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对于管理系统，常常需要展示列表数据，我们对于列表内的数据常常需要查找、过滤、排序等操作，其中查找等操作大部分是在后台进行的。django rest framework可以轻松的实现数据的查找、过滤等操作。接下来我们将以实际的例子进行介绍。
示例代码github地址：
例如cmdb系统，作为资产管理系统常常需要对数据进行过滤或查找，获取期望的信息。
实现model
1.在这个示例项目中，需要实现对物理服务器的条件过滤，物理服务器的model列表如下（apps/assets/models.py文件）:
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class server(models.model):
"""
物理服务器
"""
status_choice = (
('online', '上线'),
('offline', '下线'),
('normal', '正常'),
('abnormal', '异常')
)
server_name = models.charfield(verbose_name=u'服务器名称', max_length=128, blank=false, null=false)
server_num = models.charfield(verbose_name=u'服务器编号', max_length=128, blank=true, null=true)
brand = models.charfield(verbose_name=u'品牌', max_length=64, blank=true, null=true)
model = models.charfield(verbose_name=u'型号', max_length=64, blank=true, null=true)
cpus = models.integerfield(verbose_name=u'cpu核数', default=0)
ram = models.integerfield(verbose_name=u'内存大小', default=0)
disk = models.integerfield(verbose_name=u'磁盘大小', default=0)
product_date = models.datetimefield(verbose_name=u'生产日期', auto_now_add=true)
status = models.charfield(verbose_name=u'状态', max_length=16, choices=status_choice)
created_time = models.datetimefield(verbose_name=u'创建时间', auto_now_add=true)
modified_time = models.datetimefield(verbose_name=u'修改时间', auto_now_add=true)
class meta:
verbose_name = u'服务器'
verbose_name_plural = verbose_name
def __str__(self):
return self.server_name
实现serializer
接下来需要实现server这个model的序列化类，在apps/assets/serializers.py中编写:
class serviceserializer(serializers.modelserializer):
"""
服务器序列化
"""
class meta:
model = server
fields = ('id', 'server_name', 'server_num', 'brand', 'model', 'cpus',
'ram', 'disk', 'product_date', 'status', 'created_time',
'modified_time')
对于fields来说，可以使用 _ all _ 来代表所有的字段，除了model中定义的field外，序列化还可以指定其他的信息，比如嵌套信息或者自定义的信息。具体可以取决于业务逻辑。
实现modelviewset
对于modelviewset，我们可以围绕它对用户请求做相应的处理。常见的是对model进行增加、删除、查找、修改等。在这部分我们需要实现serverviewset：
class serverviewset(viewsets.modelviewset):
"""
物理服务器视图
"""
queryset = server.objects.all().order_by('-created_time')
serializer_class = serverserializer
pagination_class = myformatresultssetpagination
queryset指定返回列表的形式，所有的信息都返回，并且按照创建时间逆序排列，这样可以把最新的信息先返回，比较符合用户的操作习惯。
serializer_class定义了返回的序列化格式为serverserializer所指定的fields内容
pagination_class 指定了分页的类型，这个myformatresultssetpagination是我们的自定义类型
实现router
如果用户想要访问server的信息，需要指定server的路由，这个和之前介绍的类似。需要的嗯一个一个router对象，并且将server的路由注册进去。
from rest_framework import routers router = routers.defaultrouter() router.register(r'servers', views.serverviewset, base_name='servers') urlpatterns = [ url(r'^', include(router.urls)) ]
对于servers的访问都由serverviewset进行处理。
尝试访问
http://127.0.0.1:8060/assets/v1/servers/ ，信息如下：
注：我们需要添加示例信息，作为后续的各种测试使用。
按照条件获取
在日常操作中，我们需要获取指定条件的数据，例如对于物理服务器，我们需要指定品牌、指定cpu核数、指定内存大小等。有时候我们需要按照cpu核数进行排序。这些都需要我们对serverviewset进行更多的拓展。
如果进行条件过滤，需要首先安装django-filter模块：
pip install django-filter
在配置文件settings/base.py中添加应用django_filters：
installed_apps = [ # 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'rest_framework', 'django_filters', 'apps.assets', 'apps.rbac' ]
在apps/assets/views.py顶部包含如下包：
from django_filters.rest_framework import djangofilterbackend from rest_framework import filters from django_filters import rest_framework
serverviewset可以添加相应的过滤条件：
class serverviewset(viewsets.modelviewset):
"""
物理服务器视图
"""
queryset = server.objects.all()
serializer_class = serverserializer
pagination_class = myformatresultssetpagination
filter_backends = (rest_framework.djangofilterbackend, filters.searchfilter, filters.orderingfilter, )
filter_class = serverfilter
search_fields = ('server_name', '=brand', 'status', )
ordering_fields = ('cpus', 'ram', 'disk', 'product_date', )
ordering = ('-created_time', )
这里的filter_backends指定了过滤的类型，此处设定了djangofilterbackend（过滤）、searchfilter（搜索）和orderingfilter（排序）。
1.过滤
过滤设定了过滤的配置类为serverfilter，关于serverfilter在apps/assets/filters.py文件中进行了定义：
import django_filters
from .models import *
class serverfilter(django_filters.rest_framework.filterset):
"""
物理服务器过滤器
"""
server_name = django_filters.charfilter(name='server_name', lookup_expr='icontains')
brand = django_filters.charfilter(name='brand', lookup_expr='icontains')
cpus = django_filters.numberfilter(name='cpus')
ram = django_filters.numberfilter(name='ram')
disk = django_filters.numberfilter(name='disk')
class meta:
model = server
fields = ['server_name', 'brand', 'cpus', 'ram', 'disk', ]
也就是说可以通过'server_name', ‘brand', ‘cpus', ‘ram', ‘disk'对物理服务器的信息进行过滤，得到相应的序列化列表。
例如获取cpu为24核的物理服务器：
得到物理服务器列表中cpu都为24:
get /assets/v1/servers/?server_name=&brand=&cpus=24&ram=&disk=
http 200 ok
allow: get, post, head, options
content-type: application/json
vary: accept
{
"results": [
{
"id": 9,
"server_name": "data-server2",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 2500,
"product_date": "2018-06-23t13:51:09.641473z",
"status": "online",
"created_time": "2018-06-23t13:51:09.642583z",
"modified_time": "2018-06-23t13:51:09.642764z"
},
{
"id": 8,
"server_name": "data-server2",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 5000,
"product_date": "2018-06-23t13:51:02.466031z",
"status": "online",
"created_time": "2018-06-23t13:51:02.467274z",
"modified_time": "2018-06-23t13:51:02.467471z"
},
{
"id": 7,
"server_name": "data-server1",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 5000,
"product_date": "2018-06-23t13:50:55.622403z",
"status": "offline",
"created_time": "2018-06-23t13:50:55.623315z",
"modified_time": "2018-06-23t13:50:55.623431z"
},
{
"id": 6,
"server_name": "data-server",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 5000,
"product_date": "2018-06-23t13:50:48.088028z",
"status": "online",
"created_time": "2018-06-23t13:50:48.089433z",
"modified_time": "2018-06-23t13:50:48.089703z"
},
{
"id": 5,
"server_name": "harbor-server3",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:49:27.590015z",
"status": "offline",
"created_time": "2018-06-23t13:49:27.590980z",
"modified_time": "2018-06-23t13:49:27.591097z"
},
{
"id": 4,
"server_name": "harbor-server3",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:49:23.783337z",
"status": "abnormal",
"created_time": "2018-06-23t13:49:23.784243z",
"modified_time": "2018-06-23t13:49:23.784500z"
},
{
"id": 3,
"server_name": "harbor-server2",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:49:16.348672z",
"status": "online",
"created_time": "2018-06-23t13:49:16.349555z",
"modified_time": "2018-06-23t13:49:16.349663z"
},
{
"id": 2,
"server_name": "harbor-server1",
"server_num": "server-02-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:48:57.853354z",
"status": "online",
"created_time": "2018-06-23t13:48:57.853990z",
"modified_time": "2018-06-23t13:48:57.854098z"
},
{
"id": 1,
"server_name": "harbor-server",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:48:48.777153z",
"status": "online",
"created_time": "2018-06-23t13:48:48.778048z",
"modified_time": "2018-06-23t13:48:48.778166z"
}
],
"pagination": 9,
"page_size": 10,
"page": 1
}
2.搜索
搜索需要指定 search 关键字需要查询的信息，例如搜索名称为‘test'开头的服务器：
http://127.0.0.1:8060/assets/v1/servers/?search=test
获取列表：
http 200 ok
allow: get, post, head, options
content-type: application/json
vary: accept
{
"results": [
{
"id": 14,
"server_name": "test-server1",
"server_num": "server-01-shanghai",
"brand": "dell",
"model": "modular",
"cpus": 32,
"ram": 256,
"disk": 500,
"product_date": "2018-06-23t13:52:40.583743z",
"status": "offline",
"created_time": "2018-06-23t13:52:40.584409z",
"modified_time": "2018-06-23t13:52:40.584512z"
},
{
"id": 13,
"server_name": "test-server",
"server_num": "server-01-shanghai",
"brand": "dell",
"model": "modular",
"cpus": 32,
"ram": 256,
"disk": 2500,
"product_date": "2018-06-23t13:52:24.760819z",
"status": "normal",
"created_time": "2018-06-23t13:52:24.761475z",
"modified_time": "2018-06-23t13:52:24.761578z"
}
],
"pagination": 2,
"page_size": 10,
"page": 1
}
在search_fields中可以指定多种查找方式：
‘^name' 以name开头
‘=name' 精确匹配
全局检索（只有mysql数据源支持）
‘$' 正则匹配
对应的search_fileds示例如下：
search_fields = ('^server_name', '=brand', 'status', )
3.排序
在ordering字段指定了默认排序方式（按照创建时间逆序排序）：
ordering = ('-created_time', )
也可以使用如下方式指定：
queryset = server.objects.all().order_by('-created_time')
如果要自定义排序字段，需要指定 ordering 字段的内容：
例如按照内存大小排列服务器：
http://127.0.0.1:8060/assets/v1/servers/?ordering=ram
获取的信息列表如下：
http 200 ok
allow: get, post, head, options
content-type: application/json
vary: accept
{
"results": [
{
"id": 6,
"server_name": "data-server",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 5000,
"product_date": "2018-06-23t13:50:48.088028z",
"status": "online",
"created_time": "2018-06-23t13:50:48.089433z",
"modified_time": "2018-06-23t13:50:48.089703z"
},
{
"id": 7,
"server_name": "data-server1",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 5000,
"product_date": "2018-06-23t13:50:55.622403z",
"status": "offline",
"created_time": "2018-06-23t13:50:55.623315z",
"modified_time": "2018-06-23t13:50:55.623431z"
},
{
"id": 8,
"server_name": "data-server2",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 5000,
"product_date": "2018-06-23t13:51:02.466031z",
"status": "online",
"created_time": "2018-06-23t13:51:02.467274z",
"modified_time": "2018-06-23t13:51:02.467471z"
},
{
"id": 9,
"server_name": "data-server2",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 24,
"ram": 64,
"disk": 2500,
"product_date": "2018-06-23t13:51:09.641473z",
"status": "online",
"created_time": "2018-06-23t13:51:09.642583z",
"modified_time": "2018-06-23t13:51:09.642764z"
},
{
"id": 1,
"server_name": "harbor-server",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:48:48.777153z",
"status": "online",
"created_time": "2018-06-23t13:48:48.778048z",
"modified_time": "2018-06-23t13:48:48.778166z"
},
{
"id": 2,
"server_name": "harbor-server1",
"server_num": "server-02-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:48:57.853354z",
"status": "online",
"created_time": "2018-06-23t13:48:57.853990z",
"modified_time": "2018-06-23t13:48:57.854098z"
},
{
"id": 3,
"server_name": "harbor-server2",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:49:16.348672z",
"status": "online",
"created_time": "2018-06-23t13:49:16.349555z",
"modified_time": "2018-06-23t13:49:16.349663z"
},
{
"id": 4,
"server_name": "harbor-server3",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:49:23.783337z",
"status": "abnormal",
"created_time": "2018-06-23t13:49:23.784243z",
"modified_time": "2018-06-23t13:49:23.784500z"
},
{
"id": 5,
"server_name": "harbor-server3",
"server_num": "server-01-beijing",
"brand": "dell",
"model": "rack",
"cpus": 24,
"ram": 128,
"disk": 5000,
"product_date": "2018-06-23t13:49:27.590015z",
"status": "offline",
"created_time": "2018-06-23t13:49:27.590980z",
"modified_time": "2018-06-23t13:49:27.591097z"
},
{
"id": 10,
"server_name": "data-server2",
"server_num": "server-01-shanghai",
"brand": "hp",
"model": "hpe apollo 4200 gen9",
"cpus": 32,
"ram": 256,
"disk": 2500,
"product_date": "2018-06-23t13:51:30.706187z",
"status": "online",
"created_time": "2018-06-23t13:51:30.707754z",
"modified_time": "2018-06-23t13:51:30.707878z"
}
],
"pagination": 14,
"page_size": 10,
"page": 1
}
上述的排序、过滤等操作可以组合使用，一般为前端的列表搜索查询提供接口支持。
小结
本章小结的内容介绍了django rest framework如何进行model的定义、序列化、增删改查以及搜索、排序等功能，是书写后端接口必须掌握的技巧。
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