Install

pito-fetch is a library, so there is nothing to install on its own: a Rust project depends on it. It isn’t on crates.io; add it from its repository, pinned to a tag.

Linux, macOS and Windows through WSL

The line is the same on every platform. In your Cargo.toml:

[dependencies]
fetch = { git = "https://github.com/gmrdad82/pito-fetch", tag = "v1.0.1" }

The package is named fetch, so the code says use fetch::…. It needs:

• Rust 1.97 or newer (rustup update stable).
• A C compiler at build time: ring, the crypto under rustls, compiles a little C and assembly. Linux distributions ship one with their build tools (build-essential on Debian and Ubuntu); on macOS, xcode-select --install. Nothing links to a system library at run time: TLS and the Mozilla root certificates are built in.
• Windows: use it inside WSL, where it is the Linux build. It is built and tested on Linux and macOS only.

Quick start

use fetch::{CancelToken, Fetcher, Request};

fn main() -> Result<(), fetch::FetchError> {
    let request = Request {
        url: "https://example.com/model.bin".into(),
        dest_rel: "model.bin".into(),
        sha256: "<the file's sha256, in lowercase hex>".into(),
        size_hint: None,
    };
    let path = Fetcher::new("models").fetch_request(&request, &CancelToken::new(), |p| {
        eprintln!("{} of {:?} bytes, {} B/s", p.received, p.total, p.speed_bps);
    })?;
    println!("{}", path.display());
    Ok(())
}

path is models/model.bin, and its sha256 is the one you asked for. The call blocks until the file has landed or failed; Download a file goes through each part.

See it work in 30 seconds

The repository’s two examples serve a file locally and download it:

git clone https://github.com/gmrdad82/pito-fetch && cd pito-fetch
cargo build --release --examples
mkdir -p tmp/files && head -c 50000000 /dev/urandom > tmp/files/demo.bin
target/release/examples/serve tmp/files 8471 10000000 &
sum=$(sha256sum tmp/files/demo.bin | cut -d' ' -f1)   # macOS: shasum -a 256
target/release/examples/get http://127.0.0.1:8471/demo.bin $sum tmp/models/demo.bin

tmp/models/demo.bin

The server sends 10 MB a second, so the 50 MB file takes about five seconds. Press Ctrl-C halfway and run the last line again: it carries on from where it stopped. kill %1 stops the server. Try it locally has more to try with them.