PipeClient Class

Properties   Methods   Events   Config Settings   Errors  

The PipeClient class is a simple client for connecting and communicating over named pipes.

Syntax

class ipworksipc.PipeClient

Remarks

The PipeClient class is used to connect to an existing pipe server. After connecting the transfer of data is handled very similarly to socket communication.

To begin, first set pipe_name to the name of the pipe to which the connection will be made. Call connect or set on_connected to True to establish the connection. The on_connected event will fire when the connection is complete.

After connecting call send or send_file to send data. Incoming data is received through the on_data_in event.

To disconnect call disconnect or set connected to False.

Synchronous and Asynchronous Operation

If the timeout property is set to 0, the class will behave asynchronously and all operations return immediately, potentially failing with an error if they can't be completed immediately.

If timeout is set to a positive value, the class will behave synchronously and wait for the operation to complete before returning control.

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.

Note: By default, all timeouts are inactivity timeouts, that is, 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 60 seconds.

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 indicates whether data reception is currently enabled.

Syntax

def get_accept_data() -> bool: ...

accept_data = property(get_accept_data, None)

Default Value

TRUE

Remarks

This property indicates whether data reception is currently enabled. When False, data reception is disabled and the on_data_in event will not fire. Use the pause_data and process_data methods to pause and resume data reception.

This property is read-only.

bytes_sent Property

This property includes the number of bytes actually sent after a call to the SendBytes method.

Syntax

def get_bytes_sent() -> int: ...

bytes_sent = property(get_bytes_sent, None)

Default Value

0

Remarks

This property indicates how many bytes were sent after the last call to send_bytes. Please check the send_bytes method for more information.

Note: that bytes_sent will always return 0 when the class is operating in synchronous mode (i.e., the timeout property is set to a positive value.)

This property is read-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

This property indicates whether the class is connected to the remote host. Use the connect and disconnect methods to manage the connection.

This property triggers a connection or disconnection. Setting this property to True makes the class attempt to connect to the pipe identified by the pipe_name property. If successful, after the connection is achieved the value of the property changes to True and the on_connected event is fired.

Setting this property to False closes the connection.

eol Property

This property is used to break the incoming data stream into chunks separated by EOL .

Syntax

def get_eol() -> bytes: ...
def set_eol(value: bytes) -> None: ...

eol = property(get_eol, set_eol)

Default Value

""

Remarks

This property is used to define boundaries in the input stream using the value of the property.

This property is especially useful with ASCII files. Setting it to CRLF ("\r\n") enables the incoming ASCII text stream to split into defined lines. In this case, one event is fired for each line received (as well as in packet boundaries). The CRLF ("\r\n") bytes are discarded.

This property is a binary string. Notably, this means that it can be more than one byte long, and it can contain NULL bytes.

pipe_name Property

The name of the pipe.

Syntax

def get_pipe_name() -> str: ...
def set_pipe_name(value: str) -> None: ...

pipe_name = property(get_pipe_name, set_pipe_name)

Default Value

""

Remarks

This property specifies the name of the pipe.

This may be the name by itself, for instance "MyPipe", or in the format "\\.\pipe\MyPipe".

record_length Property

The length of received data records.

Syntax

def get_record_length() -> int: ...
def set_record_length(value: int) -> None: ...

record_length = property(get_record_length, set_record_length)

Default Value

0

Remarks

If set to a positive value, this property defines the length of data records to be received. The class will accumulate data until RecordLength is reached and only then fire the on_data_in event with data of length RecordLength. This allows data to be received as records of known length. This value can be changed at any time, including within the on_data_in event.

The default value is 0, meaning this property is not used.

single_line_mode Property

This property includes a special mode for line-oriented protocols.

Syntax

def get_single_line_mode() -> bool: ...
def set_single_line_mode(value: bool) -> None: ...

single_line_mode = property(get_single_line_mode, set_single_line_mode)

Default Value

FALSE

Remarks

When this property is set to True, the class treats the incoming data stream as lines separated by carriage return line feed (CRLF), CR, or LF. The eol property is ignored.

When this property is set to True, accept_data automatically will be set to False. Please refer to the get_line method for more information.

timeout Property

This property includes the timeout for the class.

Syntax

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

timeout = property(get_timeout, set_timeout)

Default Value

60

Remarks

If the timeout property is set to 0, all operations return immediately, potentially failing with a WOULDBLOCK error if data cannot be sent immediately.

If timeout is set to a positive value, data is sent in a blocking manner and the class will wait for the operation to complete before returning control. The class will handle any potential WOULDBLOCK errors internally and automatically retry the operation 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.

Note: By default, all timeouts are inactivity timeouts, that is, 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 60 seconds.

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 named pipe.

Syntax

def connect() -> None: ...

Remarks

This method connects to a named pipe specified by pipe_name. Calling this method is equivalent to setting the connected property to True.

Example (Connecting)

PipeClient.PipeName = "MyPipe"; PipeClient.Connect();

disconnect Method

Disconnects from the named pipe.

Syntax

def disconnect() -> None: ...

Remarks

This method disconnects from the pipe. Calling this method is equivalent to setting the connected property to False.

do_events Method

This 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.

get_line Method

This method gets a line of text from the server.

Syntax

def get_line() -> str: ...

Remarks

This method gets a line of text from the server. This method is an alternative method of receiving data for line-oriented protocols. The class will block if necessary and then will return the received line. accept_data will be set automatically to True when the method is called, and then will be set to False after a line is received.

Please refer to the single_line_mode property for more information.

interrupt Method

This method interrupts the current action.

Syntax

def interrupt() -> None: ...

Remarks

This method interrupts the current action. If you use send_file to upload a file, the class will run synchronously until the upload is completed. This method will allow you to stop the file from uploading without disconnecting from the host.

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.

send Method

Sends data over the connected pipe.

Syntax

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

Remarks

This method sends data to the server.

send_bytes Method

This method sends binary data over the connected pipe.

Syntax

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

Remarks

This method sends the specified binary data to the server. To send text, use the send_text method instead.

When timeout is set to 0 the class will behave asynchronously. If you are sending data to the receiving process faster than it can process it, the outgoing queue might fill up. When this happens, the class 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. (However, please note that on_ready_to_send is not fired when part of the data is successfully sent).

send_file Method

Sends the file over the connected pipe.

Syntax

def send_file(file_name: str) -> None: ...

Remarks

This method sends the specified file to the server/process over the connected pipe.

Timeout must be set to a positive value so that the class will operate synchronously.

send_line Method

This method sends a string followed by a newline.

Syntax

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

Remarks

This method sends a string followed by a newline. This method is used to send data with line-oriented protocols. The line is followed by CRLF ("\r\n") .

Please refer to the get_line method and single_line_mode property for more information.

send_text Method

This method sends text over the connected pipe.

Syntax

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

Remarks

This method sends the specified text to the server. To send binary data, use the send_bytes method instead.

When timeout is set to 0 the class will behave asynchronously. If you are sending data to the receiving process faster than it can process it, the outgoing queue might fill up. When this happens, the class 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. (However, please note that on_ready_to_send is not fired when part of the data is successfully sent).

on_connected Event

Fired immediately after a connection completes.

Syntax

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

Remarks

When the connection is successfully established this event will fire.

on_data_in Event

This event is fired when data (complete lines) come in.

Syntax

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

  @property
  def eol() -> bool: ...

# In class PipeClient:
@property
def on_data_in() -> Callable[[PipeClientDataInEventParams], None]: ...
@on_data_in.setter
def on_data_in(event_hook: Callable[[PipeClientDataInEventParams], 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 are provided through the Text parameter.

EOL indicates whether or not the eol string was found at the end of Text. If the eol string was found, then EOL is True.

If Text is part of a data portion of length larger than MaxLineLength with no eol strings in it, then EOL is False. Note: This means that one or more on_data_in events with EOL set to False can be received during a connection.

If the eol property is "" (empty string), then EOL can be disregarded (it is always True).

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

Fired when a connection is closed.

Syntax

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

Remarks

When the connection is closed this event will fire.

on_error Event

Fired when information is available about errors during data delivery.

Syntax

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

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

# In class PipeClient:
@property
def on_error() -> Callable[[PipeClientErrorEventParams], None]: ...
@on_error.setter
def on_error(event_hook: Callable[[PipeClientErrorEventParams], 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 PipeClientReadyToSendEventParams(object):
# In class PipeClient:
@property
def on_ready_to_send() -> Callable[[PipeClientReadyToSendEventParams], None]: ...
@on_ready_to_send.setter
def on_ready_to_send(event_hook: Callable[[PipeClientReadyToSendEventParams], None]) -> None: ...

Remarks

The on_ready_to_send event indicates that the underlying pipe is ready to accept data again after a failed send. The event is also fired immediately after a connection to the remote host is established.

PipeClient Config Settings

The class accepts one or more of the following configuration settings. Configuration 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.

PipeClient Config Settings

Base Config Settings

PipeClient Errors

PipeClient Errors