Module netmiko

def ConnectHandler(*args, **kwargs):
    """Factory function selects the proper class and creates object based on device_type."""
    device_type = kwargs["device_type"]
    if device_type not in platforms:
        if device_type is None:
            msg_str = platforms_str
        else:
            msg_str = telnet_platforms_str if "telnet" in device_type else platforms_str
        raise ValueError(
            "Unsupported 'device_type' "
            "currently supported platforms are: {}".format(msg_str)
        )
    ConnectionClass = ssh_dispatcher(device_type)
    return ConnectionClass(*args, **kwargs)

def FileTransfer(*args, **kwargs):
    """Factory function selects the proper SCP class and creates object based on device_type."""
    if len(args) >= 1:
        device_type = args[0].device_type
    else:
        device_type = kwargs["ssh_conn"].device_type
    if device_type not in scp_platforms:
        raise ValueError(
            "Unsupported SCP device_type: "
            "currently supported platforms are: {}".format(scp_platforms_str)
        )
    FileTransferClass = FILE_TRANSFER_MAP[device_type]
    return FileTransferClass(*args, **kwargs)

def ConnectHandler(*args, **kwargs):
    """Factory function selects the proper class and creates object based on device_type."""
    device_type = kwargs["device_type"]
    if device_type not in platforms:
        if device_type is None:
            msg_str = platforms_str
        else:
            msg_str = telnet_platforms_str if "telnet" in device_type else platforms_str
        raise ValueError(
            "Unsupported 'device_type' "
            "currently supported platforms are: {}".format(msg_str)
        )
    ConnectionClass = ssh_dispatcher(device_type)
    return ConnectionClass(*args, **kwargs)

def file_transfer(
    ssh_conn,
    source_file,
    dest_file,
    file_system=None,
    direction="put",
    disable_md5=False,
    inline_transfer=False,
    overwrite_file=False,
    socket_timeout=10.0,
    progress=None,
    progress4=None,
    verify_file=None,
):
    """Use Secure Copy or Inline (IOS-only) to transfer files to/from network devices.

    inline_transfer ONLY SUPPORTS TEXT FILES and will not support binary file transfers.

    return {
        'file_exists': boolean,
        'file_transferred': boolean,
        'file_verified': boolean,
    }
    """
    transferred_and_verified = {
        "file_exists": True,
        "file_transferred": True,
        "file_verified": True,
    }
    transferred_and_notverified = {
        "file_exists": True,
        "file_transferred": True,
        "file_verified": False,
    }
    nottransferred_but_verified = {
        "file_exists": True,
        "file_transferred": False,
        "file_verified": True,
    }

    if "cisco_ios" in ssh_conn.device_type or "cisco_xe" in ssh_conn.device_type:
        cisco_ios = True
    else:
        cisco_ios = False
    if not cisco_ios and inline_transfer:
        raise ValueError("Inline Transfer only supported for Cisco IOS/Cisco IOS-XE")

    # Replace disable_md5 argument with verify_file argument across time
    if verify_file is None:
        verify_file = not disable_md5

    scp_args = {
        "ssh_conn": ssh_conn,
        "source_file": source_file,
        "dest_file": dest_file,
        "direction": direction,
        "socket_timeout": socket_timeout,
        "progress": progress,
        "progress4": progress4,
    }
    if file_system is not None:
        scp_args["file_system"] = file_system

    TransferClass = InLineTransfer if inline_transfer else FileTransfer

    with TransferClass(**scp_args) as scp_transfer:
        if scp_transfer.check_file_exists():
            if overwrite_file:
                if verify_file:
                    if scp_transfer.verify_file():
                        return nottransferred_but_verified
                    else:
                        # File exists, you can overwrite it, MD5 is wrong (transfer file)
                        verifyspace_and_transferfile(scp_transfer)
                        if scp_transfer.verify_file():
                            return transferred_and_verified
                        else:
                            raise ValueError(
                                "MD5 failure between source and destination files"
                            )
                else:
                    # File exists, you can overwrite it, but MD5 not allowed (transfer file)
                    verifyspace_and_transferfile(scp_transfer)
                    return transferred_and_notverified
            else:
                # File exists, but you can't overwrite it.
                if verify_file:
                    if scp_transfer.verify_file():
                        return nottransferred_but_verified
                msg = "File already exists and overwrite_file is disabled"
                raise ValueError(msg)
        else:
            verifyspace_and_transferfile(scp_transfer)
            # File doesn't exist
            if verify_file:
                if scp_transfer.verify_file():
                    return transferred_and_verified
                else:
                    raise ValueError("MD5 failure between source and destination files")
            else:
                return transferred_and_notverified

def progress_bar(filename, size, sent, peername=None):
    max_width = 50
    if isinstance(filename, bytes):
        filename = filename.decode()
    clear_screen = chr(27) + "[2J"
    terminating_char = "|"

    # Percentage done
    percent_complete = sent / size
    percent_str = f"{percent_complete*100:.2f}%"
    hash_count = int(percent_complete * max_width)
    progress = hash_count * ">"

    if peername is None:
        header_msg = f"Transferring file: {filename}\n"
    else:
        header_msg = f"Transferring file to {peername}: {filename}\n"

    msg = f"{progress:<50}{terminating_char:1} ({percent_str})"
    print(clear_screen)
    print(header_msg)
    print(msg)

def redispatch(obj, device_type, session_prep=True):
    """Dynamically change Netmiko object's class to proper class.
    Generally used with terminal_server device_type when you need to redispatch after interacting
    with terminal server.
    """
    new_class = ssh_dispatcher(device_type)
    obj.device_type = device_type
    obj.__class__ = new_class
    if session_prep:
        obj._try_session_preparation()

def ssh_dispatcher(device_type):
    """Select the class to be instantiated based on vendor/platform."""
    return CLASS_MAPPER[device_type]

class BaseConnection(object):
    """
    Defines vendor independent methods.

    Otherwise method left as a stub method.
    """

    def __init__(
        self,
        ip="",
        host="",
        username="",
        password=None,
        secret="",
        port=None,
        device_type="",
        verbose=False,
        global_delay_factor=1,
        global_cmd_verify=None,
        use_keys=False,
        key_file=None,
        pkey=None,
        passphrase=None,
        allow_agent=False,
        ssh_strict=False,
        system_host_keys=False,
        alt_host_keys=False,
        alt_key_file="",
        ssh_config_file=None,
        #
        # Connect timeouts
        # ssh-connect --> TCP conn (conn_timeout) --> SSH-banner (banner_timeout)
        #       --> Auth response (auth_timeout)
        conn_timeout=5,
        auth_timeout=None,  # Timeout to wait for authentication response
        banner_timeout=15,  # Timeout to wait for the banner to be presented (post TCP-connect)
        # Other timeouts
        blocking_timeout=20,  # Read blocking timeout
        timeout=100,  # TCP connect timeout | overloaded to read-loop timeout
        session_timeout=60,  # Used for locking/sharing the connection
        keepalive=0,
        default_enter=None,
        response_return=None,
        serial_settings=None,
        fast_cli=False,
        _legacy_mode=True,
        session_log=None,
        session_log_record_writes=False,
        session_log_file_mode="write",
        allow_auto_change=False,
        encoding="ascii",
        sock=None,
        auto_connect=True,
    ):
        """
        Initialize attributes for establishing connection to target device.

        :param ip: IP address of target device. Not required if `host` is
            provided.
        :type ip: str

        :param host: Hostname of target device. Not required if `ip` is
                provided.
        :type host: str

        :param username: Username to authenticate against target device if
                required.
        :type username: str

        :param password: Password to authenticate against target device if
                required.
        :type password: str

        :param secret: The enable password if target device requires one.
        :type secret: str

        :param port: The destination port used to connect to the target
                device.
        :type port: int or None

        :param device_type: Class selection based on device type.
        :type device_type: str

        :param verbose: Enable additional messages to standard output.
        :type verbose: bool

        :param global_delay_factor: Multiplication factor affecting Netmiko delays (default: 1).
        :type global_delay_factor: int

        :param use_keys: Connect to target device using SSH keys.
        :type use_keys: bool

        :param key_file: Filename path of the SSH key file to use.
        :type key_file: str

        :param pkey: SSH key object to use.
        :type pkey: paramiko.PKey

        :param passphrase: Passphrase to use for encrypted key; password will be used for key
                decryption if not specified.
        :type passphrase: str

        :param allow_agent: Enable use of SSH key-agent.
        :type allow_agent: bool

        :param ssh_strict: Automatically reject unknown SSH host keys (default: False, which
                means unknown SSH host keys will be accepted).
        :type ssh_strict: bool

        :param system_host_keys: Load host keys from the users known_hosts file.
        :type system_host_keys: bool
        :param alt_host_keys: If `True` host keys will be loaded from the file specified in
                alt_key_file.
        :type alt_host_keys: bool

        :param alt_key_file: SSH host key file to use (if alt_host_keys=True).
        :type alt_key_file: str

        :param ssh_config_file: File name of OpenSSH configuration file.
        :type ssh_config_file: str

        :param timeout: Connection timeout.
        :type timeout: float

        :param session_timeout: Set a timeout for parallel requests.
        :type session_timeout: float

        :param auth_timeout: Set a timeout (in seconds) to wait for an authentication response.
        :type auth_timeout: float

        :param banner_timeout: Set a timeout to wait for the SSH banner (pass to Paramiko).
        :type banner_timeout: float

        :param keepalive: Send SSH keepalive packets at a specific interval, in seconds.
                Currently defaults to 0, for backwards compatibility (it will not attempt
                to keep the connection alive).
        :type keepalive: int

        :param default_enter: Character(s) to send to correspond to enter key (default: \n).
        :type default_enter: str

        :param response_return: Character(s) to use in normalized return data to represent
                enter key (default: \n)
        :type response_return: str

        :param fast_cli: Provide a way to optimize for performance. Converts select_delay_factor
                to select smallest of global and specific. Sets default global_delay_factor to .1
                (default: False)
        :type fast_cli: boolean

        :param session_log: File path or BufferedIOBase subclass object to write the session log to.
        :type session_log: str

        :param session_log_record_writes: The session log generally only records channel reads due
                to eliminate command duplication due to command echo. You can enable this if you
                want to record both channel reads and channel writes in the log (default: False).
        :type session_log_record_writes: boolean

        :param session_log_file_mode: "write" or "append" for session_log file mode
                (default: "write")
        :type session_log_file_mode: str

        :param allow_auto_change: Allow automatic configuration changes for terminal settings.
                (default: False)
        :type allow_auto_change: bool

        :param encoding: Encoding to be used when writing bytes to the output channel.
                (default: ascii)
        :type encoding: str

        :param sock: An open socket or socket-like object (such as a `.Channel`) to use for
                communication to the target host (default: None).
        :type sock: socket

        :param global_cmd_verify: Control whether command echo verification is enabled or disabled
                (default: None). Global attribute takes precedence over function `cmd_verify`
                argument. Value of `None` indicates to use function `cmd_verify` argument.
        :type global_cmd_verify: bool|None

        :param auto_connect: Control whether Netmiko automatically establishes the connection as
                part of the object creation (default: True).
        :type auto_connect: bool
        """
        self.remote_conn = None
        # Does the platform support a configuration mode
        self._config_mode = True

        self.TELNET_RETURN = "\r\n"
        if default_enter is None:
            if "telnet" not in device_type:
                self.RETURN = "\n"
            else:
                self.RETURN = self.TELNET_RETURN
        else:
            self.RETURN = default_enter

        # Line Separator in response lines
        self.RESPONSE_RETURN = "\n" if response_return is None else response_return
        if ip:
            self.host = ip.strip()
        elif host:
            self.host = host.strip()
        if not ip and not host and "serial" not in device_type:
            raise ValueError("Either ip or host must be set")
        if port is None:
            if "telnet" in device_type:
                port = 23
            else:
                port = 22
        self.port = int(port)

        self.username = username
        self.password = password
        self.secret = secret
        self.device_type = device_type
        self.ansi_escape_codes = False
        self.verbose = verbose
        self.auth_timeout = auth_timeout
        self.banner_timeout = banner_timeout
        self.blocking_timeout = blocking_timeout
        self.conn_timeout = conn_timeout
        self.session_timeout = session_timeout
        self.timeout = timeout
        self.keepalive = keepalive
        self.allow_auto_change = allow_auto_change
        self.encoding = encoding
        self.sock = sock

        # Netmiko will close the session_log if we open the file
        self.session_log = None
        self.session_log_record_writes = session_log_record_writes
        self._session_log_close = False
        # Ensures last write operations prior to disconnect are recorded.
        self._session_log_fin = False
        if session_log is not None:
            if isinstance(session_log, str):
                # If session_log is a string, open a file corresponding to string name.
                self.open_session_log(filename=session_log, mode=session_log_file_mode)
            elif isinstance(session_log, io.BufferedIOBase):
                # In-memory buffer or an already open file handle
                self.session_log = session_log
            else:
                raise ValueError(
                    "session_log must be a path to a file, a file handle, "
                    "or a BufferedIOBase subclass."
                )

        # Default values
        self.serial_settings = {
            "port": "COM1",
            "baudrate": 9600,
            "bytesize": serial.EIGHTBITS,
            "parity": serial.PARITY_NONE,
            "stopbits": serial.STOPBITS_ONE,
        }
        if serial_settings is None:
            serial_settings = {}
        self.serial_settings.update(serial_settings)

        if "serial" in device_type:
            self.host = "serial"
            comm_port = self.serial_settings.pop("port")
            # Get the proper comm port reference if a name was enterred
            comm_port = check_serial_port(comm_port)
            self.serial_settings.update({"port": comm_port})

        self.fast_cli = fast_cli
        self._legacy_mode = _legacy_mode
        self.global_delay_factor = global_delay_factor
        self.global_cmd_verify = global_cmd_verify
        if self.fast_cli and self.global_delay_factor == 1:
            self.global_delay_factor = 0.1

        # set in set_base_prompt method
        self.base_prompt = ""
        self._session_locker = Lock()

        # determine if telnet or SSH
        if "_telnet" in device_type:
            self.protocol = "telnet"
            self.password = password or ""
        elif "_serial" in device_type:
            self.protocol = "serial"
            self.password = password or ""
        else:
            self.protocol = "ssh"

            if not ssh_strict:
                self.key_policy = paramiko.AutoAddPolicy()
            else:
                self.key_policy = paramiko.RejectPolicy()

            # Options for SSH host_keys
            self.use_keys = use_keys
            self.key_file = (
                path.abspath(path.expanduser(key_file)) if key_file else None
            )
            self.pkey = pkey
            self.passphrase = passphrase
            self.allow_agent = allow_agent
            self.system_host_keys = system_host_keys
            self.alt_host_keys = alt_host_keys
            self.alt_key_file = alt_key_file

            # For SSH proxy support
            self.ssh_config_file = ssh_config_file

        # Establish the remote connection
        if auto_connect:
            self._open()

    def _open(self):
        """Decouple connection creation from __init__ for mocking."""
        self._modify_connection_params()
        self.establish_connection()
        self._try_session_preparation()

    def __enter__(self):
        """Establish a session using a Context Manager."""
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        """Gracefully close connection on Context Manager exit."""
        self.disconnect()

    def _modify_connection_params(self):
        """Modify connection parameters prior to SSH connection."""
        pass

    def _timeout_exceeded(self, start, msg="Timeout exceeded!"):
        """Raise NetmikoTimeoutException if waiting too much in the serving queue.

        :param start: Initial start time to see if session lock timeout has been exceeded
        :type start: float (from time.time() call i.e. epoch time)

        :param msg: Exception message if timeout was exceeded
        :type msg: str
        """
        if not start:
            # Must provide a comparison time
            return False
        if time.time() - start > self.session_timeout:
            # session_timeout exceeded
            raise NetmikoTimeoutException(msg)
        return False

    def _lock_netmiko_session(self, start=None):
        """Try to acquire the Netmiko session lock. If not available, wait in the queue until
        the channel is available again.

        :param start: Initial start time to measure the session timeout
        :type start: float (from time.time() call i.e. epoch time)
        """
        if not start:
            start = time.time()
        # Wait here until the SSH channel lock is acquired or until session_timeout exceeded
        while not self._session_locker.acquire(False) and not self._timeout_exceeded(
            start, "The netmiko channel is not available!"
        ):
            time.sleep(0.1)
        return True

    def _unlock_netmiko_session(self):
        """
        Release the channel at the end of the task.
        """
        if self._session_locker.locked():
            self._session_locker.release()

    def _write_channel(self, out_data):
        """Generic handler that will write to both SSH and telnet channel.

        :param out_data: data to be written to the channel
        :type out_data: str (can be either unicode/byte string)
        """
        if self.protocol == "ssh":
            self.remote_conn.sendall(write_bytes(out_data, encoding=self.encoding))
        elif self.protocol == "telnet":
            self.remote_conn.write(write_bytes(out_data, encoding=self.encoding))
        elif self.protocol == "serial":
            self.remote_conn.write(write_bytes(out_data, encoding=self.encoding))
            self.remote_conn.flush()
        else:
            raise ValueError("Invalid protocol specified")
        try:
            log.debug(
                "write_channel: {}".format(
                    write_bytes(out_data, encoding=self.encoding)
                )
            )
            if self._session_log_fin or self.session_log_record_writes:
                self._write_session_log(out_data)
        except UnicodeDecodeError:
            # Don't log non-ASCII characters; this is null characters and telnet IAC (PY2)
            pass

    def _write_session_log(self, data):
        if self.session_log is not None and len(data) > 0:
            # Hide the password and secret in the session_log
            if self.password:
                data = data.replace(self.password, "********")
            if self.secret:
                data = data.replace(self.secret, "********")
            if isinstance(self.session_log, io.BufferedIOBase):
                data = self.normalize_linefeeds(data)
                self.session_log.write(write_bytes(data, encoding=self.encoding))
            else:
                self.session_log.write(self.normalize_linefeeds(data))
            self.session_log.flush()

    def write_channel(self, out_data):
        """Generic handler that will write to both SSH and telnet channel.

        :param out_data: data to be written to the channel
        :type out_data: str (can be either unicode/byte string)
        """
        self._lock_netmiko_session()
        try:
            self._write_channel(out_data)
        finally:
            # Always unlock the SSH channel, even on exception.
            self._unlock_netmiko_session()

    def is_alive(self):
        """Returns a boolean flag with the state of the connection."""
        null = chr(0)
        if self.remote_conn is None:
            log.error("Connection is not initialised, is_alive returns False")
            return False
        if self.protocol == "telnet":
            try:
                # Try sending IAC + NOP (IAC is telnet way of sending command)
                # IAC = Interpret as Command; it comes before the NOP.
                log.debug("Sending IAC + NOP")
                # Need to send multiple times to test connection
                self.remote_conn.sock.sendall(telnetlib.IAC + telnetlib.NOP)
                self.remote_conn.sock.sendall(telnetlib.IAC + telnetlib.NOP)
                self.remote_conn.sock.sendall(telnetlib.IAC + telnetlib.NOP)
                return True
            except AttributeError:
                return False
        else:
            # SSH
            try:
                # Try sending ASCII null byte to maintain the connection alive
                log.debug("Sending the NULL byte")
                self.write_channel(null)
                return self.remote_conn.transport.is_active()
            except (socket.error, EOFError):
                log.error("Unable to send", exc_info=True)
                # If unable to send, we can tell for sure that the connection is unusable
                return False
        return False

    def _read_channel(self):
        """Generic handler that will read all the data from an SSH or telnet channel."""
        if self.protocol == "ssh":
            output = ""
            while True:
                if self.remote_conn.recv_ready():
                    outbuf = self.remote_conn.recv(MAX_BUFFER)
                    if len(outbuf) == 0:
                        raise EOFError("Channel stream closed by remote device.")
                    output += outbuf.decode("utf-8", "ignore")
                else:
                    break
        elif self.protocol == "telnet":
            output = self.remote_conn.read_very_eager().decode("utf-8", "ignore")
        elif self.protocol == "serial":
            output = ""
            while self.remote_conn.in_waiting > 0:
                output += self.remote_conn.read(self.remote_conn.in_waiting).decode(
                    "utf-8", "ignore"
                )
        if self.ansi_escape_codes:
            output = self.strip_ansi_escape_codes(output)
        log.debug(f"read_channel: {output}")
        self._write_session_log(output)
        return output

    def read_channel(self):
        """Generic handler that will read all the data from an SSH or telnet channel."""
        output = ""
        self._lock_netmiko_session()
        try:
            output = self._read_channel()
        finally:
            # Always unlock the SSH channel, even on exception.
            self._unlock_netmiko_session()
        return output

    def _read_channel_expect(self, pattern="", re_flags=0, max_loops=150):
        """Function that reads channel until pattern is detected.

        pattern takes a regular expression.

        By default pattern will be self.base_prompt

        Note: this currently reads beyond pattern. In the case of SSH it reads MAX_BUFFER.
        In the case of telnet it reads all non-blocking data.

        There are dependencies here like determining whether in config_mode that are actually
        depending on reading beyond pattern.

        :param pattern: Regular expression pattern used to identify the command is done \
        (defaults to self.base_prompt)
        :type pattern: str (regular expression)

        :param re_flags: regex flags used in conjunction with pattern to search for prompt \
        (defaults to no flags)
        :type re_flags: int

        :param max_loops: max number of iterations to read the channel before raising exception.
            Will default to be based upon self.timeout.
        :type max_loops: int
        """
        output = ""
        if not pattern:
            pattern = re.escape(self.base_prompt)
        log.debug(f"Pattern is: {pattern}")

        i = 1
        loop_delay = 0.1
        # Default to making loop time be roughly equivalent to self.timeout (support old max_loops
        # argument for backwards compatibility).
        if max_loops == 150:
            max_loops = int(self.timeout / loop_delay)
        while i < max_loops:
            if self.protocol == "ssh":
                try:
                    # If no data available will wait timeout seconds trying to read
                    self._lock_netmiko_session()
                    new_data = self.remote_conn.recv(MAX_BUFFER)
                    if len(new_data) == 0:
                        raise EOFError("Channel stream closed by remote device.")
                    new_data = new_data.decode("utf-8", "ignore")
                    if self.ansi_escape_codes:
                        new_data = self.strip_ansi_escape_codes(new_data)
                    log.debug(f"_read_channel_expect read_data: {new_data}")
                    output += new_data
                    self._write_session_log(new_data)
                except socket.timeout:
                    raise NetmikoTimeoutException(
                        "Timed-out reading channel, data not available."
                    )
                finally:
                    self._unlock_netmiko_session()
            elif self.protocol == "telnet" or "serial":
                output += self.read_channel()
            if re.search(pattern, output, flags=re_flags):
                log.debug(f"Pattern found: {pattern} {output}")
                return output
            time.sleep(loop_delay * self.global_delay_factor)
            i += 1
        raise NetmikoTimeoutException(
            f"Timed-out reading channel, pattern not found in output: {pattern}"
        )

    def _read_channel_timing(self, delay_factor=1, max_loops=150):
        """Read data on the channel based on timing delays.

        Attempt to read channel max_loops number of times. If no data this will cause a 15 second
        delay.

        Once data is encountered read channel for another two seconds (2 * delay_factor) to make
        sure reading of channel is complete.

        :param delay_factor: multiplicative factor to adjust delay when reading channel (delays
            get multiplied by this factor)
        :type delay_factor: int or float

        :param max_loops: maximum number of loops to iterate through before returning channel data.
            Will default to be based upon self.timeout.
        :type max_loops: int
        """
        # Time to delay in each read loop
        loop_delay = 0.1
        final_delay = 2

        # Default to making loop time be roughly equivalent to self.timeout (support old max_loops
        # and delay_factor arguments for backwards compatibility).
        delay_factor = self.select_delay_factor(delay_factor)
        if delay_factor == 1 and max_loops == 150:
            max_loops = int(self.timeout / loop_delay)

        # FIX: Cleanup in future versions of Netmiko
        if delay_factor < 1:
            if not self._legacy_mode and self.fast_cli:
                delay_factor = 1

        channel_data = ""
        i = 0
        while i <= max_loops:
            time.sleep(loop_delay * delay_factor)
            new_data = self.read_channel()
            if new_data:
                channel_data += new_data
            else:
                # Safeguard to make sure really done
                time.sleep(final_delay * delay_factor)
                new_data = self.read_channel()
                if not new_data:
                    break
                else:
                    channel_data += new_data
            i += 1
        return channel_data

    def read_until_prompt(self, *args, **kwargs):
        """Read channel until self.base_prompt detected. Return ALL data available."""
        return self._read_channel_expect(*args, **kwargs)

    def read_until_pattern(self, *args, **kwargs):
        """Read channel until pattern detected. Return ALL data available."""
        return self._read_channel_expect(*args, **kwargs)

    def read_until_prompt_or_pattern(self, pattern="", re_flags=0):
        """Read until either self.base_prompt or pattern is detected.

        :param pattern: the pattern used to identify that the output is complete (i.e. stop \
        reading when pattern is detected). pattern will be combined with self.base_prompt to \
        terminate output reading when the first of self.base_prompt or pattern is detected.
        :type pattern: regular expression string

        :param re_flags: regex flags used in conjunction with pattern to search for prompt \
        (defaults to no flags)
        :type re_flags: int

        """
        combined_pattern = re.escape(self.base_prompt)
        if pattern:
            combined_pattern = r"({}|{})".format(combined_pattern, pattern)
        return self._read_channel_expect(combined_pattern, re_flags=re_flags)

    def serial_login(
        self,
        pri_prompt_terminator=r"#\s*$",
        alt_prompt_terminator=r">\s*$",
        username_pattern=r"(?:[Uu]ser:|sername|ogin)",
        pwd_pattern=r"assword",
        delay_factor=1,
        max_loops=20,
    ):
        self.telnet_login(
            pri_prompt_terminator,
            alt_prompt_terminator,
            username_pattern,
            pwd_pattern,
            delay_factor,
            max_loops,
        )

    def telnet_login(
        self,
        pri_prompt_terminator=r"#\s*$",
        alt_prompt_terminator=r">\s*$",
        username_pattern=r"(?:user:|username|login|user name)",
        pwd_pattern=r"assword",
        delay_factor=1,
        max_loops=20,
    ):
        """Telnet login. Can be username/password or just password.

        :param pri_prompt_terminator: Primary trailing delimiter for identifying a device prompt
        :type pri_prompt_terminator: str

        :param alt_prompt_terminator: Alternate trailing delimiter for identifying a device prompt
        :type alt_prompt_terminator: str

        :param username_pattern: Pattern used to identify the username prompt
        :type username_pattern: str

        :param delay_factor: See __init__: global_delay_factor
        :type delay_factor: int

        :param max_loops: Controls the wait time in conjunction with the delay_factor
        (default: 20)
        """
        delay_factor = self.select_delay_factor(delay_factor)

        # FIX: Cleanup in future versions of Netmiko
        if delay_factor < 1:
            if not self._legacy_mode and self.fast_cli:
                delay_factor = 1

        time.sleep(1 * delay_factor)

        output = ""
        return_msg = ""
        i = 1
        while i <= max_loops:
            try:
                output = self.read_channel()
                return_msg += output

                # Search for username pattern / send username
                if re.search(username_pattern, output, flags=re.I):
                    # Sometimes username/password must be terminated with "\r" and not "\r\n"
                    self.write_channel(self.username + "\r")
                    time.sleep(1 * delay_factor)
                    output = self.read_channel()
                    return_msg += output

                # Search for password pattern / send password
                if re.search(pwd_pattern, output, flags=re.I):
                    # Sometimes username/password must be terminated with "\r" and not "\r\n"
                    self.write_channel(self.password + "\r")
                    time.sleep(0.5 * delay_factor)
                    output = self.read_channel()
                    return_msg += output
                    if re.search(
                        pri_prompt_terminator, output, flags=re.M
                    ) or re.search(alt_prompt_terminator, output, flags=re.M):
                        return return_msg

                # Check if proper data received
                if re.search(pri_prompt_terminator, output, flags=re.M) or re.search(
                    alt_prompt_terminator, output, flags=re.M
                ):
                    return return_msg

                self.write_channel(self.TELNET_RETURN)
                time.sleep(0.5 * delay_factor)
                i += 1
            except EOFError:
                self.remote_conn.close()
                msg = f"Login failed: {self.host}"
                raise NetmikoAuthenticationException(msg)

        # Last try to see if we already logged in
        self.write_channel(self.TELNET_RETURN)
        time.sleep(0.5 * delay_factor)
        output = self.read_channel()
        return_msg += output
        if re.search(pri_prompt_terminator, output, flags=re.M) or re.search(
            alt_prompt_terminator, output, flags=re.M
        ):
            return return_msg

        msg = f"Login failed: {self.host}"
        self.remote_conn.close()
        raise NetmikoAuthenticationException(msg)

    def _try_session_preparation(self):
        """
        In case of an exception happening during `session_preparation()` Netmiko should
        gracefully clean-up after itself. This might be challenging for library users
        to do since they do not have a reference to the object. This is possibly related
        to threads used in Paramiko.
        """
        try:
            self.session_preparation()
        except Exception:
            self.disconnect()
            raise

    def session_preparation(self):
        """
        Prepare the session after the connection has been established

        This method handles some differences that occur between various devices
        early on in the session.

        In general, it should include:
        self._test_channel_read()
        self.set_base_prompt()
        self.disable_paging()
        self.set_terminal_width()
        self.clear_buffer()
        """
        self._test_channel_read()
        self.set_base_prompt()
        self.set_terminal_width()
        self.disable_paging()

        # Clear the read buffer
        time.sleep(0.3 * self.global_delay_factor)
        self.clear_buffer()

    def _use_ssh_config(self, dict_arg):
        """Update SSH connection parameters based on contents of SSH config file.

        :param dict_arg: Dictionary of SSH connection parameters
        :type dict_arg: dict
        """
        connect_dict = dict_arg.copy()

        # Use SSHConfig to generate source content.
        full_path = path.abspath(path.expanduser(self.ssh_config_file))
        if path.exists(full_path):
            ssh_config_instance = paramiko.SSHConfig()
            with io.open(full_path, "rt", encoding="utf-8") as f:
                ssh_config_instance.parse(f)
                source = ssh_config_instance.lookup(self.host)
        else:
            source = {}

        # Keys get normalized to lower-case
        if "proxycommand" in source:
            proxy = paramiko.ProxyCommand(source["proxycommand"])
        elif "proxyjump" in source:
            hops = list(reversed(source["proxyjump"].split(",")))
            if len(hops) > 1:
                raise ValueError(
                    "ProxyJump with more than one proxy server is not supported."
                )
            port = source.get("port", self.port)
            host = source.get("hostname", self.host)
            # -F {full_path} forces the continued use of the same SSH config file
            cmd = "ssh -F {} -W {}:{} {}".format(full_path, host, port, hops[0])
            proxy = paramiko.ProxyCommand(cmd)
        else:
            proxy = None

        # Only update 'hostname', 'sock', 'port', and 'username'
        # For 'port' and 'username' only update if using object defaults
        if connect_dict["port"] == 22:
            connect_dict["port"] = int(source.get("port", self.port))
        if connect_dict["username"] == "":
            connect_dict["username"] = source.get("user", self.username)
        if proxy:
            connect_dict["sock"] = proxy
        connect_dict["hostname"] = source.get("hostname", self.host)

        return connect_dict

    def _connect_params_dict(self):
        """Generate dictionary of Paramiko connection parameters."""
        conn_dict = {
            "hostname": self.host,
            "port": self.port,
            "username": self.username,
            "password": self.password,
            "look_for_keys": self.use_keys,
            "allow_agent": self.allow_agent,
            "key_filename": self.key_file,
            "pkey": self.pkey,
            "passphrase": self.passphrase,
            "timeout": self.conn_timeout,
            "auth_timeout": self.auth_timeout,
            "banner_timeout": self.banner_timeout,
            "sock": self.sock,
        }

        # Check if using SSH 'config' file mainly for SSH proxy support
        if self.ssh_config_file:
            conn_dict = self._use_ssh_config(conn_dict)
        return conn_dict

    def _sanitize_output(
        self, output, strip_command=False, command_string=None, strip_prompt=False
    ):
        """Strip out command echo, trailing router prompt and ANSI escape codes.

        :param output: Output from a remote network device
        :type output: unicode string

        :param strip_command:
        :type strip_command:
        """
        output = self.normalize_linefeeds(output)
        if strip_command and command_string:
            command_string = self.normalize_linefeeds(command_string)
            output = self.strip_command(command_string, output)
        if strip_prompt:
            output = self.strip_prompt(output)
        return output

    def establish_connection(self, width=511, height=1000):
        """Establish SSH connection to the network device

        Timeout will generate a NetmikoTimeoutException
        Authentication failure will generate a NetmikoAuthenticationException

        :param width: Specified width of the VT100 terminal window (default: 511)
        :type width: int

        :param height: Specified height of the VT100 terminal window (default: 1000)
        :type height: int
        """
        if self.protocol == "telnet":
            self.remote_conn = telnetlib.Telnet(
                self.host, port=self.port, timeout=self.timeout
            )
            self.telnet_login()
        elif self.protocol == "serial":
            self.remote_conn = serial.Serial(**self.serial_settings)
            self.serial_login()
        elif self.protocol == "ssh":
            ssh_connect_params = self._connect_params_dict()
            self.remote_conn_pre = self._build_ssh_client()

            # initiate SSH connection
            try:
                self.remote_conn_pre.connect(**ssh_connect_params)
            except socket.error as conn_error:
                self.paramiko_cleanup()
                msg = f"""TCP connection to device failed.

Common causes of this problem are:
1. Incorrect hostname or IP address.
2. Wrong TCP port.
3. Intermediate firewall blocking access.

Device settings: {self.device_type} {self.host}:{self.port}

"""

                # Handle DNS failures separately
                if "Name or service not known" in str(conn_error):
                    msg = (
                        f"DNS failure--the hostname you provided was not resolvable "
                        f"in DNS: {self.host}:{self.port}"
                    )

                msg = msg.lstrip()
                raise NetmikoTimeoutException(msg)
            except paramiko.ssh_exception.AuthenticationException as auth_err:
                self.paramiko_cleanup()
                msg = f"""Authentication to device failed.

Common causes of this problem are:
1. Invalid username and password
2. Incorrect SSH-key file
3. Connecting to the wrong device

Device settings: {self.device_type} {self.host}:{self.port}

"""

                msg += self.RETURN + str(auth_err)
                raise NetmikoAuthenticationException(msg)
            except paramiko.ssh_exception.SSHException as no_session_err:
                self.paramiko_cleanup()
                if "No existing session" in str(no_session_err):
                    msg = (
                        "Paramiko: 'No existing session' error: "
                        "try increasing 'conn_timeout' to 10 seconds or larger."
                    )
                    raise NetmikoTimeoutException(msg)
                else:
                    raise

            if self.verbose:
                print(f"SSH connection established to {self.host}:{self.port}")

            # Use invoke_shell to establish an 'interactive session'
            self.remote_conn = self.remote_conn_pre.invoke_shell(
                term="vt100", width=width, height=height
            )

            self.remote_conn.settimeout(self.blocking_timeout)
            if self.keepalive:
                self.remote_conn.transport.set_keepalive(self.keepalive)
            self.special_login_handler()
            if self.verbose:
                print("Interactive SSH session established")
        return ""

    # @m_exec_time
    def _test_channel_read(self, count=40, pattern=""):
        """Try to read the channel (generally post login) verify you receive data back.

        :param count: the number of times to check the channel for data
        :type count: int

        :param pattern: Regular expression pattern used to determine end of channel read
        :type pattern: str
        """

        def _increment_delay(main_delay, increment=1.1, maximum=8):
            """Increment sleep time to a maximum value."""
            main_delay = main_delay * increment
            if main_delay >= maximum:
                main_delay = maximum
            return main_delay

        i = 0
        delay_factor = self.select_delay_factor(delay_factor=0)
        main_delay = delay_factor * 0.1
        time.sleep(main_delay * 10)
        new_data = ""
        while i <= count:
            new_data += self._read_channel_timing()
            if new_data and pattern:
                if re.search(pattern, new_data):
                    break
            elif new_data:
                break
            else:
                self.write_channel(self.RETURN)

            main_delay = _increment_delay(main_delay)
            time.sleep(main_delay)
            i += 1

        # check if data was ever present
        if new_data:
            return new_data
        else:
            raise NetmikoTimeoutException("Timed out waiting for data")

    def _build_ssh_client(self):
        """Prepare for Paramiko SSH connection."""
        # Create instance of SSHClient object
        remote_conn_pre = paramiko.SSHClient()

        # Load host_keys for better SSH security
        if self.system_host_keys:
            remote_conn_pre.load_system_host_keys()
        if self.alt_host_keys and path.isfile(self.alt_key_file):
            remote_conn_pre.load_host_keys(self.alt_key_file)

        # Default is to automatically add untrusted hosts (make sure appropriate for your env)
        remote_conn_pre.set_missing_host_key_policy(self.key_policy)
        return remote_conn_pre

    def select_delay_factor(self, delay_factor):
        """
        Choose the greater of delay_factor or self.global_delay_factor (default).
        In fast_cli choose the lesser of delay_factor of self.global_delay_factor.

        :param delay_factor: See __init__: global_delay_factor
        :type delay_factor: int
        """
        if self.fast_cli:
            if delay_factor and delay_factor <= self.global_delay_factor:
                return delay_factor
            else:
                return self.global_delay_factor
        else:
            if delay_factor >= self.global_delay_factor:
                return delay_factor
            else:
                return self.global_delay_factor

    def special_login_handler(self, delay_factor=1):
        """Handler for devices like WLC, Extreme ERS that throw up characters prior to login."""
        pass

    def disable_paging(
        self, command="terminal length 0", delay_factor=1, cmd_verify=True, pattern=None
    ):
        """Disable paging default to a Cisco CLI method.

        :param command: Device command to disable pagination of output
        :type command: str

        :param delay_factor: See __init__: global_delay_factor
        :type delay_factor: int
        """
        delay_factor = self.select_delay_factor(delay_factor)
        command = self.normalize_cmd(command)
        log.debug("In disable_paging")
        log.debug(f"Command: {command}")
        self.write_channel(command)
        # Make sure you read until you detect the command echo (avoid getting out of sync)
        if cmd_verify and self.global_cmd_verify is not False:
            output = self.read_until_pattern(pattern=re.escape(command.strip()))
        elif pattern:
            output = self.read_until_pattern(pattern=pattern)
        else:
            output = self.read_until_prompt()
        log.debug(f"{output}")
        log.debug("Exiting disable_paging")
        return output

    def set_terminal_width(
        self, command="", delay_factor=1, cmd_verify=False, pattern=None
    ):
        """CLI terminals try to automatically adjust the line based on the width of the terminal.
        This causes the output to get distorted when accessed programmatically.

        Set terminal width to 511 which works on a broad set of devices.

        :param command: Command string to send to the device
        :type command: str

        :param delay_factor: See __init__: global_delay_factor
        :type delay_factor: int
        """
        if not command:
            return ""
        delay_factor = self.select_delay_factor(delay_factor)
        command = self.normalize_cmd(command)
        self.write_channel(command)
        # Avoid cmd_verify here as terminal width must be set before doing cmd_verify
        if cmd_verify and self.global_cmd_verify is not False:
            output = self.read_until_pattern(pattern=re.escape(command.strip()))
        elif pattern:
            output = self.read_until_pattern(pattern=pattern)
        else:
            output = self.read_until_prompt()
        return output

    # Retry by sleeping .33 and then double sleep until 5 attempts (.33, .66, 1.32, etc)
    @retry(
        wait=wait_exponential(multiplier=0.33, min=0, max=5),
        stop=stop_after_attempt(5),
        reraise=True,
    )
    def set_base_prompt(
        self, pri_prompt_terminator="#", alt_prompt_terminator=">", delay_factor=1
    ):
        """Sets self.base_prompt

        Used as delimiter for stripping of trailing prompt in output.

        Should be set to something that is general and applies in multiple contexts. For Cisco
        devices this will be set to router hostname (i.e. prompt without > or #).

        This will be set on entering user exec or privileged exec on Cisco, but not when
        entering/exiting config mode.

        :param pri_prompt_terminator: Primary trailing delimiter for identifying a device prompt
        :type pri_prompt_terminator: str

        :param alt_prompt_terminator: Alternate trailing delimiter for identifying a device prompt
        :type alt_prompt_terminator: str

        :param delay_factor: See __init__: global_delay_factor
        :type delay_factor: int
        """
        prompt = self.find_prompt(delay_factor=delay_factor)
        if not prompt[-1] in (pri_prompt_terminator, alt_prompt_terminator):
            raise ValueError(f"Router prompt not found: {repr(prompt)}")
        # Strip off trailing terminator
        self.base_prompt = prompt[:-1]
        return self.base_prompt

    def find_prompt(self, delay_factor=1):
        """Finds the current network device prompt, last line only.

        :param delay_factor: See __init__: global_delay_factor
        :type delay_factor: int
        """
        delay_factor = self.select_delay_factor(delay_factor)
        self.clear_buffer()
        self.write_channel(self.RETURN)
        sleep_time = delay_factor * 0.1
        time.sleep(sleep_time)

        # Initial attempt to get prompt
        prompt = self.read_channel().strip()

        # Check if the only thing you received was a newline
        count = 0
        while count <= 12 and not prompt:
            prompt = self.read_channel().strip()
            if not prompt:
                self.write_channel(self.RETURN)
                time.sleep(sleep_time)
                if sleep_time <= 3:
                    # Double the sleep_time when it is small
                    sleep_time *= 2
                else:
                    sleep_time += 1
            count += 1

        # If multiple lines in the output take the last line
        prompt = self.normalize_linefeeds(prompt)
        prompt = prompt.split(self.RESPONSE_RETURN)[-1]
        prompt = prompt.strip()
        if not prompt:
            raise ValueError(f"Unable to find prompt: {prompt}")
        time.sleep(delay_factor * 0.1)
        self.clear_buffer()
        log.debug(f"[find_prompt()]: prompt is {prompt}")
        return prompt

    def clear_buffer(self, backoff=True):
        """Read any data available in the channel."""
        sleep_time = 0.1 * self.global_delay_factor
        for _ in range(10):
            time.sleep(sleep_time)
            data = self.read_channel()
            if not data:
                break
            # Double sleep time each time we detect data
            log.debug("Clear buffer detects data in the channel")
            if backoff:
                sleep_time *= 2
                sleep_time = 3 if sleep_time >= 3 else sleep_time

    @select_cmd_verify
    def send_command_timing(
        self,
        command_string,
        delay_factor=1,
        max_loops=150,
        strip_prompt=True,
        strip_command=True,
        normalize=True,
        use_textfsm=False,
        textfsm_template=None,
        use_ttp=False,
        ttp_template=None,
        use_genie=False,
        cmd_verify=False,
        cmd_echo=None,
    ):
        """Execute command_string on the SSH channel using a delay-based mechanism. Generally
        used for show commands.

        :param command_string: The command to be executed on the remote device.
        :type command_string: str

        :param delay_factor: Multiplying factor used to adjust delays (default: 1).
        :type delay_factor: int or float

        :param max_loops: Controls wait time in conjunction with delay_factor. Will default to be
            based upon self.timeout.
        :type max_loops: int

        :param strip_prompt: Remove the trailing router prompt from the output (default: True).
        :type strip_prompt: bool

        :param strip_command: Remove the echo of the command from the output (default: True).
        :type strip_command: bool

        :param normalize: Ensure the proper enter is sent at end of command (default: True).
        :type normalize: bool

        :param use_textfsm: Process command output through TextFSM template (default: False).
        :type use_textfsm: bool

        :param textfsm_template: Name of template to parse output with; can be fully qualified
            path, relative path, or name of file in current directory. (default: None).
        :type textfsm_template: str

        :param use_ttp: Process command output through TTP template (default: False).
        :type use_ttp: bool

        :param ttp_template: Name of template to parse output with; can be fully qualified
            path, relative path, or name of file in current directory. (default: None).
        :type ttp_template: str

        :param use_genie: Process command output through PyATS/Genie parser (default: False).
        :type use_genie: bool

        :param cmd_verify: Verify command echo before proceeding (default: False).
        :type cmd_verify: bool

        :param cmd_echo: Deprecated (use cmd_verify instead)
        :type cmd_echo: bool
        """

        # For compatibility; remove cmd_echo in Netmiko 4.x.x
        if cmd_echo is not None:
            cmd_verify = cmd_echo

        output = ""
        delay_factor = self.select_delay_factor(delay_factor)

        if normalize:
            command_string = self.normalize_cmd(command_string)
        self.write_channel(command_string)

        cmd = command_string.strip()
        # if cmd is just an "enter" skip this section
        if cmd and cmd_verify:
            # Make sure you read until you detect the command echo (avoid getting out of sync)
            new_data = self.read_until_pattern(pattern=re.escape(cmd))
            new_data = self.normalize_linefeeds(new_data)

            # Strip off everything before the command echo
            if new_data.count(cmd) == 1:
                new_data = new_data.split(cmd)[1:]
                new_data = self.RESPONSE_RETURN.join(new_data)
                new_data = new_data.lstrip()
                output = f"{cmd}{self.RESPONSE_RETURN}{new_data}"
            else:
                # cmd is in the actual output (not just echoed)
                output = new_data

        log.debug(f"send_command_timing current output: {output}")

        output += self._read_channel_timing(
            delay_factor=delay_factor, max_loops=max_loops
        )
        output = self._sanitize_output(
            output,
            strip_command=strip_command,
            command_string=command_string,
            strip_prompt=strip_prompt,
        )

        # If both TextFSM, TTP and Genie are set, try TextFSM then TTP then Genie
        if use_textfsm:
            structured_output = get_structured_data(
                output,
                platform=self.device_type,
                command=command_string.strip(),
                template=textfsm_template,
            )
            # If we have structured data; return it.
            if not isinstance(structured_output, str):
                return structured_output
        if use_ttp:
            structured_output = get_structured_data_ttp(output, template=ttp_template)
            # If we have structured data; return it.
            if not isinstance(structured_output, str):
                return structured_output
        if use_genie:
            structured_output = get_structured_data_genie(
                output, platform=self.device_type, command=command_string.strip()
            )
            # If we have structured data; return it.
            if not isinstance(structured_output, str):
                return structured_output

        log.debug(f"send_command_timing final output: {output}")
        return output

    def strip_prompt(self, a_string):
        """Strip the trailing router prompt from the output.

        :param a_string: Returned string from device
        :type a_string: str
        """
        response_list = a_string.split(self.RESPONSE_RETURN)
        last_line = response_list[-1]
        if self.base_prompt in last_line:
            return self.RESPONSE_RETURN.join(response_list[:-1])
        else:
            return a_string

    def _first_line_handler(self, data, search_pattern):
        """
        In certain situations the first line will get repainted which causes a false
        match on the terminating pattern.

        Filter this out.

        returns a tuple of (data, first_line_processed)

        Where data is the original data potentially with the first line modified
        and the first_line_processed is a flag indicating that we have handled the
        first line.
        """
        try:
            # First line is the echo line containing the command. In certain situations
            # it gets repainted and needs filtered
            lines = data.split(self.RETURN)
            first_line = lines[0]
            if BACKSPACE_CHAR in first_line:
                pattern = search_pattern + r".*$"
                first_line = re.sub(pattern, repl="", string=first_line)
                lines[0] = first_line
                data = self.RETURN.join(lines)
            return (data, True)
        except IndexError:
            return (data, False)

    @select_cmd_verify
    def send_command(
        self,
        command_string,
        expect_string=None,
        delay_factor=1,
        max_loops=500,
        auto_find_prompt=True,
        strip_prompt=True,
        strip_command=True,
        normalize=True,
        use_textfsm=False,
        textfsm_template=None,
        use_ttp=False,
        ttp_template=None,
        use_genie=False,
        cmd_verify=True,
    ):
        """Execute command_string on the SSH channel using a pattern-based mechanism. Generally
        used for show commands. By default this method will keep waiting to receive data until the
        network device prompt is detected. The current network device prompt will be determined
        automatically.

        :param command_string: The command to be executed on the remote device.
        :type command_string: str

        :param expect_string: Regular expression pattern to use for determining end of output.
            If left blank will default to being based on router prompt.
        :type expect_string: str

        :param delay_factor: Multiplying factor used to adjust delays (default: 1).
        :type delay_factor: int

        :param max_loops: Controls wait time in conjunction with delay_factor. Will default to be
            based upon self.timeout.
        :type max_loops: int

        :param strip_prompt: Remove the trailing router prompt from the output (default: True).
        :type strip_prompt: bool

        :param strip_command: Remove the echo of the command from the output (default: True).
        :type strip_command: bool

        :param normalize: Ensure the proper enter is sent at end of command (default: True).
        :type normalize: bool

        :param use_textfsm: Process command output through TextFSM template (default: False).
        :type normalize: bool

        :param textfsm_template: Name of template to parse output with; can be fully qualified
            path, relative path, or name of file in current directory. (default: None).

        :param use_ttp: Process command output through TTP template (default: False).
        :type use_ttp: bool

        :param ttp_template: Name of template to parse output with; can be fully qualified
            path, relative path, or name of file in current directory. (default: None).
        :type ttp_template: str

        :param use_genie: Process command output through PyATS/Genie parser (default: False).
        :type normalize: bool

        :param cmd_verify: Verify command echo before proceeding (default: True).
        :type cmd_verify: bool
        """

        # Time to delay in each read loop
        loop_delay = 0.2

        # Default to making loop time be roughly equivalent to self.timeout (support old max_loops
        # and delay_factor arguments for backwards compatibility).
        delay_factor = self.select_delay_factor(delay_factor)
        if delay_factor == 1 and max_loops == 500:
            # Default arguments are being used; use self.timeout instead
            max_loops = int(self.timeout / loop_delay)

        # Find the current router prompt
        if expect_string is None:
            if auto_find_prompt:
                try:
                    prompt = self.find_prompt(delay_factor=delay_factor)
                except ValueError:
                    prompt = self.base_prompt
            else:
                prompt = self.base_prompt
            search_pattern = re.escape(prompt.strip())
        else:
            search_pattern = expect_string

        if normalize:
            command_string = self.normalize_cmd(command_string)

        time.sleep(delay_factor * loop_delay)
        self.clear_buffer()
        self.write_channel(command_string)
        new_data = ""

        cmd = command_string.strip()
        # if cmd is just an "enter" skip this section
        if cmd and cmd_verify:
            # Make sure you read until you detect the command echo (avoid getting out of sync)
            new_data = self.read_until_pattern(pattern=re.escape(cmd))
            new_data = self.normalize_linefeeds(new_data)
            # Strip off everything before the command echo (to avoid false positives on the prompt)
            if new_data.count(cmd) == 1:
                new_data = new_data.split(cmd)[1:]
                new_data = self.RESPONSE_RETURN.join(new_data)
                new_data = new_data.lstrip()
                new_data = f"{cmd}{self.RESPONSE_RETURN}{new_data}"

        i = 1
        output = ""
        past_three_reads = deque(maxlen=3)
        first_line_processed = False

        # Keep reading data until search_pattern is found or until max_loops is reached.
        while i <= max_loops:
            if new_data:
                output += new_data
                past_three_reads.append(new_data)

                # Case where we haven't processed the first_line yet (there is a potential issue
                # in the first line (in cases where the line is repainted).
                if not first_line_processed:
                    output, first_line_processed = self._first_line_handler(
                        output, search_pattern
                    )
                    # Check if we have already found our pattern
                    if re.search(search_pattern, output):
                        break

                else:
                    # Check if pattern is in the past three reads
                    if re.search(search_pattern, "".join(past_three_reads)):
                        break

            time.sleep(delay_factor * loop_delay)
            i += 1
            new_data = self.read_channel()
        else:  # nobreak
            raise IOError(
                "Search pattern never detected in send_command: {}".format(
                    search_pattern
                )
            )

        output = self._sanitize_output(
            output,
            strip_command=strip_command,
            command_string=command_string,
            strip_prompt=strip_prompt,
        )

        # If both TextFSM, TTP and Genie are set, try TextFSM then TTP then Genie
        if use_textfsm:
            structured_output = get_structured_data(
                output,
                platform=self.device_type,
                command=command_string.strip(),
                template=textfsm_template,
            )
            # If we have structured data; return it.
            if not isinstance(structured_output, str):
                return structured_output
        if use_ttp:
            structured_output = get_structured_data_ttp(output, template=ttp_template)
            # If we have structured data; return it.
            if not isinstance(structured_output, str):
                return structured_output
        if use_genie:
            structured_output = get_structured_data_genie(
                output, platform=self.device_type, command=command_string.strip()
            )
            # If we have structured data; return it.
            if not isinstance(structured_output, str):
                return structured_output
        return output

    def send_command_expect(self, *args, **kwargs):
        """Support previous name of send_command method.

        :param args: Positional arguments to send to send_command()
        :type args: list

        :param kwargs: Keyword arguments to send to send_command()
        :type kwargs: dict
        """
        return self.send_command(*args, **kwargs)

    @staticmethod
    def strip_backspaces(output):
        """Strip any backspace characters out of the output.

        :param output: Output obtained from a remote network device.
        :type output: str
        """
        backspace_char = "\x08"
        return output.replace(backspace_char, "")

    def strip_command(self, command_string, output):
        """
        Strip command_string from output string

        Cisco IOS adds backspaces into output for long commands (i.e. for commands that line wrap)

        :param command_string: The command string sent to the device
        :type command_string: str

        :param output: The returned output as a result of the command string sent to the device
        :type output: str
        """
        backspace_char = "\x08"

        # Check for line wrap (remove backspaces)
        if backspace_char in output:
            output = output.replace(backspace_char, "")

        # Juniper has a weird case where the echoed command will be " \n"
        # i.e. there is an extra space there.
        cmd = command_string.strip()
        if output.startswith(cmd):
            output_lines = output.split(self.RESPONSE_RETURN)
            new_output = output_lines[1:]
            return self.RESPONSE_RETURN.join(new_output)
        else:
            # command_string isn't there; do nothing
            return output

    def normalize_linefeeds(self, a_string):
        """Convert `\r\r\n`,`\r\n`, `\n\r` to `\n.`

        :param a_string: A string that may have non-normalized line feeds
            i.e. output returned from device, or a device prompt
        :type a_string: str
        """
        newline = re.compile("(\r\r\r\n|\r\r\n|\r\n|\n\r)")
        a_string = newline.sub(self.RESPONSE_RETURN, a_string)
        if self.RESPONSE_RETURN == "\n":
            # Convert any remaining \r to \n
            return re.sub("\r", self.RESPONSE_RETURN, a_string)
        else:
            return a_string

    def normalize_cmd(self, command):
        """Normalize CLI commands to have a single trailing newline.

        :param command: Command that may require line feed to be normalized
        :type command: str
        """
        command = command.rstrip()
        command += self.RETURN
        return command

    def check_enable_mode(self, check_string=""):
        """Check if in enable mode. Return boolean.

        :param check_string: Identification of privilege mode from device
        :type check_string: str
        """
        self.write_channel(self.RETURN)
        output = self.read_until_prompt()
        return check_string in output

    def enable(
        self, cmd="", pattern="ssword", enable_pattern=None, re_flags=re.IGNORECASE
    ):
        """Enter enable mode.

        :param cmd: Device command to enter enable mode
        :type cmd: str

        :param pattern: pattern to search for indicating device is waiting for password
        :type pattern: str

        :param enable_pattern: pattern indicating you have entered enable mode
        :type pattern: str

        :param re_flags: Regular expression flags used in conjunction with pattern
        :type re_flags: int
        """
        output = ""
        msg = (
            "Failed to enter enable mode. Please ensure you pass "
            "the 'secret' argument to ConnectHandler."
        )

        # Check if in enable mode
        if not self.check_enable_mode():
            # Send "enable" mode command
            self.write_channel(self.normalize_cmd(cmd))
            try:
                # Read the command echo
                end_data = ""
                if self.global_cmd_verify is not False:
                    output += self.read_until_pattern(pattern=re.escape(cmd.strip()))
                    end_data = output.split(cmd.strip())[-1]

                # Search for trailing prompt or password pattern
                if pattern not in output and self.base_prompt not in end_data:
                    output += self.read_until_prompt_or_pattern(
                        pattern=pattern, re_flags=re_flags
                    )
                # Send the "secret" in response to password pattern
                if re.search(pattern, output):
                    self.write_channel(self.normalize_cmd(self.secret))
                    output += self.read_until_prompt()

                # Search for terminating pattern if defined
                if enable_pattern and not re.search(enable_pattern, output):
                    output += self.read_until_pattern(pattern=enable_pattern)
                else:
                    if not self.check_enable_mode():
                        raise ValueError(msg)
            except NetmikoTimeoutException:
                raise ValueError(msg)
        return output

    def exit_enable_mode(self, exit_command=""):
        """Exit enable mode.

        :param exit_command: Command that exits the session from privileged mode
        :type exit_command: str
        """
        output = ""
        if self.check_enable_mode():
            self.write_channel(self.normalize_cmd(exit_command))
            output += self.read_until_prompt()
            if self.check_enable_mode():
                raise ValueError("Failed to exit enable mode.")
        return output

    def check_config_mode(self, check_string="", pattern=""):
        """Checks if the device is in configuration mode or not.

        :param check_string: Identification of configuration mode from the device
        :type check_string: str

        :param pattern: Pattern to terminate reading of channel
        :type pattern: str
        """
        self.write_channel(self.RETURN)
        # You can encounter an issue here (on router name changes) prefer delay-based solution
        if not pattern:
            output = self._read_channel_timing()
        else:
            output = self.read_until_pattern(pattern=pattern)
        return check_string in output

    def config_mode(self, config_command="", pattern="", re_flags=0):
        """Enter into config_mode.

        :param config_command: Configuration command to send to the device
        :type config_command: str

        :param pattern: Pattern to terminate reading of channel
        :type pattern: str

        :param re_flags: Regular expression flags
        :type re_flags: RegexFlag
        """
        output = ""
        if not self.check_config_mode():
            self.write_channel(self.normalize_cmd(config_command))
            # Make sure you read until you detect the command echo (avoid getting out of sync)
            if self.global_cmd_verify is not False:
                output += self.read_until_pattern(
                    pattern=re.escape(config_command.strip())
                )
            if not re.search(pattern, output, flags=re_flags):
                output += self.read_until_pattern(pattern=pattern, re_flags=re_flags)
            if not self.check_config_mode():
                raise ValueError("Failed to enter configuration mode.")
        return output

    def exit_config_mode(self, exit_config="", pattern=""):
        """Exit from configuration mode.

        :param exit_config: Command to exit configuration mode
        :type exit_config: str

        :param pattern: Pattern to terminate reading of channel
        :type pattern: str
        """
        output = ""
        if self.check_config_mode():
            self.write_channel(self.normalize_cmd(exit_config))
            # Make sure you read until you detect the command echo (avoid getting out of sync)
            if self.global_cmd_verify is not False:
                output += self.read_until_pattern(
                    pattern=re.escape(exit_config.strip())
                )
            if not re.search(pattern, output, flags=re.M):
                output += self.read_until_pattern(pattern=pattern)
            if self.check_config_mode():
                raise ValueError("Failed to exit configuration mode")
        log.debug(f"exit_config_mode: {output}")
        return output

    def send_config_from_file(self, config_file=None, **kwargs):
        """
        Send configuration commands down the SSH channel from a file.

        The file is processed line-by-line and each command is sent down the
        SSH channel.

        **kwargs are passed to send_config_set method.

        :param config_file: Path to configuration file to be sent to the device
        :type config_file: str

        :param kwargs: params to be sent to send_config_set method
        :type kwargs: dict
        """
        with io.open(config_file, "rt", encoding="utf-8") as cfg_file:
            return self.send_config_set(cfg_file, **kwargs)

    def send_config_set(
        self,
        config_commands=None,
        exit_config_mode=True,
        delay_factor=1,
        max_loops=150,
        strip_prompt=False,
        strip_command=False,
        config_mode_command=None,
        cmd_verify=True,
        enter_config_mode=True,
        error_pattern="",
    ):
        """
        Send configuration commands down the SSH channel.

        config_commands is an iterable containing all of the configuration commands.
        The commands will be executed one after the other.

        Automatically exits/enters configuration mode.

        :param config_commands: Multiple configuration commands to be sent to the device
        :type config_commands: list or string

        :param exit_config_mode: Determines whether or not to exit config mode after complete
        :type exit_config_mode: bool

        :param delay_factor: Factor to adjust delays
        :type delay_factor: int

        :param max_loops: Controls wait time in conjunction with delay_factor (default: 150)
        :type max_loops: int

        :param strip_prompt: Determines whether or not to strip the prompt
        :type strip_prompt: bool

        :param strip_command: Determines whether or not to strip the command
        :type strip_command: bool

        :param config_mode_command: The command to enter into config mode
        :type config_mode_command: str

        :param cmd_verify: Whether or not to verify command echo for each command in config_set
        :type cmd_verify: bool

        :param enter_config_mode: Do you enter config mode before sending config commands
        :type exit_config_mode: bool

        :param error_pattern: Regular expression pattern to detect config errors in the
        output.
        :type error_pattern: str
        """
        delay_factor = self.select_delay_factor(delay_factor)
        if config_commands is None:
            return ""
        elif isinstance(config_commands, str):
            config_commands = (config_commands,)

        if not hasattr(config_commands, "__iter__"):
            raise ValueError("Invalid argument passed into send_config_set")

        # Send config commands
        output = ""
        if enter_config_mode:
            cfg_mode_args = (config_mode_command,) if config_mode_command else tuple()
            output += self.config_mode(*cfg_mode_args)

        # If error_pattern is perform output gathering line by line and not fast_cli mode.
        if self.fast_cli and self._legacy_mode and not error_pattern:
            for cmd in config_commands:
                self.write_channel(self.normalize_cmd(cmd))
            # Gather output
            output += self._read_channel_timing(
                delay_factor=delay_factor, max_loops=max_loops
            )

        elif not cmd_verify:
            for cmd in config_commands:
                self.write_channel(self.normalize_cmd(cmd))
                time.sleep(delay_factor * 0.05)

                # Gather the output incrementally due to error_pattern requirements
                if error_pattern:
                    output += self._read_channel_timing(
                        delay_factor=delay_factor, max_loops=max_loops
                    )
                    if re.search(error_pattern, output, flags=re.M):
                        msg = f"Invalid input detected at command: {cmd}"
                        raise ConfigInvalidException(msg)

            # Standard output gathering (no error_pattern)
            if not error_pattern:
                output += self._read_channel_timing(
                    delay_factor=delay_factor, max_loops=max_loops
                )

        else:
            for cmd in config_commands:
                self.write_channel(self.normalize_cmd(cmd))

                # Make sure command is echoed
                new_output = self.read_until_pattern(pattern=re.escape(cmd.strip()))
                output += new_output

                # We might capture next prompt in the original read
                pattern = f"(?:{re.escape(self.base_prompt)}|#)"
                if not re.search(pattern, new_output):
                    # Make sure trailing prompt comes back (after command)
                    # NX-OS has fast-buffering problem where it immediately echoes command
                    # Even though the device hasn't caught up with processing command.
                    new_output = self.read_until_pattern(pattern=pattern)
                    output += new_output

                if error_pattern:
                    if re.search(error_pattern, output, flags=re.M):
                        msg = f"Invalid input detected at command: {cmd}"
                        raise ConfigInvalidException(msg)

        if exit_config_mode:
            output += self.exit_config_mode()
        output = self._sanitize_output(output)
        log.debug(f"{output}")
        return output

    def strip_ansi_escape_codes(self, string_buffer):
        """
        Remove any ANSI (VT100) ESC codes from the output

        http://en.wikipedia.org/wiki/ANSI_escape_code

        Note: this does not capture ALL possible ANSI Escape Codes only the ones
        I have encountered

        Current codes that are filtered:
        ESC = '\x1b' or chr(27)
        ESC = is the escape character [^ in hex ('\x1b')
        ESC[24;27H   Position cursor
        ESC[?25h     Show the cursor
        ESC[E        Next line (HP does ESC-E)
        ESC[K        Erase line from cursor to the end of line
        ESC[2K       Erase entire line
        ESC[1;24r    Enable scrolling from start to row end
        ESC[?6l      Reset mode screen with options 640 x 200 monochrome (graphics)
        ESC[?7l      Disable line wrapping
        ESC[2J       Code erase display
        ESC[00;32m   Color Green (30 to 37 are different colors) more general pattern is
                     ESC[\d\d;\d\dm and ESC[\d\d;\d\d;\d\dm
        ESC[6n       Get cursor position
        ESC[1D       Move cursor position leftward by x characters (1 in this case)

        HP ProCurve and Cisco SG300 require this (possible others).

        :param string_buffer: The string to be processed to remove ANSI escape codes
        :type string_buffer: str
        """  # noqa

        code_position_cursor = chr(27) + r"\[\d+;\d+H"
        code_show_cursor = chr(27) + r"\[\?25h"
        code_next_line = chr(27) + r"E"
        code_erase_line_end = chr(27) + r"\[K"
        code_erase_line = chr(27) + r"\[2K"
        code_erase_start_line = chr(27) + r"\[K"
        code_enable_scroll = chr(27) + r"\[\d+;\d+r"
        code_insert_line = chr(27) + r"\[(\d+)L"
        code_carriage_return = chr(27) + r"\[1M"
        code_disable_line_wrapping = chr(27) + r"\[\?7l"
        code_reset_mode_screen_options = chr(27) + r"\[\?\d+l"
        code_reset_graphics_mode = chr(27) + r"\[00m"
        code_erase_display = chr(27) + r"\[2J"
        code_erase_display_0 = chr(27) + r"\[J"
        code_graphics_mode = chr(27) + r"\[\d\d;\d\dm"
        code_graphics_mode2 = chr(27) + r"\[\d\d;\d\d;\d\dm"
        code_graphics_mode3 = chr(27) + r"\[(3|4)\dm"
        code_graphics_mode4 = chr(27) + r"\[(9|10)[0-7]m"
        code_get_cursor_position = chr(27) + r"\[6n"
        code_cursor_position = chr(27) + r"\[m"
        code_attrs_off = chr(27) + r"\[0m"
        code_reverse = chr(27) + r"\[7m"
        code_cursor_left = chr(27) + r"\[\d+D"

        code_set = [
            code_position_cursor,
            code_show_cursor,
            code_erase_line,
            code_enable_scroll,
            code_erase_start_line,
            code_carriage_return,
            code_disable_line_wrapping,
            code_erase_line_end,
            code_reset_mode_screen_options,
            code_reset_graphics_mode,
            code_erase_display,
            code_graphics_mode,
            code_graphics_mode2,
            code_graphics_mode3,
            code_graphics_mode4,
            code_get_cursor_position,
            code_cursor_position,
            code_erase_display,
            code_erase_display_0,
            code_attrs_off,
            code_reverse,
            code_cursor_left,
        ]

        output = string_buffer
        for ansi_esc_code in code_set:
            output = re.sub(ansi_esc_code, "", output)

        # CODE_NEXT_LINE must substitute with return
        output = re.sub(code_next_line, self.RETURN, output)

        # Aruba and ProCurve switches can use code_insert_line for <enter>
        insert_line_match = re.search(code_insert_line, output)
        if insert_line_match:
            # Substitute each insert_line with a new <enter>
            count = int(insert_line_match.group(1))
            output = re.sub(code_insert_line, count * self.RETURN, output)

        return output

    def cleanup(self, command=""):
        """Logout of the session on the network device plus any additional cleanup."""
        pass

    def paramiko_cleanup(self):
        """Cleanup Paramiko to try to gracefully handle SSH session ending."""
        self.remote_conn_pre.close()
        del self.remote_conn_pre

    def disconnect(self):
        """Try to gracefully close the session."""
        try:
            self.cleanup()
            if self.protocol == "ssh":
                self.paramiko_cleanup()
            elif self.protocol == "telnet":
                self.remote_conn.close()
            elif self.protocol == "serial":
                self.remote_conn.close()
        except Exception:
            # There have been race conditions observed on disconnect.
            pass
        finally:
            self.remote_conn_pre = None
            self.remote_conn = None
            self.close_session_log()

    def commit(self):
        """Commit method for platforms that support this."""
        raise AttributeError("Network device does not support 'commit()' method")

    def save_config(self, *args, **kwargs):
        """Not Implemented"""
        raise NotImplementedError

    def open_session_log(self, filename, mode="write"):
        """Open the session_log file."""
        if mode == "append":
            self.session_log = open(filename, mode="a", encoding=self.encoding)
        else:
            self.session_log = open(filename, mode="w", encoding=self.encoding)
        self._session_log_close = True

    def close_session_log(self):
        """Close the session_log file (if it is a file that we opened)."""
        if self.session_log is not None and self._session_log_close:
            self.session_log.close()
            self.session_log = None

    def run_ttp(self, template, res_kwargs={}, **kwargs):
        """
        Run TTP template parsing by using input parameters to collect
        devices output.

        :param template: template content, OS path to template or reference
            to template within TTP templates collection in
            ttp://path/to/template.txt format
        :type template: str

        :param res_kwargs: ``**res_kwargs`` arguments to pass to TTP result method
        :type res_kwargs: dict

        :param kwargs: any other ``**kwargs`` to use for TTP object instantiation
        :type kwargs: dict

        TTP template must have inputs defined together with below parameters.

        :param method: name of Netmiko connection object method to call, default ``send_command``
        :type method: str

        :param kwargs: Netmiko connection object method arguments
        :type kwargs: dict

        :param commands: list of commands to collect
        :type commands: list

        Inputs' load could be of one of the supported formats and controlled by input's ``load``
        attribute, supported values - python, yaml or json. For each input output collected
        from device and parsed accordingly.
        """
        return run_ttp_template(
            connection=self, template=template, res_kwargs=res_kwargs, **kwargs
        )

class ConfigInvalidException(Exception):
    """Exception raised for invalid configuration error."""

    pass

class InLineTransfer(CiscoIosFileTransfer):
    """Use TCL on Cisco IOS to directly transfer file."""

    def __init__(
        self,
        ssh_conn,
        source_file=None,
        dest_file=None,
        file_system=None,
        direction="put",
        source_config=None,
        socket_timeout=10.0,
        progress=None,
        progress4=None,
    ):

        if source_file and source_config:
            msg = "Invalid call to InLineTransfer both source_file and source_config specified."
            raise ValueError(msg)
        if direction != "put":
            raise ValueError("Only put operation supported by InLineTransfer.")

        if progress is not None or progress4 is not None:
            raise NotImplementedError(
                "Progress bar is not supported on inline transfers."
            )
        else:
            self.progress = progress
            self.progress4 = progress4

        self.ssh_ctl_chan = ssh_conn
        if source_file:
            self.source_file = source_file
            self.source_config = None
            self.source_md5 = self.file_md5(source_file)
            self.file_size = os.stat(source_file).st_size
        elif source_config:
            self.source_file = None
            self.source_config = source_config
            self.source_md5 = self.config_md5(source_config)
            self.file_size = len(source_config.encode("UTF-8"))
        self.dest_file = dest_file
        self.direction = direction

        if not file_system:
            self.file_system = self.ssh_ctl_chan._autodetect_fs()
        else:
            self.file_system = file_system

        self.socket_timeout = socket_timeout

    @staticmethod
    def _read_file(file_name):
        with io.open(file_name, "rt", encoding="utf-8") as f:
            return f.read()

    @staticmethod
    def _tcl_newline_rationalize(tcl_string):
        r"""
        When using put inside a TCL {} section the newline is considered a new TCL
        statement and causes a missing curly-brace message. Convert "\n" to "\r". TCL
        will convert the "\r" to a "\n" i.e. you will see a "\n" inside the file on the
        Cisco IOS device.
        """
        NEWLINE = r"\n"
        CARRIAGE_RETURN = r"\r"
        tmp_string = re.sub(NEWLINE, CARRIAGE_RETURN, tcl_string)
        if re.search(r"[{}]", tmp_string):
            msg = "Curly brace detected in string; TCL requires this be escaped."
            raise ValueError(msg)
        return tmp_string

    def __enter__(self):
        self._enter_tcl_mode()
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        _ = self._exit_tcl_mode()  # noqa

    def _enter_tcl_mode(self):
        TCL_ENTER = "tclsh"
        cmd_failed = ['Translating "tclsh"', "% Unknown command", "% Bad IP address"]
        output = self.ssh_ctl_chan.send_command(
            TCL_ENTER,
            expect_string=r"\(tcl\)#",
            strip_prompt=False,
            strip_command=False,
        )
        for pattern in cmd_failed:
            if pattern in output:
                raise ValueError(f"Failed to enter tclsh mode on router: {output}")
        return output

    def _exit_tcl_mode(self):
        TCL_EXIT = "tclquit"
        self.ssh_ctl_chan.write_channel("\r")
        time.sleep(1)
        output = self.ssh_ctl_chan.read_channel()
        if "(tcl)" in output:
            self.ssh_ctl_chan.write_channel(TCL_EXIT + "\r")
        time.sleep(1)
        output += self.ssh_ctl_chan.read_channel()
        return output

    def establish_scp_conn(self):
        raise NotImplementedError

    def close_scp_chan(self):
        raise NotImplementedError

    def local_space_available(self):
        raise NotImplementedError

    def file_md5(self, file_name):
        """Compute MD5 hash of file."""
        file_contents = self._read_file(file_name)
        file_contents = file_contents + "\n"  # Cisco IOS automatically adds this
        file_contents = file_contents.encode("UTF-8")
        return hashlib.md5(file_contents).hexdigest()

    def config_md5(self, source_config):
        """Compute MD5 hash of text."""
        file_contents = source_config + "\n"  # Cisco IOS automatically adds this
        file_contents = file_contents.encode("UTF-8")
        return hashlib.md5(file_contents).hexdigest()

    def put_file(self):
        curlybrace = r"{"
        TCL_FILECMD_ENTER = 'puts [open "{}{}" w+] {}'.format(
            self.file_system, self.dest_file, curlybrace
        )
        TCL_FILECMD_EXIT = "}"

        if self.source_file:
            file_contents = self._read_file(self.source_file)
        elif self.source_config:
            file_contents = self.source_config
        file_contents = self._tcl_newline_rationalize(file_contents)

        # Try to remove any existing data
        self.ssh_ctl_chan.clear_buffer()

        self.ssh_ctl_chan.write_channel(TCL_FILECMD_ENTER)
        time.sleep(0.25)
        self.ssh_ctl_chan.write_channel(file_contents)
        self.ssh_ctl_chan.write_channel(TCL_FILECMD_EXIT + "\r")

        # This operation can be slow (depends on the size of the file)
        max_loops = 400
        sleep_time = 4
        if self.file_size >= 2500:
            max_loops = 1500
            sleep_time = 12
        elif self.file_size >= 7500:
            max_loops = 3000
            sleep_time = 25

        # Initial delay
        time.sleep(sleep_time)

        # File paste and TCL_FILECMD_exit should be indicated by "router(tcl)#"
        output = self.ssh_ctl_chan._read_channel_expect(
            pattern=r"\(tcl\)", max_loops=max_loops
        )

        # The file doesn't write until tclquit
        TCL_EXIT = "tclquit"
        self.ssh_ctl_chan.write_channel(TCL_EXIT + "\r")

        time.sleep(1)
        # Read all data remaining from the TCLSH session
        output += self.ssh_ctl_chan._read_channel_expect(max_loops=max_loops)
        return output

    def get_file(self):
        raise NotImplementedError

    def enable_scp(self, cmd=None):
        raise NotImplementedError

    def disable_scp(self, cmd=None):
        raise NotImplementedError

class NetmikoAuthenticationException(AuthenticationException):
    """SSH authentication exception based on Paramiko AuthenticationException."""

    pass

class NetmikoTimeoutException(SSHException):
    """SSH session timed trying to connect to the device."""

    pass

class NetmikoAuthenticationException(AuthenticationException):
    """SSH authentication exception based on Paramiko AuthenticationException."""

    pass

class NetmikoTimeoutException(SSHException):
    """SSH session timed trying to connect to the device."""

    pass

class SCPConn(object):
    """
    Establish a secure copy channel to the remote network device.

    Must close the SCP connection to get the file to write to the remote filesystem
    """

    def __init__(self, ssh_conn, socket_timeout=10.0, progress=None, progress4=None):
        self.ssh_ctl_chan = ssh_conn
        self.socket_timeout = socket_timeout
        self.progress = progress
        self.progress4 = progress4
        self.establish_scp_conn()

    def establish_scp_conn(self):
        """Establish the secure copy connection."""
        ssh_connect_params = self.ssh_ctl_chan._connect_params_dict()
        self.scp_conn = self.ssh_ctl_chan._build_ssh_client()
        self.scp_conn.connect(**ssh_connect_params)
        self.scp_client = scp.SCPClient(
            self.scp_conn.get_transport(),
            socket_timeout=self.socket_timeout,
            progress=self.progress,
            progress4=self.progress4,
        )

    def scp_transfer_file(self, source_file, dest_file):
        """Put file using SCP (for backwards compatibility)."""
        self.scp_client.put(source_file, dest_file)

    def scp_get_file(self, source_file, dest_file):
        """Get file using SCP."""
        platform = self.ssh_ctl_chan.device_type
        if "cisco_ios" in platform or "cisco_xe" in platform:
            try:
                self.scp_client.get(source_file, dest_file)
            except EOFError:
                pass
        else:
            self.scp_client.get(source_file, dest_file)

    def scp_put_file(self, source_file, dest_file):
        """Put file using SCP."""
        self.scp_client.put(source_file, dest_file)

    def close(self):
        """Close the SCP connection."""
        self.scp_conn.close()

class SSHDetect(object):
    """
    The SSHDetect class tries to automatically guess the device type running on the SSH remote end.
    Be careful that the kwargs 'device_type' must be set to 'autodetect', otherwise it won't work at
    all.

    Parameters
    ----------
    *args : list
        The same *args that you might provide to the netmiko.ssh_dispatcher.ConnectHandler.
    *kwargs : dict
        The same *kwargs that you might provide to the netmiko.ssh_dispatcher.ConnectHandler.

    Attributes
    ----------
    connection : netmiko.terminal_server.TerminalServerSSH
        A basic connection to the remote SSH end.
    potential_matches: dict
        Dict of (device_type, accuracy) that is populated through an interaction with the
        remote end.

    Methods
    -------
    autodetect()
        Try to determine the device type.
    """

    def __init__(self, *args, **kwargs):
        """
        Constructor of the SSHDetect class
        """
        if kwargs["device_type"] != "autodetect":
            raise ValueError("The connection device_type must be 'autodetect'")
        # Always set cmd_verify to False for autodetect
        kwargs["global_cmd_verify"] = False
        self.connection = ConnectHandler(*args, **kwargs)
        # Call the _test_channel_read() in base to clear initial data
        output = BaseConnection._test_channel_read(self.connection)
        self.initial_buffer = output
        self.potential_matches = {}
        self._results_cache = {}

    def autodetect(self):
        """
        Try to guess the best 'device_type' based on patterns defined in SSH_MAPPER_BASE

        Returns
        -------
        best_match : str or None
            The device type that is currently the best to use to interact with the device
        """
        for device_type, autodetect_dict in SSH_MAPPER_BASE:
            tmp_dict = autodetect_dict.copy()
            call_method = tmp_dict.pop("dispatch")
            autodetect_method = getattr(self, call_method)
            accuracy = autodetect_method(**tmp_dict)
            if accuracy:
                self.potential_matches[device_type] = accuracy
                if accuracy >= 99:  # Stop the loop as we are sure of our match
                    best_match = sorted(
                        self.potential_matches.items(), key=lambda t: t[1], reverse=True
                    )
                    self.connection.disconnect()
                    return best_match[0][0]

        if not self.potential_matches:
            self.connection.disconnect()
            return None

        best_match = sorted(
            self.potential_matches.items(), key=lambda t: t[1], reverse=True
        )
        self.connection.disconnect()
        return best_match[0][0]

    def _send_command(self, cmd=""):
        """
        Handle reading/writing channel directly. It is also sanitizing the output received.

        Parameters
        ----------
        cmd : str, optional
            The command to send to the remote device (default : "", just send a new line)

        Returns
        -------
        output : str
            The output from the command sent
        """
        self.connection.write_channel(cmd + "\n")
        time.sleep(1)
        output = self.connection._read_channel_timing()
        output = self.connection.strip_backspaces(output)
        return output

    def _send_command_wrapper(self, cmd):
        """
        Send command to the remote device with a caching feature to avoid sending the same command
        twice based on the SSH_MAPPER_BASE dict cmd key.

        Parameters
        ----------
        cmd : str
            The command to send to the remote device after checking cache.

        Returns
        -------
        response : str
            The response from the remote device.
        """
        cached_results = self._results_cache.get(cmd)
        if not cached_results:
            response = self._send_command(cmd)
            self._results_cache[cmd] = response
            return response
        else:
            return cached_results

    def _autodetect_remote_version(
        self, search_patterns=None, re_flags=re.IGNORECASE, priority=99, **kwargs
    ):
        """
        Method to try auto-detect the device type, by matching a regular expression on the reported
        remote version of the SSH server.

        Parameters
        ----------
        search_patterns : list
            A list of regular expression to look for in the reported remote SSH version
            (default: None).
        re_flags: re.flags, optional
            Any flags from the python re module to modify the regular expression (default: re.I).
        priority: int, optional
            The confidence the match is right between 0 and 99 (default: 99).
        """
        invalid_responses = [r"^$"]

        if not search_patterns:
            return 0

        try:
            remote_version = self.connection.remote_conn.transport.remote_version
            for pattern in invalid_responses:
                match = re.search(pattern, remote_version, flags=re.I)
                if match:
                    return 0
            for pattern in search_patterns:
                match = re.search(pattern, remote_version, flags=re_flags)
                if match:
                    return priority
        except Exception:
            return 0
        return 0

    def _autodetect_std(
        self, cmd="", search_patterns=None, re_flags=re.IGNORECASE, priority=99
    ):
        """
        Standard method to try to auto-detect the device type. This method will be called for each
        device_type present in SSH_MAPPER_BASE dict ('dispatch' key). It will attempt to send a
        command and match some regular expression from the ouput for each entry in SSH_MAPPER_BASE
        ('cmd' and 'search_pattern' keys).

        Parameters
        ----------
        cmd : str
            The command to send to the remote device after checking cache.
        search_patterns : list
            A list of regular expression to look for in the command's output (default: None).
        re_flags: re.flags, optional
            Any flags from the python re module to modify the regular expression (default: re.I).
        priority: int, optional
            The confidence the match is right between 0 and 99 (default: 99).
        """
        invalid_responses = [
            r"% Invalid input detected",
            r"syntax error, expecting",
            r"Error: Unrecognized command",
            r"%Error",
            r"command not found",
            r"Syntax Error: unexpected argument",
        ]
        if not cmd or not search_patterns:
            return 0
        try:
            # _send_command_wrapper will use already cached results if available
            response = self._send_command_wrapper(cmd)
            # Look for error conditions in output
            for pattern in invalid_responses:
                match = re.search(pattern, response, flags=re.I)
                if match:
                    return 0
            for pattern in search_patterns:
                match = re.search(pattern, response, flags=re_flags)
                if match:
                    return priority
        except Exception:
            return 0
        return 0