Dataloader

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

Documentation

Features

• [x] Batching load requests
• [x] Caching load results

Usage

Add to your Cargo.toml

toml [dependencies] futures = "0.1" dataloader = "0.5.1"

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); println!("\n -- Using Loader --"); { let v1 = loader.load(3).andthen(|v| loader.loadmany(vec![v, v + 5, v + 10])); let v2 = loader.load(4).andthen(|v| loader.loadmany(vec![v, v + 5, v + 10])); let all = v1.join(v2); let output = all.wait().unwrap(); let expected = (vec![300, 350, 400], vec![400, 450, 500]); assert_eq!(expected, output); }

let ld = loader.cached();
println!("\n -- Using Cached Loader --");
{
    let v1 = ld.load(3).and_then(|v| ld.load_many(vec![v, v + 5, v + 10]));
    let v2 = ld.load(4).and_then(|v| ld.load_many(vec![v, v + 5, v + 10]));
    let all = v1.join(v2);
    let output = all.wait().unwrap();
    let expected = (vec![300, 350, 400], vec![400, 450, 500]);
    assert_eq!(expected, output);
}

} ```