python - IOError : request data read error

Question

当我进行 Ajax 上传时，我似乎经常遇到 IOError: request data read 错误。例如，每上传 5 个文件，至少有 3 个文件出错。

其他人似乎也有同样的问题。例如。

• Django upload failing on request data read error
• Django file upload failing occasionally

其他一些观察:

• 这绝对不是我的互联网连接或浏览器问题。似乎在所有浏览器 chrome/FF/opera 上都发生了。

• 我正在运行 django 1.1.1 Apache/2.2.14 (Ubuntu) mod_ssl/2.2.14 OpenSSL/0.9.8k mod_wsgi/2.8 Python/2.6.5在 Lucid 上。

• 也不是文件大小。我有时可以上传超过 1 MB 的文件，但无法上传 180 Kb 的文件。

---

追溯

Traceback (most recent call last):

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/base.py", line 98, in get_response
    response = middleware_method(request, e)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/base.py", line 92, in get_response
    response = callback(request, *callback_args, **callback_kwargs)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/contrib/auth/decorators.py", line 78, in __call__
    return self.view_func(request, *args, **kwargs)

  File "/home/ubuntu/webapps/anonymous_app/app/do_work/views/__init__.py", line 391, in some_form_ajax_upload
    f = request.FILES.get('file_upload')

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/wsgi.py", line 187, in _get_files
    self._load_post_and_files()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/wsgi.py", line 137, in _load_post_and_files
    self._post, self._files = self.parse_file_upload(self.META, self.environ['wsgi.input'])

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/__init__.py", line 124, in parse_file_upload
    return parser.parse()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 133, in parse
    for item_type, meta_data, field_stream in Parser(stream, self._boundary):

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 606, in __iter__
    for sub_stream in boundarystream:

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 420, in next
    return LazyStream(BoundaryIter(self._stream, self._boundary))

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 446, in __init__
    unused_char = self._stream.read(1)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 299, in read
    out = ''.join(parts())

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 292, in parts
    chunk = self.next()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 314, in next
    output = self._producer.next()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 375, in next
    data = self.flo.read(self.chunk_size)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 405, in read
    return self._file.read(num_bytes)

IOError: request data read error


<WSGIRequest
GET:<QueryDict: {}>,
POST:<could not parse>,
COOKIES:{'__utma': '168279989.1688771210.1285773436.1285773436.1285773436.1',
 '__utmb': '168279989.20.10.1285773436',
 '__utmc': '168279989',
 '__utmz': '168279989.1285773436.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)',
 'beta': 'True',
 'sessionid': 'b1ecf92f2bba13e1885d07803e10aa03',
 'timezone_offset': '-330'},
META:{'CONTENT_LENGTH': '188575',
 'CONTENT_TYPE': 'multipart/form-data; boundary=---------------------------57602381214905740261171925981',
 'DOCUMENT_ROOT': '/htdocs',
 'GATEWAY_INTERFACE': 'CGI/1.1',
 'HTTPS': '1',
 'HTTP_ACCEPT': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
 'HTTP_ACCEPT_CHARSET': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
 'HTTP_ACCEPT_ENCODING': 'gzip,deflate',
 'HTTP_ACCEPT_LANGUAGE': 'en-us,en;q=0.5',
 'HTTP_CONNECTION': 'keep-alive',
 'HTTP_COOKIE': 'beta=True; __utma=168279989.1688771210.1285773436.1285773436.1285773436.1; __utmb=168279989.20.10.1285773436; __utmc=168279989; __utmz=168279989.1285773436.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); sessionid=b1ecf92f2bba13e1885d07803e10aa03; timezone_offset=-330',
 'HTTP_HOST': 'xxxxxx.compute-1.amazonaws.com',
 'HTTP_KEEP_ALIVE': '115',
 'HTTP_REFERER': 'https://ec2-184-72-79-96.compute-1.amazonaws.com/do-my-somees/enter/some-documents/',
 'HTTP_USER_AGENT': 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.10) Gecko/20100915 Ubuntu/10.04 (lucid) Firefox/3.6.10',
 'PATH': '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin',
 'PATH_INFO': u'/do-my-somees/enter/some-documents/ajax-upload/Other-some-Document/',
 'PATH_TRANSLATED': '/home/ubuntu/webapps/anonymous_app/settings/apache/qa.wsgi.py/do-my-somees/enter/some-documents/ajax-upload/Other-some-Document/',
 'QUERY_STRING': '',
 'REMOTE_ADDR': '',
 'REMOTE_PORT': '15561',
 'REQUEST_METHOD': 'POST',
 'REQUEST_URI': '/do-my-somees/enter/some-documents/ajax-upload/Other-some-Document/',
 'SCRIPT_FILENAME': '/home/ubuntu/webapps/anonymous_app/settings/apache/qa.wsgi.py',
 'SCRIPT_NAME': u'',
 'SERVER_ADDR': '10.196.142.182',
 'SERVER_ADMIN': 'dev@anonymous_app.com',
 'SERVER_NAME': 'ec2-184-72-79-96.compute-1.amazonaws.com',
 'SERVER_PORT': '443',
 'SERVER_PROTOCOL': 'HTTP/1.1',
 'SERVER_SIGNATURE': '<address>Apache/2.2.14 (Ubuntu) Server at ec2-184-72-79-96.compute-1.amazonaws.com Port 443</address>\n',
 'SERVER_SOFTWARE': 'Apache/2.2.14 (Ubuntu)',
 'SSL_TLS_SNI': 'ec2-184-72-79-96.compute-1.amazonaws.com',
 'mod_wsgi.application_group': 'qa.anonymous_app.com|',
 'mod_wsgi.callable_object': 'application',
 'mod_wsgi.listener_host': '',
 'mod_wsgi.listener_port': '443',
 'mod_wsgi.process_group': '',
 'mod_wsgi.reload_mechanism': '0',
 'mod_wsgi.script_reloading': '1',
 'mod_wsgi.version': (2, 8),
 'wsgi.errors': <mod_wsgi.Log object at 0xb9456860>,
 'wsgi.file_wrapper': <built-in method file_wrapper of mod_wsgi.Adapter object at 0xb936a968>,
 'wsgi.input': <mod_wsgi.Input object at 0xb9720e30>,
 'wsgi.multiprocess': True,
 'wsgi.multithread': False,
 'wsgi.run_once': False,
 'wsgi.url_scheme': 'https',
 'wsgi.version': (1, 0)}>

Answer 1

我也遇到了这个异常。在 Apache 错误日志文件中，我看到:

[Wed Aug 17 08:30:45 2011] [error] [client 10.114.48.206] (70014)End of file found: mod_wsgi (pid=9722): Unable to get bucket brigade for request., referer: https://egs-work/modwork/beleg/188074/edit/
[Wed Aug 17 08:30:45 2011] [error] [client 10.114.48.206] mod_wsgi (pid=3572): Exception occurred processing WSGI script '/home/modwork_egs_p/modwork_egs/apache/django_wsgi.py'.
[Wed Aug 17 08:30:45 2011] [error] [client 10.114.48.206] IOError: failed to write data

版本:

apache2-prefork-2.2.15-3.7.x86_64
apache2-mod_wsgi-3.3-1.8.x86_64 WSGIDaemonProcess with threads=1
mod_ssl/2.2.15
Linux egs-work 2.6.34.8-0.2-default #1 SMP 2011-04-06 18:11:26 +0200 x86_64 x86_64 x86_64 GNU/Linux
openSUSE 11.3 (x86_64)

首先我很困惑，因为最后一行“无法写入数据”不适合 django 代码“加载发布数据”。但我猜django想给客户端写一个错误页面。但是客户端已经取消了tcp连接。而且现在 http 500 页面无法写入客户端。

客户端在发送请求后，在得到响应之前断开连接:

• 用户关闭了浏览器或导航到其他页面。
• 用户按下了重新加载按钮。

我只在 POST 请求(不是 GET)中看到了这一点。如果使用 POST，网络服务器至少会读取两次:第一次获取 header ，第二次获取数据。第二次读取失败。

很容易复制:

插入一些在第一次访问 request.POST 之前等待的代码(请确保在 time.sleep() 之前没有中间件访问 request.POST):

def edit(request):
    import time
    time.sleep(3)
    #.....

现在做一个大的 POST(例如文件上传)。我不知道 apache 缓冲区的大小。但是 5 MB 应该足够了。当浏览器显示沙漏时，浏览到另一个页面。浏览器将取消请求，异常应该在日志文件中。

这是我的中间件，因为我不想在我们的日志文件中获得上述回溯:

class HandleExceptionMiddleware:

    def process_exception(self, request, exception):
        if isinstance(exception, IOError) and 'request data read error' in unicode(exception):
            logging.info('%s %s: %s: Request was canceled by the client.' % (
                    request.build_absolute_uri(), request.user, exception))
            return HttpResponseServerError()