feat:增加存储用户对话记录

services/db_service.py

@@ -0,0 +1,54 @@
+import sqlite3
+import os
+
+
+def init_db():
+    conn = sqlite3.connect(os.getenv("SQLITE_DB_PATH"))
+
+    # 业务表：会话
+    conn.execute("""
+    CREATE TABLE IF NOT EXISTS session (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        thread_id TEXT NOT NULL UNIQUE,
+        username TEXT NOT NULL,
+        title TEXT NOT NULL,
+        created_time DATETIME DEFAULT CURRENT_TIMESTAMP
+    );
+    """)
+
+    conn.commit()
+    conn.close()
+
+
+def exists_session(thread_id: str, username: str) -> bool:
+    conn = sqlite3.connect(os.getenv("SQLITE_DB_PATH"))
+    cursor = conn.cursor()
+
+    cursor.execute(
+        """
+        SELECT 1
+        FROM session
+        WHERE thread_id = ? AND username = ?
+        LIMIT 1
+        """,
+        (thread_id, username)
+    )
+
+    result = cursor.fetchone()
+    conn.close()
+
+    return result is not None
+
+
+def save_session(thread_id: str, username: str, title: str):
+    conn = sqlite3.connect(os.getenv("SQLITE_DB_PATH"))
+    conn.execute(
+        """
+        INSERT OR REPLACE INTO session
+        (thread_id, username, title)
+        VALUES (?, ?, ?)
+        """,
+        (thread_id, username, title)
+    )
+    conn.commit()
+    conn.close()