Dataloader

Rust implementation of Facebook's DataLoader using futures.

Documentation

Features

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

Usage

Add to your Cargo.toml: toml [dependencies] dataloader = "0.6.0" futures = "0.3"

Add to your crate: ```rust use dataloader::{BatchFn, BatchFuture, Loader}; use futures::{executor, future, FutureExt as _, TryFutureExt as _};

struct Batcher;

impl BatchFn for Batcher { type Error = ();

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

}

fn main() { let mut rt = executor::LocalPool::new();

let loader = Loader::new(Batcher);
println!("\n -- Using Loader --");
{
    let v1 = loader
        .load(3)
        .and_then(|v| loader.load_many(vec![v, v + 5, v + 10]));
    let v2 = loader
        .load(4)
        .and_then(|v| loader.load_many(vec![v, v + 5, v + 10]));
    let output = rt.run_until(future::try_join(v1, v2)).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 output = rt.run_until(future::try_join(v1, v2)).unwrap();
    let expected = (vec![300, 350, 400], vec![400, 450, 500]);
    assert_eq!(expected, output);
}

} ```

For using with Tokio checkout Tokio example.