Persist chat history locally

.gitignore

@@ -2,3 +2,4 @@
 __pycache__/
 *.pyc
 .env
+data/*.json

README.md

@@ -1,6 +1,6 @@
 # llm_web
 
-Local LLM chat web page powered by Ollama.
+Local LLM chat web page powered by Ollama and `qwen2.5:7b`.
 
 ## Run
 
@@ -15,3 +15,11 @@ Open:
 ```text
 http://127.0.0.1:8787
 ```
+
+LAN access uses the notebook IP:
+
+```text
+http://<notebook-ip>:8787
+```
+
+Chat history is stored locally in `data/chats.json`. The `data/*.json` files are ignored by Git.

app.js

@@ -3,7 +3,10 @@ const promptInput = document.querySelector("#prompt");
 const messagesEl = document.querySelector("#messages");
 const sendButton = document.querySelector("#sendButton");
 const newChatButton = document.querySelector("#newChat");
+const historyEl = document.querySelector("#history");
+const chatTitleEl = document.querySelector("#chatTitle");
 
+let activeChatId = null;
 let messages = [];
 
 function addMessage(role, content) {
@@ -24,10 +27,53 @@ function addMessage(role, content) {
   return bubble;
 }
 
-function resetChat() {
-  messages = [];
+function renderMessages() {
   messagesEl.innerHTML = "";
-  addMessage("assistant", "새 대화를 시작합니다.");
+
+  if (!messages.length) {
+    addMessage("assistant", "안녕하세요. 이 노트북에서 실행되는 로컬 LLM입니다.");
+    return;
+  }
+
+  messages.forEach((message) => addMessage(message.role, message.content));
+}
+
+function setTitle(title) {
+  chatTitleEl.textContent = title || "Local LLM";
+}
+
+async function loadHistory() {
+  const response = await fetch("/api/chats");
+  const data = await response.json();
+  historyEl.innerHTML = "";
+
+  data.chats.forEach((chat) => {
+    const item = document.createElement("button");
+    item.className = `history-item ${chat.id === activeChatId ? "active" : ""}`;
+    item.type = "button";
+    item.textContent = chat.title;
+    item.addEventListener("click", () => loadChat(chat.id));
+    historyEl.append(item);
+  });
+}
+
+async function loadChat(chatId) {
+  const response = await fetch(`/api/chats/${chatId}`);
+  const data = await response.json();
+  activeChatId = data.chat.id;
+  messages = data.chat.messages || [];
+  setTitle(data.chat.title);
+  renderMessages();
+  await loadHistory();
+  promptInput.focus();
+}
+
+function resetChat() {
+  activeChatId = null;
+  messages = [];
+  setTitle("Local LLM");
+  renderMessages();
+  loadHistory();
   promptInput.focus();
 }
 
@@ -65,7 +111,7 @@ form.addEventListener("submit", async (event) => {
     const response = await fetch("/api/chat", {
       method: "POST",
       headers: { "Content-Type": "application/json" },
-      body: JSON.stringify({ messages }),
+      body: JSON.stringify({ chatId: activeChatId, messages }),
     });
 
     const data = await response.json();
@@ -74,7 +120,10 @@ form.addEventListener("submit", async (event) => {
     }
 
     pending.textContent = data.reply;
-    messages.push({ role: "assistant", content: data.reply });
+    activeChatId = data.chatId;
+    messages = data.chat.messages || [...messages, { role: "assistant", content: data.reply }];
+    setTitle(data.chat.title);
+    await loadHistory();
   } catch (error) {
     pending.textContent = `오류: ${error.message}`;
   } finally {
@@ -82,3 +131,6 @@ form.addEventListener("submit", async (event) => {
     promptInput.focus();
   }
 });
+
+renderMessages();
+loadHistory();

index.html

@@ -9,26 +9,19 @@
   <body>
     <aside class="sidebar">
       <button class="new-chat" id="newChat" type="button">+ 새 대화</button>
-      <div class="history">
-        <button class="history-item active" type="button">로컬 LLM</button>
-      </div>
+      <div class="history" id="history"></div>
       <div class="model">qwen2.5:7b</div>
     </aside>
 
     <main class="chat-shell">
       <header class="topbar">
         <div>
-          <strong>Local LLM</strong>
+          <strong id="chatTitle">Local LLM</strong>
           <span>Ollama on this notebook</span>
         </div>
       </header>
 
-      <section class="messages" id="messages" aria-live="polite">
-        <article class="message assistant">
-          <div class="avatar">L</div>
-          <div class="bubble">안녕하세요. 이 노트북에서 실행되는 로컬 LLM입니다.</div>
-        </article>
-      </section>
+      <section class="messages" id="messages" aria-live="polite"></section>
 
       <form class="composer" id="chatForm">
         <textarea id="prompt" rows="1" placeholder="메시지를 입력하세요" autofocus></textarea>

server.py

@@ -2,6 +2,8 @@ from __future__ import annotations
 
 import json
 import socket
+import uuid
+from datetime import datetime, timezone
 from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
 from pathlib import Path
 
@@ -9,15 +11,71 @@ import ollama
 
 
 ROOT = Path(__file__).parent
+DATA_DIR = ROOT / "data"
+CHATS_FILE = DATA_DIR / "chats.json"
 MODEL = "qwen2.5:7b"
 HOST = "0.0.0.0"
 PORT = 8787
 
 
+def now_iso() -> str:
+    return datetime.now(timezone.utc).isoformat()
+
+
+def read_store() -> dict:
+    if not CHATS_FILE.exists():
+        return {"chats": []}
+
+    try:
+        return json.loads(CHATS_FILE.read_text(encoding="utf-8"))
+    except json.JSONDecodeError:
+        return {"chats": []}
+
+
+def write_store(store: dict) -> None:
+    DATA_DIR.mkdir(exist_ok=True)
+    CHATS_FILE.write_text(json.dumps(store, ensure_ascii=False, indent=2), encoding="utf-8")
+
+
+def chat_title(messages: list[dict]) -> str:
+    for message in messages:
+        if message.get("role") == "user" and message.get("content"):
+            title = " ".join(str(message["content"]).split())
+            return title[:40] or "새 대화"
+    return "새 대화"
+
+
 class Handler(SimpleHTTPRequestHandler):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, directory=str(ROOT), **kwargs)
 
+    def do_GET(self) -> None:
+        if self.path == "/api/chats":
+            store = read_store()
+            chats = [
+                {
+                    "id": chat["id"],
+                    "title": chat.get("title", "새 대화"),
+                    "updatedAt": chat.get("updatedAt", ""),
+                }
+                for chat in store.get("chats", [])
+            ]
+            self._send_json(200, {"chats": chats})
+            return
+
+        if self.path.startswith("/api/chats/"):
+            chat_id = self.path.rsplit("/", 1)[-1]
+            store = read_store()
+            chat = next((item for item in store.get("chats", []) if item["id"] == chat_id), None)
+            if not chat:
+                self._send_json(404, {"error": "Chat not found"})
+                return
+
+            self._send_json(200, {"chat": chat})
+            return
+
+        super().do_GET()
+
     def do_POST(self) -> None:
         if self.path != "/api/chat":
             self.send_error(404)
@@ -25,6 +83,7 @@ class Handler(SimpleHTTPRequestHandler):
 
         length = int(self.headers.get("content-length", 0))
         data = json.loads(self.rfile.read(length) or b"{}")
+        chat_id = data.get("chatId")
         messages = data.get("messages", [])
 
         try:
@@ -38,11 +97,46 @@ class Handler(SimpleHTTPRequestHandler):
                     *messages,
                 ],
             )
-            payload = {"reply": response["message"]["content"]}
+            reply = response["message"]["content"]
+            saved_messages = [*messages, {"role": "assistant", "content": reply}]
+            chat = self._save_chat(chat_id, saved_messages)
+            payload = {"chatId": chat["id"], "reply": reply, "chat": chat}
             self._send_json(200, payload)
         except Exception as exc:
             self._send_json(500, {"error": str(exc)})
 
+    def do_DELETE(self) -> None:
+        if not self.path.startswith("/api/chats/"):
+            self.send_error(404)
+            return
+
+        chat_id = self.path.rsplit("/", 1)[-1]
+        store = read_store()
+        store["chats"] = [item for item in store.get("chats", []) if item["id"] != chat_id]
+        write_store(store)
+        self._send_json(200, {"ok": True})
+
+    def _save_chat(self, chat_id: str | None, messages: list[dict]) -> dict:
+        store = read_store()
+        chats = store.setdefault("chats", [])
+        chat = next((item for item in chats if item["id"] == chat_id), None)
+
+        if not chat:
+            chat = {
+                "id": str(uuid.uuid4()),
+                "createdAt": now_iso(),
+                "title": chat_title(messages),
+                "messages": [],
+            }
+            chats.insert(0, chat)
+
+        chat["title"] = chat_title(messages)
+        chat["messages"] = messages
+        chat["updatedAt"] = now_iso()
+        chats.sort(key=lambda item: item.get("updatedAt", ""), reverse=True)
+        write_store(store)
+        return chat
+
     def _send_json(self, status: int, payload: dict[str, str]) -> None:
         body = json.dumps(payload, ensure_ascii=False).encode("utf-8")
         self.send_response(status)