django 文件下载

1. 最简单下载:将文件流放入HttpResponse对象即可，适合小文件的下载，但如果这个文件非常大，这种方式会占用大量. 如：

def file_download(request):

# do something...

with open('file_name.txt') as f:

    c = f.read()

return HttpResponse(c)

2. 合理的文件下载

Django的HttpResponse对象允许将迭代器作为传入参数，将上面代码中的传入参数c换成一个迭代器，便可以将上述下载功能优化为对大小文件均适合.更加合理的文件下载功能，应该先写一个迭代器，用于处理文件，然后将这个迭代器作为参数传递给StreaminghttpResponse对象，如：

from django.http import StreamingHttpResponse

def big_file_download(request):

    # do something...

    def file_iterator(file_name, chunk_size=):

        with open(file_name) as f:

            while True:

                c = f.read(chunk_size)

                if c:

                    yield c

                else:

                    break

    the_file_name = "file_name.txt"

    response = StreamingHttpResponse(file_iterator(the_file_name))

    return response

3.最优文件下载

上述的代码，已经完成了将服务器上的文件，通过文件流传输到浏览器，但文件流通常会以乱码形式显示到浏览器中，而非下载到硬盘上，因此，还要在做点优化，让文件流写入硬盘。优化很简单，给StreamingHttpResponse对象的Content-Type和Content-Disposition字段赋下面的值即可，如：

response['Content-Type'] = 'application/octet-stream'

response['Content-Disposition'] = 'attachment;filename="test.pdf"'

完整代码如下:

from django.http import StreamingHttpResponse

def big_file_download(request):

    # do something...

    def file_iterator(file_name, chunk_size=):

        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

4.文件名包含中文下载时文件名不对,原因是: url编码解码 ,解决方法如下

from django.utils.http import urlquote

response[‘Content-Disposition‘] = ‘attachment;filename="%s"‘ % (urlquote(title))

5. 遇到的问题：

下面可以下载成功：

def cmdb_export(request):

    """

    下载文件，发调用写好的 下载文件的 函数总是报错，直接写过来没问题.

    :param request:

    :return:

    """

    if request.method=="GET":

        print("导出ip...........hosts")

        dir_create()

        remove_file("hosts")

        obj = ServerConfInfo.objects.filter(deleted=False)

        for i in obj:

            filename = file_creat(file_name='hosts', mode="a", content=i.ip_net)

        response = StreamingHttpResponse(file_iterator(filename))

        response['Content-Type'] = 'application/octet-stream'

        response['Content-Disposition'] = 'attachment;filename="{0}"'.format(filename)

        return response

    else:

        pass

可是改成调用写好的下载函数就报错 didn't return an HttpResponse object. It returned None instead

def cmdb_export(request):

    """

    下载文件，发调用写好的 下载文件的 函数总是报错，直接写过来没问题.

    :param request:

    :return:

    """

    if request.method=="GET":

        print("导出ip...........hosts")

        dir_create()

        remove_file("hosts")

        obj = ServerConfInfo.objects.filter(deleted=False)

        for i in obj:

            filename = file_creat(file_name='hosts', mode="a", content=i.ip_net)

        dj_downloadfile(request,filename)   ##这里调用写好的下载函数。

        # txt = file_iterator(filename)

        # response = StreamingHttpResponse(file_iterator(filename))

        # response['Content-Type'] = 'application/octet-stream'

        # response['Content-Disposition'] = 'attachment;filename="{0}"'.format(filename)

        # return response

    else:

        pass

dj_downloadfile（）函数如下：

def dj_downloadfile(request,filename):

    """

    网页下载数据,发现引用该函数会出现错误，但是把代码拷贝过去是正常的.

    :param request:

    :param filename:

    :return:

    """

    response = StreamingHttpResponse(file_iterator(filename))

    response['Content-Type'] = 'application/octet-stream'

    response['Content-Disposition'] = 'attachment;filename="{0}"'.format(filename)

    return response

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django 文件下载

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