Records and JSON in C#

Hello and welcome to another blog post! Today I am going over how and why I made use of Records and the JSON file type in my Discord Bot.

Context: I am building a set of commands where the user can either: • Input a Game's name into the list, along with a description if they choose to • Remove a Game from the list by it's name only • Output a random game name from the list available • See the list of games at any point I made each command in this order so I began with putting a game name into the list.

Problem: While I have experience with JSON in other forms of programming, I have never used it while programming in C#. I actually began this problem using a plain text file which was most definitely the wrong choice. I actually did just lie a little there by saying I have never used JSON in C#, because in my last post about creating the JokeCommand, I made use of a JSON formatted data received from an API in the form of an HTTP request. I made use of this knowledge that I can serialize objects from a JSON format into a class and decided that this would be the best option for me going forward.

Solution: I ended up trying to copy my solution to the JokeCommand problem and try and replicate it for this one. I knew I needed to create a new class where I could store the data for the Games so I made use of Records here to make GameData.

This is what my record looks like :

public record GameData(string Name, string Description);

Records are an amazing way to build classes that are meant to hold data! They are super simple to declare as you can see too which is amazing. I then created a static class called GameDataFileUtils so that I can call methods from this class anywhere to change my GameData from the JSON file. I'll go over each method here and explain what it does.

public static void Write(object obj, string filePath) {
    var jsonString = JsonConvert.SerializeObject(obj, Formatting.Indented, options);
    File.WriteAllText(filePath, jsonString);
}

This is my Write method. Pretty simple, but it takes an object and a file path and writes it to that file in the form of JSON with indentation turned on.

public static void Add(GameData data, string fileName) {
    var contents = ReadFromJSON(fileName);
    contents.Add(data);
    Write(contents, fileName);
}

This is the Add method. This takes in a GameData and a filepath. I will explain what ReadFromJSON does in just a second, but that method returns a list of GameData, reading from the file. I have to do this because when I write to the file, I am rewriting the entire file, so if I were to write a single entry in a file that has many more, it will wipe it out and leave only the single entry. I cache the contents of the file, add the new GameData and then write it back to the file.

public static void Remove(string gameName, string fileName) {
    var contents = ReadFromJSON(fileName);
    for (int i = 0; i < contents.Count; i++) {
        if (contents[i].Name == gameName) {
            contents.Remove(contents[i]);
            break;
        }
    }
    Write(contents, fileName);
}

This Remove method searches through the file linearly (which I could optimize), and removes the first element of the JSON file which matches the string input from the user.

public static List<GameData>; ReadFromJSON(string filePath) {
    using StreamReader reader = new(filePath);
    var json = reader.ReadToEnd();
    List<GameData> data = JsonConvert.DeserializeObject<List<GameData>>(json);
    return data;
}

This ReadFromJSON method reads the JSON file, and converts it's contents into a list of <GameData> by use of the JsonConvert.DeserializeObject<List<GameData>>(json) line.

This works for now, but I know that I will run into a problem with this GameFileUtils class if I ever want to manipulate a JSON file that would be of a data type other than GameData. For now this is my solution, but I will work on another one in the meantime. Thank you for reading and have a great rest of your day!