rusty-cmd

A crate for creating custom line-oriented command interpreters in Rust.

I wrote this as a Rust learning project and was inspired by Python's cmd and the dev.to article: A small library for writing line oriented-command interpreters in rust.

Features

Create custom command interpreters.
Easily define and execute commands.
Implement optional command arguments.
Redirect output to types that implement io::Write.
Create teardown function by returing 0 from a command handler.

Overview

rusty-cmd provides two crates:

cmd: Used for creating the Cmd struct that contains the CommandHandler implementations in a HashMap.
command_handler: Contains the CommandHandler trait.

Example

use std::io;
use std::io::Write;

use rusty_cmd::command_handler::{CommandHandler, CommandResult};
use rusty_cmd::cmd::Cmd;
use rusty_cmd::handlers::Quit;


/// CommandHandler that prints out help message
#[derive(Debug, Default)]
pub struct Help;

impl CommandHandler for Help {
    fn execute(&self, _stdout: &mut io::Stdout, _args: &[&str]) -> CommandResult {
        writeln!(_stdout, "Help message").unwrap();
        CommandResult::Continue
    }
}

/// CommandHandler that emulates the basic bash touch command to create a new file
#[derive(Debug, Default)]
pub struct Touch;

impl CommandHandler for Touch {
    fn execute(&self, _stdout: &mut io::Stdout, _args: &[&str]) -> CommandResult {
        let option_filename = _args.first();
    
        match option_filename {
            Some(filename) => {
                let fs_result = std::fs::File::create(filename);
                match fs_result {
                    Ok(file) => println!("Created file: {:?}", file),
                    Err(_) => println!("Could not create file: {}", filename),
                }
            }
            None => println!("Need to specify a filename"),
        }
        CommandResult::Continue
    }
}


fn main() -> Result<(), std::io::Error>{
    let mut cmd = Cmd::new(
        io::BufReader::new(io::stdin()),
        io::stdout()
    );


    let help = Help::default();
    let hello = Touch::default();
    let quit = Quit::default();

    cmd.add_cmd(String::from("help"), Box::new(help))?;
    cmd.add_cmd(String::from("touch"), Box::new(hello))?;
    cmd.add_cmd(String::from("quit"), Box::new(quit))?;

    cmd.run()?;

    Ok(())

}

Usage

To use rusty-cmd in your project, add the following to your Cargo.toml file:

[dependencies]
rusty-cmd = "1.0.0"

Then import the crate in your Rust code:

use rusty_cmd::command_handler::{CommandHandler, CommandResult};
use rusty_cmd::cmd::Cmd;

License