Concurrency Limiter

Concurrency Limiter 中間件可以控製同時並發的請求數量. 具體 API 請查看文檔.

示例代碼

use std::fs::create_dir_all;
use std::path::Path;

use salvo::prelude::*;

#[handler]
async fn index(res: &mut Response) {
    res.render(Text::Html(INDEX_HTML));
}
#[handler]
async fn upload(req: &mut Request, res: &mut Response) {
    let file = req.file("file").await;
    tokio::time::sleep(tokio::time::Duration::from_secs(10)).await;
    if let Some(file) = file {
        let dest = format!("temp/{}", file.name().unwrap_or("file"));
        tracing::debug!(dest = %dest, "upload file");
        if let Err(e) = std::fs::copy(file.path(), Path::new(&dest)) {
            res.status_code(StatusCode::INTERNAL_SERVER_ERROR);
            res.render(Text::Plain(format!("file not found in request: {e}")));
        } else {
            res.render(Text::Plain(format!("File uploaded to {dest}")));
        }
    } else {
        res.status_code(StatusCode::BAD_REQUEST);
        res.render(Text::Plain("file not found in request"));
    }
}

#[tokio::main]
async fn main() {
    tracing_subscriber::fmt().init();

    create_dir_all("temp").unwrap();
    let router = Router::new()
        .get(index)
        .push(
            Router::new()
                .hoop(max_concurrency(1))
                .path("limited")
                .post(upload),
        )
        .push(Router::with_path("unlimit").post(upload));

    let acceptor = TcpListener::new("0.0.0.0:5800").bind().await;
    Server::new(acceptor).serve(router).await;
}

static INDEX_HTML: &str = r#"<!DOCTYPE html>
<html>
    <head>
        <title>Upload file</title>
    </head>
    <body>
        <h1>Upload file</h1>
        <form action="/unlimit" method="post" enctype="multipart/form-data">
            <h3>Unlimit</h3>
            <input type="file" name="file" />
            <input type="submit" value="upload" />
        </form>
        <form action="/limited" method="post" enctype="multipart/form-data">
            <h3>Limited</h3>
            <input type="file" name="file" />
            <input type="submit" value="upload" />
        </form>
    </body>
</html>
"#;
[package]
name = "example-concurrency-limiter"
version.workspace = true
edition.workspace = true
publish.workspace = true


[dependencies]
salvo = { workspace = true, features = ["concurrency-limiter"]}
tokio = { workspace = true, features = ["macros"] }
tracing.workspace = true
tracing-subscriber.workspace = true