Building chat applications and robots for Skype

Command line is powerful interface. Everyone who has taken head first dive into UNIX and survived back to tell about it can confirm. However, you do not need to be a computer guru to interact with command line. In this blog post, I’ll want to open you the window of opportunity to realize some potential here in (Skype) chats. Please note that this blog post is not limited to the scope of Skype, but principles presented here can be applied to any chat media your team is using.


1. Why build a chat robot?

Generally, non-IT-sawy folks interact with few command-line-likes in their daily work

  • Browser address bar (Firefox’s Awesome Bar has made awesome progress to shift my cognitive load into the browser address bar)
  • Search engine’s search box (autocompletion, but DuckDuckGo offers even more awesome tricks here)
  • Microsoft Excel input box, or similar
  • Chat and instant messaging message inputs
  • etc.

Command line is powerful, as stated before. It’s fast to type, but it’s also more error prone and more difficult to discover, as opposite to e.g. menu-driven interface or a web application. Clickety-click encourages discoverability by showing you the options as you progress. Command line is more like you need to know what you type and you do it as single pass – if there are errors you restart the process from the start. For this very reason command line is more effective for repeating tasks: typing has no speed limit and comes from your muscle memory. After you get past the command line learning curve it’ll be all harder, better, faster, stronger.

2. Skype chat, universal command line

Here is a real-life example: a managerial person in a small organization wanted to have a better picture what all of their team members are doing. Due to nature the of the work, the persons are not present at the office: they work here and there in client premises.

We could use a nice web app or even a mobile app to track the task everybody is working on. However, this particular manager thought “It’s too heavy weight.” The business case was that when he gets a call from a customer asking whether this task is done or started yet, he needs to know it at the moment. The organization is small, everybody is a geek and doing Bring Your Own Devices, so the app should be reachable on whatever you have in hand.

The manager had seen some the earlier automation efforts we had made with a Skype chat bot, Sevabot. So he asked me if we could build a Skype-chat-driven keep-it-simple task list application: just to mark whatever you are working on and mark again when you are done, all this by Skype chat commands.

Benefits of this approach

  • Everybody in the team was already using Skype: people are familiar with it
  • Skype is notoriously famous for working on every device, every network, everywhere
  • Skype syncs: even in offline you have some status messages left on your mobile device
  • Command line is efficient: Writing a chat message to output ongoing tasks can be done even when you are on mobile call. It literally takes a second.
  • Writing a simple command-driven application has very good cost-benefit ratio: writing a text based applications is a quick task, can be done in couple of hours (as opposite to build a web app, some forms, etc.)

And this is how it works:

Screen Shot 2013-03-28 at 1.47.40 PM

3. Creating a stateful chat app with Sevabot

Sevabot is an on-going open source Skype chat bot project. Before (version 1.2) it already had support for running UNIX scripts through chat commands and HTTP webhooks to send chat notifications from external services. The task in hand could have been created with little bit UNIX scripting magic. However, I had been in touch with Naoto Yokoyama who had a need for more advanced Skype chat commands besides simple triggers. Based on the discussion and Naoto’s original work we created a stateful chat scripting support for Sevabot.

  • You define your (stateful) chat application as a simple Python module and class
  • The modules are reloadable
  • Installing a new stateful script is simple as dropping the .py file into the correct folder
  • The script can install event handlers for all raw Skype4Py events, including handling of Skype calls
  • You can utilize background processes, timers, threads, native extensions and all the power of normal long-running Python UNIX apps

Below is the Python source for the task management application described above.

Some notes about the module

  • We persistent the script state to the disk. Sevabot is running in the cloud and it can be restarted at any moment. We simply use Python pickles, no databases needed here.
  • Each group chat has its own task list, so it is safe to multiplex one bot instance across different teams and working groups.
  • There is a timer which will poke the people if they forgot to close the tasks they have started.

4. Future

Next, I’d like to try the following

5. Source code

The module source code is also on Github and distributed with Sevabot 1.2.


    Simple group chat task manager.

    This also serves as an example how to write stateful handlers.


from __future__ import unicode_literals

from threading import Timer
from datetime import datetime
import os
import logging
import pickle
from collections import OrderedDict

from import StatefulSkypeHandler
from sevabot.utils import ensure_unicode, get_chat_id

logger = logging.getLogger("Tasks")

# Set to debug only during dev

logger.debug("Tasks module level load import")

# How long one can work on a task before we give a warning

HELP_TEXT = """!tasks is a noteboard where virtual team members can share info which tasks they are currently working on.


!tasks: This help text

Start task: You start working on a task. When you started is recorded. Example:

    start task I am now working on new Sevabot module interface

Stop task: Stop working on the current task. Example:

    stop task

List tasks: List all tasks an people working on them. Example:

    list tasks

Task lists are chat specific and the list is secure to the members of the chat.
All commands are case-insensitive.

class TasksHandler(StatefulSkypeHandler):
    Skype message handler class for the task manager.

    def __init__(self):
        """Use `init` method to initialize a handler.
        logger.debug("Tasks constructed")

    def init(self, sevabot):
        Set-up our state. This is called

        :param skype: Handle to Skype4Py instance
        logger.debug("Tasks init")
        self.sevabot = sevabot
        self.status_file = os.path.join(os.path.dirname(__file__), "sevabot-tasks.tmp")
        self.status =

        self.commands = {
            "start task": self.start_task,
            "list tasks": self.list_tasks,
            "stop task": self.stop_task,


    def handle_message(self, msg, status):
        """Override this method to customize a handler.

        # Skype API may give different encodings
        # on different platforms
        body = ensure_unicode(msg.Body)

        logger.debug("Tasks handler got: %s" % body)

        # Parse the chat message to commanding part and arguments
        words = body.split(" ")
        lower = body.lower()

        if len(words) == 0:
            return False

        # Parse argument for two part command names
        if len(words) >= 2:
            desc = " ".join(words[2:])
            desc = None

        chat_id = get_chat_id(msg.Chat)

        # Check if we match any of our commands
        for name, cmd in self.commands.items():
            if lower.startswith(name):
                cmd(msg, status, desc, chat_id)
                return True

        return False

    def shutdown(self):
        """ Called when the module is reloaded.
        logger.debug("Tasks shutdown")

    def save(self):
        Persistent our state.
        Status.write(self.status_file, self.status)

    def reset_timeout_notifier(self):
        Check every minute if there are overdue jobs
        self.notifier = Timer(60.0, self.check_overdue_jobs)
        self.notifier.daemon = True  # Make sure CTRL+C works and does not leave timer blocking it

    def stop_timeout_notifier(self):

    def help(self, msg, status, desc, chat_id):
        Print help text to chat.

        # Make sure we don't trigger ourselves with the help text
        if not desc:

    def warn_overdue(self, chat_id, job):
        Generate overdue warning.
        self.sevabot.sendMessage(chat_id, "Task hanging: %s started working on %s, %s" % (job.real_name, job.desc, pretty_time_delta(job.started)))
        job.warned = True

    def check_overdue_jobs(self):
        Timer callback to go through jobs which might be not going forward.

        found = False

        logger.debug("Running overdue check")

        now =

        for chat_id, chat in self.status.chats.items():
            for job in chat.values():
                if (now - job.started).total_seconds() > MAX_TASK_DURATION and not job.warned:
                    found = True
                    self.warn_overdue(chat_id, job)

        if found:
            logger.debug("Found overdue jobs")
            logger.debug("Did not found overdue jobs")


    def start_task(self, msg, status, desc, chat_id):
        Command handler.

        if desc.strip() == "":
            msg.Chat.SendMessage("Please give task description also")

        tasks = self.status.get_tasks(chat_id)
        existing_job = tasks.get(msg.Sender.Handle, None)
        if existing_job:
            msg.Chat.SendMessage("Stopped existing task %s" % existing_job.desc)

        job = Job(msg.Sender.FullName,, desc)
        tasks = self.status.get_tasks(chat_id)
        tasks[msg.Sender.Handle] = job
        msg.Chat.SendMessage("%s started working on %s." % (job.real_name, job.desc))

    def list_tasks(self, msg, status, desc, chat_id):
        Command handler.

        jobs = self.status.get_tasks(chat_id).values()

        if len(jobs) == 0:
            msg.Chat.SendMessage("No active tasks for anybody")

        for job in jobs:
            msg.Chat.SendMessage("%s started working on %s, %s" % (job.real_name, job.desc, pretty_time_delta(job.started)))

    def stop_task(self, msg, status, desc, chat_id):
        Command handler.
        tasks = self.status.get_tasks(chat_id)
        if msg.Sender.Handle in tasks:
            job = tasks[msg.Sender.Handle]
            del tasks[msg.Sender.Handle]
            msg.Chat.SendMessage("%s finished" % job.desc)
            msg.Chat.SendMessage("%s had no active task" % msg.Sender.FullName)

class Status:
    Stored pickled state of the tasks.

    Use Python pickling serialization for making status info persistent.

    def __init__(self):
        # Chat id -> OrderedDict() of jobs mappings
        self.chats = dict()

    def read(cls, path):
        Read status file.

        Return fresh status if file does not exist.

        if not os.path.exists(path):
            # Status file do not exist, get default status
            return Status()

        f = open(path, "rb")

            return pickle.load(f)

    def write(cls, path, status):
        Write status file
        f = open(path, "wb")
        pickle.dump(status, f)

    def get_tasks(self, chat_id):
        Get jobs of a particular chat.
        if not chat_id in self.chats:
            # Skype username -> Task instance mappings
            self.chats[chat_id] = OrderedDict()

        return self.chats[chat_id]

class Job:
    Tracks who is doing what

    def __init__(self, real_name, started, desc):
        :param started: datetime when the job was started
        self.started = started
        self.desc = desc
        self.real_name = real_name
        # Have we given timeout warning for this job
        self.warned = False

# The following has been
# ripped off from

_ = lambda x: x

def pretty_time_delta(time):

    now =

    if time > now:
        past = False
        diff = time - now
        past = True
        diff = now - time

    days = diff.days

    if days is 0:
        return get_small_increments(diff.seconds, past)
        return get_large_increments(days, past)

def get_small_increments(seconds, past):
    if seconds < 10:
        result = _('just now')
    elif seconds < 60:
        result = _pretty_format(seconds, 1, _('seconds'), past)
    elif seconds < 120:
        result = past and _('a minute ago') or _('in a minute')
    elif seconds < 3600:
        result = _pretty_format(seconds, 60, _('minutes'), past)
    elif seconds < 7200:
        result = past and _('an hour ago') or _('in an hour')
        result = _pretty_format(seconds, 3600, _('hours'), past)
    return result

def get_large_increments(days, past):
    if days == 1:
        result = past and _('yesterday') or _('tomorrow')
    elif days < 7:
        result = _pretty_format(days, 1, _('days'), past)
    elif days < 14:
        result = past and _('last week') or _('next week')
    elif days < 31:
        result = _pretty_format(days, 7, _('weeks'), past)
    elif days < 61:
        result = past and _('last month') or _('next month')
    elif days < 365:
        result = _pretty_format(days, 30, _('months'), past)
    elif days < 730:
        result = past and _('last year') or _('next year')
        result = _pretty_format(days, 365, _('years'), past)
    return result

def _pretty_format(diff_amount, units, text, past):
    pretty_time = (diff_amount + units / 2) / units

    if past:
        base = "%(amount)d %(quantity)s ago"
        base = "%(amount)d %(quantity)s"

    return base % dict(amount=pretty_time, quantity=text)

# Export the instance to Sevabot
sevabot_handler = TasksHandler()

__all__ = ["sevabot_handler"]





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One thought on “Building chat applications and robots for Skype

  1. “Please note that this blog post is not limited to the scope of Skype, but principles presented here can be applied to any chat media your team is using.”

    Good, because Skype is far from open source.

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