Django StreamingHttpResponse下载完成后删除文件

Question

在使用StreamingHttpResponse时，当文件下载完成时，我遇到了跟踪问题。我的意图是在用户下载文件后将其删除。

执行以下操作会在终端终止服务器时返回异常。

def down(request, file_name):
    if request.method == 'GET':
        if file_name:
            import os
            fh = get_object_or_404(FileHandler, filename=file_name)
            csv_path = os.path.join(fh.path, fh.filename)
            csv_file = open(csv_path)
            response = StreamingHttpResponse(csv_file, content_type='text/csv')
            response['Content-Disposition'] = 'attachment; filename="{}"'.format(fh.filename)
            csv_file.close()
            # I can now delete the file using os.remove(csv_path). Not sure since response has not been returned
            return response
    return HttpResponseRedirect('/b2b/export/')

回溯：

----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 59899)
Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 599, in process_request_thread
    self.finish_request(request, client_address)
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 334, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/Users/Michael/.virtualenvs/scrape/lib/python2.7/site-packages/django/core/servers/basehttp.py", line 102, in __init__
    super(WSGIRequestHandler, self).__init__(*args, **kwargs)
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/SocketServer.py", line 655, in __init__
    self.handle()
  File "/Users/Michael/.virtualenvs/scrape/lib/python2.7/site-packages/django/core/servers/basehttp.py", line 182, in handle
    handler.run(self.server.get_app())
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/handlers.py", line 92, in run
    self.close()
  File "/usr/local/Cellar/python/2.7.10_2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/wsgiref/simple_server.py", line 33, in close
    self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'
----------------------------------------

工作原理如下，但不确定何时删除文件，也不知道何时下载已完成。最重要的是如何关闭文件：

def down(request, file_name):
    if request.method == 'GET':
        if file_name:
            import os
            fh = get_object_or_404(FileHandler, filename=file_name)
            csv_path = os.path.join(fh.path, fh.filename)

            response = StreamingHttpResponse(open(csv_path), content_type='text/csv')
            response['Content-Disposition'] = 'attachment; filename="{}"'.format(fh.filename)
            return response
    return HttpResponseRedirect('/b2b/export/')

Answer 1

尝试创建一个类，它将在文件被gc时将其删除。例如，下面这样的代码可能会起作用：

class open_then_delete(object):
    def __init__(self, filename, mode='rb'):
        self.filename = filename
        self.file_obj = open(filename, mode)

    def __del__(self):
        self.close()


    def close(self):
        if self.file_obj:
           self.file_obj.close()
           self.file_obj = None
        self.cleanup()

    def cleanup(self):
        if self.filename:
            try:
                sys.stderr.write('open_then_delete: del ' + self.filename)
                os.remove(self.filename)
            except:
                pass
            self.filename = None

    def __getattr__(self, attr):
        return getattr(self.file_obj, attr)

    def __iter__(self):
        return iter(self.file_obj)

# below is your code, modified to use use_then_delete
def down(request, file_name):
    if request.method == 'GET':
        if file_name:
            import os
            fh = get_object_or_404(FileHandler, filename=file_name)
            csv = open_then_delete(os.path.join(fh.path, fh.filename))

            response = StreamingHttpResponse(csv.open(), content_type='text/csv')
            response['Content-Disposition'] = 'attachment; filename="{}"'.format(fh.filename)
            return response
    return HttpResponseRedirect('/b2b/export/')

Answer 2

我已经尝试了@mwag的上述建议，不过是用FileWrapper。

在我的例子中，我想压缩目录，并在下载完成后删除归档文件。

import os, time, zipfile
from django.http import StreamingHttpResponse
from wsgiref.util import FileWrapper

class FileDeleteWrapper(FileWrapper):
    def __init__(self, filepath, *args, **kwargs):
        self.filepath = filepath
        super(FileDeleteWrapper, self).__init__(*args, **kwargs)

    def __del__(self, *args, **kwargs):
        os.remove(self.filepath)
# View function
def zipFiles(request, assetId):
    asset = get_object_or_404(Asset, id=assetId)
    try:
        files = File.objects.filter(asset=asset)
        prefix = str(time.time()) +'_'

        zipPath = os.path.join(
            settings.ZIPPED_FILES_DIR,
            prefix + asset.label+'.zip'
        )

        z = zipfile.ZipFile(zipPath, 'w', zipfile.ZIP_DEFLATED)

        for f in files:
            path = os.path.join(
                mainSet.MEDIA_ROOT,
                str(f.file)
            )
            z.write(path, str(f))
        z.close()

        chunkSize = 16384

        response = StreamingHttpResponse(
            FileDeleteWrapper(
                filepath = zipPath,
                filelike=open(zipPath, 'rb'),
                blksize=chunkSize
            )
        )
        response['Content-Length'] = os.path.getsize(zipPath)
        response['Content-Disposition'] = "attachment; filename=%s" % asset.label+'.zip'
        return response
    except Exception as e:
            if mainSet.DEBUG:
                print(type(e))
            else:
                # log expception
                raise Http404