refac

backend/open_webui/internal/db.py

@@ -323,25 +323,41 @@ elif 'sqlite' in SQLALCHEMY_DATABASE_URL:
     def _apply_sqlite_pragmas(dbapi_connection):
         """Apply all configured SQLite PRAGMAs to a raw DBAPI connection."""
         # SQLite LIKE folds ASCII only; SQLAlchemy SQLite ILIKE compiles to lower(x) LIKE lower(?).
+        compiled_patterns = {}
+
         def like(pattern, value, escape=None):
             if pattern is None or value is None:
                 return None
 
-            regex = []
-            escaped = False
+            pattern = str(pattern).lower()
             escape = str(escape).lower() if escape is not None else None
-            for char in str(pattern).lower():
-                if escape and not escaped and char == escape:
-                    escaped = True
-                    continue
-                regex.append(
-                    '.*' if not escaped and char == '%' else '.' if not escaped and char == '_' else re.escape(char)
-                )
-                escaped = False
-            if escaped:
+            key = (pattern, escape)
+            compiled = compiled_patterns.get(key)
+            if compiled is False:
                 return False
+            if compiled is None:
+                regex = []
+                escaped = False
+                for char in pattern:
+                    if escape and not escaped and char == escape:
+                        escaped = True
+                        continue
+                    regex.append(
+                        '.*' if not escaped and char == '%' else '.' if not escaped and char == '_' else re.escape(char)
+                    )
+                    escaped = False
+                if escaped:
+                    compiled = False
+                    if len(compiled_patterns) >= 512:
+                        compiled_patterns.clear()
+                    compiled_patterns[key] = compiled
+                    return False
+                compiled = re.compile(''.join(regex), re.DOTALL)
+                if len(compiled_patterns) >= 512:
+                    compiled_patterns.clear()
+                compiled_patterns[key] = compiled
 
-            return re.fullmatch(''.join(regex), str(value).lower(), re.DOTALL) is not None
+            return compiled.fullmatch(str(value).lower()) is not None
 
         dbapi_connection.create_function('like', 2, like, deterministic=True)
         dbapi_connection.create_function('like', 3, like, deterministic=True)