PipeExec Class

Properties   Methods   Events   Config Settings   Errors  

PipeExec provides an easy way to start and interact with a process over Stdin, Stdout, and Stderr.

Syntax

class ipworksipc.PipeExec

Remarks

The PipeExec component provides a way to launch a process and then send/receive data to/from the process. To begin set process_file_name to the path of the process on disk. Optionally set process_args and process_working_dir.

Call start_process to start the process. Next set stdin or call send to send data to the process. Received data will be provided through the on_stdout and on_stderr events.

To terminate the process call stop_process.

Example Code Pipeexec exec = new Pipeexec(); exec.OnStdout += exec_OnStdout; exec.ProcessFileName = @"C:\Windows\system32\cmd.exe"; exec.ProcessArgs = "/Q"; exec.StartProcess(); exec.Stdin = "dir" + System.Environment.NewLine; while (true) //Wait for output exec.DoEvents(); static void exec_OnStdout(object sender, PipeexecStdoutEventArgs e) { Console.WriteLine(e.Text); }

Property List

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

Method List

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

Event List

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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

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

accept_data Property

Enables or disables data reception (the Stdout and Stderr events).

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 on_stdout and on_stderr events). Setting this property to False, temporarily disables data reception. Setting this property to True, re-enables data reception.

bytes_sent Property

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

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 assignment to stdin. Please check the stdin property for more information.

This property is read-only.

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.

process_args Property

The arguments to pass to the process.

Syntax

def get_process_args() -> str: ...
def set_process_args(value: str) -> None: ...

process_args = property(get_process_args, set_process_args)

Default Value

""

Remarks

This property specifies the arguments that will be passed to the process when it is started.

process_file_name Property

The path to the file on disk to execute.

Syntax

def get_process_file_name() -> str: ...
def set_process_file_name(value: str) -> None: ...

process_file_name = property(get_process_file_name, set_process_file_name)

Default Value

""

Remarks

This property specifies the path to the file on disk that will be executed. process_args optionally specifies the arguments that will be passed. process_working_dir optionally specifies the working directory in which the process will run.

process_running Property

Whether the process is running.

Syntax

def get_process_running() -> bool: ...

process_running = property(get_process_running, None)

Default Value

FALSE

Remarks

This property indicates whether the process specified by process_file_name is running.

After calling start_process this property returns True. After calling stop_process this property returns False.

This property is read-only.

process_working_dir Property

The working directory of the process.

Syntax

def get_process_working_dir() -> str: ...
def set_process_working_dir(value: str) -> None: ...

process_working_dir = property(get_process_working_dir, set_process_working_dir)

Default Value

""

Remarks

This property optionally specifies the working directory in which the process will run.

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.

stdin Property

A string of data to be sent over the connected pipe.

Syntax

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

stdin = property(None, set_stdin)

Default Value

""

Remarks

Assigning a string to this property makes the class send the string to the server over Stdin. The send method provides similar functionality.

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).

This property is write-only.

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

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.

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 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.

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.

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.

send Method

Sends data over the connected pipe.

Syntax

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

Remarks

This method sends data to the server. Calling this method is equivalent to setting the stdin property to Text.

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_stdin_bytes Method

This method sends binary data over the connected pipe.

Syntax

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

Remarks

This method sends the specified binary data to the server over Stdin. To send text, use the send_stdin_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_stdin_text Method

This method sends text over the connected pipe.

Syntax

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

Remarks

This method sends the specified text to the server over Stdin. To send binary data, use the send_stdin_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).

start_process Method

Starts the process.

Syntax

def start_process() -> None: ...

Remarks

This method starts the process specified by start_process. After starting the process data may be sent to the process by calling send, send_line, send or setting stdin.

Data received from the process will be available from the on_stdout and on_stderr events.

The following properties are applicable when calling this method:

• process_file_name (required)
• process_args
• process_working_dir

stop_process Method

Stops the process.

Syntax

def stop_process() -> None: ...

Remarks

This method stops the process.

on_error Event

Information about errors during data delivery.

Syntax

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

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

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

Remarks

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

ErrorCode contains an error code and Description 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 PipeExecReadyToSendEventParams(object):
# In class PipeExec:
@property
def on_ready_to_send() -> Callable[[PipeExecReadyToSendEventParams], None]: ...
@on_ready_to_send.setter
def on_ready_to_send(event_hook: Callable[[PipeExecReadyToSendEventParams], 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.

on_stderr Event

Fired when data come in through stderr.

Syntax

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

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

# In class PipeExec:
@property
def on_stderr() -> Callable[[PipeExecStderrEventParams], None]: ...
@on_stderr.setter
def on_stderr(event_hook: Callable[[PipeExecStderrEventParams], None]) -> None: ...

Remarks

The on_stderr event is fired every time the process outputs a line in its standard output. The incoming data is provided through the Text parameter.

on_stdout Event

Fired when data come in through stdout.

Syntax

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

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

# In class PipeExec:
@property
def on_stdout() -> Callable[[PipeExecStdoutEventParams], None]: ...
@on_stdout.setter
def on_stdout(event_hook: Callable[[PipeExecStdoutEventParams], None]) -> None: ...

Remarks

The on_stdout event is fired every time the process outputs a line in its standard output. The incoming data is 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).

PipeExec 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.

PipeExec Config Settings

Base Config Settings

PipeExec Errors

PipeExec Errors

	401   Failed to create event.
	402   Failed to create security descriptor.
	403   Error creating named pipe.
	404   Error connecting to named pipe.
	405   Error disconnecting named pipe.
	408   Error sending data.
	410   Invalid MaxLineLength value.
	411   Error reading data.
	412   Error invoking RegisterWaitForSingleObject.
	413   Operation would block.
	414   Named pipe does not exist.
	415   Named pipe is already connected.
	416   Error connecting to named pipe.
	417   Named pipe not connected.
	419   Unsupported operation, see error message for details.
	420   Failed to create named pipe for Stdin/Stdout/Stderr.
	421   Failed to set handle information for Stdin/Stdout/Stderr.
	422   Failed to create process.
	423   Failed to terminate process.