Usually users' profiles are stored in single model. When there are multiple user types, separation is made by some field like user_type.
Situation is a little more complicated when different data is needed for each user type.
Of course it's better when all users have same type and are granted different permissions. But since we got task to have separate user types - we'll have to solve it.
Simple solution
The most obvious solution is to make base profile with type identifier, which will pull needed model instance:
request.user.get_profile().get_final_profile()But I don't really like this solution. Firstly, get_final_profile method is basically a big switch-case. Secondly - we must not forget to call extra method.
I wanted to simply write request.user.profile ans get needed profile instance. This is possible by combining two known tricks - Upcast and AutoOneToOneField.
Upcast
Allows to get sublass instance from base class instance.
AutoOneToOneField
Allows creating related objects on request. This field is not needed per se, only idea. Taking AutoOneToOneField as a base, it's easy to create a new one that calls upcast when related objects is requested.
Solution
class UpCastModel(models.Model):
"""
Base class for models that are ment to be inherited.
Introduces upcast method that returns child instance.
"""
final_type = models.ForeignKey(ContentType, editable=False)
def save(self, args, **kwargs):
if not self.pk:
self.final_type = ContentType.objects.get_for_model(type(self))
super(UpCastModel, self).save(args, **kwargs)
def upcast(self):
if not hasattr(self, '_upcast'):
if self.final_type.model_class == self.class:
self._upcast = self
else:
self._upcast = self.final_type.get_object_for_this_type(id=self.pk)
return self._upcast
class Meta:
abstract = True
class UpCastSingleRelatedObjectDescriptor(SingleRelatedObjectDescriptor):
def get(self, instance, instance_type=None):
parent = super(
UpCastSingleRelatedObjectDescriptor, self
).get(instance, instance_type)
return parent.upcast()
class UpCastOneToOneField(models.OneToOneField):
"""
UpCastOneToOneField gets child of related object.
"""
def contribute_to_related_class(self, cls, related):
setattr(
cls, related.get_accessor_name(),
UpCastSingleRelatedObjectDescriptor(related)
)
Now profile looks like this:
class BaseProfile(UpcastModel):
user = UpCastOneToOneField(User)
class BoyProfile(BaseProfile):
pass
class GirlProfile(CitizenProfile):
passIn order to get users, profile, we just need to write requst.user.profile.
Subscribe for the news and updates
One of our ongoing projects, Neptyne, introduces an Excel-like grid written in React. We used a library to apply virtual scroll to it, but we stumbled upon a problem with fixed rows and columns inside the grid. Here I would like to describe this problem, how it occurs, and how we handled it.
We have reviewed the top web frameworks for server and client-side development and compared their pros and cons. Find out which one can be a great fit for your next project.
For any project there may be a need to use a database full-text search. We expect high speed and relevant results from this search. When we face such problem, we usually think about Solr, ElasticSearch, Sphinx, AWS CloudSearch, etc. But in this article we will talk about PostgreSQL. Starting from version 8.3, a full-text search support in PostgreSQL is available. Let's look at how it is implemented in the DBMS itself.
I've created this small sprite to create css sprites. It glues images from directory directory into single file and generates corresponding css.
In VIM there is a command for char search: f. After first use it can be repeated with ;. I like to navigate in line with it. You see that you need to go to bracket in a middle of a line - you press f( and one-two ; and you are there. There's no such command in Emacs, so I had to write my own. I've managed even to implement repetition with ;.
Everybody knows about permalink, but it's usually used only in get_absolute_url. I prefer to use it for all related model urls.class Event(models.Model):# ...@models.permalinkdef edit_url(self):return ('event_edit', (self.pk, ))And then in template:<a href="{{ event.edit_url }}">Редактировать событие</a>