django rest framework 數(shù)據(jù)的查找、過濾、排序的示例
對于管理系統(tǒng),常常需要展示列表數(shù)據(jù),我們對于列表內的數(shù)據(jù)常常需要查找、過濾、排序等操作,其中查找等操作大部分是在后臺進行的。django rest framework可以輕松的實現(xiàn)數(shù)據(jù)的查找、過濾等操作。接下來我們將以實際的例子進行介紹。
示例代碼github地址: https://github.com/jinjidejuren/drf_learn
例如cmdb系統(tǒng),作為資產(chǎn)管理系統(tǒng)常常需要對數(shù)據(jù)進行過濾或查找,獲取期望的信息。
實現(xiàn)model
1.在這個示例項目中,需要實現(xiàn)對物理服務器的條件過濾,物理服務器的model列表如下(apps/assets/models.py文件):
class Server(models.Model): """ 物理服務器 """ status_choice = ( ('online', '上線'), ('offline', '下線'), ('normal', '正常'), ('abnormal', '異常') ) server_name = models.CharField(verbose_name=u'服務器名稱', max_length=128, blank=False, null=False) server_num = models.CharField(verbose_name=u'服務器編號', 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'型號', max_length=64, blank=True, null=True) cpus = models.IntegerField(verbose_name=u'cpu核數(shù)', default=0) ram = models.IntegerField(verbose_name=u'內存大小', default=0) disk = models.IntegerField(verbose_name=u'磁盤大小', default=0) product_date = models.DateTimeField(verbose_name=u'生產(chǎn)日期', auto_now_add=True) status = models.CharField(verbose_name=u'狀態(tài)', max_length=16, choices=status_choice) created_time = models.DateTimeField(verbose_name=u'創(chuàng)建時間', auto_now_add=True) modified_time = models.DateTimeField(verbose_name=u'修改時間', auto_now_add=True) class Meta: verbose_name = u'服務器' verbose_name_plural = verbose_name def __str__(self): return self.server_name
實現(xiàn)serializer
接下來需要實現(xiàn)server這個model的序列化類,在apps/assets/serializers.py中編寫:
class ServiceSerializer(serializers.ModelSerializer): """ 服務器序列化 """ class Meta: model = Server fields = ('id', 'server_name', 'server_num', 'brand', 'model', 'cpus', 'ram', 'disk', 'product_date', 'status', 'created_time', 'modified_time')
對于fields來說,可以使用 _ all _ 來代表所有的字段,除了model中定義的field外,序列化還可以指定其他的信息,比如嵌套信息或者自定義的信息。具體可以取決于業(yè)務邏輯。
實現(xiàn)modelviewset
對于modelviewset,我們可以圍繞它對用戶請求做相應的處理。常見的是對model進行增加、刪除、查找、修改等。在這部分我們需要實現(xiàn)ServerViewSet:
class ServerViewSet(viewsets.ModelViewSet): """ 物理服務器視圖 """ 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,并且按照創(chuàng)建時間逆序排列,這樣可以把最新的信息先返回,比較符合用戶的操作習慣。
serializer_class定義了返回的序列化格式為ServerSerializer所指定的fields內容
pagination_class 指定了分頁的類型,這個MyFormatResultsSetPagination是我們的自定義類型
實現(xiàn)router
如果用戶想要訪問server的信息,需要指定server的路由,這個和之前介紹的類似。需要的嗯一個一個router對象,并且將server的路由注冊進去。
from rest_framework import routers router = routers.DefaultRouter() router.register(r'servers', views.ServerViewSet, base_name='servers') urlpatterns = [ url(r'^', include(router.urls)) ]
對于servers的訪問都由ServerViewSet進行處理。
嘗試訪問
http://127.0.0.1:8060/assets/v1/servers/ ,信息如下:
注:我們需要添加示例信息,作為后續(xù)的各種測試使用。
按照條件獲取
在日常操作中,我們需要獲取指定條件的數(shù)據(jù),例如對于物理服務器,我們需要指定品牌、指定cpu核數(shù)、指定內存大小等。有時候我們需要按照cpu核數(shù)進行排序。這些都需要我們對ServerViewSet進行更多的拓展。
如果進行條件過濾,需要首先安裝django-filter模塊:
pip install django-filter
在配置文件settings/base.py中添加應用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頂部包含如下包:
from django_filters.rest_framework import DjangoFilterBackend from rest_framework import filters from django_filters import rest_framework
ServerViewSet可以添加相應的過濾條件:
class ServerViewSet(viewsets.ModelViewSet): """ 物理服務器視圖 """ 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', )
這里的filter_backends指定了過濾的類型,此處設定了DjangoFilterBackend(過濾)、SearchFilter(搜索)和OrderingFIlter(排序)。
1.過濾
過濾設定了過濾的配置類為ServerFilter,關于ServerFilter在apps/assets/filters.py文件中進行了定義:
import django_filters from .models import * class ServerFilter(django_filters.rest_framework.FilterSet): """ 物理服務器過濾器 """ 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', ]
也就是說可以通過'server_name', ‘brand', ‘cpus', ‘ram', ‘disk'對物理服務器的信息進行過濾,得到相應的序列化列表。
例如獲取cpu為24核的物理服務器:
得到物理服務器列表中cpu都為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 關鍵字需要查詢的信息,例如搜索名稱為‘test'開頭的服務器:
http://127.0.0.1:8060/assets/v1/servers/?search=test
獲取列表:
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中可以指定多種查找方式:
‘^name' 以name開頭
‘=name' 精確匹配
‘@' 全局檢索(只有mysql數(shù)據(jù)源支持)
‘$' 正則匹配
對應的search_fileds示例如下:
search_fields = ('^server_name', '=brand', 'status', )
3.排序
在ordering字段指定了默認排序方式(按照創(chuàng)建時間逆序排序):
ordering = ('-created_time', )
也可以使用如下方式指定:
queryset = Server.objects.all().order_by('-created_time')
如果要自定義排序字段,需要指定 ordering 字段的內容:
例如按照內存大小排列服務器:
http://127.0.0.1:8060/assets/v1/servers/?ordering=ram
獲取的信息列表如下:
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、過濾等操作可以組合使用,一般為前端的列表搜索查詢提供接口支持。
小結
本章小結的內容介紹了django rest framework如何進行model的定義、序列化、增刪改查以及搜索、排序等功能,是書寫后端接口必須掌握的技巧。
以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支持腳本之家。