快用Django REST framework寫寫API吧
阿新 • • 發佈：2020-12-16
Django預設是前後端繫結的，提供了Template和Form，現在流行前後端分離專案，Python大佬坐不住了，於是便有了Django REST framework：https://github.com/tomchristie
/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
```
> 一般不會把app放到project裡面，這裡是為了避免命名衝突。
接著同步資料庫：
```shell
python manage.py migrate
```
然後建立一個超級管理員，密碼`password123`：
```shell
python manage.py createsuperuser --email [email protected] --username admin
```
# Serializers
序列化是指把資料庫模型轉換為JSON。新建模組`tutorial/quickstart/serializers.py`：
```python
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
檢視用來接受Web請求並且返回Web響應。開啟`tutorial/quickstart/views.py`，新增程式碼：
```python
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，開啟`tutorial/urls.py`，新增程式碼：
```python
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'))
]
```
因為這裡用的不是view而是viewsets，所以可以自動生成API的URLconf，只需要註冊class即可。
> 也可以不用viewsets，用view，再自定義API URL。
# Pagination
分頁用來控制每頁返回多少資料，在`tutorial/settings.py`中新增：
```python
REST_FRAMEWORK = {
'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
'PAGE_SIZE': 10
}
```
# Settings
在`tutorial/settings.py`中，把`'rest_framework'`新增到`INSTALLED_APPS`：
```python
INSTALLED_APPS = [
...
'rest_framework',
]
```
# 測試API
啟動專案：
```shell
python manage.py runserver
```
訪問`http://127.0.0.1:8000/users/`，點選右上角用超管登入，即可看到：
