django - Django 中非常独立的数据库中的 "Foreign Keys"

Question

我正在编写一个使用两个不同数据库的 Django 网站。一个是本地数据库，我们称之为“Django”，它存储来自相当标准安装的所有标准表——身份验证、站点、评论等——以及一些额外的表。

大多数数据(包括用户)来自另一台服务器上的数据库，我们将其称为“旧版”数据库。

我正在寻找有关连接两个数据库的干净、Pythonic 方式的建议，尤其对于用户而言。

我正在使用代理模型，当我可以显式使用它时它效果很好，但是当我将用户对象作为相关对象访问时(例如，使用内置的 django 注释时)，我遇到了问题系统)。

代码如下:

models.py:(指向Django数据库)

from django.db import models
from django.conf import settings
from django.contrib.auth.models import User as AuthUser, UserManager as AuthUserManager, AnonymousUser as AuthAnonymousUser

class UserPerson(models.Model):
    user = models.OneToOneField(AuthUser, related_name="person")
    person_id = models.PositiveIntegerField(verbose_name='Legacy ID')

    def __unicode__(self):
        return "%s" % self.get_person()

    def get_person(self):
        if not hasattr(self, '_person'):
            from legacy_models import Person
            from utils import get_person_model
            Person = get_person_model() or Person
            self._person = Person.objects.get(pk=self.person_id)
        return self._person
    person=property(get_person)

class UserManager(AuthUserManager):
    def get_for_id(self, id):
        return self.get(person__person_id=id)

    def get_for_email(self, email):
        try:
            person = Person.objects.get(email=email)
            return self.get_for_id(person.pk)
        except Person.DoesNotExist:
            return User.DoesNotExist

    def create_user(self, username, email, password=None, *args, **kwargs):
        user = super(UserManager,self).create_user(username, email, password, *args, **kwargs)
        try:
            person_id = Person.objects.get(email=email).pk
            userperson, created = UserPerson.objects.get_or_create(user=user, person_id=person_id)
        except Person.DoesNotExist:
            pass
        return user

class AnonymousUser(AuthAnonymousUser):
    class Meta:
        proxy = True

class User(AuthUser):
    class Meta:
        proxy=True

    def get_profile(self):  
        """
        Returns the Person record from the legacy database
        """
        if not hasattr(self, '_profile_cache'):
            self._profile_cache = UserPerson.objects.get(user=self).person
        return self._profile_cache

    objects = UserManager()

legacy_models.py:(指向“Legacy”数据库)

class Person(models.Model):
    id = models.AutoField(primary_key=True, db_column='PeopleID') # Field name made lowercase.
    code = models.CharField(max_length=40, blank=True, db_column="person_code", unique=True)
    first_name = models.CharField(max_length=50, db_column='firstName', blank=True) # Field name made lowercase.
    last_name = models.CharField(max_length=50, db_column='lastName', blank=True) # Field name made lowercase.
    email = models.CharField(max_length=255, blank=True)

    def __unicode__(self):
        return "%s %s" % (self.first_name, self.last_name)

    def get_user(self):
        from models import User
        if not hasattr(self,'_user'):
            self._user = User.objects.get_for_id(self.pk)
        return self._user
    user = property(get_user)

    class Meta:
        db_table = u'People'

我还创建了自己的中间件，因此 request.user 也是代理 User 对象。

真正的问题是当我使用将用户作为相关对象的东西时，特别是在我控制权更少的模板中。

在模板中:

{{ request.user.get_profile }} 
{# this works and returns the related Person object for the user #}

{% for comment in comments %} {# retrieved using the built-in comments app %}
    {{ comment.user.get_profile }}
    {# this throws an error because AUTH_PROFILE_MODULE is not defined by design #}
{% endfor %}

除了创建使用我的代理用户模型的评论系统的包装版本之外，我还能做些什么吗？

Answer 1

这是我解决这个问题的方法。我完全停止使用用户代理。

models.py:

from django.db import models
from legacy_models import Person
from django.contrib.auth.models import User

class UserPerson(models.Model):
    user = models.OneToOneField(User, related_name="person")
    person_id = models.PositiveIntegerField(verbose_name='PeopleID', help_text='ID in the Legacy Login system.')

    def __unicode__(self):
        return "%s" % self.get_person()

    def get_person(self):
        if not hasattr(self, '_person'):
            self._person = Person.objects.get(pk=self.person_id)
        return self._person
    person=property(get_person)

class LegacyPersonQuerySet(models.query.QuerySet):
    def get(self, *args, **kwargs):
        person_id = UserPerson.objects.get(*args, **kwargs).person_id
        return LegacyPerson.objects.get(pk=person_id)

class LegacyPersonManager(models.Manager):
    def get_query_set(self, *args, **kwargs):
        return LegacyPersonQuerySet(*args, **kwargs)

class LegacyPerson(Person):
    objects = LegacyPersonManager()

    class Meta:
        proxy=True

和legacy_models.py:

class Person(models.Model):
    id = models.AutoField(primary_key=True, db_column='PeopleID') # Field name made lowercase.
    code = models.CharField(max_length=40, blank=True, db_column="person_code", unique=True)
    first_name = models.CharField(max_length=50, db_column='firstName', blank=True) # Field name made lowercase.
    last_name = models.CharField(max_length=50, db_column='lastName', blank=True) # Field name made lowercase.
    email = models.CharField(max_length=255, blank=True)

    def __unicode__(self):
        return "%s %s" % (self.first_name, self.last_name)

    def get_user(self):
        from models import User
        if not hasattr(self,'_user'):
            self._user = User.objects.get_for_id(self.pk)
        return self._user
    def set_user(self, user=None):
        self._user=user
    user = property(get_user, set_user)

    class Meta:
        db_table = u'People'

最后，在settings.py中:

AUTH_PROFILE_MODULE = 'myauth.LegacyPerson'

这是一个更简单的解决方案，但至少它有效!这确实意味着每当我想要旧记录时，我都必须调用 user_profile，这意味着每个用户记录都有一个额外的查询，但这是一个公平的权衡，因为实际上它不是我很可能会经常进行交叉检查。