Futurify

Convert your sync functions into non-thread blocking futures.

When to use it

This is just an example to illustrate when this library could be useful.

Imagine you're creating an actix-web API and you have and endpoint that has to execute a very long synchronous task.

Normally, most of the modern crates will provide some async variants but still there are some of them that only provide a sync implementation.

This could be problematic as this endpoint could block the main thread and avoid other endpoints from being executed.

Take a look at this code:

```rust use actix_web::{web, App, Error, HttpResponse, HttpServer, Responder}; use futures::{Async, Future, Poll};

fn index_async() -> impl Future { futures::future::ok("Hello world") }

fn indexasyncblocking() -> impl Future { futures::lazy(|| { std::thread::sleep(Duration::from_secs(5)); futures::future::ok("Hello blocking world") }) }

fn main() -> std::io::Result<()> { HttpServer::new(|| { App::new() .route("/", web::get().toasync(indexasync)) .route("/blocking", web::get().toasync(indexasync_blocking)) }) .workers(1) .bind("localhost:8080")? .run() } ```

If you try to get localhost:8080/blocking and then get localhost:8080, you will be able to see that you won't get any response until the blocking endpoint has returned.

With just a slight change we could get rid of this issue:

```rust fn indexasyncnonblocking() -> impl Future { futurify::wrap(|| { std::thread::sleep(Duration::fromsecs(5)); "Hello blocking world" }) }

fn main() -> std::io::Result<()> { HttpServer::new(|| { App::new() .route("/", web::get().toasync(indexasync)) .route("/blocking", web::get().toasync(indexasyncblocking)) .route("/non-blocking", web::get().toasync(indexasyncnon_blocking)) }) .workers(1) .bind("localhost:8080")? .run() } ````

Just wrap a closure with futurify::wrap and you'll get a futures 0.1 future ready to be polled.