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use std::future::Future; use http::header::LOCATION; use http::{StatusCode, Uri}; use crate::{async_trait, throw, Context, Result, Status}; /// ### Middleware /// /// #### Build-in middlewares /// /// - Functional middleware /// /// A functional middleware is an async function with signature: /// `async fn(&mut Context, Next<'_>) -> Result`. /// /// ```rust /// 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. /// /// ```rust /// let app = roa_core::App::new().gate(()); /// ``` /// /// #### Custom middleware /// /// You can implement custom `Middleware` for other types. /// /// ```rust /// 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); /// ``` #[async_trait(?Send)] pub trait Middleware<'a, S = ()>: 'static + Sync + Send { /// Handle context and next, return status. async fn handle(&'a self, ctx: &'a mut Context<S>, next: Next<'a>) -> Result; } #[async_trait(?Send)] impl<'a, S, T, F> Middleware<'a, S> for T where S: 'a, T: 'static + Send + Sync + Fn(&'a mut Context<S>, Next<'a>) -> F, F: 'a + Future<Output = Result>, { #[inline] async fn handle(&'a self, ctx: &'a mut Context<S>, next: Next<'a>) -> Result { (self)(ctx, next).await } } /// ### Endpoint /// /// An endpoint is a request handler. /// /// #### Build-in endpoint /// /// There are some build-in endpoints. /// /// - Functional endpoint /// /// A normal functional endpoint is an async function with signature: /// `async fn(&mut Context) -> Result`. /// /// ```rust /// use roa_core::{App, Context, Result}; /// /// async fn endpoint(ctx: &mut Context) -> Result { /// Ok(()) /// } /// /// let app = App::new().end(endpoint); /// ``` /// - Ok endpoint /// /// `()` is an endpoint always return `Ok(())` /// /// ```rust /// let app = roa_core::App::new().end(()); /// ``` /// /// - Status endpoint /// /// `Status` is an endpoint always return `Err(Status)` /// /// ```rust /// use roa_core::{App, status}; /// use roa_core::http::StatusCode; /// let app = App::new().end(status!(StatusCode::BAD_REQUEST)); /// ``` /// /// - String endpoint /// /// Write string to body. /// /// ```rust /// use roa_core::App; /// /// let app = App::new().end("Hello, world"); // static slice /// let app = App::new().end("Hello, world".to_owned()); // string /// ``` /// /// - Redirect endpoint /// /// Redirect to an uri. /// /// ```rust /// use roa_core::App; /// use roa_core::http::Uri; /// /// let app = App::new().end("/target".parse::<Uri>().unwrap()); /// ``` /// /// #### Custom endpoint /// /// You can implement custom `Endpoint` for your types. /// /// ```rust /// use roa_core::{App, Endpoint, Context, Next, Result, async_trait}; /// use async_std::sync::Arc; /// use std::time::Instant; /// /// fn is_endpoint(endpoint: impl for<'a> Endpoint<'a>) { /// } /// /// struct Logger; /// /// #[async_trait(?Send)] /// impl <'a> Endpoint<'a> for Logger { /// async fn call(&'a self, ctx: &'a mut Context) -> Result { /// Ok(()) /// } /// } /// /// let app = App::new().end(Logger); /// ``` #[async_trait(?Send)] pub trait Endpoint<'a, S = ()>: 'static + Sync + Send { /// Call this endpoint. async fn call(&'a self, ctx: &'a mut Context<S>) -> Result; } #[async_trait(?Send)] impl<'a, S, T, F> Endpoint<'a, S> for T where S: 'a, T: 'static + Send + Sync + Fn(&'a mut Context<S>) -> F, F: 'a + Future<Output = Result>, { #[inline] async fn call(&'a self, ctx: &'a mut Context<S>) -> Result { (self)(ctx).await } } /// blank middleware. #[async_trait(?Send)] impl<'a, S> Middleware<'a, S> for () { #[allow(clippy::trivially_copy_pass_by_ref)] #[inline] async fn handle(&'a self, _ctx: &'a mut Context<S>, next: Next<'a>) -> Result { next.await } } /// ok endpoint, always return Ok(()) #[async_trait(?Send)] impl<'a, S> Endpoint<'a, S> for () { #[allow(clippy::trivially_copy_pass_by_ref)] #[inline] async fn call(&'a self, _ctx: &'a mut Context<S>) -> Result { Ok(()) } } /// status endpoint. #[async_trait(?Send)] impl<'a, S> Endpoint<'a, S> for Status { #[inline] async fn call(&'a self, _ctx: &'a mut Context<S>) -> Result { Err(self.clone()) } } /// String endpoint. #[async_trait(?Send)] impl<'a, S> Endpoint<'a, S> for String { #[inline] #[allow(clippy::ptr_arg)] async fn call(&'a self, ctx: &'a mut Context<S>) -> Result { ctx.resp.write(self.clone()); Ok(()) } } /// Static slice endpoint. #[async_trait(?Send)] impl<'a, S> Endpoint<'a, S> for &'static str { #[inline] async fn call(&'a self, ctx: &'a mut Context<S>) -> Result { ctx.resp.write(*self); Ok(()) } } /// Redirect endpoint. #[async_trait(?Send)] impl<'a, S> Endpoint<'a, S> for Uri { #[inline] async fn call(&'a self, ctx: &'a mut Context<S>) -> Result { ctx.resp.headers.insert(LOCATION, self.to_string().parse()?); throw!(StatusCode::PERMANENT_REDIRECT) } } /// Type of the second parameter in a middleware, /// an alias for `&mut (dyn Unpin + Future<Output = Result>)` /// /// Developer of middleware can jump to next middleware by calling `next.await`. /// /// ### Example /// /// ```rust /// use roa_core::{App, Context, Result, Status, MiddlewareExt, Next}; /// use roa_core::http::StatusCode; /// /// let app = App::new() /// .gate(first) /// .gate(second) /// .gate(third) /// .end(end); /// async fn first(ctx: &mut Context, next: Next<'_>) -> Result { /// assert!(ctx.store("id", "1").is_none()); /// next.await?; /// assert_eq!("5", *ctx.load::<&'static str>("id").unwrap()); /// Ok(()) /// } /// async fn second(ctx: &mut Context, next: Next<'_>) -> Result { /// assert_eq!("1", *ctx.load::<&'static str>("id").unwrap()); /// assert_eq!("1", *ctx.store("id", "2").unwrap()); /// next.await?; /// assert_eq!("4", *ctx.store("id", "5").unwrap()); /// Ok(()) /// } /// async fn third(ctx: &mut Context, next: Next<'_>) -> Result { /// assert_eq!("2", *ctx.store("id", "3").unwrap()); /// next.await?; // next is none; do nothing /// assert_eq!("3", *ctx.store("id", "4").unwrap()); /// Ok(()) /// } /// /// async fn end(ctx: &mut Context) -> Result { /// assert_eq!("3", *ctx.load::<&'static str>("id").unwrap()); /// Ok(()) /// } /// ``` /// /// ### Error Handling /// /// You can catch or straightly throw a Error returned by next. /// /// ```rust /// use roa_core::{App, Context, Result, Status, MiddlewareExt, Next, status}; /// use roa_core::http::StatusCode; /// /// let app = App::new() /// .gate(catch) /// .gate(gate) /// .end(status!(StatusCode::IM_A_TEAPOT, "I'm a teapot!")); /// /// async fn catch(ctx: &mut Context, next: Next<'_>) -> Result { /// // catch /// if let Err(err) = next.await { /// // teapot is ok /// if err.status_code != StatusCode::IM_A_TEAPOT { /// return Err(err); /// } /// } /// Ok(()) /// } /// async fn gate(ctx: &mut Context, next: Next<'_>) -> Result { /// next.await?; // just throw /// unreachable!() /// } /// ``` /// pub type Next<'a> = &'a mut (dyn Unpin + Future<Output = Result>); #[cfg(test)] mod tests { use futures::{AsyncReadExt, TryStreamExt}; use http::header::LOCATION; use http::{StatusCode, Uri}; use crate::{status, App, Request}; const HELLO: &str = "Hello, world"; #[async_std::test] async fn status_endpoint() { let app = App::new().end(status!(StatusCode::BAD_REQUEST)); let service = app.http_service(); let resp = service.serve(Request::default()).await; assert_eq!(StatusCode::BAD_REQUEST, resp.status); } #[async_std::test] async fn string_endpoint() { let app = App::new().end(HELLO.to_owned()); let service = app.http_service(); let mut data = String::new(); service .serve(Request::default()) .await .body .into_async_read() .read_to_string(&mut data) .await .unwrap(); assert_eq!(HELLO, data); } #[async_std::test] async fn static_slice_endpoint() { let app = App::new().end(HELLO); let service = app.http_service(); let mut data = String::new(); service .serve(Request::default()) .await .body .into_async_read() .read_to_string(&mut data) .await .unwrap(); assert_eq!(HELLO, data); } #[async_std::test] async fn redirect_endpoint() { let app = App::new().end("/target".parse::<Uri>().unwrap()); let service = app.http_service(); let resp = service.serve(Request::default()).await; assert_eq!(StatusCode::PERMANENT_REDIRECT, resp.status); assert_eq!("/target", resp.headers[LOCATION].to_str().unwrap()) } }