input_handler

A tiny, reusable input editor for Rust CLI apps. It provides readline-like terminal editing with in-memory and optional on-disk history, arrow-key navigation, backspace/delete handling, and sane defaults, without external C deps beyond libc/termios.

Features

• Line editing: insert, backspace, left/right cursor movement
• History navigation: up/down to traverse previous inputs
• Persistent history (optional): load/save to a file you choose
• Minimal API: Editor and ergonomic wrapper InputHandler
• Raw mode management: enables raw mode and restores it on drop

Installation

Add to your Cargo.toml:

[dependencies]
input_handler = "0.1"

Quick start

use input_handler::InputHandler;

fn main() -> std::io::Result<()> {
	let mut ih = InputHandler::new()?;
	loop {
		let line = ih.readline("app> ")?;
		if line.trim() == "exit" { break; }
		println!("you typed: {}", line);
	}
	Ok(())
}

With persistent history

use input_handler::InputHandler;
use std::path::PathBuf;

fn main() -> std::io::Result<()> {
	let history_path = PathBuf::from("/tmp/.app_history");
	let mut ih = InputHandler::with_history_file(history_path)?;
	let line = ih.readline("app> ")?;
	println!("{}", line);
	Ok(())
}

Key bindings

• Enter: submit current line
• Backspace: delete character before cursor
• Left/Right: move cursor
• Up/Down: previous/next history entry
• Ctrl-C: returns an empty string (line is cleared), prints ^C
• Ctrl-D: when the buffer is empty, returns the literal string "exit"

API overview

Exports from the crate root:

• Editor
  • new() -> io::Result<Editor>
  • with_history_file(path: PathBuf) -> io::Result<Editor>
  • readline(prompt: &str) -> io::Result<String>
• History
  • new(max_size: usize) -> History
  • with_file(max_size: usize, path: PathBuf) -> History
  • add(command: String)
  • previous() -> Option<&String> / next_command() -> Option<&String>
• InputHandler (light wrapper around Editor)
  • new() -> io::Result<InputHandler>
  • with_history_file(path: PathBuf) -> io::Result<InputHandler>
  • readline(prompt: &str) -> io::Result<String>

Notes:

• History de-duplicates consecutive identical inputs and ignores empty lines.
• When backed by a file, history is loaded on start and rewritten on each add.
• Raw mode is enabled before reading and restored automatically on drop.

Platform support

This crate uses termios and libc to enter raw mode and read keys. It targets Unix-like systems (Linux, macOS). Windows is not supported out of the box.

Example behavior

• Pressing Up/Down cycles through history. When you reach the newest entry and press Down again, the buffer clears.
• Pressing Ctrl-D with an empty buffer returns "exit" so you can exit loops easily; otherwise, it is ignored.

License

MIT © Contributors

Repository

https://github.com/Arshdeep54/input_handler