更新历史记录消息（获得更加准确的历史消息，后面考虑将 conv.history 移除）

web/src/components/ChatComponent.vue

@@ -271,7 +271,7 @@ const meta = reactive(JSON.parse(localStorage.getItem('meta')) || {
   selectedKB: null,
   stream: true,
   summary_title: false,
-  history_round: 5,
+  history_round: 20,
   db_id: null,
   fontSize: 'default',
   wideScreen: false,
@@ -303,6 +303,24 @@ const renderMarkdown = (msg) => {
   }
 }
 
+// 从 message 中获取 history 信息，每个消息都是 {role, content} 的格式
+const getHistory = () => {
+  const history = conv.value.messages.map((msg) => {
+    if (msg.text) {
+      return {
+        role: msg.role === 'sent' ? 'user' : 'assistant',
+        content: msg.text
+      }
+    }
+  }).reduce((acc, cur) => {
+    if (cur) {
+      acc.push(cur)
+    }
+    return acc
+  }, [])
+  return history.slice(-meta.history_round)
+}
+
 const useDatabase = (index) => {
   const selected = opts.databases[index]
   console.log(selected)
@@ -494,14 +512,17 @@ const fetchChatResponse = (user_input, cur_res_id) => {
   const controller = new AbortController();
   const signal = controller.signal;
 
+  const params = {
+    query: user_input,
+    history: getHistory(),
+    meta: meta,
+    cur_res_id: cur_res_id,
+  }
+  console.log(params)
+
   fetch('/api/chat/', {
     method: 'POST',
-    body: JSON.stringify({
-      query: user_input,
-      history: conv.value.history,
-      meta: meta,
-      cur_res_id: cur_res_id,
-    }),
+    body: JSON.stringify(params),
     headers: {
       'Content-Type': 'application/json'
     },