PasiLunch - the Next-Gen Lunch Menu Bot for Slack & Web

02.03.2025
node.js express cheerio slack bot project workplace web
Illustration of LunchBot fetching and displaying menus on Slack and a web dashboard.

Building a Next-Gen LunchBot for Slack & Web

Introduction

A few years ago, I built a Slack bot to fetch and display lunch menus from restaurants near my office. It worked well, but it was a simple script. Over time, I wanted more: a real-time web interface, better caching, and a smoother Slack integration. So, I revamped the whole project. Meet the new PasiLunch LunchBot – a powerful, fun, and efficient way to check what’s for lunch!

Features

  • 🏢 Slack Command (/lunch) – Fetches the daily lunch menus and posts them in Slack with a witty message.
  • 🌐 Web Dashboard – A sleek, auto-updating website that displays all available menus.
  • ⚡ Fast Caching – Stores menus locally to prevent unnecessary scrapes and API requests.
  • 🤖 Fun & Engaging – The bot serves its menus with humorous messages to lighten up your day.
  • 🔄 Keep-Alive Mechanism – Prevents the bot from sleeping on free hosting platforms.

Tech Stack

  • Node.js – The backbone of the bot.
  • Express.js – Powers the web dashboard.
  • Cheerio.js – Scrapes menus from restaurant websites.
  • Slack API – Handles the /lunch command responses.
  • Axios – Fetches data from APIs and restaurant pages.
  • JSON File Storage – Caches menus locally for quick responses.

How It Works

1️⃣ Fetching Menus

LunchBot scrapes menus from various restaurants using custom-built scrapers. Some menus are in HTML, some in JSON, and some even in XML. Each restaurant has a dedicated function to extract data.

2️⃣ Caching Mechanism

The bot saves each menu to a JSON file along with the current date. If a request comes in on the same day, it serves the cached menu instead of re-fetching it. This improves performance and prevents overloading restaurant websites.

3️⃣ Slack Integration

Users in our Slack workspace can simply type /lunch, and LunchBot responds with the day’s menu options in a neatly formatted message. The bot also keeps track of how many Slack requests it has handled!

4️⃣ Web Dashboard

LunchBot also serves a web page that displays all the menus in a beautiful, structured way. It updates automatically and includes a fun animated header.

Challenges & Learnings

  • Scraping Complexity 🏗️ – Each restaurant’s website had a different structure, requiring unique parsing logic.
  • Keeping It Fresh 🔄 – Some sites changed frequently, breaking the scrapers. Error handling and fallbacks were crucial.
  • Slack Formatting 💬 – Slack’s markdown-like syntax needed careful formatting to ensure menus displayed correctly.

Try It Out!

This project has been a blast to build, and it’s now a daily essential for our office. Let me know if you want to build something similar – always happy to share insights! 🚀 LunchBot The LunchBot project aims to streamline workplace communication and dining decisions.