在这个例子中，我们将使用Django编写饿了么高校外卖商家查询API接口，并且使用AJAX技术来实现API接口的使用，包括使用ajax get方法加载更多数据，使用ajax方法来更新、修改、新增、删除数据。利用API可以做到前后端分离，为开发web应用提供了便利。

首先使用Pycharm新建一个Django项目，并且使用virtualenv或者pipenv虚拟环境

创建成功会自动安装Django2.1和所需依赖，restframework框架需要自己手动安装

//激活虚拟环境安装以下(venv)$ pip install djangorestframework(venv)$ pip install django-filter (venv)$ pip install pytest(venv)$ pip install pytest-django //由于笔者使用Postgresql数据库，所以还需要安装以下(venv)$ pip install psycopg2//使用mysql数据库安装如下(venv)$ pip install pymysql

准备数据来提供服务

数据来源：饿了么爬虫

数据内容：全国所有大学附近的外卖商家Top20

数据需要导入数据库

Django编写rest api接口

项目结构

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settings.py.

// 安装的app如下INSTALLED_APPS = [ #... 'rest_framework', 'django_filters', 'api.apps.ApiConfig', 'front.apps.FrontConfig',]//restframework 配置如下REST_FRAMEWORK = {//这里配置了分页处理，每页最多20个项目'DEFAULT_PAGINATION_CLASS':'api.custompagination.LimitOffsetPaginationWithUpperBound', 'PAGE_SIZE': 20, 'DEFAULT_FILTER_BACKENDS': ( //这里配置了排序、过滤、搜索器 'django_filters.rest_framework.DjangoFilterBackend', 'rest_framework.filters.OrderingFilter', 'rest_framework.filters.SearchFilter', ), //这里配置了用户认证，管理员才可以更改内容，未登录不能更改 'DEFAULT_AUTHENTICATION_CLASSES':( 'rest_framework.authentication.BasicAuthentication', 'rest_framework.authentication.SessionAuthentication', ), //这里配置了访问次数限制，过多会返回429错误 too many requests 'DEFAULT_THROTTLE_CLASSES': ( 'rest_framework.throttling.AnonRateThrottle', 'rest_framework.throttling.UserRateThrottle', ), //这里配置了访问次数，anon代表匿名用户，user代表已登录用户，entries是我自己设置的作用域，300/hour代表最多300次每小时 'DEFAULT_THROTTLE_RATES': { 'anon': '300/hour', 'user': '100/hour', 'entries': '200/hour', }, 'DEFAULT_VERSIONING_CLASS':'rest_framework.versioning.NamespaceVersioning',}

models.py.

from django.db import modelsclass Entry(models.Model): city = models.CharField(max_length=50) school = models.CharField(max_length=100) link = models.CharField(max_length=100,null=True,default='null') name = models.CharField(max_length=200) lat = models.CharField(max_length=20,null=True,default='0.0') lng = models.CharField(max_length=20,null=True,default='0.0') address = models.CharField(max_length=200,null=True,default='null') distance = models.CharField(max_length=20,null=True,default='0') time = models.CharField(max_length=20,null=True,default='0:00') contact = models.CharField(max_length=200,null=True,default='null') score = models.CharField(max_length=10,null=True,default='0') comments = models.CharField(max_length=20,null=True,default='0') sell = models.CharField(max_length=20,null=True,default='0') image = models.CharField(max_length=200,null=True,default='null') owner = models.ForeignKey('auth.User',related_name='entries',on_delete=models.CASCADE) # class Meta: # ordering = ('name',) def __str__(self): return self.name

serializers.py.

from rest_framework import serializersfrom api.models import Entry//这里继承自超链接模型序列器，用于把数据转换为json格式，并且显示链接class EntrySerializer(serializers.HyperlinkedModelSerializer): owner = serializers.ReadOnlyField(source='owner.username') class Meta: model = Entry fields = ('url','pk','name','city','school','link','lat','lng','address','distance','time','contact', 'score','comments','sell','image','owner')

views.py.

from rest_framework import genericsfrom rest_framework.response import Responsefrom rest_framework.reverse import reversefrom api.models import Entryfrom api.serializers import EntrySerializerfrom rest_framework import permissionsfrom rest_framework.permissions import IsAuthenticatedfrom rest_framework.throttling import ScopedRateThrottlefrom api import custompermission//这里是获取所有数据，可实现HTTP get、Post、Option操作class EntryList(generics.ListCreateAPIView): //限流自定义作用域 throttle_scope = 'entries' throttle_classes = (ScopedRateThrottle,) queryset = Entry.objects.all() serializer_class = EntrySerializer name = 'entry-list' filter_fields = ('city','school','name') search_fields = ('school','city') ordering_fields = ('city')  //管理员才能post操作创建新的数据 permission_classes = ( permissions.IsAuthenticatedOrReadOnly, custompermission.IsCurrentUserOwnerOrReadOnly, ) def perform_create(self, serializer): serializer.save(owner=self.request.user) //这里是获取具体某一项的数据，可实现HTTP GET、PUT、PATCH、Option操作class EntryDetail(generics.RetrieveUpdateDestroyAPIView): throttle_scope = 'entries' throttle_classes = (ScopedRateThrottle,) queryset = Entry.objects.all() serializer_class = EntrySerializer name = 'entry-detail' permission_classes = ( permissions.IsAuthenticatedOrReadOnly, custompermission.IsCurrentUserOwnerOrReadOnly, )//api根目录class ApiRoot(generics.GenericAPIView): name = 'api-root' def get(self, request, *args, **kwargs): return Response({ 'entries': reverse(EntryList.name, request=request), })

urls.py.

from django.urls import pathfrom api import viewsurlpatterns = [ path('entries/', views.EntryList.as_view(), name=views.EntryList.name), path('entry-detail/<int:pk>', views.EntryDetail.as_view(), name=views.EntryDetail.name), path('', views.ApiRoot.as_view(), name=views.ApiRoot.name)]

ele/urls.py.

from django.urls import path,includeurlpatterns = [ path('v1/',include('api.urls')), path('v1/api-auth/',include('rest_framework.urls')), path('',include('front.urls'))] 

以下为启动界面

到此为止非常简单的api就写完了，接下来就是自动化测试是否达到预期效果。

如图，测试通过！

在程序中调用刚刚写好的api

创建一个新的app并且添加到settings.py里面

(venv)$ python manage.py startapp front

做好的效果如下：点击加载更多会触发ajax

由于篇幅有限，这里贴出js代码

使用ajax get请求刚刚写好的api接口并且添加到表格中

myjs.js.

$('#load-more').click(function () { $.ajax({ method:'GET', url:api_url, dataType:'json', success:function (data) { api_url = data['next']; if (api_url == null){ $('#load-more').val('已加载全部'); $('#load-more').attr('disabled',true); //api_url这里就是刚刚写好的api接口 api_url = 'v1/entries/'; } var results = data['results']; for (i=0;i<results.length;i++){ $('#ele-table-body').append( ' <tr>n' + ' <th scope="col">'+results[i]['pk']+'</th>n' + ' <th scope="col">'+results[i]['city']+'</th>n' + ' <th scope="col"><a href="/detail/' + results[i]['pk'] +'">' + results[i]['name'] + '</a></th>n' + ' <th scope="col">'+results[i]['school']+'</th>n' + ' <th scope="col">'+results[i]['score']+'</th>n' + ' </tr>' ) } } }) });

可以修改具体的一条数据，使用ajax patch方法提交数据。

注：PUT方法是修改所有数据，而PATCH方法是修改局部数据

myjs.js.

 $('#edit-confirm-btn').click(function () { var name = $('#name').val(); var distance = $('#distance').val(); var adderss = $('#address').val(); var time = $('#time').val(); var score = $('#score').val(); var comments = $('#comments').val(); var sell = $('#sell').val(); var pk = $('#pk').val(); $.ajax({ type:'PATCH', url:'/detail/' + pk, data:{ "name": name, "distance": distance, "address": adderss, "time": time, "score": score, "comments": comments, "sell": sell, }, success:function (data) { if (data.status == 'ok'){ console.log('success'); location.reload(); } } }) })

本文通过一个小例子介绍了如何使用Django调用自己写的api