mirror of
https://github.com/jazzband/django-eav2.git
synced 2026-03-17 06:50:24 +00:00
92 lines
2.8 KiB
Python
92 lines
2.8 KiB
Python
from django.db.models.signals import post_init, pre_save
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from .managers import EntityManager
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from .models import EavEntity, EavAttribute
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class EavConfig(object):
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@classmethod
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def get_eav_attributes(cls):
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"""
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By default, all attributes apply to an entity,
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unless otherwise specified.
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"""
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return EavAttribute.objects.all()
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class EavRegistry(object):
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"""
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Tools to add eav features to models
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"""
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field_cache = {}
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@staticmethod
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def attach(sender, *args, **kwargs):
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"""
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Attache EAV toolkit to an instance after init.
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"""
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instance = kwargs['instance']
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cls = instance.__class__
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proxy_name = EavRegistry.field_cache[cls.__name__]['proxy']
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setattr(instance, proxy_name, EavEntity(instance))
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@staticmethod
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def register(model_cls, admin_cls=EavConfig, eav_proxy_field='eav',
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eav_manager_field='objects'):
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"""
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Inject eav features into the given model and attach a signal
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listener to it for setup.
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"""
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if model_cls.__name__ in EavRegistry.field_cache:
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return
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post_init.connect(EavRegistry.attach, sender=model_cls)
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pre_save.connect(EavEntity.pre_save_handler, sender=model_cls)
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EavRegistry.field_cache[model_cls.__name__] = {
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'proxy': eav_proxy_field,
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'mgr': eav_manager_field}
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if hasattr(model_cls, eav_manager_field):
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mgr = getattr(model_cls, eav_manager_field)
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EavRegistry.field_cache[model_cls.__name__]['old_mgr'] = mgr
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setattr(model_cls, eav_proxy_field, EavEntity)
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setattr(getattr(model_cls, eav_proxy_field),
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'get_eav_attributes', admin_cls.get_eav_attributes)
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mgr = EntityManager()
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mgr.contribute_to_class(model_cls, eav_manager_field)
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@staticmethod
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def unregister(model_cls):
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"""
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Inject eav features into the given model and attach a signal
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listener to it for setup.
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"""
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if not model_cls.__name__ in EavRegistry.field_cache:
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return
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cache = EavRegistry.field_cache[model_cls.__name__]
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post_init.disconnect(EavRegistry.attach, sender=model_cls)
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pre_save.disconnect(EavEntity.pre_save_handler, sender=model_cls)
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proxy_name = cache['proxy']
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mgr_name = cache['mgr']
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try:
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delattr(model_cls, mgr_name)
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except AttributeError:
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pass
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if 'old_mgr' in cache:
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cache['old_mgr'].contribute_to_class(model_cls, mgr_name)
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try:
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delattr(model_cls, proxy_name)
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except AttributeError:
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pass
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EavRegistry.field_cache.pop(model_cls.__name__)
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