在Django REST Framework中用LZ4处理含图片请求的压缩与解压

嘿，我来帮你搞定这个需求！要在POST上传文档后自动用LZ4压缩，还能提供解压下载的链接，咱们可以按下面的步骤一步步来：

1. 先安装LZ4依赖 #

首先得把LZ4的Python包装上，打开终端跑这个命令：

pip install lz4

2. 调整你的模型 #

咱们需要给EmployeeDocument模型加一个字段来存储压缩后的文件，这样后续才能提供解压服务。修改后的模型大概是这样：

# models.py
from django.db import models
from lz4.frame import compress, decompress
import os
from django.core.files.base import ContentFile

class EmployeeDocument(models.Model):
    """
    Model, Which holds Employee documents uploaded.
    """
    employee = models.ForeignKey(
        Employee, related_name="employee_docs", null=True, blank=True, on_delete=models.SET_NULL)
    document = models.FileField(upload_to='employee_docs/original/')
    # 新增字段存储压缩后的文件
    compressed_document = models.FileField(upload_to='employee_docs/compressed/', blank=True, null=True)

    def compress_document(self):
        """用LZ4压缩上传的原始文件"""
        if self.document and not self.compressed_document:
            # 读取原始文件内容
            self.document.open()
            file_content = self.document.read()
            self.document.close()
            
            # 用LZ4压缩（frame格式带校验，更适合文件存储）
            compressed_content = compress(file_content)
            
            # 生成压缩后的文件名，比如在原文件名后加.lz4后缀
            original_name = os.path.splitext(self.document.name)[0]
            compressed_filename = f"{original_name}.lz4"
            
            # 将压缩内容保存到compressed_document字段
            self.compressed_document.save(compressed_filename, ContentFile(compressed_content), save=False)
    
    def save(self, *args, **kwargs):
        # 保存前自动触发压缩逻辑
        self.compress_document()
        super().save(*args, **kwargs)

3. 实现解压的类视图 #

接下来写一个专门处理解压请求的视图，让用户能下载解压后的原始文件：

# views.py
from django.views.generic import View
from django.http import HttpResponse
from lz4.frame import decompress
from .models import EmployeeDocument
import os

class DecompressDocumentView(View):
    def get(self, request, doc_id):
        try:
            emp_doc = EmployeeDocument.objects.get(id=doc_id)
            if not emp_doc.compressed_document:
                return HttpResponse("未找到对应的压缩文件", status=404)
            
            # 读取压缩文件内容
            emp_doc.compressed_document.open()
            compressed_content = emp_doc.compressed_document.read()
            emp_doc.compressed_document.close()
            
            # 执行解压操作
            decompressed_content = decompress(compressed_content)
            
            # 还原原始文件名（去掉.lz4后缀）
            original_filename = os.path.splitext(emp_doc.compressed_document.name)[0].split('/')[-1]
            
            # 返回解压后的文件供下载
            response = HttpResponse(decompressed_content, content_type='application/octet-stream')
            response['Content-Disposition'] = f'attachment; filename="{original_filename}"'
            return response
        except EmployeeDocument.DoesNotExist:
            return HttpResponse("指定文档不存在", status=404)
        except Exception as e:
            return HttpResponse(f"解压失败: {str(e)}", status=500)

4. 整合到POST上传的类视图 #

如果你用CreateView处理文档上传，可以在上传成功后把解压链接传递给前端模板：

# views.py
from django.views.generic.edit import CreateView
from .models import EmployeeDocument
from .forms import EmployeeDocumentForm

class EmployeeDocumentCreateView(CreateView):
    model = EmployeeDocument
    form_class = EmployeeDocumentForm
    success_url = '/employee-docs/'  # 替换成你的实际成功跳转URL

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        # 上传成功后，把解压链接加入上下文
        if self.object:
            context['decompress_url'] = f'/decompress/{self.object.id}/'
        return context

5. 配置URL路由 #

最后在你的urls.py里添加对应的路由规则：

# urls.py
from django.urls import path
from .views import EmployeeDocumentCreateView, DecompressDocumentView

urlpatterns = [
    path('upload-doc/', EmployeeDocumentCreateView.as_view(), name='upload_doc'),
    path('decompress/<int:doc_id>/', DecompressDocumentView.as_view(), name='decompress_doc'),
]

这样一来，用户上传文档后，系统会自动用LZ4压缩并保存，你可以在上传成功页面通过{{ decompress_url }}展示解压链接，用户点击就能下载解压后的原始文件啦！

内容的提问来源于stack exchange，提问作者Philip Mutua