Currently filters check updates via the __call__ method. When switching from function-based filters to class-based filters, this was mainly done to maintain backwards compatibility with filter(update). However with some of the new filters functionalities, this leads to ugly workarounds like
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class _Text(MessageFilter): |
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name = 'Filters.text' |
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class _TextStrings(MessageFilter): |
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def __init__(self, strings: List[str]): |
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self.strings = strings |
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self.name = 'Filters.text({})'.format(strings) |
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def filter(self, message: Message) -> bool: |
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if message.text: |
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return message.text in self.strings |
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return False |
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def __call__( # type: ignore[override] |
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self, update: Union[Update, List[str]] |
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) -> Union[bool, '_TextStrings']: |
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if isinstance(update, Update): |
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return self.filter(update.effective_message) |
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return self._TextStrings(update) |
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def filter(self, message: Message) -> bool: |
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return bool(message.text) |
I therefore propose to refactor to something along the lines of
class BaseFilter:
def __call__(self, *args, **kwargs):
return self.__class__(*args, **kwargs)
@abstractmethod
def check_update(update/method):
...This matches the Handler.check_update interface and allows for filters having a custom __init__, wich can still be called through instances of those filters.
However, this is somewhat breaking: While BaseFilter.__call__ is undocumented, people might still have Filters.existing_filter(update) somewhere within their custom filters. So maybe this is better suited for a major release.
Currently filters check updates via the
__call__method. When switching from function-based filters to class-based filters, this was mainly done to maintain backwards compatibility withfilter(update). However with some of the new filters functionalities, this leads to ugly workarounds likepython-telegram-bot/telegram/ext/filters.py
Lines 329 to 350 in 8e7c0d6
I therefore propose to refactor to something along the lines of
This matches the
Handler.check_updateinterface and allows for filters having a custom__init__, wich can still be called through instances of those filters.However, this is somewhat breaking: While
BaseFilter.__call__is undocumented, people might still haveFilters.existing_filter(update)somewhere within their custom filters. So maybe this is better suited for a major release.