Trait roa::Middleware

source · [−]
pub trait Middleware<'a, S = ()>: 'static + Sync + Send {
    fn handle<'async_trait>(
        &'a self, 
        ctx: &'a mut Context<S>, 
        next: &'a mut (dyn Future<Output = Result<(), Status>> + Unpin + 'a)
    ) -> Pin<Box<dyn Future<Output = Result<(), Status>> + 'async_trait, Global>>
    where
        'a: 'async_trait,
        Self: 'async_trait;
}
Expand description

Middleware

Build-in middlewares
  • Functional middleware

A functional middleware is an async function with signature: async fn(&mut Context, Next<'_>) -> Result.

use roa_core::{App, Context, Next, Result};

async fn middleware(ctx: &mut Context, next: Next<'_>) -> Result {
    next.await
}

let app = App::new().gate(middleware);
  • Blank middleware

() is a blank middleware, it just calls the next middleware or endpoint.

let app = roa_core::App::new().gate(());
Custom middleware

You can implement custom Middleware for other types.

use roa_core::{App, Middleware, Context, Next, Result, async_trait};
use std::sync::Arc;
use std::time::Instant;


struct Logger;

#[async_trait(?Send)]
impl <'a> Middleware<'a> for Logger {
    async fn handle(&'a self, ctx: &'a mut Context, next: Next<'a>) -> Result {
        let start = Instant::now();
        let result = next.await;
        println!("time elapsed: {}ms", start.elapsed().as_millis());
        result
    }
}

let app = App::new().gate(Logger);

Required methods

Handle context and next, return status.

Implementations on Foreign Types

blank middleware.

Implementors