python web中的文件上传与下载

django 框架下 实现服务端的文件上传与下载：

import json
import os
import uuid

def attachment_upload(request):
    """文件上传"""
    ret = {"status": False, "data": {"path": "", "name": ""}, "summary": ""}
    target ="media/upload/avatar" # 文件保存路径
    try:
        # 获取文件对象
        file_obj = request.FILES.get("file")
        raw_name = file_obj.name
        if not file_obj:
            pass
        else:
            # 检查目录存不存在,如果不存在新建一个
            if not os.path.exists(os.path.dirname(target)):
                os.makedirs(target)
            file_name = str(uuid.uuid4())
            file_path = os.path.join(target, file_name)
            with open(file_path, "wb") as f:
                for chunk in file_obj.chunks(): # chuck是分块写入文件 （.chunks()上循环而不是用read()保证大文件不会大量使用你的系统内存。）
                    f.write(chunk)
            ret["status"] = True
            ret["data"]['path'] = file_path
            ret["data"]['name'] = raw_name
    except Exception as e:
        ret["summary"] = str(e)
    return HttpResponse(json.dumps(ret))


def attachment_download(request):
     """文件下载"""
    name = request.GET.get("name", None)
    file_path = request.GET['url']
    def file_iterator(file_path, chunk_size=512):
        with open(file_path, 'rb') as f:
            while True:
                c = f.read(chunk_size)
                if c:
                    yield c
                else:
                    break
    response = StreamingHttpResponse(file_iterator(file_path))
    response['Content-Type'] = 'application/octet-stream'
    response['Content-Disposition'] = 'attachment;filename="{0}"'.format(name.encode('utf-8').decode('ISO-8859-1'))
    return response