Bob's Blog

经过前一篇的步骤，后端基本上可以用了，那么需要开始新建一个能返回数据的模块。

运行: python manage.py startapp projects

在automation_center\settings.py中加上刚创建的app。

INSTALLED_APPS = [
    ...
    'rest_framework',
    'projects',
]

在projects\models.py中增加一个model

from django.db import models
from django.utils import timezone


class Project(models.Model):
    name = models.CharField(max_length=100)
    create_time = models.DateTimeField(default=timezone.now)
    update_time = models.DateTimeField(default=timezone.now)

    def __str__(self):
        return self.name

打算把所有的app放进一个目录(modules)管理，于是在settings.py中添加如下，并把新建的projects目录放进modules目录里面

import sys

sys.path.insert(0,os.path.join(BASE_DIR, 'modules'))

迁移数据表变动

python manage.py makemigrations
python manage.py migrate

# output：
# Operations to perform:
#   Apply all migrations: admin, auth, contenttypes, projects, sessions
# Running migrations:
#   Applying projects.0001_initial... OK

此时检查本地数据表时会发现多了一个表：projects_project。

接下来添加一个文件serializers.py。serializers可以将queryset和model序列化转换成json格式用于api接口，也可以用于验证。

from .models import Project
from rest_framework import serializers

class ProjectSerializer(serializers.ModelSerializer):

    class Meta:
        model = Project
        fields = "__all__"

## 下面的部分和上面的等价，ModelSerializer可以替代与model中重复的代码，并包含了create和update方法。如果我们需要自定义，则重写这两个方法
# class ProjectSerializer(serializers.Serializer):
#     id = serializers.IntegerField(read_only=True)
#     name = serializers.CharField(max_length=100)
#     create_time = serializers.DateTimeField()
#     update_time = serializers.DateTimeField()
#
#     def create(self, validated_data):
#         """
#         Create and return a new `project` instance, given the validated data.
#         """
#         return Project.objects.create(**validated_data)
#
#     def update(self, instance, validated_data):
#         """
#         Update and return an existing `project` instance, given the validated data.
#         """
#         instance.name = validated_data.get('name', instance.name)
#         instance.create_time = validated_data.get('create_time', instance.create_time)
#         instance.update_time = validated_data.get('update_time', instance.update_time)
#         instance.save()
#         return instance

在view.ps中添加相关的viewset

from .models import Project
from rest_framework import viewsets
from .serializers import ProjectSerializer


class ProjectViewSet(viewsets.ModelViewSet):
    """
    API endpoint that allows projects to be viewed or edited.
    """
    queryset = Project.objects.all()
    serializer_class = ProjectSerializer

在automation_center\urls.py中添加对应的router

from django.contrib import admin
from django.urls import include, path
from rest_framework import routers
from projects.views import ProjectViewSet


router = routers.DefaultRouter()
router.register(r'projects', ProjectViewSet)

urlpatterns = [
    path('api/', include(router.urls)),
    path('admin/', admin.site.urls),
    path('api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

此时我们再度运行python manage.py runserver时，便可以访问到新加的简单api，比如：

http://127.0.0.1:8000/api/ 列出了目前的api列表

http://127.0.0.1:8000/api/projects/ Get方法，返回了目前所有的project信息

http://127.0.0.1:8000/api/projects/ Post方法，post数据并新建了一条数据列在project表中

{
    "name": "debug",
    "create_time": "2019-12-21T00:58:00",
    "update_time": "2019-12-21T00:59:00"
}

http://127.0.0.1:8000/api/projects/1/  Get方法，返回了id为1的project信息

http://127.0.0.1:8000/api/projects/1/  Put或Patch方法，传上面的部分修改的数据后可以更新该project信息

于是一个简单的api就已经可以工作啦。