refactor: optimize structure, stability and runtime performance

db/announcements.py

@@ -6,12 +6,38 @@ import db_pool
 from db.utils import get_cst_now_str
 
 
+def _normalize_limit(value, default: int, *, minimum: int = 1, maximum: int = 500) -> int:
+    try:
+        parsed = int(value)
+    except Exception:
+        parsed = default
+    parsed = max(minimum, parsed)
+    parsed = min(maximum, parsed)
+    return parsed
+
+
+def _normalize_offset(value, default: int = 0) -> int:
+    try:
+        parsed = int(value)
+    except Exception:
+        parsed = default
+    return max(0, parsed)
+
+
+def _normalize_announcement_payload(title, content, image_url):
+    normalized_title = str(title or "").strip()
+    normalized_content = str(content or "").strip()
+    normalized_image = str(image_url or "").strip() or None
+    return normalized_title, normalized_content, normalized_image
+
+
+def _deactivate_all_active_announcements(cursor, cst_time: str) -> None:
+    cursor.execute("UPDATE announcements SET is_active = 0, updated_at = ? WHERE is_active = 1", (cst_time,))
+
+
 def create_announcement(title, content, image_url=None, is_active=True):
     """创建公告（默认启用；启用时会自动停用其他公告）"""
-    title = (title or "").strip()
-    content = (content or "").strip()
-    image_url = (image_url or "").strip()
-    image_url = image_url or None
+    title, content, image_url = _normalize_announcement_payload(title, content, image_url)
     if not title or not content:
         return None
 
@@ -20,7 +46,7 @@ def create_announcement(title, content, image_url=None, is_active=True):
         cst_time = get_cst_now_str()
 
         if is_active:
-            cursor.execute("UPDATE announcements SET is_active = 0, updated_at = ? WHERE is_active = 1", (cst_time,))
+            _deactivate_all_active_announcements(cursor, cst_time)
 
         cursor.execute(
             """
@@ -44,6 +70,9 @@ def get_announcement_by_id(announcement_id):
 
 def get_announcements(limit=50, offset=0):
     """获取公告列表（管理员用）"""
+    safe_limit = _normalize_limit(limit, 50)
+    safe_offset = _normalize_offset(offset, 0)
+
     with db_pool.get_db() as conn:
         cursor = conn.cursor()
         cursor.execute(
@@ -52,7 +81,7 @@ def get_announcements(limit=50, offset=0):
             ORDER BY created_at DESC, id DESC
             LIMIT ? OFFSET ?
             """,
-            (limit, offset),
+            (safe_limit, safe_offset),
         )
         return [dict(row) for row in cursor.fetchall()]
 
@@ -64,7 +93,7 @@ def set_announcement_active(announcement_id, is_active):
         cst_time = get_cst_now_str()
 
         if is_active:
-            cursor.execute("UPDATE announcements SET is_active = 0, updated_at = ? WHERE is_active = 1", (cst_time,))
+            _deactivate_all_active_announcements(cursor, cst_time)
             cursor.execute(
                 """
                 UPDATE announcements
@@ -121,13 +150,12 @@ def dismiss_announcement_for_user(user_id, announcement_id):
     """用户永久关闭某条公告（幂等）"""
     with db_pool.get_db() as conn:
         cursor = conn.cursor()
-        cst_time = get_cst_now_str()
         cursor.execute(
             """
             INSERT OR IGNORE INTO announcement_dismissals (user_id, announcement_id, dismissed_at)
             VALUES (?, ?, ?)
             """,
-            (user_id, announcement_id, cst_time),
+            (user_id, announcement_id, get_cst_now_str()),
         )
         conn.commit()
         return cursor.rowcount >= 0