Build a Full‑Featured Rust CLI with interactcli‑rs in Four Simple Steps

Learning a programming language is similar to learning a human language: start with keywords, basic syntax, and standard libraries, then practice by building simple applications that communicate with a machine.

To avoid overwhelming beginners, begin with the simplest possible command‑line interface (CLI) program, which is essentially a "hello world" application.

CLI programs often need to handle two types of interaction: the classic shell‑style one‑command‑per‑execution model (well supported by Rust's clap crate) and domain‑specific interactive sessions (e.g., MySQL or Redis clients) that require custom handling.

The interactcli‑rs scaffold provides a ready‑made framework for building interactive CLIs with common features.

Quick Start

Clone the project and run the example:

git clone https://github.com/jiashiwen/interactcli-rs.git
cd interactcli-rs

Run a simple request sample in command mode: cargo run requestsample baidu Enter interactive mode:

cargo run -- -i
interact-rs> requestsample baidu

The command sends an HTTP request to Baidu.

Four Steps to a Complete CLI

1. Project Structure

.
├── examples
├── log
├── logs
└── src
    ├── cmd
    ├── commons
    ├── configure
    ├── interact
    ├── logger
    └── request

The cmd directory holds the command implementations.

2. Define Commands

use clap::Command;

pub fn new_requestsample_cmd() -> Command<'static> {
    clap::Command::new("requestsample")
        .about("requestsample")
        .subcommand(get_baidu_cmd())
}

pub fn get_baidu_cmd() -> Command<'static> {
    clap::Command::new("baidu")
        .about("request www.baidu.com")
}

The new_requestsample_cmd creates the requestsample command and its baidu sub‑command.

3. Register Commands

lazy_static! {
    static ref CLIAPP: clap::Command<'static> = clap::Command::new("interact-rs")
        .version("1.0")
        .author("Your Name. <[email protected]>")
        .about("command line sample")
        .arg_required_else_help(true)
        .arg(Arg::new("config").short('c').long("config").value_name("FILE").help("Sets a custom config file").takes_value(true))
        .arg(Arg::new("daemon").short('d').long("daemon").help("run as daemon"))
        .arg(Arg::new("interact").short('i').long("interact").conflicts_with("daemon").help("run as interact mod"))
        .arg(Arg::new("v").short('v').multiple_occurrences(true).takes_value(true).help("Sets the level of verbosity"))
        .subcommand(new_requestsample_cmd())
        .subcommand(new_config_cmd())
        .subcommand(new_multi_cmd())
        .subcommand(new_task_cmd())
        .subcommand(new_loop_cmd())
        .subcommand(clap::Command::new("test")
            .about("controls testing features")
            .version("1.3")
            .author("Someone E. <[email protected]>")
            .arg(Arg::new("debug").short('d').help("print debug information verbosely")));
}

static ref SUBCMDS: Vec<SubCmd> = subcommands();

The command tree is built at runtime, enabling automatic help and sub‑command discovery.

4. Parse Commands

fn cmd_match(matches: &ArgMatches) {
    if let Some(ref matches) = matches.subcommand_matches("requestsample") {
        if let Some(_) = matches.subcommand_matches("baidu") {
            let rt = tokio::runtime::Runtime::new().unwrap();
            let async_req = async {
                let result = req::get_baidu().await;
                println!("{:?}", result);
            };
            rt.block_on(async_req);
        }
    }
}

The cmd_match function dispatches the appropriate logic based on the parsed sub‑commands.

To customize the interactive prompt, edit src/interact/cli.rs:

pub fn run() {
    loop {
        let p = format!("{}> ", "interact-rs");
        rl.helper_mut().expect("No helper").colored_prompt = format!("\x1b[1;32m{}\x1b[0m", p);
        // ... handle input ...
    }
}

This sets a green-colored prompt for the interactive mode.

The article concludes by promising a future post that will dive deeper into the various features implemented by interactcli‑rs.