1. DRF 分页器

目录

• Django DRF 分页器
  • 1. 环境准备
    • 1.1 编辑models.py
    • 1.2 编译初始化脚本，为数据库添加数据
  • 2. 使用分页器
  • 3. 源码分析
    • 3.1 LimitOffsetPagination源码分析
    • 3.2 PageNumberPagination源码分析

Django DRF 分页器

1. 环境准备

1.1 编辑models.py

from django.db import models

# Create your models here.

class UserInfo(models.Model):
    username = models.CharField(verbose_name="姓名", max_length=32)
    age = models.SmallIntegerField(verbose_name="年龄")

1.2 编译初始化脚本，为数据库添加数据

import os
import django

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "drf_day3.settings")
django.setup()

from app01 import models

for i in range(200):
    models.UserInfo.objects.create(username=f"test-{i}", age=i)

print("Insert data into DB successfully.")

运行后查看数据库，已经成功插入两百条数据。

2. 使用分页器

from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework.pagination import PageNumberPagination, LimitOffsetPagination
from app01 import models
from rest_framework import serializers

# Create your views here.

class UserSerilizer(serializers.ModelSerializer):
    class Meta:
        model = models.UserInfo
        fields = ["id", "username", "age"]

class UserPagination(PageNumberPagination):
    """
    A simple page number based style that supports page numbers as
    query parameters. For example:

    http://api.example.org/accounts/?page=4
    http://api.example.org/accounts/?page=4&page_size=100
    """
    page_size_query_param = "page_size"
    max_page_size = 20


class UserView(APIView):
    def get(self, request):

        queryset = models.UserInfo.objects.all()

        pagernator = UserPagination()
        queryset = pagernator.paginate_queryset(queryset=queryset, request=request, view=self)

        ser = UserSerilizer(instance=queryset, many=True)

        return Response({"status": True, "data": ser.data})


class InfoPagination(LimitOffsetPagination):
    """
    A limit/offset based style. For example:

    http://api.example.org/accounts/?limit=100
    http://api.example.org/accounts/?offset=400&limit=100
    """
    max_limit = 100


class InfoView(APIView):
    def get(self, request):

        queryset = models.UserInfo.objects.all()

        pagernator = InfoPagination()
        queryset = pagernator.paginate_queryset(queryset=queryset, request=request, view=self)

        ser = UserSerilizer(instance=queryset, many=True)

        return Response({"status": True, "data": ser.data})

3. 源码分析

分页器主要有两个功能， PageNumberPagination， LimitOffsetPagination

3.1 LimitOffsetPagination源码分析

url: http://api.example.org/accounts/?offset=400&limit=100
从第四百个object,拿后面一百个 (400-500)
例如在滑动加载数据中使用

3.2 PageNumberPagination源码分析