Basic Rust TOML Config Handler

lib.rs

# cargo add serde toml

pub mod config {
    use serde::{Deserialize, Serialize};
    use std::{fs, path::Path};

    #[derive(Serialize, Deserialize)]
    pub struct Config {
        pub version: i8,
        pub host: String,
        pub port: u32,
        pub root: String,
    }

    impl Default for Config {
        fn default() -> Self {
            Self {
                version: 1,
                host: String::from("localhost"),
                port: 3032,
                root: String::from("/var/www/html"),
            }
        }
    }

    impl Config {
        /// Config file path
        fn path() -> &'static str {
            "config.toml"
        }

        /// Initializes a new Config.
        ///
        /// If a config file exists, it is read and returned.
        /// If it does not, a new one is created with default options and returned.
        pub fn new() -> Config {
            let mut cfg = Config::default();
            let exists = Path::new(Config::path()).try_exists().unwrap();
            if exists {
                cfg.read();
            } else {
                cfg.write();
            }
            cfg
        }

        /// Reads Config from file.
        ///
        /// Must be called after `new()` to make sure the file is initialized properly.
        pub fn read(&mut self) {
            let file = fs::read_to_string(Config::path()).unwrap();
            let config: Config = toml::from_str(&file).unwrap();
            *self = config;
        }

        /// Writes Config to a file.
        pub fn write(&self) {
            let config = toml::to_string(&self).unwrap();
            fs::write(Config::path(), config).unwrap();
        }
    }
}

#[cfg(test)]
mod config_test {
    use crate::config::Config;

    #[test]
    fn config_example() {
        // warning: this may panic as I haven't implemented error handling at all.
        let mut cfg = Config::new();

        println!(
            "Version: {}\nHost: {}\nPort: {}\nRoot: {}",
            cfg.version, cfg.host, cfg.port, cfg.root
        );

        cfg.host = String::from("127.0.0.1");
        cfg.write();
    }
}