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How to create a Telegram bot

Written by
Updated at July 8, 2024

Serverless technologies enable you to create a Telegram bot that will respond to chat messages.

To create a bot:

  1. Prepare the environment.
  2. Set up resources.
  3. Register the Telegram bot.
  4. Post a bot image.
  5. Create an API gateway.
  6. Create a function.
  7. Configure a link between the function and the Telegram bot.
  8. Check that the Telegram bot works.

If you no longer need the resources you created, delete them.

Getting started

Sign up for Yandex Cloud and create a billing account:

  1. Go to the management console and log in to Yandex Cloud or create an account if you do not have one yet.
  2. On the Yandex Cloud Billing page, make sure you have a billing account linked and it has the ACTIVE or TRIAL_ACTIVE status. If you do not have a billing account, create one.

If you have an active billing account, you can go to the cloud page to create or select a folder for your infrastructure to operate in.

Learn more about clouds and folders.

The cost of Telegram bot support includes:

  • Fee for the number of function calls, computing resources allocated to executing the function, and outgoing traffic (see Cloud Functions pricing).
  • Fee for the amount of stored data, the number of data transactions, and outgoing traffic (see Object Storage pricing).
  • Fee for the number of requests to the API gateway and outgoing traffic (see Yandex API Gateway pricing).

Create resources

  1. Download the archive with the files required to create a bot.
  2. Create a service account and assign it the editor and functions.functionInvoker roles for your folder.

Register the Telegram bot

Register your bot in Telegram and get a token.

  1. To register the new bot, launch the BotFather bot and run the command below:

    /newbot

  2. In the name field, enter a name for the bot being created, such as Serverless Hello Telegram Bot. This is the name users will see when communicating with the bot.

  3. In the username field, enter the user name for the bot being created, such as ServerlessHelloTelegramBot. You can use the user name to search for the bot in Telegram. The user name must end with ...Bot or ..._bot.

    As a result, you will get a token. Save it. You will need it later.

  4. Set an icon for the bot using sayhello.png from the saved archive. Send the BotFather bot the command below:

    /setuserpic

Post a bot image

For the bot to respond to user messages with an image, create a bucket in Object Storage and upload sayhello.png from the saved archive to the bucket.

Create a bucket in Object Storage

  1. In the management console, select the folder where you want to create a bucket.

  2. Select Object Storage.

  3. Click Create bucket.

  4. On the bucket creation page:

    1. Enter the name of the bucket. Save the bucket name. You will need it later.

    2. Specify the bucket settings:

      • Max size: 1 GB
      • Object read access: Public
      • Storage class: Standard

    3. Click Create bucket.

Upload the image to the bucket

  1. In the management console, select the folder that contains the previously created bucket.
  2. Select Object Storage.
  3. Select the previously created bucket.
  4. Click Upload.
  5. In the window that opens, select sayhello.png from the saved archive. The management console will display the file selected for upload.
  6. Click Upload.
  1. In the management console, select the folder that contains the previously created bucket.
  2. Select Object Storage.
  3. Select the previously created bucket.
  4. Select sayhello.png.
  5. Click Get link.
  6. Check that the image is available in your browser.

Create an API gateway

Create and configure an API Gateway.

  1. In the management console, select the folder where you want to create an API gateway.

  2. Select API Gateway.

  3. Click Create API gateway.

  4. Enter a name for the gateway: for-serverless-hello-telegram-bot.

  5. Clear the contents of the Specification field and replace them with the code below:

    openapi: 3.0.0
info:
  title: for-serverless-hello-telegram-bot
  version: 1.0.0
paths:
  /sayhello.png:
    get:
      x-yc-apigateway-integration:
        type: object_storage
        bucket: <bucket_name>
        object: sayhello.png
        presigned_redirect: false
        service_account_id: <service_account_ID>
      operationId: static

    Where:

  6. Click Create.

  7. Select the created API gateway. Save the name of the Default domain field from the General information section. You will need it later.

Create a function

To have the Telegram bot respond to the /start and /help commands and send an image in response to any other text, create a function.

  1. In the management console, select the folder to create the function in.

  2. Select Cloud Functions.

  3. Click Create function.

  4. Enter a name for the function: fshtb-function.

  5. Click Create.

  6. Under Editor, select the Node.js runtime environment and click Continue.

  7. Under Function code, replace the contents of the index.js file with the code below: Replace <API_gateway_domain> with the API gateway's service domain.

    const { Telegraf } = require('telegraf');

const bot = new Telegraf(process.env.BOT_TOKEN);
bot.start((ctx) => ctx.reply(`Hello. \nMy name is Serverless Hello Telegram Bot \nI'm working on Cloud Function in Yandex Cloud.`))
bot.help((ctx) => ctx.reply(`Hello, ${ctx.message.from.username}.\nI can say Hello and nothing more`))
bot.on('text', (ctx) => {
    ctx.replyWithPhoto({url: '<API_gateway_domain>/sayhello.png'});
    ctx.reply(`Hello, ${ctx.message.from.username}`);

});

module.exports.handler = async function (event, context) {
    const message = JSON.parse(event.body);
    await bot.handleUpdate(message);
    return {
        statusCode: 200,
        body: '',
    };
};

  8. Under Function code, create a file named package.json with the following code:

    {
  "name": "ycf-telegram-example",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "MIT",
  "dependencies": {
    "telegraf": "^4.12.0"
  }
}

  9. Specify the following parameters:

    • Runtime environment: nodejs16
    • Entry point: index.handler
    • Timeout, sec: 5

  10. Add the BOT_TOKEN variable to the environment. In the Value field, specify the Telegram bot token.

  11. Click Save changes.

  12. Make sure that the function is public. To do this, go to the Overview page and, under General information, switch the Public function option to on.

  13. Save your function ID. You will need it later.

Configure a link between the function and the Telegram bot

  1. In the management console, select the appropriate folder.

  2. Select API Gateway.

  3. Select the for-serverless-hello-telegram-bot API gateway.

  4. Edit the API gateway specification by appending a fshtb-function section at the end:

      /fshtb-function:
    post:
      x-yc-apigateway-integration:
        type: cloud_functions
        function_id: <function_ID>
      operationId: fshtb-function

    Where function_id is the fshtb-function function ID.

  5. Click Save.

  6. Run the following request in the terminal:

    • Linux, macOS:

      curl \
  --request POST \
  --url https://api.telegram.org/bot<bot_token>/setWebhook \
  --header 'content-type: application/json' \
  --data '{"url": "<API_gateway_domain>/fshtb-function"}'

    • Windows (cmd):

      curl ^
  --request POST ^
  --url https://api.telegram.org/bot<bot_token>/setWebhook ^
  --header "content-type: application/json" ^
  --data "{\"url\": \"<API_gateway_domain>/fshtb-function\"}"

    • Windows (PowerShell):

      curl.exe `
  --request POST `
  --url https://api.telegram.org/bot<bot_token>/setWebhook `
  --header '"content-type: application/json"' `
  --data '"{ \"url\": \"<API_gateway_domain>/fshtb-function\" }"'

    Where:

    • <bot token>: Telegram bot token.
    • <API_gateway_domain>: API gateway's service domain.

    Result:

    {"ok":true,"result":true,"description":"Webhook was set"}

Check that the Telegram bot works

Talk to the bot:

  1. Open Telegram and search for the bot using the previously created username as its username.

  2. Send a message saying /start to the chat.

    The bot must respond with:

    Hello.
My name is Serverless Hello Telegram Bot
I'm working on Cloud Function in the Yandex Cloud.

  3. Send the message /help in the chat.

    The bot must respond with:

    Hello, <username>.
I can say Hello and nothing more

  4. Send any text message to the chat. The bot must respond with an image and Hello, <username>.

How to delete the resources you created

To stop paying for the resources you created:

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