fix: resolve learning assistant response hanging

Author: FenjuFu

api/chat.js

@@ -1,3 +1,28 @@
+const API_URL = 'https://maas-coding-api.cn-huabei-1.xf-yun.com/v2/chat/completions'
+const REQUEST_TIMEOUT = 55000
+
+async function pipeStream(response, res) {
+  res.status(200)
+  res.setHeader('Content-Type', 'text/event-stream; charset=utf-8')
+  res.setHeader('Cache-Control', 'no-cache, no-transform')
+  res.setHeader('Connection', 'keep-alive')
+  res.flushHeaders?.()
+
+  const reader = response.body.getReader()
+
+  while (true) {
+    const { value, done } = await reader.read()
+
+    if (done) {
+      break
+    }
+
+    res.write(Buffer.from(value))
+  }
+
+  res.end()
+}
+
 module.exports = async function handler(req, res) {
   const ALLOWED_ORIGINS = new Set([
     'https://iflytek.github.io',
@@ -8,42 +33,66 @@ module.exports = async function handler(req, res) {
 
   const requestOrigin = req.headers.origin;
 
-  // Allow localhost, the main site, and any vercel preview deployments
   if (requestOrigin && (ALLOWED_ORIGINS.has(requestOrigin) || requestOrigin.endsWith('.vercel.app'))) {
-    res.setHeader('Access-Control-Allow-Origin', requestOrigin);
-    res.setHeader('Vary', 'Origin');
+    res.setHeader('Access-Control-Allow-Origin', requestOrigin)
+    res.setHeader('Vary', 'Origin')
   }
 
-  res.setHeader('Access-Control-Allow-Methods', 'GET,POST,OPTIONS');
-  res.setHeader('Access-Control-Allow-Headers', 'Content-Type,Authorization');
+  res.setHeader('Access-Control-Allow-Methods', 'GET,POST,OPTIONS')
+  res.setHeader('Access-Control-Allow-Headers', 'Content-Type,Authorization')
 
   if (req.method === 'OPTIONS') {
-    return res.status(204).end();
+    return res.status(204).end()
   }
 
   if (req.method !== 'POST') {
-    return res.status(405).json({ error: 'Method Not Allowed' });
+    return res.status(405).json({ error: 'Method Not Allowed' })
   }
 
+  const controller = new AbortController()
+  const timeoutId = setTimeout(() => controller.abort(), REQUEST_TIMEOUT)
+  const requestBody = req.body && typeof req.body === 'object' ? req.body : {}
+
   try {
-    const response = await fetch('https://maas-coding-api.cn-huabei-1.xf-yun.com/v2/chat/completions', {
+    const response = await fetch(API_URL, {
       method: 'POST',
       headers: {
         'Content-Type': 'application/json',
         'Authorization': `Bearer ${process.env.VITE_API_KEY}`
       },
-      body: JSON.stringify({ ...req.body, stream: false })
-    });
+      body: JSON.stringify(requestBody),
+      signal: controller.signal
+    })
 
     if (!response.ok) {
-      const errorText = await response.text();
-      return res.status(response.status).send(`API Error: ${response.status} ${errorText}`);
+      const errorText = await response.text()
+      return res.status(response.status).send(`API Error: ${response.status} ${errorText}`)
     }
 
-    const data = await response.json();
-    return res.status(200).json(data);
+    if (requestBody.stream && response.body) {
+      await pipeStream(response, res)
+      return
+    }
+
+    const data = await response.json()
+    return res.status(200).json(data)
   } catch (error) {
-    console.error('Proxy Error:', error);
-    return res.status(500).json({ error: 'Internal Server Error', details: error.message });
+    console.error('Proxy Error:', error)
+
+    if (res.headersSent) {
+      if (!res.writableEnded) {
+        res.write(`data: ${JSON.stringify({ error: error.message })}\n\n`)
+        res.end()
+      }
+      return
+    }
+
+    if (controller.signal.aborted) {
+      return res.status(504).json({ error: 'Gateway Timeout', details: 'Upstream request timed out' })
+    }
+
+    return res.status(500).json({ error: 'Internal Server Error', details: error.message })
+  } finally {
+    clearTimeout(timeoutId)
   }
 }