Creating Microsoft Bot Framework In Python 😍

Note

• Python language support starts from Bot Framework SDK V4 and is in the preview stage.
• Currently, the predefined template is not available for Visual Studio 2019. We are using Flask template to create the Bot Application.
  

This article focuses on how to write the “Hello World” application in Bot Framework using Python language. It has been divided into two sections. The first section focuses on the Project template changes and the next section focuses on the code changes.

1. Project template changes
2. Code file changes 

First, I will start Project template changes,

 

Project template changes

 

Prerequisites

Visual Studio 2019 Preview (Version 16.4.0) and make sure Python development is installed.

 

 

Create a Project

The project type: “Blank Flask Web Project”.

 

 

Project Name

Enter the project name “HelloWorld” and create a project.

 

 

The project is successfully created.

 

Create a virtual environment

 

Go to the Solution Explorer and open the “requirements.txt” file and add the below namespace:

 

botbuilder-core>=4.4.0b1 ,botbuilder-dialogs>=4.4.0b1 save and close the file.

 

 

In the tab, view header click the “Create virtual environment” and create the environment

 

 

Create a virtual environment,

 

 

The virtual environment was created successfully.

 

 

For conformation check the module name displayed in the solution explorer in the ("Env") area.

 

 

Our Project template changes are done. Next, I am going to change the code files 

 

Code changes

 

Delete the default route function

 

Goto app.py file

Delete the hello() : function including app.route

@app.route('/')
def hello():
    """Renders a sample page."""
    return "Hello World!"

Port number update ( optional changes)

goto __main__ function and change the port number

if __name__ == '__main__':
    import os
    HOST = os.environ.get('SERVER_HOST', 'localhost')
    try:
        PORT = int(os.environ.get('SERVER_PORT', '5555'))
    except ValueError:
        PORT = 5555
    app.run(HOST, PORT)

Delete the PORT = int(os.environ.get('SERVER_PORT', '5555')) line and hardcode the port value otherwise every time you run the application  anew port will be created, here I am using default bot framework port “PORT = 3978”

 

After changes the code looks like below:

if __name__ == '__main__':
    import os
    HOST = os.environ.get('SERVER_HOST', 'localhost')
    try:
        PORT = 3978
    except ValueError:
        PORT = 5555
    app.run(HOST, PORT)

Create on_turn function handling the IO operation.

 

Create a new Python class file (ex: file name is: “echobot.py”). Add the new class “EchoBot”,  this class adds the on_turn function. This function has two arguments

1. Self, ref the current object 
2. “context” object, This object handles the activity details.

In this sample, we are reading the string which is sent by the user and sends back to the user the same string with the length of string.

from sys import exit

class EchoBot:
    async def on_turn(self, context):
        if context.activity.type == "message" and context.activity.text:
            strlen = len(context.activity.text)
            sendInfo = "Hey you send text : " + context.activity.text + "  and  the lenght of the string is  " + str(strlen)
            await context.send_activity(sendInfo)

asyn/await concept

 

Go to the “app.py” and add “import asyncio”, this has supported the async/await concept and "import sys" provides the information about constants, functions, and methods.  

import asyncio
import sys

Request and Response module

 

Add the request and response module in flask module. 

from flask import Flask, request, Response

Bot Framework module

 

Import the BotFrameworkAdapter, BotFrameworkAdapterSettings, TurnContext from botbuilder.core to handle the Bot related queries. 

from botbuilder.core import (
    BotFrameworkAdapter,
    BotFrameworkAdapterSettings,
    TurnContext,
)

Import the Activity from botbuilder.schema,

from botbuilder.schema import Activity

Add the EchoBot class in the app.py file to handle the activity type,

from echobot import*

Object creation

 

Create the object for Echobot class and  

bot = EchoBot()

SETTINGS = BotFrameworkAdapterSettings("","")
ADAPTER = BotFrameworkAdapter(SETTINGS)

Create an object for event loop, when called from a coroutine or a callback, this function will always return the running event loop.

LOOP = asyncio.get_event_loop()

Message handler function

 

This function is the heart of our application, and it handles all the requests and responses. Receiving the information from the request object as a JSON format and call the "await bot.on_turn(turn_context)" pass the turn_context as an argument.

In on_turn function we are checking the activity type. If its type is message, find the length of the string and send the information to the user using context.send_activity function.

@app.route("/api/messages", methods=["POST"])
def messages():
    if "application/json" in request.headers["Content-Type"]:
        body = request.json
    else:
        return Response(status=415)

    activity = Activity().deserialize(body)
    auth_header = (
        request.headers["Authorization"] if "Authorization" in request.headers else ""
    )

    async def aux_func(turn_context):
        await bot.on_turn(turn_context)

    try:
        task = LOOP.create_task(
            ADAPTER.process_activity(activity, auth_header, aux_func)
        )
        LOOP.run_until_complete(task)
        return Response(status=201)
    except Exception as exception:
        raise exception

That's it -- all the changes are done. Rebuild and run the application. 

 

Testing Steps

1. Open the bot emulator and connect to the URL (http://localhost:3978/api/messages).
2. Once it is connected, send the message
3. Bot response to the channel and the information display in the emulator. 

Output

 

 

Please find the source from here

Conclusion

I hope you can understand the concept of how to create a bot application using Python. More articles are coming soon in Python languages, stay tuned.

Happy reading!!! Happy coding!!!