Dataloader

Rust implementation of Facebook's DataLoader using futures and tokio-core.

Documentation

Status

This project is a work in progress. - [x] Batching load requests - [ ] Cache load result

Usage

Add to your Cargo.toml toml [dependencies] futures = "0.1" dataloader = "0.1"

Add to your crate ```rust extern crate futures; extern crate dataloader;

use dataloader::{Loader, BatchFn, BatchFuture}; use futures::Future; use futures::future::ok;

struct Batcher; impl BatchFn for Batcher { type Error = ();

fn load(&self, keys: &[i32]) -> BatchFuture<i32, Self::Error> {
    println!("load batch {:?}", keys);
    ok(keys.into_iter().map(|v| v * 10).collect()).boxed()
}

}

fn main() { let loader = Loader::new(Batcher); let v1 = loader.load(1); let v2 = loader.load(2); assert_eq!((10, 20), v1.join(v2).wait().unwrap());

let many = loader.load_many(vec![10, 20, 30]);
assert_eq!(vec![100, 200, 300], many.wait().unwrap());

let loader_ref = &loader;
{
    let v1 = loader_ref.load(3)
        .map(|v| loader_ref.load_many(vec![v, v + 1, v + 2]).wait().unwrap());
    let v2 = loader_ref.load(4)
        .map(|v| loader_ref.load_many(vec![v, v + 1, v + 2]).wait().unwrap());

    let expected = (vec![300, 310, 320], vec![400, 410, 420]);
    assert_eq!(expected, v1.join(v2).wait().unwrap());
}

} ```