Django异步查询并下载CSV文件

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Django异步查询并下载CSV文件

通过循环遍历数据库,自动生成CSV文件的表头和内容.
Django V5.1

1. 视图

1.1 将同步的数据库查询转换为异步

async def get_blogs():# 使用sync_to_async包装Queryset方法blog_list = await sync_to_async(Blog.objects.all)()return blog_list

1.2 定义一个异步生成器逐行生成CSV数据

async def generate_csv():# 获取queryset listblogs = await get_blogs()# 生成csv文件头async for blog in blogs.values():# 打印查看遍历的内容 await sync_to_async(print)(blog.keys())yield ','.join(blog.keys()) + '\n'break# 生成csv文件内容async for values in blogs.values_list():# 打印查看遍历的内容 await sync_to_async(print)(values)yield ','.join(map(str, values)) + '\n'

1.3 异步下载

async def export_csv(request):response = StreamingHttpResponse(generate_csv(),content_type='text/csv')response['Content-Disposition'] = 'attachment; filename="blogs.csv"'return response

2. 模板

    <div class="container-fluid mt-3"><form action="{% url 'blog:export_csv' %}">{% csrf_token %}<button type="submit" class="btn btn-primary form-control">异步下载测试</button></form></div>

3. url

path('export-csv', views.export_csv, name="export_csv")

4. model

class Blog(models.Model):title = models.CharField(max_length=200, verbose_name="标题")content = models.TextField(verbose_name="内容")pub_time = models.DateTimeField(auto_now_add=True, verbose_name="发布时间")category = models.ForeignKey(to=BlogCategory, on_delete=models.CASCADE, verbose_name="分类")author = models.ForeignKey(to=User, on_delete=models.CASCADE, verbose_name="作者")class Meta:verbose_name = "博客"verbose_name_plural = verbose_nameordering = ['-pub_time']def __str__(self):return self.title