Hosting: Cloudflare Workers (Deno)

Cloudflare Workers is a public serverless computing platform that offers a convenient and simple solution for running small workloads at the edge.

This guide will take you through the process of hosting your bot on Cloudflare Workers.

Looking for the Node.js Version?

This tutorial explains how to deploy a Telegram bot to Cloudflare Workers using Deno. If you’re looking for the Node.js version, please check out this tutorial instead.

Prerequisites

To follow along, please make sure that you have a Cloudflare account with your workers subdomain configured.

Setting Things Up

Make sure you have Deno and Denoflare installed.

Create a new directory, and create a new file .denoflare in that directory. Put the following contents in the file:

Note: The “$schema” key in the following JSON code specifies a fixed version in its URL (“v0.5.12”). At the time of writing, this was the latest version available. You should update them to the newest version.

{
  "$schema": "https://raw.githubusercontent.com/skymethod/denoflare/v0.5.12/common/config.schema.json",
  "scripts": {
    "my-bot": {
      "path": "bot.ts",
      "localPort": 3030,
      "bindings": {
        "BOT_TOKEN": {
          "value": "YOUR_BOT_TOKEN"
        }
      },
      "workersDev": true
    }
  },
  "profiles": {
    "account1": {
      "accountId": "YOUR_ACCOUNT_ID",
      "apiToken": "YOUR_API_TOKEN"
    }
  }
}

Make sure to replace YOUR_ACCOUNT_ID, YOUR_API_TOKEN, and YOUR_BOT_TOKEN appropriately. When creating your API token, you can choose the Edit Cloudflare Workers preset from the pre-configured permissions.

Creating Your Bot

Create a new file named bot.ts and put the following contents in it:

import { Bot, webhookCallback } from "https://deno.land/x/grammy@v1.27.0/mod.ts";
import { UserFromGetMe } from "https://deno.land/x/grammy@v1.27.0/types.ts";

interface Environment {
  BOT_TOKEN: string;
}

let botInfo: UserFromGetMe | undefined = undefined;

export default {
  async fetch(request: Request, env: Environment) {
    try {
      const bot = new Bot(env.BOT_TOKEN, { botInfo });

      if (botInfo === undefined) {
        await bot.init();
        botInfo = bot.botInfo;
      }

      bot.command("start", (ctx) => ctx.reply("Welcome! Up and running."));
      bot.on("message", (ctx) => ctx.reply("Got another message!"));

      const cb = webhookCallback(bot, "cloudflare-mod");

      return await cb(request);
    } catch (e) {
      return new Response(e.message);
    }
  },
};

Deploying Your Bot

It’s as easy as running:

denoflare push my-bot

The output of the above command will provide you with the host the worker is running on. Watch out for a line containing something like <MY_BOT>.<MY_SUBDOMAIN>.workers.dev. That’s the host where your bot is waiting to be called.

Setting Your Webhook

We need to tell Telegram where to send updates to. Open your browser and visit this URL:

https://api.telegram.org/bot<BOT_TOKEN>/setWebhook?url=https://<MY_BOT>.<MY_SUBDOMAIN>.workers.dev/

Replace <BOT_TOKEN>, <MY_BOT>, and <MY_SUBDOMAIN> with your values. If the setup is successful, you’ll see a JSON response like this:

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

Testing Your Bot

Open your Telegram app, and start your bot. If it responds, it means you’re good to go!

Debugging Your Bot

For testing and debugging purposes, you can run a local or remote development server before deploying your bot to production. Simply run the following command:

denoflare serve my-bot

Once the development server has started, you can test your bot by sending sample updates to it using tools like curl, Insomnia, or Postman. Refer to here for update examples and here for more information on the update structure.