Message Interfaces

The Message Interfaces module contains several basic classes that define the message interfaces. These classes provide a way to define the structure of the messengers that are used to communicate with the DFF.

class MessengerInterface

Bases: ABC

Class that represents a message interface used for communication between pipeline and users. It is responsible for connection between user and pipeline, as well as for request-response transactions.

abstract async connect(pipeline_runner)

Method invoked when message interface is instantiated and connection is established. May be used for sending an introduction message or displaying general bot information.

Parameters:

pipeline_runner (PipelineRunnerFunction) – A function that should process user request and return context; usually it’s a _run_pipeline() function.

class PollingMessengerInterface

Bases: MessengerInterface

Polling message interface runs in a loop, constantly asking users for a new input.

abstract _request()

Method used for sending users request for their input.

Return type:

List[Tuple[Message, Hashable]]

Returns:

A list of tuples: user inputs and context ids (any user ids) associated with the inputs.

abstract _respond(responses)

Method used for sending users responses for their last input.

Parameters:

responses (List[Context]) – A list of contexts, representing dialogs with the users; last_response, id and some dialog info can be extracted from there.

_on_exception(e)

Method that is called on polling cycle exceptions, in some cases it should show users the exception. By default, it logs all exit exceptions to info log and all non-exit exceptions to error.

Parameters:

e (BaseException) – The exception.

async _polling_loop(pipeline_runner, timeout=0)

Method running the request - response cycle once.

async connect(pipeline_runner, loop=<function PollingMessengerInterface.<lambda>>, timeout=0)

Method, running a request - response cycle in a loop. The looping behavior is determined by loop and timeout, for most cases the loop itself shouldn’t be overridden.

Parameters:

• pipeline_runner (PipelineRunnerFunction) – A function that should process user request and return context; usually it’s a _run_pipeline() function.

• loop (Callable[[], bool]) – a function that determines whether polling should be continued; called in each cycle, should return True to continue polling or False to stop.

• timeout (float) – a time interval between polls (in seconds).

class CallbackMessengerInterface

Bases: MessengerInterface

Callback message interface is waiting for user input and answers once it gets one.

async connect(pipeline_runner)

Method invoked when message interface is instantiated and connection is established. May be used for sending an introduction message or displaying general bot information.

Parameters:

pipeline_runner (PipelineRunnerFunction) – A function that should process user request and return context; usually it’s a _run_pipeline() function.

async on_request_async(request, ctx_id=None, update_ctx_misc=None)

Method that should be invoked on user input. This method has the same signature as PipelineRunnerFunction.

Return type:

Context

on_request(request, ctx_id=None, update_ctx_misc=None)

Method that should be invoked on user input. This method has the same signature as PipelineRunnerFunction.

Return type:

Context

class CLIMessengerInterface(intro=None, prompt_request='request: ', prompt_response='response: ', out_descriptor=None)

Bases: PollingMessengerInterface

Command line message interface is the default message interface, communicating with user via STDIN/STDOUT. This message interface can maintain dialog with one user at a time only.

_request()

Method used for sending users request for their input.

Return type:

List[Tuple[Message, Any]]

Returns:

A list of tuples: user inputs and context ids (any user ids) associated with the inputs.

_respond(responses)

Method used for sending users responses for their last input.

Parameters:

responses (List[Context]) – A list of contexts, representing dialogs with the users; last_response, id and some dialog info can be extracted from there.

async connect(pipeline_runner, **kwargs)

The CLIProvider generates new dialog id used to user identification on each connect call.

Parameters:

• pipeline_runner (PipelineRunnerFunction) – A function that should process user request and return context; usually it’s a _run_pipeline() function.

• **kwargs – argument, added for compatibility with super class, it shouldn’t be used normally.