2020-01-13

A simple and easy NodeJS Telegram bot

Bots, they are everywhere, right? Why not have a bot, that's doing some fancy work for you?

Telegrams 'BotFather' is the way to get you started: see the docs

It is as easy as open telegram, search @botfather and send him /newbot as a message, few more steps like naming aaaand boom - bot is up!

DISCLAIMER The following code is a quick and dirty solution! It is simply sending me memes from subreddit 'ProgrammerHumor'.
Checkout my reddit-api-image-getter package on npm.

Want to know what telegraf does?
Telegraf does not explicitely tell, but adding a caption to a photo is added in the code example below.

All what's left to do now is create a new Node project:

$ mkdir reddit-image-telegraf && cd reddit-image-telegraf
$ yarn init
$ yarn add telegraf reddit-api-image-getter@1.0.5 select-random-file
// content of your entrypoint file, usually index.js

const fs = require("fs");
const path = require("path");
const randomFile = require("select-random-file");
const Telegraf = require("telegraf");

// use the key Botfather gave you here
const bot = new Telegraf("YOUR-SECRET-TOKEN");

const redditApiImageGetter = require("reddit-api-image-getter");
getter = new redditApiImageGetter();

bot.start((ctx) => ctx.reply("This is here to make me happy."));

bot.command("makemehappy", (ctx) => {
  // limit to your own chat.id
  // (you can get it by using a debugger and inspecting ctx object)
  // use a telegraf middleware for limiting if you are really fancy
  //
  // if you do not need limitation, drop the conditional!
  if (ctx.chat.id != 00013370001) {
    ctx.reply("Your ID is not whitelisted, I am sorry. Not sorry!");
  } else {
    const channelOrders = ["hot", "top"];
    const hotOrTop =
      channelOrders[Math.floor(Math.random() * channelOrders.length)];
    const dir = path.resolve(__dirname, "images", hotOrTop, "ProgrammerHumor");
    randomFile(dir, (err, file) => {
      console.log(`The random file is: ${file}.`);
      const pathToFile = path.resolve(dir, file);
      ctx.replyWithPhoto({
        source: fs.readFileSync(pathToFile),
      }, { caption: "Send with telegraf bot" }); // add a caption/text to your media (< 1024 signs)
    });
  }
});

bot.command("refresh", function (ctx) {
  // limit to your own chat.id
  // (you can get it by using a debugger and inspecting ctx object)
  // use a telegraf middleware for limiting if you are really fancy
  //
  // if you do not need limitation, drop the conditional!
  if (ctx.chat.id != 00013370001) {
    ctx.reply("Your ID is not whitelisted, I am sorry. Not sorry!");
  } else {
    // gets hot images
    getter.getHotImagesOfSubReddit("ProgrammerHumor").then(function (result) {
      for (let imageEntry of result) {
        console.log(`top ${imageEntry.formattedFilename}`);
        getter.saveRedditImageEntryToDisk(
          imageEntry,
          path.resolve(__dirname, "images", "hot"),
        );
      }
      ctx.reply("refreshed hot images");
    }).catch(function (error) {
      console.log(error);
    });
    // gets top images
    getter.getTopImagesOfSubReddit("ProgrammerHumor").then(function (result) {
      for (let imageEntry of result) {
        console.log(`top ${imageEntry.formattedFilename}`);
        getter.saveRedditImageEntryToDisk(
          imageEntry,
          path.resolve(__dirname, "images", "top"),
        );
      }
      ctx.reply("refreshed top images");
    }).catch(function (error) {
      console.log(error);
    });
  }
});

bot.launch();

Run

$ node index.js

Grab your phone, start your bot and send /refresh watch the picture pop up on your filesystem, then send /makemehappy and have a laugh.

Send me a message on telegram and chat with me, best let me know what kind of bot you brought to life: https://t.me/simonneutert

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