Python HTTP Server /客户端：远端关闭连接，没有响应错误 [英] Python HTTP Server/Client: Remote end closed connection without response error

问题描述

我使用 BaseHTTPRequestHandler 制作了简单的HTTP Server。问题是，当我想使用来自客户端的请求发布一些数据时，我得到 ConnectionError 。我从 requests lib文档进行了简单的请求。同样有趣的是，HTTP Server将从客户端接收数据并将其打印到控制台。我不明白这怎么可能。

I made simple HTTP Server using BaseHTTPRequestHandler. The problem is, that when I want to post some data using requests from client, I get ConnectionError. I did simple request from requests lib documentation. Also interesting thing is, that HTTP Server will receive data from client and print it to console. I don't understand how its possible.

客户：

def post_data():
    """Client method"""
    json_data = {
        'sender': 'User',
        'receiver': 'MY_SERVER',
        'message': 'Hello server! Sending some data.'}
    data_headers = {'Content-type': 'application/json', 'Accept': 'text/plain'}
    data_payload = json.dumps(json_data)

    try:
        post = requests.post('http://localhost:8080/post', data=data_payload,
                             headers=data_headers)
        print(post.status_code)
    except ConnectionError as e:
        print("CONNECTION ERROR: ")
        print(e)

HTTP服务器：

def do_POST(self):
    """Server method"""
    self.send_response(200)
    print("Receiving new data ...")
    content_length = int(self.headers['Content-Length'])
    post_data = self.rfile.read(content_length)
    print(post_data)

服务器结果：

C:\Users\mypc\Projects\PythonFiles\httpserver>python server.py

Fri Jan  5 01:09:12 2018: HTTP Server started on port 8080.
127.0.0.1 - - [05/Jan/2018 01:09:21] "POST /post HTTP/1.1" 200 -
Receiving new data ...
b'{"sender": "User", "receiver": "MY_SERVER", "message": "Hello server! Sending some data."}'

客户结果：

C:\Users\mypc\Projects\PythonFiles\httpserver>python client.py
CONNECTION ERROR:
('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',))

C:\Users\mypc\Projects\PythonFiles\httpserver>

没有异常阻止的错误：

Traceback (most recent call last):
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 387, in _make_request
    six.raise_from(e, None)
  File "<string>", line 2, in raise_from
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 383, in _make_request
    httplib_response = conn.getresponse()
  File "C:\Python36\lib\http\client.py", line 1331, in getresponse
    response.begin()
  File "C:\Python36\lib\http\client.py", line 297, in begin
    version, status, reason = self._read_status()
  File "C:\Python36\lib\http\client.py", line 266, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
http.client.RemoteDisconnected: Remote end closed connection without response

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python36\lib\site-packages\requests\adapters.py", line 440, in send
    timeout=timeout
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 639, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "C:\Python36\lib\site-packages\urllib3\util\retry.py", line 357, in increment
    raise six.reraise(type(error), error, _stacktrace)
  File "C:\Python36\lib\site-packages\urllib3\packages\six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 387, in _make_request
    six.raise_from(e, None)
  File "<string>", line 2, in raise_from
  File "C:\Python36\lib\site-packages\urllib3\connectionpool.py", line 383, in _make_request
    httplib_response = conn.getresponse()
  File "C:\Python36\lib\http\client.py", line 1331, in getresponse
    response.begin()
  File "C:\Python36\lib\http\client.py", line 297, in begin
    version, status, reason = self._read_status()
  File "C:\Python36\lib\http\client.py", line 266, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
urllib3.exceptions.ProtocolError: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "client.py", line 137, in <module>
    start_parser()
  File "client.py", line 101, in start_parser
    send_requests(args.get, args.post)
  File "client.py", line 51, in send_requests
    post_data()
  File "client.py", line 129, in post_data
    headers=data_headers)
  File "C:\Python36\lib\site-packages\requests\api.py", line 112, in post
    return request('post', url, data=data, json=json, **kwargs)
  File "C:\Python36\lib\site-packages\requests\api.py", line 58, in request
    return session.request(method=method, url=url, **kwargs)
  File "C:\Python36\lib\site-packages\requests\sessions.py", line 508, in request
    resp = self.send(prep, **send_kwargs)
  File "C:\Python36\lib\site-packages\requests\sessions.py", line 618, in send
    r = adapter.send(request, **kwargs)
  File "C:\Python36\lib\site-packages\requests\adapters.py", line 490, in send
    raise ConnectionError(err, request=request)
requests.exceptions.ConnectionError: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response',))

推荐答案

服务器似乎在不发送完整响应的情况下尽早终止了连接。我已经浏览了文档，并且我认为这是问题所在（添加了重点）：

It looks like the server is terminating the connection early without sending a full response. I've skimmed the docs and I think this is the problem (emphasis added):

send_response(code, message=None) 

向
标头缓冲区和日志中添加响应标头接受的请求。 HTTP响应行
被写入内部缓冲区，然后是Server和Date
标头。这两个标头的值分别从
version_string（）和date_time_string（）方法中选取。如果
服务器不打算使用
send_header（）方法发送任何其他标头，则在send_response（）之后应进行
end_headers（）调用。

Adds a response header to the headers buffer and logs the accepted request. The HTTP response line is written to the internal buffer, followed by Server and Date headers. The values for these two headers are picked up from the version_string() and date_time_string() methods, respectively. If the server does not intend to send any other headers using the send_header() method, then send_response() should be followed by an end_headers() call.

在版本3.3中进行了更改：标头存储在内部缓冲区中，需要显式调用
end_headers（）。

所以您可能只需要将调用添加到 end_headers 。如果您正在阅读一个旧示例（Python 3.3之前的版本），则不需要这样做。

So you probably just need to add the call to end_headers. If you were reading an old example (prior to Python 3.3) this wouldn't have been needed.

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