全栈一路坑(4)——创建博客的API

这一篇要搭建一个API平台，一是为了给博客补充一些功能，二是为以后做APP提供数据接口。

首先需要安装Django REST Framework的RESTful API库，记得先打开virtualenv，避免全局污染。

pip install djangorestframework

然后添加到INSTALLED_APPS中

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'blogpost',
    'django.contrib.sites',
    'django.contrib.flatpages',
    'django_comments',
    'django.contrib.sitemaps',
    'rest_framework',
]

然后添加url

urlpatterns = [
    url(r'^$', 'blogpost.views.index', name='main'),
    url(r'^index.html$', 'blogpost.views.index', name='main'),
    url(r'^blog/(?P<slug>[^.]+).html', 'blogpost.views.view_post', name='view_blog_post'),
    url(r'^admin/', admin.site.urls),
    url(r'^pages/', include('django.contrib.flatpages.urls')),
    url(r'^comments/', include('django_comments.urls')),
    url(r'^sitemap.xml$', sitemap, {'sitemaps': sitemaps}, name='django.contrib.sitemaps.views.sitemap'),
    url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework')),
]

准备工作完成，先来创建一个博客列表的API，在blogpost下面创建一个serializers.py的文件。BlogpostSet用来定义视图的展现形式，返回需要展示的内容，BlogpostSerializers用户定义API的表现形式，返回哪些字段，返回怎样的格式

from django.contrib.auth.models import User
from rest_framework import serializers, viewsets
from blogpost.models import Blogpost


class BlogpostSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Blogpost
        fields = ('title', 'author', 'body', 'slug')

    class BlogpostSet(viewsets.ModelViewSet):
        queryset = Blogpost.objects.all()
        serializer_class = BlogpostSerializer

然后配置url,添加

from django.conf.urls import url, include
from django.contrib import admin
from django.contrib.sitemaps.views import sitemap
from sitemap.sitemaps import PageSitemap, FlatPageSitemap, BlogSitemap
from rest_framework import routers
from blogpost.serializers import BlogpostSet

sitemaps = {
    "page": PageSitemap,
    'flatpages': FlatPageSitemap,
    'blog': BlogSitemap
}

apiRouter = routers.DefaultRouter()
apiRouter.register(r'blogpost', BlogpostSet)

urlpatterns = [
    url(r'^$', 'blogpost.views.index', name='main'),
    url(r'^index.html$', 'blogpost.views.index', name='main'),
    url(r'^blog/(?P<slug>[^.]+).html', 'blogpost.views.view_post', name='view_blog_post'),
    url(r'^admin/', admin.site.urls),
    url(r'^pages/', include('django.contrib.flatpages.urls')),
    url(r'^comments/', include('django_comments.urls')),
    url(r'^sitemap.xml$', sitemap, {'sitemaps': sitemaps}, name='django.contrib.sitemaps.views.sitemap'),
    url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework')),
    url(r'^api/', include(apiRouter.urls)),
]

然后访问http://127.0.0.1:8000/api/

点击链接之后就可以看到博客列表的API了

自动完成API

自动完成API其实就是一个搜索接口,首先修改一下博客API，添加了一个搜索字段search_fields,指向title

from django.contrib.auth.models import User
from rest_framework import serializers, viewsets, permissions
from rest_framework.response import Response

from blogpost.models import Blogpost


class BlogpostSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Blogpost
        fields = ('title', 'author', 'body', 'slug')


class BlogpostSet(viewsets.ModelViewSet):
    permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
    serializer_class = BlogpostSerializer
    search_fields = 'title'

    def list(self, request):
        queryset = Blogpost.objects.all()
        search_param = self.request.query_params.get('title', None)
        if search_param is not None:
            queryset = Blogpost.objects, filter(title__contains=search_param)
        serializers = BlogpostSerializer(queryset, many=True)
        return Response(serializers.data)

然后测试报错了

作者的代码又一次出错了，修改代码如下

from django.contrib.auth.models import User
from rest_framework import serializers, viewsets, permissions
from rest_framework.response import Response

from blogpost.models import Blogpost


class BlogpostSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Blogpost
        fields = ('title', 'author', 'body', 'slug')


class BlogpostSet(viewsets.ModelViewSet):
    permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
    serializer_class = BlogpostSerializer
    search_fields = 'title'

    def get_queryset(self):
        return Blogpost.objects.all()

    def list(self, request):
        queryset = Blogpost.objects.all()
        search_param = self.request.query_params.get('title', None)
        if search_param is not None:
            queryset = Blogpost.objects.filter(title__contains=search_param)
        serializers = BlogpostSerializer(queryset, many=True)
        return Response(serializers.data)

然后就是一段前端的工作了，由于我直接把前端代码拷贝过来了，所以直接能用了

然后就是每一个做API都头疼的问题了，跨域问题

首先添加django-cors-headers

pip install django-cors-headers

然后注册它

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'blogpost',
    'django.contrib.sites',
    'django.contrib.flatpages',
    'django_comments',
    'django.contrib.sitemaps',
    'rest_framework',
    'corsheaders',
]

还要注册中间件

MIDDLEWARE_CLASSES = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    'django.contrib.flatpages.middleware.FlatpageFallbackMiddleware',
    'corsheaders.middleware.CorsMiddleware',
]

然后在settings.py中再添加对应的配置

CORS_ALLOW_CREDENTIALS = True

上传完代码之后测试一下，pycharm自带了一个很方便的测试restful服务器的工具

填入相关的测试信息

然后得到了正确的结果

至此，服务端的开发工作暂时就告一段落了，下一篇将开始移动端的开发。