分页

在查看数据列表的API中，如果数据量比较大，肯定不能把所有的数据都展示给用户，而需要通过分页展示。

在drf中为我们提供了一些分页先关类：

BasePagination，分页基类
PageNumberPagination(BasePagination)	支持 /accounts/?page=4&page_size=100 格式的分页
LimitOffsetPagination(BasePagination)	支持 ?offset=100&limit=10 格式的分页
CursorPagination(BasePagination)		支持 上一下 & 下一页 格式的分页（不常用）

1. 继承APIView视图时：

如果编写视图是直接继承APIView，那么在使用分页时，就必须自己手动实例化和调用相关方法。

1.PageNumberPagination

继承APIView使用时，如上图：

python

from rest_framework.pagination import PageNumberPagination

class UserView(APIView):
    def get(self, request, *args, **kwargs):
        queryset = UserInfo.objects.all()
        pager = PageNumberPagination()
        pagination_queryset = pager.paginate_queryset(queryset, request, self)
        serializer = UserInfoSerializer(instance=pagination_queryset, many=True)
        return Response(serializer.data)

或定义size等参数：如上图

python

from rest_framework.pagination import PageNumberPagination

class MyPageNumberPagination(PageNumberPagination):
    page_size_query_param = 'size'  # 定义的搜索关键词
    page_size = 2  # 每页默认数量
    max_page_size = 20  # 每页允许的最大数量

class UserView(APIView):
    def get(self, request, *args, **kwargs):
        queryset = UserInfo.objects.all().order_by('id')
        pager = MyPageNumberPagination()
        pager_queryset = pager.paginate_queryset(queryset, request, self)
        serializer = UserInfoSerializer(instance=pager_queryset, many=True)
        return Response(serializer.data)

2.LimitOffsetPagination

python

from rest_framework.pagination import LimitOffsetPagination

class UserView(APIView):
    def get(self, request, *args, **kwargs):
        queryset = UserInfo.objects.all().order_by('id')

        pager = LimitOffsetPagination()
        pager_queryset = pager.paginate_queryset(queryset)

        serializer = UserInfoSerializer(instance=pager_queryset, many=True)
        return Response(serializer.data)

3.CursorPagination

python

from rest_framework.pagination import CursorPagination


class MyCursorPagination(CursorPagination):
    ordering = 'id'  # 先排序后分页，排序关键词
    page_size_query_param = 'size'  # 每页页数关键词
    page_size = 2  # 默认的每页页数
    max_page_size = 20  # 每页允许的最大页数


class UserInfoView(APIView):
    def get(self, request, *args, **kwargs):
        queryset = UserInfo.objects.all().order_by('id')
        pager = MyCursorPagination()
        pager_queryset = pager.paginate_queryset(queryset)
        serializer = UserInfoSerializer(instance=pager_queryset, many=True)
        return Response(serializer.data)

2. 继承GenericAPIView派生类时

如果是使用 ListModelMixin 或 ModelViewSet ，则只需要配置相关类即可，内部会自动执行相关分页的方法。

1.PageNumberPagination

python

from rest_framework.pagination import PageNumberPagination


class MyPageNumberPagination(PageNumberPagination):
    page_size = 2
    page_size_query_param = 'size'
    page_query_param = 'page'
    max_page_size = 20


class UserInfoView(ListCreateAPIView):
    serializer_class = UserInfoSerializer
    queryset = UserInfo.objects.all()
    pagination_class = MyPageNumberPagination

2.LimitOffsetPagination

python

from rest_framework.pagination import LimitOffsetPagination


class MyLimitOffsetPagination(LimitOffsetPagination):
    default_limit = 2
    max_limit = 20


class UserInfoView(ListCreateAPIView):
    serializer_class = UserInfoSerializer
    queryset = UserInfo.objects.all()
    pagination_class = MyLimitOffsetPagination

3.CursorPagination

python

from rest_framework.pagination import CursorPagination


class MyCursorPagination(CursorPagination):
    ordering = 'id'
    page_size_query_param = 'size'
    page_size = 2
    max_page_size = 20


class UserInfoView(ListCreateAPIView):
    serializer_class = UserInfoSerializer
    queryset = UserInfo.objects.all()
    pagination_class = MyCursorPagination

案例：分页，加载更多的实现

需要前端传来最后一条数据的latest_id和每页几条数据：limit。

python

from django_filters import FilterSet, filters
from django_filters.rest_framework import DjangoFilterBackend
from rest_framework.pagination import LimitOffsetPagination
from rest_framework.generics import ListCreateAPIView,RetrieveUpdateDestroyAPIView
from api import models
from rest_framework.viewsets import ViewSet
from api.serializers.topic import TopicSerializer
from api.utils.filters import SelfFilterBackend

class MyLimitOffsetPagination(LimitOffsetPagination): #负责筛选每页几条数据
    default_limit = 2
    max_limit = 20
    offset_query_param = None


class TopicFilterSet(FilterSet):              #筛选所有id<latest_id的数据
    # ?latest_id=99             ->  id<99
    # ?latest_id=99&limit=10    ->  id<99  limit 10
    latest_id = filters.NumberFilter(field_name='id', lookup_expr='lt')

    class Meta:
        model = models.Topic
        fields = ["latest_id", ]
        
        
class SelfFilterBackend(BaseFilterBackend):       #筛选用户
    def filter_queryset(self, request, queryset, view):
        return queryset.filter(user=request.user)


class TopicView(ListCreateAPIView,RetrieveUpdateDestroyAPIView,ViewSet):
    """ 主题 """

    # 当前登录用户的调教
    filter_backends = [SelfFilterBackend, DjangoFilterBackend]  #DjangoFilterBackend是django需要的类，不能省略
    
    filterset_class = TopicFilterSet
    pagination_class = MyLimitOffsetPagination

    queryset = models.Topic.objects.filter(deleted=False).order_by('-id')

    serializer_class = TopicSerializer

    def perform_create(self, serializer):
        serializer.save(user=self.request.user)

    def perform_destroy(self, instance):
        instance.deleted = True
        instance.save()

路由

在之前进行drf开发时，对于路由我们一般进行两种配置：

视图继承APIView

python

from django.urls import path
from app01 import views

urlpatterns = [
    path('api/users/', views.UserView.as_view()),
]

视图继承 ViewSetMixin（GenericViewSet、ModelViewSet）

python

from django.urls import path, re_path, include
from app01 import views

urlpatterns = [
    path('api/users/', views.UserView.as_view({"get":"list","post":"create"})),
    path('api/users/<int:pk>/', views.UserView.as_view({"get":"retrieve","put":"update","patch":"partial_update","delete":"destory"})),
]

对于这种形式的路由，drf中提供了更简便的方式：

python

from rest_framework import routers
from app01 import views

router = routers.SimpleRouter()
router.register(r'api/users', views.UserView)

urlpatterns = [
    # 其他URL
    # path('xxxx/', xxxx.as_view()),
]

urlpatterns += router.urls

也可以利用include，给URL加前缀：

python

from django.urls import path, include
from rest_framework import routers
from app01 import views

router = routers.SimpleRouter()
router.register(r'users', views.UserView)

urlpatterns = [
    path('api/', include((router.urls, 'app_name'), namespace='instance_name')),
    # 其他URL
    # path('forgot-password/', ForgotPasswordFormView.as_view()),
]

解析器

之前使用 request.data 获取请求体中的数据。

这个 reqeust.data 的数据怎么来的呢？其实在drf内部是由解析器，根据请求者传入的数据格式 + 请求头来进行处理。

1.JSONParser

2.FormParser

3.MultiPartParser

html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="http://127.0.0.1:8000/test/" method="post" enctype="multipart/form-data">
    <input type="text" name="user" />
    <input type="file" name="img">

    <input type="submit" value="提交">

</form>
</body>
</html>

4.FileUploadParser

解析器可以设置多个，默认解析器：

python

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.parsers import MultiPartParser, JSONParser, FormParser


class UserView(APIView):

    def post(self, request):
        print(request.content_type)
        print(request.data)

        return Response("...")

drf实战案例

1. 需求

请结合上述学习的drf知识开发简易版《抽屉新热榜》。其中包含的功能如下：

输入：手机号、用户名、密码、确认密码。

输入：手机号 或 用户名  + 密码

注意：登录成功后给用户返回token，后续请求需要在url中携带token（有效期2周）

我的话题

- 我的话题列表
- 创建话题
- 修改话题
- 删除话题（逻辑删除）

我的资讯

- 创建资讯（5分钟创建一个，需要根据用户限流）    问题1：5/h   2/m； 问题2：成功后，下次再创建；
	- 文本（你问我答、42区、挨踢1024、段子）
	- 图片（图片、你问我答、42区、挨踢1024、段子）
	- 连接（图片、你问我答、42区、挨踢1024、段子）
	注意：创建时默认自己做1个推荐。
- 我的资讯列表

首页

- 资讯首页
	- 时间倒序，读取已审核通过的资讯
	- 加载更多，分页处理
	- 支持传入参数，查询各分区资讯：图片、你问我答、42区、挨踢1024、段子   ?zone=2

2. 参考表结构

表结构参考：

python

from django.db import models


class DeletedModel(models.Model):
    deleted = models.BooleanField(verbose_name="已删除", default=False)

    class Meta:
        abstract = True


class UserInfo(DeletedModel):
    """ 用户表 """
    username = models.CharField(verbose_name="用户名", max_length=32)
    phone = models.CharField(verbose_name="手机号", max_length=32, db_index=True)
    password = models.CharField(verbose_name="密码", max_length=64)

    token = models.CharField(verbose_name="token", max_length=64, null=True, blank=True, db_index=True)
    token_expiry_date = models.DateTimeField(verbose_name="token有效期", null=True, blank=True)

    status_choice = (
        (1, "激活"),
        (2, "禁用"),
    )
    status = models.IntegerField(verbose_name="状态", choices=status_choice, default=1)
    create_datetime = models.DateTimeField(verbose_name="创建时间", auto_now_add=True)

    class Meta:
        # The newer indexes option provides more functionality than index_together
        # index_together may be deprecated in the future.
        # https://docs.djangoproject.com/en/3.2/ref/models/options/#index-together
        indexes = [
            models.Index(fields=['username', "password"], name='idx_name_pwd')
        ]


class Topic(DeletedModel):
    """ 话题 """
    title = models.CharField(verbose_name="话题", max_length=16, db_index=True)

    is_hot = models.BooleanField(verbose_name="热门话题", default=False)
    user = models.ForeignKey(verbose_name="用户", to="UserInfo", on_delete=models.CASCADE)
    create_datetime = models.DateTimeField(verbose_name="创建时间", auto_now_add=True)


class News(DeletedModel):
    """ 新闻资讯 """
    zone_choices = ((1, "42区"), (2, "段子"), (3, "图片"), (4, "挨踢1024"), (5, "你问我答"))
    zone = models.IntegerField(verbose_name="专区", choices=zone_choices)

    title = models.CharField(verbose_name="文字", max_length=150)
    url = models.CharField(verbose_name="链接", max_length=200, null=True, blank=True)

    # xxxxx?xxxxxx.png,xxxxxxxx.jeg
    image = models.TextField(verbose_name="图片地址", help_text="逗号分割", null=True, blank=True)

    topic = models.ForeignKey(verbose_name="话题", to="Topic", on_delete=models.CASCADE, null=True, blank=True)
    user = models.ForeignKey(verbose_name="用户", to="UserInfo", on_delete=models.CASCADE)

    create_datetime = models.DateTimeField(verbose_name="创建时间", auto_now_add=True)
    status_choice = (
        (1, "待审核"),
        (2, "已通过"),
        (3, "未通过"),
    )
    status = models.IntegerField(verbose_name="状态", choices=status_choice, default=1)

    collect_count = models.IntegerField(verbose_name="收藏数", default=0)
    recommend_count = models.IntegerField(verbose_name="推荐数", default=0)
    comment_count = models.IntegerField(verbose_name="评论数", default=0)


class Collect(models.Model):
    """ 收藏 """
    news = models.ForeignKey(verbose_name="资讯", to="News", on_delete=models.CASCADE)
    user = models.ForeignKey(verbose_name="用户", to="UserInfo", on_delete=models.CASCADE)
    create_datetime = models.DateTimeField(verbose_name="创建时间", auto_now_add=True)

    class Meta:
        # unique_together = [['news', 'user']]
        constraints = [
            models.UniqueConstraint(fields=['news', 'user'], name='uni_collect_news_user')
        ]


class Recommend(models.Model):
    """ 推荐 """
    news = models.ForeignKey(verbose_name="资讯", to="News", on_delete=models.CASCADE)
    user = models.ForeignKey(verbose_name="用户", to="UserInfo", on_delete=models.CASCADE)
    create_datetime = models.DateTimeField(verbose_name="创建时间", auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=['news', 'user'], name='uni_recommend_news_user')
        ]


class Comment(models.Model):
    """ 评论表 """
    news = models.ForeignKey(verbose_name="资讯", to="News", on_delete=models.CASCADE)
    user = models.ForeignKey(verbose_name="用户", to="UserInfo", on_delete=models.CASCADE)
    content = models.CharField(verbose_name="内容", max_length=150)

    depth = models.IntegerField(verbose_name="深度", default=0)

    root = models.ForeignKey(verbose_name="根评论", to="Comment", related_name="descendant", on_delete=models.CASCADE,
                             null=True, blank=True)

    reply = models.ForeignKey(verbose_name="回复", to="Comment", related_name="reply_list", on_delete=models.CASCADE,
                              null=True, blank=True)

    create_datetime = models.DateTimeField(verbose_name="创建时间", auto_now_add=True)

    # 针对根评论
    descendant_update_datetime = models.DateTimeField(verbose_name="后代更新时间", auto_now_add=True)

3. 案例讲解

3.1 环境准备

基于django创建项目，例如：dig

安装必备模块

django-filter==2.4.0
django-redis==5.0.0
djangorestframework==3.12.4

创建app，例如：api

注册app

python

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework',
    'django_filters',
    'api.apps.ApiConfig'
]

拷贝表结构到 models.py 并 生成数据库

3.2 接口开发

1.注册

2.登陆

3.我的话题增删改查

4.自定义限流类，限流频率为1/5m，并解决访问不成功时的限流问题

Serializer.py

python

from rest_framework import serializers
from api.models import UserInfo, Topic, News, Recommend
from rest_framework import exceptions
import re


class RegisterSerializer(serializers.ModelSerializer):
    re_password = serializers.CharField(max_length=32, allow_null=False, write_only=True)
    password = serializers.CharField(max_length=32, allow_null=False, write_only=True)

    class Meta:
        model = UserInfo
        fields = ['username', 'phone', 'password', 're_password']

    def validate_phone(self, value):
        is_exist = UserInfo.objects.filter(phone=value).exists()
        if is_exist:
            raise exceptions.ValidationError('手机号已注册，请直接登陆')
        if not re.match(r'^(13[0-9]|14[01456879]|15[0-35-9]|16[2567]|17[0-8]|18[0-9]|19[0-35-9])\d{8}$', value):
            raise exceptions.ValidationError('手机号格式错误')
        return value

    def validate_password(self, value):
        print(self.initial_data, 'init')
        re_password = self.initial_data.get('re_password')
        if re_password != value:
            raise exceptions.ValidationError('密码不一致')
        return value


class LoginSerializer(serializers.ModelSerializer):
    class Meta:
        model = UserInfo
        fields = ['username', 'phone', 'password']
        extra_kwargs = {
            'token': {'write_only': True},
            'token_expiry_date': {'write_only': True},
            'username': {'required': False},
            'phone': {'required': False},
            'password': {'required': True},
        }

    def validate(self, attrs):
        username = attrs.get('username', None)
        phone = attrs.get('phone', None)
        if not username and not phone:
            raise exceptions.ValidationError('用户名或手机号为空')
        return attrs


class TopicSerializer(serializers.ModelSerializer):
    class Meta:
        model = Topic
        fields = ['id', 'title', 'is_hot']


class NewsSerializer(serializers.ModelSerializer):
    image_list = serializers.SerializerMethodField(read_only=True)
    topic_title = serializers.CharField(source="topic.title", read_only=True)
    zone_title = serializers.CharField(source="get_zone_display", read_only=True)
    status = serializers.CharField(source="get_status_display", read_only=True)

    # title、url、image、'topic', "zone"
    #   - 只有title，只创建文本 + 分区不能是图片
    #   - 有title，image，
    #   - 有title，url
    class Meta:
        model = News
        fields = ['id', "title", "url",
                  'image', 'topic', "zone",
                  "zone_title", 'image_list', "topic_title", 'collect_count', 'recommend_count', 'comment_count',
                  "status"]
        read_only_fields = ['collect_count', 'recommend_count', 'comment_count']
        extra_kwargs = {
            'topic': {'write_only': True},  # 新增时，topic=1
            'image': {'write_only': True},  # 图片地址   xxxx,xxxx,xxxx
            'zone': {'write_only': True},
        }

    def get_image_list(self, obj):
        if not obj.image:
            return []
        return obj.image.split(',')

    def validate_topic(self, value):
        if not value:
            return value
        request = self.context['request']
        exists = Topic.objects.filter(deleted=False, id=value.id, user=request.user).exists()
        if not exists:
            raise exceptions.ValidationError("话题不存在")
        return value

    def validate_title(self, value):
        url = self.initial_data.get('url')
        image = self.initial_data.get('image')
        zone = self.initial_data.get('zone')

        if url and image:
            raise exceptions.ValidationError("请求数据错误")
        if not url and not image:
            if zone == 3:
                raise exceptions.ValidationError("分区选择错误")
        return value

    def create(self, validated_data):
        request = self.context["request"]

        # 1.创建新闻资讯
        new_object = News.objects.create(recommend_count=1, **validated_data)

        # 2.推荐记录
        Recommend.objects.create(
            news=new_object,
            user=request.user
        )
        return new_object


    def create(self, validated_data):
        news_obj = News.objects.create(**validated_data, recommend_count=1)
        Recommend.objects.create(
            news=news_obj,
            user=self.context["request"].user,
        )
        return news_obj

Views.py

python

from rest_framework.generics import CreateAPIView
from rest_framework.views import APIView
from api.models import UserInfo
from api.serialisers import RegisterSerializer, LoginSerializer
from api.utils import encrypt
from django.db.models import Q
from rest_framework.response import Response
from api import ResponseCode
import random
import datetime


class RegisterView(CreateAPIView):
    serializer_class = RegisterSerializer
    queryset = UserInfo.objects.filter(deleted=False, status=1)

    def perform_create(self, serializer):
        serializer.validated_data.pop('re_password')
        password = serializer.validated_data.pop('password')
        password = encrypt.Mymd5(password)
        serializer.validated_data['password'] = password
        token = random.randint(1000, 9999)
        token_expiry_date = datetime.datetime.now() + datetime.timedelta(weeks=2)
        serializer.validated_data['token_expiry_date'] = token_expiry_date
        serializer.validated_data['token'] = token
        serializer.save()


class LoginView(CreateAPIView):
    queryset = UserInfo.objects.filter(deleted=False, status=1)
    serializer_class = LoginSerializer

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        # print(111, serializer.validated_data)
        username = serializer.validated_data.get('username', None)
        password = serializer.validated_data.get('password', None)
        password = encrypt.Mymd5(password)
        phone = serializer.validated_data.get('phone', None)
        user_obj = UserInfo.objects.filter(Q(Q(username=username) | Q(phone=phone)), password=password).first()
        if not user_obj:
            return Response({'code': ResponseCode.LOGIN_FAILURE, 'detail': '用户名或密码错误'})

        token = random.randint(1000, 9999)
        token_expiry_date = datetime.datetime.now() + datetime.timedelta(weeks=2)
        user_obj.token_expiry_date = token_expiry_date
        user_obj.token = token
        # print(222, serializer.validated_data)
        return Response({'code': ResponseCode.LOGIN_SUCCESS, 'detail': '登陆成功'})

settings.py

python

TIME_ZONE = 'Asia/Shanghai'
USE_TZ = False

Urls.py

python

from django.urls import path
from api.views import RegisterView, LoginView

urlpatterns = [

    path('register/', RegisterView.as_view(), name='register'),
    path('login/', LoginView.as_view(), name='login')
]

throttle.py

python

from rest_framework.throttling import SimpleRateThrottle
from django.core.cache import cache as default_cache
from api.utils import return_code
from rest_framework import exceptions
from rest_framework import status


class ThrottledException(exceptions.APIException):
    status_code = status.HTTP_429_TOO_MANY_REQUESTS
    default_code = 'throttled'


class MySimpleRateThrottle(SimpleRateThrottle):
    cache = default_cache  # 访问记录存放在django的缓存中（需设置缓存）
    scope = "user"  # 构造缓存中的key
    cache_format = 'throttle_%(scope)s_%(ident)s'

    # 设置访问频率，例如：1/5m
    THROTTLE_RATES = {"user": "1/5m"}

    def parse_rate(self, rate):
        """
        Given the request rate string, return a two tuple of:
        <allowed number of requests>, <period of time in seconds>
        """
        if rate is None:
            return (None, None)
        num, period = rate.split('/')
        num_requests = int(num)
        duration = {'s': 1, 'm': 60, 'h': 3600, 'd': 86400}[period[-1]]
        count = int(period[0])
        return (num_requests, duration * count)

    def get_cache_key(self, request, view):
        ident = request.user.pk
        return self.cache_format % {'scope': self.scope, 'ident': ident}

    def throttle_success(self):
        return True

    def throttle_failure(self):
        wait = self.wait()
        detail = {
            "code": return_code.TOO_MANY_REQUESTS,
            "data": "访问频率限制",
            'detail': "需等待{}秒后才能访问".format(int(wait))
        }
        raise ThrottledException(detail)  # 自定义的exception，在上面

    def done(self):
        self.history.insert(0, self.now)
        self.cache.set(self.key, self.history, self.duration)

django各种片段代码

c2

素材

项目静态文件资源

uploads

chapter1-项目搭建

素材

chapter3-基于jwt的分布式认证流程

分页

1. 继承APIView视图时：

1.PageNumberPagination

2.LimitOffsetPagination

3.CursorPagination

2. 继承GenericAPIView派生类时

1.PageNumberPagination

2.LimitOffsetPagination

3.CursorPagination

案例：分页，加载更多的实现

路由

解析器

1.JSONParser

2.FormParser

3.MultiPartParser

4.FileUploadParser

drf实战案例

1. 需求

2. 参考表结构

3. 案例讲解

3.1 环境准备

3.2 接口开发

素材

项目静态文件资源

uploads

素材

分页 ​

1. 继承APIView视图时： ​

1.PageNumberPagination ​

2.LimitOffsetPagination ​

3.CursorPagination ​

2. 继承GenericAPIView派生类时 ​

1.PageNumberPagination ​

2.LimitOffsetPagination ​

3.CursorPagination ​

案例：分页，加载更多的实现 ​

路由 ​

解析器 ​

1.JSONParser ​

2.FormParser ​

3.MultiPartParser ​

4.FileUploadParser ​

drf实战案例 ​

1. 需求 ​

2. 参考表结构 ​

3. 案例讲解 ​

3.1 环境准备 ​

3.2 接口开发 ​

分页

1. 继承APIView视图时：

1.PageNumberPagination

2.LimitOffsetPagination

3.CursorPagination

2. 继承GenericAPIView派生类时

1.PageNumberPagination

2.LimitOffsetPagination

3.CursorPagination

案例：分页，加载更多的实现

路由

解析器

1.JSONParser

2.FormParser

3.MultiPartParser

4.FileUploadParser

drf实战案例

1. 需求

2. 参考表结构

3. 案例讲解

3.1 环境准备

3.2 接口开发