如何在DRF视图中根据评论ID跳转到对应分页页面？

核心问题分析 #

你之前的错误在于在get_queryset方法中处理跳转逻辑，这个方法的职责是返回查询集，不能返回URL或响应对象，必须在请求处理的方法（比如get）中处理重定向或参数修改。

方案一：重定向到目标分页URL #

这种方式会让浏览器跳转到带正确分页参数的URL，用户地址栏会更新为目标分页地址。

步骤1：配置分页类 #

先定义符合你需求的分页类（和代码中的page_size保持一致）：

from rest_framework.pagination import PageNumberPagination

class CommentPagination(PageNumberPagination):
    page_size = 10  # 与你计算时用的每页数量一致

步骤2：修改视图类逻辑 #

重写get方法处理参数判断与重定向，get_queryset只负责过滤查询集：

from django.shortcuts import redirect
from django.urls import reverse
from rest_framework import generics, permissions
from .models import Comment
from .serializers import CommentSerializer

class CommentList(generics.ListCreateAPIView):
    permission_classes = [permissions.AllowAny]
    queryset = Comment.objects.all()
    serializer_class = CommentSerializer
    pagination_class = CommentPagination  # 绑定分页类

    def get(self, request, *args, **kwargs):
        comment_id = request.GET.get('comment_id')
        thread_id = request.GET.get('thread')
        
        # 仅当同时存在comment_id和thread参数时处理跳转
        if comment_id and thread_id:
            try:
                # 验证评论是否存在于当前thread
                Comment.objects.get(id=comment_id, thread=thread_id)
            except Comment.DoesNotExist:
                # 评论不存在，直接返回正常列表
                return super().get(request, *args, **kwargs)
            
            # 计算评论所在页码
            num_preceeding = Comment.objects.filter(thread=thread_id, id__lt=comment_id).count()
            page_size = self.pagination_class.page_size
            page_num = num_preceeding // page_size + 1

            # 构建重定向URL，使用DRF默认的page分页参数
            redirect_url = f"{reverse('comment-view')}?thread={thread_id}&page={page_num}"
            return redirect(redirect_url)
        
        # 无comment_id参数时，正常处理列表请求
        return super().get(request, *args, **kwargs)

    def get_queryset(self):
        thread_id = self.request.GET.get('thread')
        if thread_id:
            return Comment.objects.filter(thread=thread_id)
        return super().get_queryset()

方案二：直接返回目标分页结果（无需重定向） #

如果不想让用户地址栏变化，可直接修改请求的分页参数，返回目标页内容：

from rest_framework import generics, permissions
from .models import Comment
from .serializers import CommentSerializer

class CommentList(generics.ListCreateAPIView):
    permission_classes = [permissions.AllowAny]
    queryset = Comment.objects.all()
    serializer_class = CommentSerializer
    pagination_class = CommentPagination

    def get(self, request, *args, **kwargs):
        comment_id = request.GET.get('comment_id')
        thread_id = request.GET.get('thread')
        
        if comment_id and thread_id:
            try:
                Comment.objects.get(id=comment_id, thread=thread_id)
            except Comment.DoesNotExist:
                return super().get(request, *args, **kwargs)
            
            num_preceeding = Comment.objects.filter(thread=thread_id, id__lt=comment_id).count()
            page_size = self.pagination_class.page_size
            page_num = num_preceeding // page_size + 1

            # 复制并修改GET参数，替换为page参数，移除comment_id避免循环
            request.GET = request.GET.copy()
            request.GET['page'] = str(page_num)
            request.GET.pop('comment_id', None)
        
        return super().get(request, *args, **kwargs)

    def get_queryset(self):
        thread_id = self.request.GET.get('thread')
        if thread_id:
            return Comment.objects.filter(thread=thread_id)
        return super().get_queryset()

内容的提问来源于stack exchange，提问作者Mulham