fix: cache the detector

Signed-off-by: Frost Ming <me@frostming.com>

xiaogpt/utils.py

@@ -5,11 +5,14 @@
 import re
 import socket
 from http.cookies import SimpleCookie
-from typing import AsyncIterator
+from typing import TYPE_CHECKING, AsyncIterator
 from urllib.parse import urlparse
 
 from requests.utils import cookiejar_from_dict
 
+if TYPE_CHECKING:
+    from lingua import LanguageDetector
+
 
 ### HELP FUNCTION ###
 def parse_cookie_string(cookie_string):
@@ -71,11 +74,19 @@ def get_hostname() -> str:
         return s.getsockname()[0]
 
 
-def detect_language(text: str) -> str:
+def _get_detector() -> LanguageDetector | None:
     try:
         from lingua import LanguageDetectorBuilder
     except ImportError:
+        return None
+    return LanguageDetectorBuilder.from_all_spoken_languages().build()
+
+
+_detector = _get_detector()
+
+
+def detect_language(text: str) -> str:
+    if _detector is None:
         return "zh"  # default to Chinese if langdetect module is not available
-    detector = LanguageDetectorBuilder.from_all_spoken_languages().build()
-    lang = detector.detect_language_of(text)
+    lang = _detector.detect_language_of(text)
     return lang.iso_code_639_1.name.lower() if lang is not None else "zh"