[broken] Generalize timed_recv_from_server and use it

log = logging.getLogger(__name__)

def timed_recv_from_server(sock, conf, yet_to_read):

    ''' Return the time in seconds it took to read <yet_to_read> bytes from

    the server. Return None if error '''

    assert yet_to_read > 0

def timed_recv_from_server(session, dest, byte_range):

    ''' Request the **byte_range** from the URL at **dest**. If successful,

    return True and the time it took to download. Otherwise return False and an

    error string. '''

    headers = {'Range': byte_range}

    start_time = time.time()

    while yet_to_read > 0:

        limit = min(conf.getint('scanner', 'max_recv_per_read'), yet_to_read)

    # TODO:

    # - What other exceptions can this throw?

    # - Do we have to read the content, or did requests already do so?

    # - Add timeout

    try:

            read_this_time = len(sock.recv(limit))

        except (socket.timeout, ConnectionResetError, BrokenPipeError) as e:

            log.info(e)

            return

        if read_this_time == 0:

            return

        yet_to_read -= read_this_time

        session.get(dest.url, headers=headers)

    except requests.exceptions.ConnectionError as e:

        return False, e

    end_time = time.time()

    return end_time - start_time

    return True, end_time - start_time

def get_random_range_string(content_length, size):

    log.debug('Measuring RTT to %s', dest.url)

    for _ in range(0, conf.getint('scanner', 'num_rtts')):

        random_range = get_random_range_string(content_length, size)

        headers = {'Range': random_range}

        start_time = time.time()

        # TODO:

        # - What other exceptions can this throw?

        # - Do we have to read the content, or did requests already do so?

        # - Add timeout

        try:

            session.get(dest.url, headers=headers)

        except requests.exceptions.ConnectionError as e:

            log.warning(

                'While measuring RTT to %s we hit an exception (does the '

                'webserver support Range requests?): %s', dest.url, e)

        success, data = timed_recv_from_server(session, dest, random_range)

        if not success:

            # data is an error string

            assert isinstance(data, str)

            log.warning('While measuring the RTT to %s we hit an exception '

                        '(does the webserver support Range requests?): %s',

                        dest.url, data)

            return None

        end_time = time.time()

        rtts.append(end_time - start_time)

        assert success

        # data is an RTT

        assert isinstance(data, float) or isinstance(data, int)

        rtts.append(data)

    return rtts