快用Django REST framework写写API吧

Django默认是前后端绑定的,提供了Template和Form,现在流行前后端分离项目,Python大佬坐不住了,于是便有了Django REST framework:https://github.com/tomchristie

快用Django REST framework写写API吧

官网:https://www.django-rest-framework.org/

快用Django REST framework写写API吧

Django REST framework(简称DRF)是个Python技术栈的后端框架,用来构建RESTful API。

RESTful API

REST,是指REpresentational State Transfer,有个精辟的解释什么是RESTful:

  • 看URL就知道要什么
  • 看Method就知道干什么
  • 看Status Code就知道结果如何

良好的RESTful API设计的基本原则是:

  • 返回JSON
  • 严禁乱用状态码
  • 处理好分页
  • 返回具体的实体数据而不是返回通用的JSON数据
  • 请求对象有默认值

创建项目

接下来我们使用DRF创建一个简单的API,允许管理员查看和编辑用户和组。

先创建名为tutorial的project和名为quickstart的app:

# 创建项目目录
mkdir tutorial
cd tutorial

# 创建Python虚拟环境
python -m venv env
# 激活虚拟环境
env\Scripts\activate.bat  
# Mac中使用`source env/bin/activate`

# 在虚拟环境中安装Django和Django REST framework
pip install django
pip install djangorestframework

# 创建project,注意最后有个“.”,表示在当前目录创建
django-admin startproject tutorial .
cd tutorial
# 创建app
django-admin startapp quickstart
cd ..

创建好的目录结构如下:

$ pwd
<some path>/tutorial
$ find .
.
./manage.py
./tutorial
./tutorial/__init__.py
./tutorial/quickstart
./tutorial/quickstart/__init__.py
./tutorial/quickstart/admin.py
./tutorial/quickstart/apps.py
./tutorial/quickstart/migrations
./tutorial/quickstart/migrations/__init__.py
./tutorial/quickstart/models.py
./tutorial/quickstart/tests.py
./tutorial/quickstart/views.py
./tutorial/settings.py
./tutorial/urls.py
./tutorial/wsgi.py

一般不会把app放到project里面,这里是为了避免命名冲突。

接着同步数据库:

python manage.py migrate

然后创建一个超级管理员,密码password123

python manage.py createsuperuser --email admin@example.com --username admin

Serializers

序列化是指把数据库模型转换为JSON。新建模块tutorial/quickstart/serializers.py

from django.contrib.auth.models import User, Group
from rest_framework import serializers


class UserSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = User
        fields = ['url', 'username', 'email', 'groups']


class GroupSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Group
        fields = ['url', 'name']

Views

视图用来接受Web请求并且返回Web响应。打开tutorial/quickstart/views.py,添加代码:

from django.contrib.auth.models import User, Group
from rest_framework import viewsets
from rest_framework import permissions
from tutorial.quickstart.serializers import UserSerializer, GroupSerializer


class UserViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows users to be viewed or edited.
    """
    queryset = User.objects.all().order_by('-date_joined')
    serializer_class = UserSerializer
    permission_classes = [permissions.IsAuthenticated]


class GroupViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows groups to be viewed or edited.
    """
    queryset = Group.objects.all()
    serializer_class = GroupSerializer
    permission_classes = [permissions.IsAuthenticated]

URLs

配置路由,打开tutorial/urls.py,添加代码:

from django.urls import include, path
from rest_framework import routers
from tutorial.quickstart import views

router = routers.DefaultRouter()
router.register(r'users', views.UserViewSet)
router.register(r'groups', views.GroupViewSet)

# Wire up our API using automatic URL routing.
# Additionally, we include login URLs for the browsable API.
urlpatterns = [
    path('', include(router.urls)),
    path('api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

因为这里用的不是view而是viewsets,所以可以自动生成API的URLconf,只需要注册class即可。

也可以不用viewsets,用view,再自定义API URL。

Pagination

分页用来控制每页返回多少数据,在tutorial/settings.py中添加:

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
    'PAGE_SIZE': 10
}

Settings

tutorial/settings.py中,把'rest_framework'添加到INSTALLED_APPS

INSTALLED_APPS = [
    ...
    'rest_framework',
]

测试API

启动项目:

python manage.py runserver

访问http://127.0.0.1:8000/users/,点击右上角用超管登录,即可看到:

快用Django REST framework写写API吧

东方说

本文是Django REST framework系列的开篇,内容参考的是官网的Tutorial。学了Django再看DRF,思路清晰多了,虽然我代码能力不强,但总是在追求规范和标准,难道是因为做测试的职业病么?

终于修复了从博客园复制粘贴到公众号代码块自动换行没有滚动条的问题,F12看了才知道有个样式被覆盖了,加上这句就搞定了:

#topics .postBody pre {
    white-space: pre !important;
}

参考资料:

https://www.django-rest-framework.org/tutorial/quickstart/

http://www.ruanyifeng.com/blog/2014/05/restful_api.html

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