ -924,7 +924,7 @@ async function handleStreamGenerateContent(req, res) {
     res.setHeader('X-Accel-Buffering', 'no')
 
     // 处理流式响应并捕获usage数据
-    // 方案 A++：透明转发 + 异步 usage 提取
+    // 方案 A++：透明转发 + 异步 usage 提取 + SSE 心跳机制
     let streamBuffer = '' // 缓冲区用于处理不完整的行
     let totalUsage = {
       promptTokenCount: 0,
@@ -933,8 +933,26 @@ async function handleStreamGenerateContent(req, res) {
     }
     let usageReported = false // 修复：改为 let 以便后续修改
 
+    // SSE 心跳机制：防止 Clash 等代理 120 秒超时
+    let heartbeatTimer = null
+    let lastDataTime = Date.now()
+    const HEARTBEAT_INTERVAL = 15000 // 15 秒
+
+    const sendHeartbeat = () => {
+      const timeSinceLastData = Date.now() - lastDataTime
+      if (timeSinceLastData >= HEARTBEAT_INTERVAL && !res.destroyed) {
+        res.write('\n') // 发送空行保持连接活跃
+        logger.info(`💓 Sent SSE keepalive (gap: ${(timeSinceLastData / 1000).toFixed(1)}s)`)
+      }
+    }
+
+    heartbeatTimer = setInterval(sendHeartbeat, HEARTBEAT_INTERVAL)
+
     streamResponse.on('data', (chunk) => {
       try {
+        // 更新最后数据时间
+        lastDataTime = Date.now()
+
         // 1️⃣ 立即转发原始数据（零延迟，最高优先级）
         // 对所有版本（v1beta 和 v1internal）都采用透明转发
         if (!res.destroyed) {
@@ -973,13 +991,13 @@ async function handleStreamGenerateContent(req, res) {
                   logger.debug('📊 Captured Gemini usage data:', totalUsage)
                 }
               } catch (parseError) {
-                // 静默失败，不影响转发
-                logger.debug('Failed to parse usage line:', parseError.message)
+                // 解析失败但不影响转发
+                logger.warn('⚠️ Failed to parse usage line:', parseError.message)
               }
             }
           } catch (error) {
-            // 静默失败，不影响转发
-            logger.debug('Error extracting usage data:', error.message)
+            // 提取失败但不影响转发
+            logger.warn('⚠️ Error extracting usage data:', error.message)
           }
         })
       } catch (error) {
@@ -988,13 +1006,22 @@ async function handleStreamGenerateContent(req, res) {
       }
     })
 
-    streamResponse.on('end', async () => {
+    streamResponse.on('end', () => {
       logger.info('Stream completed successfully')
 
-      // 记录使用统计
+      // 清理心跳定时器
+      if (heartbeatTimer) {
+        clearInterval(heartbeatTimer)
+        heartbeatTimer = null
+      }
+
+      // 立即结束响应，不阻塞
+      res.end()
+
+      // 异步记录使用统计（不阻塞响应）
       if (!usageReported && totalUsage.totalTokenCount > 0) {
-        try {
-          await apiKeyService.recordUsage(
+        Promise.all([
+          apiKeyService.recordUsage(
             req.apiKey.id,
             totalUsage.promptTokenCount || 0,
             totalUsage.candidatesTokenCount || 0,
@@ -1002,12 +1029,8 @@ async function handleStreamGenerateContent(req, res) {
             0, // cacheReadTokens
             model,
             account.id
-          )
-          logger.info(
-            `📊 Recorded Gemini stream usage - Input: ${totalUsage.promptTokenCount}, Output: ${totalUsage.candidatesTokenCount}, Total: ${totalUsage.totalTokenCount}`
-          )
-
-          await applyRateLimitTracking(
+          ),
+          applyRateLimitTracking(
             req,
             {
               inputTokens: totalUsage.promptTokenCount || 0,
@@ -1018,19 +1041,28 @@ async function handleStreamGenerateContent(req, res) {
             model,
             'gemini-stream'
           )
-
-          // 修复：标记 usage 已上报，避免重复上报
-          usageReported = true
-        } catch (error) {
-          logger.error('Failed to record Gemini usage:', error)
-        }
+        ])
+          .then(() => {
+            logger.info(
+              `📊 Recorded Gemini stream usage - Input: ${totalUsage.promptTokenCount}, Output: ${totalUsage.candidatesTokenCount}, Total: ${totalUsage.totalTokenCount}`
+            )
+            usageReported = true
+          })
+          .catch((error) => {
+            logger.error('Failed to record Gemini usage:', error)
+          })
       }
-
-      res.end()
     })
 
     streamResponse.on('error', (error) => {
       logger.error('Stream error:', error)
+
+      // 清理心跳定时器
+      if (heartbeatTimer) {
+        clearInterval(heartbeatTimer)
+        heartbeatTimer = null
+      }
+
       if (!res.headersSent) {
         // 如果还没发送响应头，可以返回正常的错误响应
         res.status(500).json({