devscripts/lazy_load_template.py

   1 import importlib
   2 import random
   3 import re
   4
   5 from ..utils import (
   6     age_restricted,
   7     bug_reports_message,
   8     classproperty,
   9     write_string,
  10 )
  11
  12 # These bloat the lazy_extractors, so allow them to passthrough silently
  13 ALLOWED_CLASSMETHODS = {'extract_from_webpage', 'get_testcases', 'get_webpage_testcases'}
  14 _WARNED = False
  15
  16
  17 class LazyLoadMetaClass(type):
  18     def __getattr__(cls, name):
  19         global _WARNED
  20         if ('_real_class' not in cls.__dict__
  21                 and name not in ALLOWED_CLASSMETHODS and not _WARNED):
  22             _WARNED = True
  23             write_string('WARNING: Falling back to normal extractor since lazy extractor '
  24                          f'{cls.__name__} does not have attribute {name}{bug_reports_message()}\n')
  25         return getattr(cls.real_class, name)
  26
  27
  28 class LazyLoadExtractor(metaclass=LazyLoadMetaClass):
  29     @classproperty
  30     def real_class(cls):
  31         if '_real_class' not in cls.__dict__:
  32             cls._real_class = getattr(importlib.import_module(cls._module), cls.__name__)
  33         return cls._real_class
  34
  35     def __new__(cls, *args, **kwargs):
  36         instance = cls.real_class.__new__(cls.real_class)
  37         instance.__init__(*args, **kwargs)
  38         return instance