對于管理系統(tǒng)，常常需要展示列表數據，我們對于列表內的數據常常需要查找、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)數據的查找、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)，作為資產管理系統(tǒng)常常需要對數據進行過濾或查找，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）:
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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', 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:
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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：
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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。
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from rest_framework import routersrouter = 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據，例如對于物理服務器，我們需要指定品牌、指定cpu核數、指定內存大小等。有時候我們需要按照cpu核數進行排序。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：
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pip install django-filter |
在配置文件settings/base.py中添加應用django_filters：
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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：
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from django_filters.rest_framework import djangofilterbackendfrom rest_framework import filtersfrom django_filters import rest_framework |
serverviewset可以添加相應的過濾條件：
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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：
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import django_filtersfrom .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:
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get /assets/v1/servers/?server_name=&brand=&cpus=24&ram=&disk=http 200 okallow: get, post, head, optionscontent-type: application/jsonvary: 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：
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http 200 okallow: get, post, head, optionscontent-type: application/jsonvary: 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數據源支持）
‘$' 正則匹配
對應的search_fileds示例如下：
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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）：
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ordering = ('-created_time', ) |
也可以使用如下方式指定：
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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：
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http 200 okallow: get, post, head, optionscontent-type: application/jsonvary: 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服務器之家。
原文鏈接：https://blog.csdn.net/linux_player_c/article/details/80779059
