shell-download

crate	docs	version
shell-download

A zero-dependency Rust library for downloading a URL to a file by delegating to whatever download tools are available on the current system.

It hunts for (in order): curl, wget, pwsh/powershell, python3, then the built-in tunnel (HTTP over TCP, HTTPS via OpenSSL / openssl s_client). You can still force only the TCP or only the OpenSSL stack with [Downloader::Tcp] and [Downloader::OpenSSL].

• The caller provides a target path.
• That file is unlinked before the request starts.
• The response body is written to that path (decompressed if the response is gzip).
• The request runs in a background thread and returns a cancellable handle.

When to use this crate

If you can afford the compile-time cost and binary size of a much fuller-featured crate such as reqwest, that's probably a better choice. But if you need a small, zero-dependency library for just downloading a file, and you'd prefer not to add code to call into curl or wget or pwsh or whatever happens to be installed on a random machine, this crate is a good choice.

Features

By default, these features are not enabled, making the crate zero-dependency.

• url: Parse URLs using the url crate (adds a number of dependencies, but makes URL parsing more accurate).

Usage

use shell_download::{Downloader, RequestBuilder};

fn main() -> Result<(), shell_download::ResponseError> {
    // NOTE: This should use a secure temporary file name!
    let out = std::env::temp_dir().join("downloaded.json");

    let handle = RequestBuilder::new("https://httpbin.org/redirect/5")
        .header("User-Agent", "shell-download/0.1")
        .follow_redirects(true)
        // Optional: force a specific backend (useful for tests)
        .preferred_downloader(Downloader::Curl)
        .start(&out)
        .map_err(shell_download::ResponseError::Start)?;

    // Optional: cancel from another thread if you need to abort
    // handle.cancel();

    let response = handle.join()?;
    println!("status={}", response.status_code);

    let body = std::fs::read_to_string(out).unwrap();
    assert!(body.contains("httpbin.org/get"));

    Ok(())
}