Telnet Class

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The Telnet Class is used to communicate with servers implementing the TELNET protocol.

Syntax

class ipworksssl.Telnet

Remarks

The Telnet Class supports both plaintext and SSL/TLS connections. When connecting over SSL/TLS the on_ssl_server_authentication event allows you to check the server identity and other security attributes. The on_ssl_status event provides information about the SSL handshake. Additional SSL related settings are also supported via the config method.

The Telnet Class provides a simple interface to Telnet communications as specified by RFC 854. It allows sending of Telnet command codes to remote Telnet servers and it scans the input data for Telnet commands. Appropriate events are fired for received commands.

The connection interface is very similar to that of TCPClient. The same properties and events are used for sending and receiving normal data, and the same property set is used for setting properties of the connection. The Telnet Class adds a number of properties like command, do_option, etc. which allow sending of Telnet commands to the other end. The respective events (on_command, on_do, etc.) are fired when the corresponding Telnet commands are received.

Property List

The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the class with short descriptions. Click on the links for further details.

accept_data Property

This property enables or disables data reception (the DataIn event).

Syntax

def get_accept_data() -> bool: ...
def set_accept_data(value: bool) -> None: ...

accept_data = property(get_accept_data, set_accept_data)

Default Value

TRUE

Remarks

This property enables or disables data reception (the DataIn event). Setting this property to False, temporarily disables data reception (and the on_data_in event). Setting this property to True, reenables data reception.

Note: It is recommended to use the pause_data or process_data method instead of setting this property.

bytes_sent Property

The number of bytes actually sent after an assignment to DataToSend .

Syntax

def get_bytes_sent() -> int: ...

bytes_sent = property(get_bytes_sent, None)

Default Value

0

Remarks

The bytes_sent property shows how many bytes were sent after the last assignment to data_to_send or urgent_data. Please check the data_to_send property for more information.

This property is read-only.

command Property

A single character Telnet command code to be sent to the server.

Syntax

def set_command(value: int) -> None: ...

command = property(None, set_command)

Default Value

0

Remarks

Codes for Telnet commands and their meanings are defined in the Telnet RFCs. Here are some examples:

This property is write-only.

connected Property

Triggers a connection or disconnection.

Syntax

def get_connected() -> bool: ...
def set_connected(value: bool) -> None: ...

connected = property(get_connected, set_connected)

Default Value

FALSE

Remarks

Setting the connected property to True makes the class attempt to connect to the host identified by the remote_host property. If successful, after the connection is achieved, the value of the property changes to True and the on_connected event is fired.

Setting Connected to False closes the connection. How and when the connection is closed is controlled by the linger property.

Note: It is recommended to use the connect or disconnect method instead of setting this property.

data_to_send Property

A string of data to be sent to the remote host.

Syntax

def set_data_to_send(value: bytes) -> None: ...

data_to_send = property(None, set_data_to_send)

Default Value

""

Remarks

Assigning a string to the data_to_send property makes the class send the string to the remote host. The send method provides similar functionality.

If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, the operation fails with error 10035: "[10035] Operation would block" (WSAEWOULDBLOCK). You can check this error, and then try to send the data again. . The bytes_sent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the on_ready_to_send event before attempting to send data again.

Note: The on_ready_to_send event is not fired when part of the data is sent successfully.

This property is write-only.

dont_option Property

A single character Telnet option code to be sent to the server with the Telnet DONT command.

Syntax

def set_dont_option(value: int) -> None: ...

dont_option = property(None, set_dont_option)

Default Value

0

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

This property is write-only.

do_option Property

A single character Telnet option code to be sent to the server with the Telnet DO command.

Syntax

def set_do_option(value: int) -> None: ...

do_option = property(None, set_do_option)

Default Value

0

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

This property is write-only.

do_sub_option Property

A Telnet SubOption to send to the server with the SubOption command.

Syntax

def set_do_sub_option(value: bytes) -> None: ...

do_sub_option = property(None, set_do_sub_option)

Default Value

""

Remarks

For a list of valid Telnet suboptions and their descriptions please look at the Telnet RFCs.

You don't need to specify the suboption start and suboption end codes. Those are appended automatically by the class. For example, to send a terminal type suboption to request setting the terminal type to 'vt100', you must send ASCII 24, followed by ASCII 0, followed by "vt100" (without the quotes).

This property is write-only.

firewall_auto_detect Property

This property tells the class whether or not to automatically detect and use firewall system settings, if available.

Syntax

def get_firewall_auto_detect() -> bool: ...
def set_firewall_auto_detect(value: bool) -> None: ...

firewall_auto_detect = property(get_firewall_auto_detect, set_firewall_auto_detect)

Default Value

FALSE

Remarks

This property tells the class whether or not to automatically detect and use firewall system settings, if available.

firewall_type Property

This property determines the type of firewall to connect through.

Syntax

def get_firewall_type() -> int: ...
def set_firewall_type(value: int) -> None: ...

firewall_type = property(get_firewall_type, set_firewall_type)

Default Value

0

Remarks

This property determines the type of firewall to connect through. The applicable values are as follows:

firewall_host Property

This property contains the name or IP address of firewall (optional).

Syntax

def get_firewall_host() -> str: ...
def set_firewall_host(value: str) -> None: ...

firewall_host = property(get_firewall_host, set_firewall_host)

Default Value

""

Remarks

This property contains the name or IP address of firewall (optional). If a firewall_host is given, the requested connections will be authenticated through the specified firewall when connecting.

If this property is set to a Domain Name, a DNS request is initiated. Upon successful termination of the request, this property is set to the corresponding address. If the search is not successful, the class fails with an error.

firewall_password Property

This property contains a password if authentication is to be used when connecting through the firewall.

Syntax

def get_firewall_password() -> str: ...
def set_firewall_password(value: str) -> None: ...

firewall_password = property(get_firewall_password, set_firewall_password)

Default Value

""

Remarks

This property contains a password if authentication is to be used when connecting through the firewall. If firewall_host is specified, the firewall_user and firewall_password properties are used to connect and authenticate to the given firewall. If the authentication fails, the class fails with an error.

firewall_port Property

This property contains the transmission control protocol (TCP) port for the firewall Host .

Syntax

def get_firewall_port() -> int: ...
def set_firewall_port(value: int) -> None: ...

firewall_port = property(get_firewall_port, set_firewall_port)

Default Value

0

Remarks

This property contains the transmission control protocol (TCP) port for the firewall firewall_host. See the description of the firewall_host property for details.

Note: This property is set automatically when firewall_type is set to a valid value. See the description of the firewall_type property for details.

firewall_user Property

This property contains a user name if authentication is to be used connecting through a firewall.

Syntax

def get_firewall_user() -> str: ...
def set_firewall_user(value: str) -> None: ...

firewall_user = property(get_firewall_user, set_firewall_user)

Default Value

""

Remarks

This property contains a user name if authentication is to be used connecting through a firewall. If the firewall_host is specified, this property and firewall_password properties are used to connect and authenticate to the given firewall. If the authentication fails, the class fails with an error.

keep_alive Property

When True, KEEPALIVE packets are enabled (for long connections).

Syntax

def get_keep_alive() -> bool: ...
def set_keep_alive(value: bool) -> None: ...

keep_alive = property(get_keep_alive, set_keep_alive)

Default Value

FALSE

Remarks

The keep_alive enables the SO_KEEPALIVE option on the socket. This option prevents long connections from timing out in case of inactivity.

Note: System Transmission Control Protocol (TCP)/IP stack implementations are not required to support SO_KEEPALIVE.

linger Property

When set to True, this property ensures that connections are terminated gracefully.

Syntax

def get_linger() -> bool: ...
def set_linger(value: bool) -> None: ...

linger = property(get_linger, set_linger)

Default Value

TRUE

Remarks

This property controls how a connection is closed. The default is True.

In the case that Linger is True (default), two scenarios determine how long the connection will linger. In the first, if LingerTime is 0 (default), the system will attempt to send pending data for a connection until the default IP timeout expires.

In the second scenario, if LingerTime is a positive value, the system will attempt to send pending data until the specified LingerTime is reached. If this attempt fails, then the system will reset the connection.

The default behavior (which is also the default mode for stream sockets) might result in a long delay in closing the connection. Although the class returns control immediately, the system could hold system resources until all pending data are sent (even after your application closes).

Setting this property to False forces an immediate disconnection. If you know that the other side has received all the data you sent (e.g., by a client acknowledgment), setting this property to False might be the appropriate course of action.

local_host Property

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

Syntax

def get_local_host() -> str: ...
def set_local_host(value: str) -> None: ...

local_host = property(get_local_host, set_local_host)

Default Value

""

Remarks

The local_host property contains the name of the local host as obtained by the gethostname() system call, or if the user has assigned an IP address, the value of that address.

In multi-homed hosts (machines with more than one IP interface) setting LocalHost to the value of an interface will make the class initiate connections (or accept in the case of server classs) only through that interface.

If the class is connected, the local_host property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multi-homed hosts (machines with more than one IP interface).

NOTE: local_host is not persistent. You must always set it in code, and never in the property window.

local_port Property

The TCP port in the local host where TCPClient binds.

Syntax

def get_local_port() -> int: ...
def set_local_port(value: int) -> None: ...

local_port = property(get_local_port, set_local_port)

Default Value

0

Remarks

The local_port property must be set before a connection is attempted. It instructs the class to bind to a specific port (or communication endpoint) in the local machine.

Setting it to 0 (default) enables the TCP/IP stack to choose a port at random. The chosen port will be shown by the local_port property after the connection is established.

local_port cannot be changed once a connection is made. Any attempt to set the local_port property when a connection is active will generate an error.

The local_port property is useful when trying to connect to services that require a trusted port in the client side.

remote_host Property

This property includes the address of the remote host. Domain names are resolved to IP addresses.

Syntax

def get_remote_host() -> str: ...
def set_remote_host(value: str) -> None: ...

remote_host = property(get_remote_host, set_remote_host)

Default Value

""

Remarks

This property specifies the IP address (IP number in dotted internet format) or the domain name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If this property is set to a domain name, a DNS request is initiated, and upon successful termination of the request, this property is set to the corresponding address. If the search is not successful, an error is returned.

If the class is configured to use a SOCKS firewall, the value assigned to this property may be preceded with an "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

Example. Connecting:

TCPClientControl.RemoteHost = "MyHostNameOrIP" TCPClientControl.RemotePort = 777 TCPClientControl.Connected = true

remote_port Property

The secure Telnet port in the remote host (default is 23).

Syntax

def get_remote_port() -> int: ...
def set_remote_port(value: int) -> None: ...

remote_port = property(get_remote_port, set_remote_port)

Default Value

23

Remarks

For implicit SSL, use port 992 (please refer to the ssl_start_mode property for more information).

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change this property while connected will fail with an error.

ssl_accept_server_cert_encoded Property

This is the certificate (PEM/base64 encoded).

Syntax

def get_ssl_accept_server_cert_encoded() -> bytes: ...
def set_ssl_accept_server_cert_encoded(value: bytes) -> None: ...

ssl_accept_server_cert_encoded = property(get_ssl_accept_server_cert_encoded, set_ssl_accept_server_cert_encoded)

Default Value

""

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The ssl_accept_server_cert_store and ssl_accept_server_cert_subject properties also may be used to specify a certificate.

When ssl_accept_server_cert_encoded is set, a search is initiated in the current ssl_accept_server_cert_store for the private key of the certificate. If the key is found, ssl_accept_server_cert_subject is updated to reflect the full subject of the selected certificate; otherwise, ssl_accept_server_cert_subject is set to an empty string.

ssl_cert_encoded Property

This is the certificate (PEM/base64 encoded).

Syntax

def get_ssl_cert_encoded() -> bytes: ...
def set_ssl_cert_encoded(value: bytes) -> None: ...

ssl_cert_encoded = property(get_ssl_cert_encoded, set_ssl_cert_encoded)

Default Value

""

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The ssl_cert_store and ssl_cert_subject properties also may be used to specify a certificate.

When ssl_cert_encoded is set, a search is initiated in the current ssl_cert_store for the private key of the certificate. If the key is found, ssl_cert_subject is updated to reflect the full subject of the selected certificate; otherwise, ssl_cert_subject is set to an empty string.

ssl_cert_store Property

This is the name of the certificate store for the client certificate.

Syntax

def get_ssl_cert_store() -> bytes: ...
def set_ssl_cert_store(value: bytes) -> None: ...

ssl_cert_store = property(get_ssl_cert_store, set_ssl_cert_store)

Default Value

"MY"

Remarks

This is the name of the certificate store for the client certificate.

The ssl_cert_store_type property denotes the type of the certificate store specified by ssl_cert_store. If the store is password protected, specify the password in ssl_cert_store_password.

ssl_cert_store is used in conjunction with the ssl_cert_subject property to specify client certificates. If ssl_cert_store has a value, and ssl_cert_subject or ssl_cert_encoded is set, a search for a certificate is initiated. Please see the ssl_cert_subject property for details.

Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

When the certificate store type is PFXFile, this property must be set to the name of the file. When the type is PFXBlob, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

ssl_cert_store_password Property

If the type of certificate store requires a password, this property is used to specify the password needed to open the certificate store.

Syntax

def get_ssl_cert_store_password() -> str: ...
def set_ssl_cert_store_password(value: str) -> None: ...

ssl_cert_store_password = property(get_ssl_cert_store_password, set_ssl_cert_store_password)

Default Value

""

Remarks

If the type of certificate store requires a password, this property is used to specify the password needed to open the certificate store.

ssl_cert_store_type Property

This is the type of certificate store for this certificate.

Syntax

def get_ssl_cert_store_type() -> int: ...
def set_ssl_cert_store_type(value: int) -> None: ...

ssl_cert_store_type = property(get_ssl_cert_store_type, set_ssl_cert_store_type)

Default Value

0

Remarks

This is the type of certificate store for this certificate.

The class supports both public and private keys in a variety of formats. When the cstAuto value is used, the class will automatically determine the type. This property can take one of the following values:

ssl_cert_subject Property

This is the subject of the certificate used for client authentication.

Syntax

def get_ssl_cert_subject() -> str: ...
def set_ssl_cert_subject(value: str) -> None: ...

ssl_cert_subject = property(get_ssl_cert_subject, set_ssl_cert_subject)

Default Value

""

Remarks

This is the subject of the certificate used for client authentication.

This property must be set after all other certificate properties are set. When this property is set, a search is performed in the current certificate store to locate a certificate with a matching subject.

If a matching certificate is found, the property is set to the full subject of the matching certificate.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks a random certificate in the certificate store.

The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=support@nsoftware.com". Common fields and their meanings are as follows:

If a field value contains a comma, it must be quoted.

ssl_provider Property

This specifies the SSL/TLS implementation to use.

Syntax

def get_ssl_provider() -> int: ...
def set_ssl_provider(value: int) -> None: ...

ssl_provider = property(get_ssl_provider, set_ssl_provider)

Default Value

0

Remarks

This property specifies the SSL/TLS implementation to use. In most cases the default value of 0 (Automatic) is recommended and should not be changed. When set to 0 (Automatic) the class will select whether to use the platform implementation or the internal implementation depending on the operating system as well as the TLS version being used.

Possible values are:

In most cases using the default value (Automatic) is recommended. The class will select a provider depending on the current platform.

When Automatic is selected, on Windows the class will use the platform implementation. On Linux/macOS the class will use the internal implementation. When TLS 1.3 is enabled via SSLEnabledProtocols the internal implementation is used on all platforms.

ssl_server_cert_encoded Property

This is the certificate (PEM/base64 encoded).

Syntax

def get_ssl_server_cert_encoded() -> bytes: ...

ssl_server_cert_encoded = property(get_ssl_server_cert_encoded, None)

Default Value

""

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The ssl_server_cert_store and ssl_server_cert_subject properties also may be used to specify a certificate.

When ssl_server_cert_encoded is set, a search is initiated in the current ssl_server_cert_store for the private key of the certificate. If the key is found, ssl_server_cert_subject is updated to reflect the full subject of the selected certificate; otherwise, ssl_server_cert_subject is set to an empty string.

This property is read-only.

ssl_start_mode Property

Determines how the class starts the SSL negotiation.

Syntax

def get_ssl_start_mode() -> int: ...
def set_ssl_start_mode(value: int) -> None: ...

ssl_start_mode = property(get_ssl_start_mode, set_ssl_start_mode)

Default Value

0

Remarks

The ssl_start_mode property may have one of the following values:

timeout Property

A timeout for the class.

Syntax

def get_timeout() -> int: ...
def set_timeout(value: int) -> None: ...

timeout = property(get_timeout, set_timeout)

Default Value

0

Remarks

If the timeout property is set to 0, all operations return immediately, potentially failing with an 'WOULDBLOCK' error if data can't be sent or received immediately.

If timeout is set to a positive value, the class will automatically retry each operation that would otherwise result in a 'WOULDBLOCK' error for a maximum of timeout seconds.

The class will use do_events to enter an efficient wait loop during any potential waiting period, making sure that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If timeout expires, and the operation is not yet complete, the class fails with an error.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by timeout seconds when any amount of data is successfully sent or received.

The default value for the timeout property is 0 (asynchronous operation).

transparent Property

When True, Telnet command processing is disabled.

Syntax

def get_transparent() -> bool: ...
def set_transparent(value: bool) -> None: ...

transparent = property(get_transparent, set_transparent)

Default Value

FALSE

Remarks

The transparent property allows you to enable or disable Telnet command processing. When command processing is disabled, any data received is provided with no modifications.

urgent_data Property

A string of data to be sent urgently (out-of-band) to the remote host.

Syntax

def set_urgent_data(value: bytes) -> None: ...

urgent_data = property(None, set_urgent_data)

Default Value

""

Remarks

The urgent_data property behaves exactly like the data_to_send property except that the data is sent Out Of Band (urgent). This means that the data assigned to urgent_data will bypass the normal TCP queuing mechanism. Use this property with caution.

This property is write-only.

will_option Property

A single character Telnet option code to be sent to the server with the Telnet WILL command.

Syntax

def set_will_option(value: int) -> None: ...

will_option = property(None, set_will_option)

Default Value

0

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

This property is write-only.

wont_option Property

A single character Telnet option code to be sent to the server with the Telnet WONT command.

Syntax

def set_wont_option(value: int) -> None: ...

wont_option = property(None, set_wont_option)

Default Value

0

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

This property is write-only.

config Method

Sets or retrieves a configuration setting.

Syntax

def config(configuration_string: str) -> str: ...

Remarks

config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

connect Method

Connects to a remote host.

Syntax

def connect() -> None: ...

Remarks

This method connects to the remote host specified by remote_host. For instance: component.RemoteHost = "MyHostNameOrIP"; component.Connect();

To specify a non-standard port number set remote_port before calling this method.

connect_to Method

Connects to a remote host.

Syntax

def connect_to(host: str) -> None: ...

Remarks

This method connects to the remote host specified by the Host. For instance: component.Connect("MyTelnetServer");

To specify a non-standard port number set remote_port before calling this method.

disconnect Method

Disconnect from the remote host.

Syntax

def disconnect() -> None: ...

Remarks

Calling this method is equivalent to setting the connected property to False.

do_events Method

Processes events from the internal message queue.

Syntax

def do_events() -> None: ...

Remarks

When do_events is called, the class processes any available events. If no events are available, it waits for a preset period of time, and then returns.

pause_data Method

This method pauses data reception.

Syntax

def pause_data() -> None: ...

Remarks

This method pauses data reception when called. While data reception is paused, the on_data_in event will not fire. Call process_data to reenable data reception.

process_data Method

This method reenables data reception after a call to PauseData .

Syntax

def process_data() -> None: ...

Remarks

This method reenables data reception after a previous call to pause_data. When pause_data is called, the on_data_in event will not fire. To reenable data reception and allow on_data_in to fire, call this method.

Note: This method is used only after previously calling pause_data. It does not need to be called to process incoming data by default.

reset Method

Reset the class.

Syntax

def reset() -> None: ...

Remarks

This method will reset the class's properties to their default values.

send Method

Sends binary data to the remote host.

Syntax

def send(text: bytes) -> None: ...

Remarks

This method sends the specified binary data to the remote host. To send text use the send_text method instead.

send_bytes Method

Sends binary data to the remote host.

Syntax

def send_bytes(data: bytes) -> None: ...

Remarks

This method sends the specified binary data to the remote host. To send text use the send_text method instead.

send_command Method

Sends a single character Telnet command code to the server.

Syntax

def send_command(command: int) -> None: ...

Remarks

This method sends the single character command code specified by Command to the server. Codes for Telnet commands and their meanings are defined in the Telnet RFCs. Some common commands are:

send_dont_option Method

This method sends a single character Telnet option code to the server with the Telnet DONT command.

Syntax

def send_dont_option(dont_option: int) -> None: ...

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

send_do_option Method

This method sends a single character Telnet option code to the server with the Telnet DO command.

Syntax

def send_do_option(do_option: int) -> None: ...

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

send_do_sub_option Method

This methods sends a Telnet SubOption to send to the server with the SubOption command.

Syntax

def send_do_sub_option(do_sub_option: bytes) -> None: ...

Remarks

Valid suboptions and their descriptions are defined in the Telnet RFCs.

For example, to send a terminal type suboption to request setting the terminal type to 'vt100', send ASCII 24, followed by ASCII 0, followed by vt100.

Suboption start and end codes are automatically added by the class.

send_text Method

Sends text to the remote host.

Syntax

def send_text(text: str) -> None: ...

Remarks

This method sends the specified text to the remote host. To send binary data use the send_bytes method instead.

send_urgent_bytes Method

Urgently sends binary data to the remote host.

Syntax

def send_urgent_bytes(urgent_bytes: bytes) -> None: ...

Remarks

This method sends the bytes specified by UrgentBytes as urgent data (out-of-band) to the remote host. To send text urgently use the send_urgent_text method instead.

Data sent using this method will bypass the normal TCP queuing mechanism. Use this method with caution.

send_urgent_text Method

Urgently sends text to the remote host.

Syntax

def send_urgent_text(urgent_text: str) -> None: ...

Remarks

This method sends the text specified by UrgentText as urgent data (out-of-band) to the remote host. To send binary data urgently use the send_urgent_bytes method instead.

Data sent using this method will bypass the normal TCP queuing mechanism. Use this method with caution.

send_will_option Method

This method sends a single character Telnet option code the server with the Telnet WILL command.

Syntax

def send_will_option(will_option: int) -> None: ...

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

send_wont_option Method

This method sends a single character Telnet option code to the server with the Telnet WONT command.

Syntax

def send_wont_option(wont_option: int) -> None: ...

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

on_command Event

Fired when a Telnet command comes from the Telnet server.

Syntax

class TelnetCommandEventParams(object):
  @property
  def command_code() -> int: ...

# In class Telnet:
@property
def on_command() -> Callable[[TelnetCommandEventParams], None]: ...
@on_command.setter
def on_command(event_hook: Callable[[TelnetCommandEventParams], None]) -> None: ...

Remarks

Codes for Telnet commands and their meanings are defined in the Telnet RFCs. Here are some examples:

on_connected Event

This event is fired immediately after a connection completes (or fails).

Syntax

class TelnetConnectedEventParams(object):
  @property
  def status_code() -> int: ...

  @property
  def description() -> str: ...

# In class Telnet:
@property
def on_connected() -> Callable[[TelnetConnectedEventParams], None]: ...
@on_connected.setter
def on_connected(event_hook: Callable[[TelnetConnectedEventParams], None]) -> None: ...

Remarks

If the connection is made normally, StatusCode is 0 and Description is "OK".

If the connection fails, StatusCode has the error code returned by the Transmission Control Protocol (TCP)/IP stack. Description contains a description of this code. The value of StatusCode is equal to the value of the error.

Please refer to the Error Codes section for more information.

on_connection_status Event

This event is fired to indicate changes in the connection state.

Syntax

class TelnetConnectionStatusEventParams(object):
  @property
  def connection_event() -> str: ...

  @property
  def status_code() -> int: ...

  @property
  def description() -> str: ...

# In class Telnet:
@property
def on_connection_status() -> Callable[[TelnetConnectionStatusEventParams], None]: ...
@on_connection_status.setter
def on_connection_status(event_hook: Callable[[TelnetConnectionStatusEventParams], None]) -> None: ...

Remarks

The on_connection_status event is fired when the connection state changes: for example, completion of a firewall or proxy connection or completion of a security handshake.

The ConnectionEvent parameter indicates the type of connection event. Values may include the following:

on_data_in Event

Fired when data is received from the remote host.

Syntax

class TelnetDataInEventParams(object):
  @property
  def text() -> bytes: ...

# In class Telnet:
@property
def on_data_in() -> Callable[[TelnetDataInEventParams], None]: ...
@on_data_in.setter
def on_data_in(event_hook: Callable[[TelnetDataInEventParams], None]) -> None: ...

Remarks

Trapping the on_data_in event is your only chance to get the data coming from the other end of the connection. The incoming data is provided through the Text parameter.

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

on_disconnected Event

This event is fired when a connection is closed.

Syntax

class TelnetDisconnectedEventParams(object):
  @property
  def status_code() -> int: ...

  @property
  def description() -> str: ...

# In class Telnet:
@property
def on_disconnected() -> Callable[[TelnetDisconnectedEventParams], None]: ...
@on_disconnected.setter
def on_disconnected(event_hook: Callable[[TelnetDisconnectedEventParams], None]) -> None: ...

Remarks

If the connection is broken normally, StatusCode is 0 and Description is "OK".

If the connection is broken for any other reason, StatusCode has the error code returned by the Transmission Control Protocol (TCP/IP) subsystem. Description contains a description of this code. The value of StatusCode is equal to the value of the TCP/IP error.

Please refer to the Error Codes section for more information.

on_do Event

Fired when a Telnet DO OPTION command comes from the Telnet server.

Syntax

class TelnetDoEventParams(object):
  @property
  def option_code() -> int: ...

# In class Telnet:
@property
def on_do() -> Callable[[TelnetDoEventParams], None]: ...
@on_do.setter
def on_do(event_hook: Callable[[TelnetDoEventParams], None]) -> None: ...

Remarks

The OptionCode parameter identifies the option code. For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

on_dont Event

Fired when a Telnet DONT OPTION command comes from the Telnet server.

Syntax

class TelnetDontEventParams(object):
  @property
  def option_code() -> int: ...

# In class Telnet:
@property
def on_dont() -> Callable[[TelnetDontEventParams], None]: ...
@on_dont.setter
def on_dont(event_hook: Callable[[TelnetDontEventParams], None]) -> None: ...

Remarks

The OptionCode parameter identifies the option code. For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

on_error Event

Information about errors during data delivery.

Syntax

class TelnetErrorEventParams(object):
  @property
  def error_code() -> int: ...

  @property
  def description() -> str: ...

# In class Telnet:
@property
def on_error() -> Callable[[TelnetErrorEventParams], None]: ...
@on_error.setter
def on_error(event_hook: Callable[[TelnetErrorEventParams], None]) -> None: ...

Remarks

The on_error event is fired in case of exceptional conditions during message processing. Normally the class fails with an error.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

on_ready_to_send Event

Fired when the class is ready to send data.

Syntax

class TelnetReadyToSendEventParams(object):
# In class Telnet:
@property
def on_ready_to_send() -> Callable[[TelnetReadyToSendEventParams], None]: ...
@on_ready_to_send.setter
def on_ready_to_send(event_hook: Callable[[TelnetReadyToSendEventParams], None]) -> None: ...

Remarks

The on_ready_to_send event indicates that the underlying TCP/IP subsystem is ready to accept data after a failed data_to_send. The event is also fired immediately after a connection to the remote host is established.

on_ssl_server_authentication Event

Fired after the server presents its certificate to the client.

Syntax

class TelnetSSLServerAuthenticationEventParams(object):
  @property
  def cert_encoded() -> bytes: ...

  @property
  def cert_subject() -> str: ...

  @property
  def cert_issuer() -> str: ...

  @property
  def status() -> str: ...

  @property
  def accept() -> bool: ...
  @accept.setter
  def accept(value) -> None: ...

# In class Telnet:
@property
def on_ssl_server_authentication() -> Callable[[TelnetSSLServerAuthenticationEventParams], None]: ...
@on_ssl_server_authentication.setter
def on_ssl_server_authentication(event_hook: Callable[[TelnetSSLServerAuthenticationEventParams], None]) -> None: ...

Remarks

During this event, the client can decide whether or not to continue with the connection process. The Accept parameter is a recommendation on whether to continue or close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When Accept is False, Status shows why the verification failed (otherwise, Status contains the string OK). If it is decided to continue, you can override and accept the certificate by setting the Accept parameter to True.

on_ssl_status Event

Shows the progress of the secure connection.

Syntax

class TelnetSSLStatusEventParams(object):
  @property
  def message() -> str: ...

# In class Telnet:
@property
def on_ssl_status() -> Callable[[TelnetSSLStatusEventParams], None]: ...
@on_ssl_status.setter
def on_ssl_status(event_hook: Callable[[TelnetSSLStatusEventParams], None]) -> None: ...

Remarks

The event is fired for informational and logging purposes only. This event tracks the progress of the connection.

on_sub_option Event

Fired when a Telnet SubOption command comes from the Telnet server.

Syntax

class TelnetSubOptionEventParams(object):
  @property
  def sub_option() -> bytes: ...

# In class Telnet:
@property
def on_sub_option() -> Callable[[TelnetSubOptionEventParams], None]: ...
@on_sub_option.setter
def on_sub_option(event_hook: Callable[[TelnetSubOptionEventParams], None]) -> None: ...

Remarks

The SubOption parameter contains the suboption data as sent by the other end. The enclosing suboption command codes are stripped away.

For a list of valid Telnet suboptions and their descriptions please look at the Telnet RFCs.

on_will Event

Fired when a Telnet WILL OPTION command comes from the Telnet server.

Syntax

class TelnetWillEventParams(object):
  @property
  def option_code() -> int: ...

# In class Telnet:
@property
def on_will() -> Callable[[TelnetWillEventParams], None]: ...
@on_will.setter
def on_will(event_hook: Callable[[TelnetWillEventParams], None]) -> None: ...

Remarks

For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

on_wont Event

Fired when a Telnet WONT OPTION command comes from the Telnet server.

Syntax

class TelnetWontEventParams(object):
  @property
  def option_code() -> int: ...

# In class Telnet:
@property
def on_wont() -> Callable[[TelnetWontEventParams], None]: ...
@on_wont.setter
def on_wont(event_hook: Callable[[TelnetWontEventParams], None]) -> None: ...

Remarks

The OptionCode parameter identifies the option code. For a list of option codes and their descriptions, please look at the Telnet RFCs. The following are a few examples:

Telnet Config Settings

TCPClient Config Settings

SSL Config Settings

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
..
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
..
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----

Socket Config Settings

Base Config Settings

Telnet Errors

Telnet Errors

The class may also return one of the following error codes, which are inherited from other classes.

SSLClient Errors

SSL Errors

TCP/IP Errors