🖍️ Syntax Highlighter Bot

Kind of a copy; highly inspired from Piterden/syntax-highlighter-bot - Telegram Bot here

Minimal syntax highlighting bot for Telegram. Use it private chat or add to group chats. Send text inside three backticks, or any message containing pre or multiline code entities, and the bot will reply you with syntax highlighted images of that piece of code. Useful in Development groups.

Try the running bot here: Syntax Highlighter Bot 🚀

Written in TypeScript and grammY and runs on Deno.

• Built Using
• Features (and usage)
• Setup › Running Locally
• Setup › Deploy to Heroku
• Setup › Environment Variables

Built Using

Thanks to these tools and libraries.

1. highlight.js — Syntax highlighting for the Web. Behind-the-scenes of this bot.
2. Puppeteer — Puppeteer is a library which provides a high-level API to control Chrome, Chromium, or Firefox Nightly over the DevTools Protocol. Also a core part of this bot, used for generating syntax highlighted images.
3. grammY — The Telegram Bot Framework.
4. Deta.sh Base — Free and unlimited Cloud Database service.

Features

(and usage)

• 🖍️ · Syntax Highlighting for almost 200 languages with automatic language detection - power of highlight.js!

• 🎨 · Custom theming for the images. Use the /theme command to set any theme from this list. See themes in action here.

• 🗛 · Multiple fonts support. See the /font command in chat for the list of available fonts.

• 🗎 · Send images as documents. Sometimes long code might make the image blurry due to the default Telegram image compression. Sending them as documents fixes the issue. Use either /as_doc or /as_document command.

• 👀 · Language Detection: Tries to detect and use the language for more accurate results.

  • bot.ts <code> - Detects ts.
  • ts <code> - Detects ts.
  • <code> - Auto detection by highlight.js.

  NOTE: The <code> should be a pre formatted code block could be a pre entity formatted code block, or a multiline code entity.

• 🖌️ · Forced highlighting: Replying /highlight or /hl to a message containing text or caption, will

  • check for pre and code (multiline) entities and if there is any, only highlights those as it normally do. Useful if the original message was edited later.

  • If no pre or code (multiline) entities were found, highlights the whole message. Useful if you forgot to format them before sending.

  • You can optionally pass arguments separated by commas or white spaces. The accepted arguments are integers corresponding to the position of the pre/code entity in the message. Starting from 1. See the example below.

    Additionally, you can also pass any of 0, full, f to get the whole message highlighted. (why?: If you ever need to highlight the full message which contains pre/code entities).

    Take this message as an example:

    Lorem ipsum <code (inline)> dolor sit amet.
    
    <code (multi line)>
    
    Nunc in ligula vehicula quam efficitur vehicula at lacinia erat.
    
    <pre>
    

    Now, replying,

    NOTE: /hl is the same as /highlight. It's just a short form.

    • /hl will highlight <code (multi line)> and <pre> (Default).
    • /hl 1 will only highlight the <code (inline)>.
    • /hl 2 will only highlight the <code (multi line)>.
    • /hl 3 will only highlight the <pre>.
    • /hl 1 3 will highlight both <code (inline)> and <pre>.
    • /hl 0 or /hl f or /hl full will highlight the whole message.

• Not a very useful feature; use /stats command to find how many times the bot has sent syntax highlighted images for you.

"Maybe" features that I'd like to add if possible.

• Forced /highlighting by replying to a message - if the message contains pre code blocks, highlight them in the usual way. If not, highlight the whole message.
• Highlight only if the code block contains more than x number of characters. It would be a mess if someone use three backticks instead of one backtick, even for a single monospace word.
• Automatically toggle "Send as Document" mode if there is more than x number of characters.

Setup

Running Locally

Make sure you have installed Deno.

• Clone the repository.

  git clone https://github.com/dcdunkan/syntax-highlighter-bot.git

• Change directory (cd) to the cloned repository.

• Create a .env file and set environment variables like in example.env.

• Run the bot using the command below.

  deno run --allow-net --allow-env --allow-read --allow-write --allow-run --unstable local.ts

  Required permissions

  • --allow-net - To communicate with Telegram servers and receive updates.
  • --allow-env - To access environment variables.
  • --allow-read - To read translations, styles and .env file.
  • --allow-write - Required by puppeteer for writing temp files.
  • --allow-run - To run launch Google Chrome (via puppeteer)

If everything is done correct, you should see "(Username) started" in your console.

Deploy to Heroku

The working bot, @syntaxybot is currently deployed on Heroku free web dynos. It's pretty easy to setup.

Click the button to deploy to Heroku.

_{Or click here}

After deploying you will get a link to your application, in the format https://<appname>.herokuapp.com/.

Open browser and go to the link down below.

• Replace the <BOT_TOKEN> with your BOT_TOKEN.
• Replace <APP_URL> with the link to your application.

https://api.telegram.org/bot<BOT_TOKEN>/setWebhook?url=<APP_URL>

This will set the bot's webhook to the deployed application, so Telegram will send updates there and it will be able to handle them there.

Environment Variables

License

MIT License. Copyright (c) 2022 dcdunkan (Dunkan)

Contributing

Feel free to contribute! And if you are having issues or if you want suggest something, please open an issue here: dcdunkan/syntax-highlighter-bot/issues. Or, open a PQ!

Translating

If you like to translate this bot into your language, please follow the English translation file. This project uses Fluent for localization.

Made with ❤️ and ☕