asiocmd 1.0.0

Modern and asynchronous support for cmd.Cmd

asiocmd: Modern cmd with async support

Overview

asiocmd provides a very lightweight repacking of Python's cmd.Cmd class for building command line interfaces. The package contains 2 classes, namely Cmd and an inherited AsyncCmd

Cmd

Cmd provides virtually the same functionality and development interface as cmd.Cmd, with the primary difference being in the way methods are looked up at runtime.

AsyncCmd

An implementation of Cmd with added support for asynchronous methods

Usage

from asiocmd import (AsyncCmd,
                  command, command_helper,
                  async_command, async_command_helper)

class DemoCmd(AsyncCmd):
    # Instance methods decorated with @command are registered as CLI commands

    # Command names can be specified as the decorator argument
    @command("foo")
    def arbitrary_name(self, line: str) -> None: ...

    # If the name argument is not provided,
    # the function name is taken as command name
    @command
    def bar(self, line: str) -> None: ...

    # Legacy support for cmd.Cmd's naming convention of do_*
    def do_xyz(self, line: str) -> None: ...

    # Helpers can be registered with @command_helper(<command_name>)
    @command_helper("foo")
    def arbitrary_helper(self) -> None: ...

    # Again, cmd.Cmd's helper naming convention is still supported
    def help_bar(self) -> None: ...

    # Asynchronous methods and helpers follow
    # the same convention, just with different decorators

    @async_command("afoo")
    async def async_name(self, line: str) -> None: ...

    @async_command
    async def abar(self, line: str) -> None: ...

    async def do_abc(self, line: str) -> None: ...

    @async_command_helper("afoo")
    async def afoo_helper(self) -> None: ...

# Launching the CLI
if __name__ == '__main__':
    asyncio.run(DemoCmd().acmdloop())

Note: Cmd uses cmdloop() to launch itself, the coroutine acmdloop belongs only to AsyncCmd to provide support for asynchronous methods.

Stacking of decorators are also supported, given that function metadata is preserved using functools.wraps

from asiocmd import (AsyncCmd, command)
import functools

def generic_method_decorator(func):
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        # Some working
        return func(*args, **kwargs)
    return wrapper

class DemoCmd(AsyncCmd):
    @generic_method_decorator
    @command_helper("foo")
    def abc(self) -> None: pass

    @generic_method_decorator
    def do_bar(self, line: str) -> None: pass