为多表继承Django模型填充tastypie资源

Populating a tastypie resource for a multi-table inheritance Django model

考虑到以下代码，我想知道如何用每个实际记录数据填充RecordsResource：

江户十一〔一〕号

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

class Record(models.Model):
content_type = models.ForeignKey(ContentType, editable=False, null=True)
user = models.ForeignKey(User, related_name='records')
issued = models.DateTimeField(auto_now_add=True)
date = models.DateField()

def save(self, *args, **kwargs):
if not self.content_type:
self.content_type = ContentType.objects.get_for_model(self.__class__)
super(Record, self).save(*args, **kwargs)

def as_leaf_class(self):
model = self.content_type.model_class()
if model == self.__class__:
return self
return model.objects.get(pk=self.id)

class Record1(Record):
# some fields

# ...

class RecordN(Record):
# some fields

埃多克斯1〔2〕

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

class BaseModelResource(ModelResource):
class Meta(object):
authentication = ApiKeyPlusWebAuthentication()
authorization= Authorization()
cache = SimpleCache()
throttle = CacheDBThrottle(
throttle_at=350,
# 1 day
expiration=86400
)
if settings.DEBUG:
serializer = PrettyJSONSerializer()

def obj_create(self, bundle, request=None, **kwargs):
return super(BaseModelResource, self).obj_create(bundle, request, user=request.user)

def apply_authorization_limits(self, request, object_list):
return object_list.filter(user=request.user)

class BaseRecordResource(BaseModelResource):
class Meta(BaseModelResource.Meta):
filtering = {
'date': ALL
}
excludes = ['issued']

class RecordsResource(BaseRecordResource):
class Meta(BaseRecordResource.Meta):
resource_name = 'records'
queryset = Record.objects.all()

class Record1Resource(BaseRecordResource):
class Meta(BaseRecordResource.Meta):
resource_name = 'record1'
queryset = Record1.objects.all()

# ...

class RecordNResource(BaseRecordResource):
class Meta(BaseRecordResource.Meta):
resource_name = 'recordn'
queryset = RecordN.objects.all()

号

好吧，我刚刚解决了。我简化了代码。

给出以下代码…

埃多克斯1〔9〕

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

from django.db import models
from model_utils.managers import InheritanceManager

class Place(models.Model):
name = models.CharField(max_length=50)
address = models.CharField(max_length=80)

# https://github.com/carljm/django-model-utils#inheritancemanager
objects = InheritanceManager()

class Restaurant(Place):
custom_field = models.BooleanField()

class Bar(Place):
custom_field = models.BooleanField()

埃多克斯1〔10〕

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

。

产量

江户十一〔11〕。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 1
},
"objects": [
{
"address":"dawdaw",
"custom_field": true,
"id":"1",
"name":"dwdwad",
"resource_uri":"/api/v1/bar/1/"
}
]
}

好啊

埃多克斯1〔12〕

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 1
},
"objects": [
{
"address":"nhnhnh",
"custom_field": true,
"id":"2",
"name":"nhnhnh",
"resource_uri":"/api/v1/restaurant/2/"
}
]
}

。

好啊

埃多克斯1〔13〕

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 2
},
"objects": [
{
"address":"dawdaw",
"id":"1",
"name":"dwdwad",
"resource_uri":"/api/v1/place/1/"
},
{
"address":"nhnhnh",
"id":"2",
"name":"nhnhnh",
"resource_uri":"/api/v1/place/2/"
}
]
}

。

我想达到的目标

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 2
},
"objects": [
{
"address":"dawdaw",
"custom_field": true,
"id":"1",
"name":"dwdwad",
"resource_uri":"/api/v1/bar/1/"
},
{
"address":"nhnhnh",
"custom_field": true,
"id":"2",
"name":"nhnhnh",
"resource_uri":"/api/v1/restaurant/2/"
}
]
}

解决方案：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35

from core.models import Place, Restaurant, Bar
# http://django-tastypie.readthedocs.org/en/latest/cookbook.html#pretty-printed-json-serialization
from core.utils import PrettyJSONSerializer
from tastypie.resources import ModelResource

class RestaurantResource(ModelResource):
class Meta:
queryset = Restaurant.objects.all()
resource_name = 'restaurant'
serializer = PrettyJSONSerializer()

class BarResource(ModelResource):
class Meta:
queryset = Bar.objects.all()
resource_name = 'bar'
serializer = PrettyJSONSerializer()

class PlaceResource(ModelResource):
class Meta:
queryset = Place.objects.select_subclasses()
resource_name = 'place'
serializer = PrettyJSONSerializer()

def dehydrate(self, bundle):
# bundle.data['custom_field'] ="Whatever you want"
if isinstance(bundle.obj, Restaurant):
restaurant_res = RestaurantResource()
rr_bundle = restaurant_res.build_bundle(obj=bundle.obj, request=bundle.request)
bundle.data = restaurant_res.full_dehydrate(rr_bundle).data
elif isinstance(bundle.obj, Bar):
bar_res = BarResource()
br_bundle = bar_res.build_bundle(obj=bundle.obj, request=bundle.request)
bundle.data = bar_res.full_dehydrate(br_bundle).data
return bundle

。

在recordsresource类中，还需要添加model字段(请参见https://github.com/tomcristie/django rest framework/blob/master/djangorestframework/resources.py l232-234)

1
2
3
4
5
6

class RecordsResource(BaseRecordResource):
model = Record

class Meta(BaseRecordResource.Meta):
resource_name = 'records'
queryset = Record.objects.all()

从一开始就解释：

Django有三种继承方式。

通常，您只需要使用父类来保存您不想为每个孩子输入的信息模型。这个类不会单独使用，所以抽象基类就是你想要的。

如果您正在对现有模型进行子类化(可能是完全是另一个应用程序)，并希望每个模型都有自己的数据库表，多表继承是前进的道路。

最后，如果只想修改模型，在不以任何方式更改模型字段的情况下，可以使用代理模型。

这里的选择是多表继承

多表继承Django支持的第二种类型的模型继承是，当层次结构中的每个模型都是一个单独的模型时。每个模型都对应于自己的数据库表，可以单独查询和创建。继承关系引入子模型与其每个父模型之间的链接(通过自动创建的OneTooneField)引用

从Record到Recordx，在1 <= x <= n的地方，你要做a_example_record = Record.objects,get(pk=3)，然后用下面的方法检查什么类型的Recordx。

1
2
3
4

if hasattr(a_example_record, 'record1'):
# ...
elif hasattr(a_example_record, 'record2'):
# ...

号

因此，既然我们知道了如何从父母那里得到孩子，并且我们需要向TastyPie提供元中的queryset，那么您需要在Record模型上编写一个由自定义管理器支持的自定义queryset，该模型会记录您的所有记录(更多信息，请参阅自定义查询集和管理器，而不必断开干系？)，检查它是什么类型的子级，并将其附加到查询集或列表。您可以阅读关于在这里追加如何在django视图中组合2个或多个查询集的内容？