django_dynproxy
===============
Dynamic proxy models for Django
With django_dynproxy, you can dynamically modify a Django proxy model by :
* hiding one or many fields (from the concrete parent model)
* making mandatory one or many fields (who are not mandatory in the concrete parent model)
This can be useful when you want to use inheritance in your code, but not in your database
WARNING : THIS IS AN ALPHA RELEASE. NOT RECOMMENDED FOR PRODUCTION USE
Requirements :
--------------
django>=1.4.3
Installation :
--------------
pip install django_dynproxy
Usage :
---------
1) Create a concrete model
2) Create a Django proxy model deriving from the concrete model
3) Define a metaclass using dynproxy_metaclass_factory and specify :
- which base fields you want to exclude from your proxy model
- which non-mandatory base fields you want to be mandatory your proxy model
4) Add the __metaclass__ to your proxy model class
Sample :
---------
from dynproxy.utils import dynproxy_metaclass_factory
TRAVELER_TYPE_PILOT = '1'
TRAVELER_TYPE_PASSENGER = '2'
TRAVELER_TYPES = (
(TRAVELER_TYPE_PILOT,_(u"Pilot")),
(TRAVELER_TYPE_PASSENGER,_(u"Passenger"))
)
class Traveler(models.Model):
first_name = models.CharField(max_length=200)
last_name = models.CharField(max_length=200)
type = models.CharField(max_length=200,choices=TRAVELER_TYPES)
passport_number = models.CharField(max_length=200,blank=True)
trigram = models.CharField(max_length=200,blank=True)
pilot_category = models.ForeignKey(PilotCategory,null=True,blank=True)
def __unicode__(self):
return "%s %s" % (self.first_name,self.last_name)
def traveler_manager_factory(traveler_type):
class _TravelerManager(Manager):
def get_query_set(self):
return super(_TravelerManager,self).get_query_set().filter(type=traveler_type)
return _TravelerManager
PilotManager = traveler_manager_factory(TRAVELER_TYPE_PILOT)
PassengerManager = traveler_manager_factory(TRAVELER_TYPE_PASSENGER)
PilotMetaclass = dynproxy_metaclass_factory(
mandatory_fields=['trigram','pilot_category'],
fields_to_exclude=['passport_number']
)
PassengerMetaclass = dynproxy_metaclass_factory(
mandatory_fields = ['passport_number'],
fields_to_exclude =['trigram','pilot_category']
)
class Pilot(Traveler):
__metaclass__ = PilotMetaclass
objects = PilotManager()
class Meta:
proxy = True
class Passenger(Traveler):
__metaclass__ = PassengerMetaclass
objects = PassengerManager()
class Meta:
proxy = True