微信小程序页面迁移校验之前 P5任务处理之前

apps/backend/app/ai/conversation_service.py

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+"""
+对话记录持久化服务。
+
+负责 biz.ai_conversations 和 biz.ai_messages 两张表的 CRUD。
+所有 8 个 AI 应用的每次调用都通过本服务记录对话和消息。
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+from datetime import datetime
+
+from app.database import get_connection
+
+logger = logging.getLogger(__name__)
+
+
+class ConversationService:
+    """AI 对话记录持久化服务。"""
+
+    def create_conversation(
+        self,
+        user_id: int | str,
+        nickname: str,
+        app_id: str,
+        site_id: int,
+        source_page: str | None = None,
+        source_context: dict | None = None,
+    ) -> int:
+        """创建对话记录，返回 conversation_id。
+
+        系统自动调用时 user_id 为 'system'。
+        """
+        conn = get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute(
+                    """
+                    INSERT INTO biz.ai_conversations
+                        (user_id, nickname, app_id, site_id, source_page, source_context)
+                    VALUES (%s, %s, %s, %s, %s, %s)
+                    RETURNING id
+                    """,
+                    (
+                        str(user_id),
+                        nickname,
+                        app_id,
+                        site_id,
+                        source_page,
+                        json.dumps(source_context, ensure_ascii=False) if source_context else None,
+                    ),
+                )
+                row = cur.fetchone()
+                conn.commit()
+                return row[0]
+        except Exception:
+            conn.rollback()
+            raise
+        finally:
+            conn.close()
+
+    def add_message(
+        self,
+        conversation_id: int,
+        role: str,
+        content: str,
+        tokens_used: int | None = None,
+    ) -> int:
+        """添加消息记录，返回 message_id。"""
+        conn = get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute(
+                    """
+                    INSERT INTO biz.ai_messages
+                        (conversation_id, role, content, tokens_used)
+                    VALUES (%s, %s, %s, %s)
+                    RETURNING id
+                    """,
+                    (conversation_id, role, content, tokens_used),
+                )
+                row = cur.fetchone()
+                conn.commit()
+                return row[0]
+        except Exception:
+            conn.rollback()
+            raise
+        finally:
+            conn.close()
+
+    def get_conversations(
+        self,
+        user_id: int | str,
+        site_id: int,
+        page: int = 1,
+        page_size: int = 20,
+    ) -> list[dict]:
+        """查询用户历史对话列表，按 created_at 降序，分页。"""
+        offset = (page - 1) * page_size
+        conn = get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute(
+                    """
+                    SELECT id, user_id, nickname, app_id, site_id,
+                           source_page, source_context, created_at
+                    FROM biz.ai_conversations
+                    WHERE user_id = %s AND site_id = %s
+                    ORDER BY created_at DESC
+                    LIMIT %s OFFSET %s
+                    """,
+                    (str(user_id), site_id, page_size, offset),
+                )
+                columns = [desc[0] for desc in cur.description]
+                rows = cur.fetchall()
+                return [
+                    _row_to_dict(columns, row)
+                    for row in rows
+                ]
+        finally:
+            conn.close()
+
+    def get_messages(
+        self,
+        conversation_id: int,
+    ) -> list[dict]:
+        """查询对话的所有消息，按 created_at 升序。"""
+        conn = get_connection()
+        try:
+            with conn.cursor() as cur:
+                cur.execute(
+                    """
+                    SELECT id, conversation_id, role, content,
+                           tokens_used, created_at
+                    FROM biz.ai_messages
+                    WHERE conversation_id = %s
+                    ORDER BY created_at ASC
+                    """,
+                    (conversation_id,),
+                )
+                columns = [desc[0] for desc in cur.description]
+                rows = cur.fetchall()
+                return [
+                    _row_to_dict(columns, row)
+                    for row in rows
+                ]
+        finally:
+            conn.close()
+
+
+def _row_to_dict(columns: list[str], row: tuple) -> dict:
+    """将数据库行转换为 dict，处理特殊类型序列化。"""
+    result = {}
+    for col, val in zip(columns, row):
+        if isinstance(val, datetime):
+            result[col] = val.isoformat()
+        else:
+            result[col] = val
+    return result