In this lesson, we will go through the steps of creating a bot in the Slack messaging app which automatically determines the user's age based on the user's input. We will be implementing this app in Python and deploying it locally.

Prerequisites

• Must be familiar with Python

Creating a Slack Workspace for AgeBot Project

Go to Slack and Sign in or Sign up with Email if you don't have an account.
After signing in, click Create Another Workspace or Create a Workspace. Fill out the required information. You can invite team members or create channels for specific topics.

Setting up the Slack Workspace for AgeBot Project

Create an app by going to Slack API apps. Click Create an App. If you have create apps before in Slack, this page will look different. In that case, there will be a Create New App button.

Click create From scratch

Give your app a name and choose a workspace to develop your app in. In this example, we will be using a workspace we have already created called Cyber Coder. Please use one of the workspaces you created. Click Create App.

Scroll down to Display Section. Give your app a Short description and Long description. Then click Save Changes.

Scroll up and click Bots.

Click Review Scopes to Add.

Scroll down to the Scopes Section. Under Bot Token Scopes, click Add an OAuth Scope.

Search for the following and add them. app_mentions:read views messages that directly mention @AgeBot in conversations that the app is in. chat:write sends messages as @AgeBot. im:history views messages and other content in direct messages that AgeBot has been added to.

• app_mentions:read
• chat:write
• im:history

Scroll up to the OAuth Tokens for Your Workspace Section. Click Install to Workspace.

Click Allow.

Click Socket Mode under Settings and turn on Enable Socket Mode. Turning on Socket Mode will route your app’s interactions and events over a WebSockets connection instead sending these payloads to Request URLs. Since we will be running this app locally, we need to enable this feature.

Click Basic Information under Settings.

Scroll down to the App-Level Tokens Section. Click Generate Token and Scopes.

Give your App level token a name. Then click Add Scope. Select connections:write and click Generate. This setting will route your app's interactions and event payloads over WebSockets.

Copy this token in a notepad. Store this token in a variable call SLACK_APP_TOKEN. Click Done.

Scroll back up to the Building Apps for Slack Section. Click Add features and functionality Section. Then click Event Subscriptions. Turn on Enable Events.

Under the Subscribe to bot events Section, click Add Bot User Event. Select the following events. app_mention subscribes to only the message events that mention your app or bot. message.im checks if a message was posted in a direct message channel.

• app_mention
• message.im

Click OAuth & Permissions under Features. Under OAuth Tokens for Your Workspace copy the Bot User OAuth Token into a notepad. Store this token in a variable call SLACK_BOT_TOKEN.

Writing the Python code

This app will automatically calculate the user's age based on the user's input. To trigger this function, go on Slack and in the chat type @AgeBot [day-month-year]. For example, @AgeBot 25-12-2012. Given that the date of writing this blog is 30-11-2023 the response from AgeBot is 10.

Create a folder called agebot. Navigate into this folder by typing the following in the command terminal.

cd agebot

Create a virtual environment by entering the following in the command terminal.

virtualenv venv

Activate the virtual environment using the following command.

venv\Scripts\activate

Install the required libraries: slack-bolt and python-dotenv

pip install slack-bolt
pip install python-dotenv

Create a .env file and copy and paste your tokens here.

SLACK_APP_TOKEN = "YOUR APP TOKEN"
SLACK_BOT_TOKEN = "YOUR BOT TOKEN"

Import the required libraries.

import os
from slack_bolt import App
from slack_bolt.adapter.socket_mode import SocketModeHandler
from slack_sdk import WebClient
from datetime import datetime, date
import re

from dotenv import load_dotenv
load_dotenv()
import os
SLACK_APP_TOKEN = os.environ.get("SLACK_APP_TOKEN")
SLACK_BOT_TOKEN = os.environ.get("SLACK_BOT_TOKEN")

app = App(token=SLACK_APP_TOKEN)
client = WebClient(token=SLACK_BOT_TOKEN)

Create a function to calculate the user's age. First we need to extract the date from the user input. Then we define the date format. The date string is converted to a datetime object. We call the function date.today() to get today's date. The difference between today's date and the user's input date is calculated. This result is then divided by 365 to get the number of years. Finally, return the result as a chat message.

def handle_age_request(channel, text):
    # Example string containing a date
    date_string = re.sub('<.*?>', '', text)
    date_string = re.sub(r"\s+", "", date_string)

    # Define the date format
    date_format = "%d-%m-%Y"

    # Convert the string to a datetime object
    date_object = datetime.strptime(date_string, date_format)
    dob = date_object.date()

    today = date.today()

    # Calculate the difference between the two dates
    delta = today - dob

    # Calculate the number of years
    years = delta.days // 365


    client.chat_postMessage(channel=channel, text=str(years))

Create a function to handle app_mention. This function is called whenever a message mentions the app or bot.

@app.event("app_mention")
def handle_mention(event, say):
    channel = event.get('channel')
    text = event.get('text')
    handle_age_request(channel, text)

Start the Socket.

print("Start your bot")
handler = SocketModeHandler(app, app_token=SLACK_APP_TOKEN)
handler.start()

The entire script should look like this.

import os
from slack_bolt import App
from slack_bolt.adapter.socket_mode import SocketModeHandler
from slack_sdk import WebClient
from datetime import datetime, date
import re

from dotenv import load_dotenv
load_dotenv()
import os
SLACK_APP_TOKEN = os.environ.get("SLACK_APP_TOKEN")
SLACK_BOT_TOKEN = os.environ.get("SLACK_BOT_TOKEN")

app = App(token=SLACK_APP_TOKEN)
client = WebClient(token=SLACK_BOT_TOKEN)

def handle_age_request(channel, text):
    # Example string containing a date
    date_string = re.sub('<.*?>', '', text)
    date_string = re.sub(r"\s+", "", date_string)

    # Define the date format
    date_format = "%d-%m-%Y"

    # Convert the string to a datetime object
    date_object = datetime.strptime(date_string, date_format)
    dob = date_object.date()

    today = date.today()

    # Calculate the difference between the two dates
    delta = today - dob

    # Calculate the number of years
    years = delta.days // 365


    client.chat_postMessage(channel=channel, text=str(years))


@app.event("app_mention")
def handle_mention(event, say):
    channel = event.get('channel')
    text = event.get('text')
    handle_age_request(channel, text)


print("Start your bot")
handler = SocketModeHandler(app, app_token=SLACK_APP_TOKEN)
handler.start()

Now go to your workspace in Slack. In any of your channels, start a conversation with @AgeBot. You may get this message "You mentioned @AgeBot, but they’re not in this channel". Click Invite Them. You can now message @AgeBot. Type @AgeBot 25-12-2000. Given that the date of writing this blog is 30-11-2023 AgeBot will respond with 22. This concludes our lesson.