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