LeetCode Bot

Overview

This is a Discord Bot created using Discord.py. Its purpose is to facilitate LeetCoding within a Discord server. It achieves this goal through the usage of custom settings, customizable daily problems, notifications for upcoming contests, and other features.

As a live service product, it is a constant work in progress and always changing. The source code is available on GitHub. If interested in setting it up in your own server, you can follow the instructions here.

Technologies Used

Python: Discord.py, Requests
APIs: GraphQL, JSON

The Product

The final product was a Discord bot that helps users with LeetCode problems by providing a system of customizable reoccurring problems, contest reminders, and other various alerts.

The bot is designed to be easily configurable, allowing server administrators to set their own preferences for problem difficulty, frequency of these problems, and more.

The bot uses the LeetCode API to fetch problems and user data, ensuring that users receive relevant content.

It also includes features such as reminders for upcoming contests, a leaderboard to track user progress, and a help command to assist users in navigating the bot's features.

The image shows an example of a problem being sent to a user.

For a more in depth look about the product itself, I highly recommend checking it out for yourself! Otherwise, take a look at the Help & Setup Page.

Challenges & Solutions

At the time of making this, it was the biggest project I've ever worked on and designed on my own. This naturally came with a lot of unique challenges that I had not encountered yet. This project required a lot of foresight into not only what I knew I wanted to build, but to try and make it easier to adapt to new and different ideas that I could come up with. The way I designed this project was in two stages. First I built the backend and the core. Once that was complete, I moved onto the integration using Discord.py. Despite my best efforts, I still had issues where I was missing something in my backend that I should've had implemented already. Many instances like this let me value the planning that I did. While I encounted many issues of this kind, I am very very sure it would've been a much bigger problem if I did not take the original efforts that I did to try and plan ahead.

One of the main challenges was designing a bot that could scale with the needs of the users. I had to ensure that the bot could handle multiple servers and users without performance issues. One particular performance struggle I was dealing with was originally I would save to a file and read on every access, later I switched to having both saved to a JSON file as well as being cached in memory. However, this led to it's own problems with there being mismatches between the cached data and the saved data. This problem occurred when I would update the saved data but failed to properly reflect that change in the cached data, leading to inconsistencies. I fixed this problem through the use of a "Synchronizer" that ensured both the cached data and saved data were updated together.

Additionally, a major challenge was getting the notification and problem delivery system to work. Ultimately through the usage of the Observer pattern and some custom made buckets, I was able to accurately notify users. The way I implemented this was adding to the buckets based on settings and other parameters. Then I have a loop running that is constantly checking the time. On specific times, I would search through the buckets and essentially notify each server with the type of notification.

Finally, I had to ensure that the bot was user-friendly and easy to use. I spent a lot of time designing the commands and interactions to be intuitive and straightforward. This included creating a help command that provided users with information on how to use the bot and its features. I also spent some time developing a Help & Setup Page.

Takeaways

This was an incredibly useful project for my development. Building this product allowed me to put together everything I know and learned in a way that allowed me to apply my skills effectively. Not only did I learn an enormous amount about building and maintaining a live service product, but I also gained valuable experience in project management and design.

I also realized how useful it is to have a solid understanding of the underlying technologies and frameworks when building a complex system. Whenever I would have a problem, I would go refer to the documentation.

Some key takeaways include: