socketutil.py 文件源码

def receive_data(sock, size):
    """Retrieve a given number of bytes from a socket.
    It is expected the socket is able to supply that number of bytes.
    If it isn't, an exception is raised (you will not get a zero length result
    or a result that is smaller than what you asked for). The partial data that
    has been received however is stored in the 'partialData' attribute of
    the exception object."""
    try:
        delays = __retrydelays()
        msglen = 0
        data = bytearray()
        if USE_MSG_WAITALL and not hasattr(sock, "getpeercert"):    # ssl doesn't support recv flags
            while True:
                try:
                    chunk = sock.recv(size, socket.MSG_WAITALL)
                    if len(chunk) == size:
                        return chunk
                    # less data than asked, drop down into normal receive loop to finish
                    msglen = len(chunk)
                    data.extend(chunk)
                    break
                except socket.timeout:
                    raise TimeoutError("receiving: timeout")
                except socket.error as x:
                    err = getattr(x, "errno", x.args[0])
                    if err not in ERRNO_RETRIES:
                        raise ConnectionClosedError("receiving: connection lost: " + str(x))
                    time.sleep(next(delays))  # a slight delay to wait before retrying
        # old fashioned recv loop, we gather chunks until the message is complete
        while True:
            try:
                while msglen < size:
                    # 60k buffer limit avoids problems on certain OSes like VMS, Windows
                    chunk = sock.recv(min(60000, size - msglen))
                    if not chunk:
                        break
                    data.extend(chunk)
                    msglen += len(chunk)
                if len(data) != size:
                    err = ConnectionClosedError("receiving: not enough data")
                    err.partialData = data  # store the message that was received until now
                    raise err
                return data  # yay, complete
            except socket.timeout:
                raise TimeoutError("receiving: timeout")
            except socket.error as x:
                err = getattr(x, "errno", x.args[0])
                if err not in ERRNO_RETRIES:
                    raise ConnectionClosedError("receiving: connection lost: " + str(x))
                time.sleep(next(delays))  # a slight delay to wait before retrying
    except socket.timeout:
        raise TimeoutError("receiving: timeout")