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Dioxus 0.3.2AsyncSpawning Futures
You are currently viewing the docs for Dioxus 0.3.2 which is no longer maintained.

Spawning Futures

The use_future and use_coroutine hooks are useful if you want to unconditionally spawn the future. Sometimes, though, you'll want to only spawn a future in response to an event, such as a mouse click. For example, suppose you need to send a request when the user clicks a "log in" button. For this, you can use cx.spawn:

src/spawn.rs
let logged_in = use_state(cx, || false);

let log_in = move |_| {
    cx.spawn({
        let logged_in = logged_in.to_owned();

        async move {
            let resp = reqwest::Client::new()
                .post("http://example.com/login")
                .send()
                .await;

            match resp {
                Ok(_data) => {
                    println!("Login successful!");
                    logged_in.set(true);
                }
                Err(_err) => {
                    println!(
                        "Login failed - you need a login server running on localhost:8080."
                    )
                }
            }
        }
    });
};

cx.render(rsx! {
    button {
        onclick: log_in,
        "Login",
    }
})

Note: spawn will always spawn a new future. You most likely don't want to call it on every render.

Calling spawn will give you a JoinHandle which lets you cancel or pause the future.

Spawning Tokio Tasks

Sometimes, you might want to spawn a background task that needs multiple threads or talk to hardware that might block your app code. In these cases, we can directly spawn a Tokio task from our future. For Dioxus-Desktop, your task will be spawned onto Tokio's Multithreaded runtime:

src/spawn.rs
cx.spawn(async {
    let _ = tokio::spawn(async {}).await;

    let _ = tokio::task::spawn_local(async {
        // some !Send work
    })
    .await;
});
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