5 releases (3 breaking)

0.4.0	Sep 29, 2022
0.3.0	Jul 13, 2018
0.2.0	Jul 10, 2018
0.1.1	Jun 3, 2018
0.1.0	Jun 3, 2018

#1933 in Network programming

285 downloads per month
Used in 4 crates (2 directly)

MIT/Apache

22KB
90 lines

clap-port-flag

Easily add a --port flag to CLIs using clap.

Usage

Example: Base

With the following code in src/main.rs:

use clap::Parser;
use clap_port_flag::Port;

#[derive(Debug, Parser)]
struct Cli {
    #[clap(flatten)]
    port: Port,
}

fn main() {
    let args = Cli::parse();
    let _tcp_listener = args.port.bind().unwrap();
}

When you run the binary, it'll provide the following output:

my-cool-app 0.2.0
Alice Person <alice@person.com>
Application that does things over TCP.

USAGE:
    main [OPTIONS]

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
        --listen-fd <fd>         A previously opened network socket. [env: LISTEN_FD=]
    -a, --address <hostname>     The network address to listen to. [default: 127.0.0.1]
    -p, --port <port>            The network port to listen to. [env: PORT=]

Example: Hyper

use clap_port_flag::Port;
use futures::prelude::*;
use hyper::service::service_fn;
use hyper::{Body, Response, Request};
use clap::Parser;

#[derive(Debug, Parser)]
struct Cli {
    #[clap(flatten)]
    port: Port,
}

async fn hello(_: Request<Body>) -> Result<Response<String>, std::convert::Infallible> {
    Ok(Response::new(String::from("Hello World!")))
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let args = Cli::parse();
    let listener = args.port.bind()?;
    let listener = tokio::net::TcpListener::from_std(listener)?;
    let addr = listener.local_addr()?;

    println!("Server listening on {}", addr);

    let (stream, _) = listener.accept().await?;
    if let Err(e) = hyper::server::conn::Http::new()
        .serve_connection(stream, service_fn(hello))
        .await
    {
        eprintln!("server error: {}", e);
    }
    Ok(())
}

Installation

$ cargo add clap-port-flag

Acknowledgements

The original version of this crate was sketched out by @TeXitoi in rust-lang-nursery/cli-wg#37.

License

MIT OR Apache-2.0

Dependencies

~1.2–1.8MB
~35K SLoC