在django中有多种方式可以让前端下载一个文件，比如excel的文件。这里记录下几种实现的方式。

一. 直接在django项目中有一个现成的excel文件且其中内容都有

1.使用django中的HttpResponse类

（1）.使用open（）打开二进制方式

from django.http import HttpResponse
path = "a.xlsx"
f = open(path,"rb")
response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
response['Content-Disposition'] = f'attachment; filename="{escape_uri_path(self.__template_name)}"'
response['Access-Control-Expose-Headers'] = 'content-disposition'
response.write(f.read())
f.close()
return response

(2). 使用io.BytesIO() 

import io
from  django.http import HttpResponse

path = "a.xlsx"
f =open(path,"rb")
response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
response['Content-Disposition'] = f'attachment; filename="{escape_uri_path(self.__template_name)}"'
response['Access-Control-Expose-Headers'] = 'content-disposition'
io_obj = io.BytesIO(f.read())
response.write(io_obj.getvalue())
f.close()
return respons

注意：使用io.BytesIO效率会更高。

2.使用django中的FileResponse类

from django.http import FileResponse
f = open(path_, 'rb')
response = FileResponse(f)
response['Content-Type'] = 'application/octet-stream'
response['Content-Disposition'] = 'attachment; filename="%s"' % (urlquote(filename))
response['Access-Control-Expose-Headers'] = 'content-disposition'
f.close()
return response

3.使用django中的StreamingHttpResponse类

def file_iterator(file_name, chunk_size=512):
        with open(file_name) as f:
            while True:
                c = f.read(chunk_size)
                if c:
                    yield c
                else:
                    break

    the_file_name = "big_file.pdf"
    response = StreamingHttpResponse(file_iterator(the_file_name))
    response['Content-Type'] = 'application/octet-stream'
    response['Content-Disposition'] = 'attachment;filename="{0}"'.format(the_file_name)

    return response

二. 在django项目中没有现成的excel

这里只举例使用openpyxl来创建excel。

from django.http import HttpResponse
import io
from openpyxl import Workbook

# 创建一个工作簿并向其中添加一些数据
workbook = Workbook()
sheet = workbook.active
sheet['A1'] = 'Hello'
sheet['B1'] = 'World'

# 将工作簿保存到 BytesIO 对象
buffer = io.BytesIO()
workbook.save(buffer)

# 将文件指针重置到开头
buffer.seek(0)

# 创建 HTTP 响应
response = HttpResponse(content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
response['Content-Disposition'] = 'attachment; filename="example.xlsx"'

# 将 BytesIO 对象中的数据作为响应内容发送
response.write(buffer.getvalue())

# 返回响应
return response

当然，上述中的HttpResponse也可以是FileResponse, StreamingHttpResponse