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80 lines
2.4 KiB
80 lines
2.4 KiB
5 years ago
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"""
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Provide django-style hooks for model events.
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"""
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from peewee import Model as _Model
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class Signal(object):
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def __init__(self):
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self._flush()
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def _flush(self):
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self._receivers = set()
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self._receiver_list = []
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def connect(self, receiver, name=None, sender=None):
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name = name or receiver.__name__
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key = (name, sender)
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if key not in self._receivers:
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self._receivers.add(key)
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self._receiver_list.append((name, receiver, sender))
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else:
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raise ValueError('receiver named %s (for sender=%s) already '
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'connected' % (name, sender or 'any'))
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def disconnect(self, receiver=None, name=None, sender=None):
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if receiver:
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name = name or receiver.__name__
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if not name:
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raise ValueError('a receiver or a name must be provided')
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key = (name, sender)
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if key not in self._receivers:
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raise ValueError('receiver named %s for sender=%s not found.' %
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(name, sender or 'any'))
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self._receivers.remove(key)
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self._receiver_list = [(n, r, s) for n, r, s in self._receiver_list
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if n != name and s != sender]
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def __call__(self, name=None, sender=None):
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def decorator(fn):
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self.connect(fn, name, sender)
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return fn
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return decorator
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def send(self, instance, *args, **kwargs):
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sender = type(instance)
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responses = []
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for n, r, s in self._receiver_list:
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if s is None or isinstance(instance, s):
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responses.append((r, r(sender, instance, *args, **kwargs)))
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return responses
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pre_save = Signal()
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post_save = Signal()
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pre_delete = Signal()
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post_delete = Signal()
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pre_init = Signal()
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class Model(_Model):
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def __init__(self, *args, **kwargs):
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super(Model, self).__init__(*args, **kwargs)
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pre_init.send(self)
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def save(self, *args, **kwargs):
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pk_value = self._pk
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created = kwargs.get('force_insert', False) or not bool(pk_value)
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pre_save.send(self, created=created)
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ret = super(Model, self).save(*args, **kwargs)
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post_save.send(self, created=created)
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return ret
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def delete_instance(self, *args, **kwargs):
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pre_delete.send(self)
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ret = super(Model, self).delete_instance(*args, **kwargs)
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post_delete.send(self)
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return ret
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