feat: add Express API server with chat endpoint and static proxy

api/server.js

@@ -0,0 +1,101 @@
+// api/server.js
+const express = require('express');
+const { createProxyMiddleware } = require('http-proxy-middleware');
+const { search } = require('./search/indexer');
+const { streamChat } = require('./llm/deepseek');
+
+const API_PORT = parseInt(process.env.API_PORT || '3000', 10);
+const SERVE_PORT = parseInt(process.env.SERVE_PORT || '3001', 10);
+const MAX_HISTORY = 10;
+
+const SYSTEM_PROMPT = `你是 GitLink 帮助中心的 AI 助手。请基于提供的文档内容回答用户的问题。
+
+要求：
+1. 回答要简洁明了，直接回答用户的问题
+2. 如果提供的文档中没有相关内容，请诚实说明
+3. 回答时引用具体的操作步骤和页面位置`;
+
+function buildMessages(query, history, searchResults) {
+  const messages = [{ role: 'system', content: SYSTEM_PROMPT }];
+
+  if (searchResults.length > 0) {
+    const context = searchResults.map((doc, i) =>
+      `[文档${i + 1}] 标题: ${doc.title}\n路径: ${doc.breadcrumb}\nURL: ${doc.url}\n内容:\n${doc.text}`
+    ).join('\n\n---\n\n');
+    messages.push({
+      role: 'system',
+      content: `以下是相关的帮助中心文档内容:\n\n${context}`,
+    });
+  }
+
+  const recentHistory = history.slice(-MAX_HISTORY);
+  for (const msg of recentHistory) {
+    messages.push({ role: msg.role, content: msg.content });
+  }
+
+  messages.push({ role: 'user', content: query });
+
+  return messages;
+}
+
+const app = express();
+app.use(express.json());
+
+// Health check
+app.get('/api/health', (req, res) => {
+  res.json({ status: 'ok' });
+});
+
+// Chat endpoint (SSE streaming)
+app.post('/api/chat', async (req, res) => {
+  const { message, history = [] } = req.body;
+
+  if (!message || typeof message !== 'string') {
+    return res.status(400).json({ error: 'message is required' });
+  }
+
+  let searchResults = [];
+  try {
+    searchResults = search(message, 3);
+  } catch (err) {
+    console.error('Search error:', err.message);
+  }
+
+  res.setHeader('Content-Type', 'text/event-stream');
+  res.setHeader('Cache-Control', 'no-cache');
+  res.setHeader('Connection', 'keep-alive');
+  res.setHeader('X-Accel-Buffering', 'no');
+
+  if (searchResults.length > 0) {
+    const links = searchResults.map(doc => ({
+      title: doc.title,
+      path: encodeURI(doc.url),
+      breadcrumb: doc.breadcrumb,
+    }));
+    res.write(`data: ${JSON.stringify({ type: 'sources', links })}\n\n`);
+  }
+
+  try {
+    const messages = buildMessages(message, history, searchResults);
+    for await (const chunk of streamChat(messages)) {
+      res.write(`data: ${JSON.stringify({ type: 'content', text: chunk })}\n\n`);
+    }
+    res.write(`data: ${JSON.stringify({ type: 'done' })}\n\n`);
+  } catch (err) {
+    console.error('LLM error:', err.message);
+    res.write(`data: ${JSON.stringify({ type: 'error', message: 'AI 服务暂时不可用，请稍后重试' })}\n\n`);
+  }
+
+  res.end();
+});
+
+// Proxy all other requests to Docusaurus serve
+app.use('/', createProxyMiddleware({
+  target: `http://localhost:${SERVE_PORT}`,
+  changeOrigin: true,
+  ws: true,
+}));
+
+app.listen(API_PORT, () => {
+  console.log(`API server listening on port ${API_PORT}, proxying to Docusaurus on port ${SERVE_PORT}`);
+});

package.json

@@ -11,7 +11,9 @@
     "clear": "docusaurus clear",
     "serve": "docusaurus serve",
     "write-translations": "docusaurus write-translations",
-    "write-heading-ids": "docusaurus write-heading-ids"
+    "write-heading-ids": "docusaurus write-heading-ids",
+    "build:api": "node scripts/generate-doc-index.js",
+    "serve:api": "node api/server.js"
   },
   "dependencies": {
     "@docusaurus/core": "3.9.2",
@@ -21,6 +23,9 @@
     "@node-rs/jieba": "^1.7.0",
     "clsx": "1.2.1",
     "docusaurus-plugin-image-zoom": "1.0.1",
+    "express": "^5.2.1",
+    "http-proxy-middleware": "^4.0.0",
+    "pm2": "^7.0.1",
     "prism-react-renderer": "^1.3.5",
     "prismjs": "^1.30.0",
     "react": "18.2.0",