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#![macro_use] use core::{Request, Response}; use futures::future; use hyper::rt::Future; pub type MiddleWareFuture<I> = Box<Future<Item = I, Error = Response> + Send>; /// The middleware Trait. /// In arc-reactor the middleware system is designed to be as intuitive and as /// simple as possible. /// /// # How it works. /// /// Think of a `MiddleWare<T>` as a function that returns `Result<T, Response>` /// /// E.g A middleware is given a `Request` to do some processing, if that /// MiddleWare, returns Ok(request). Then the returned request is passed to the /// next middleware or route handler. /// /// ```rust,ignore /// use arc_reactor::prelude::*; /// /// //#### #[middleware(Request)] /// fn hasAccessToken(req: Request) { /// let token = req.query::<AccessToken>(); /// if let Some(user) = await!(db::fetchUserFromToken(token)).ok() { /// req.set::<User>(user); /// return Ok(req); /// } /// let res = Response::new().with_status(401); /// return Err(res) /// } /// /// /// //#### #[service] /// fn UserService(req: Request, res: Response) { /// let user = req.get::<User>().unwrap(); // It's safe to unwrap here, because the service is only called when `hasAccessToken` returns Ok(request). /// .... /// } /// /// /// fn main() { /// let router = Router::new() /// .get2("/user", mw![hasAccessToken], UserService); /// ..... /// // start the server mount the routes. /// /// } /// ``` /// /// ## Working With a `Vec<MiddleWare<T>>` /// /// The same rules as above applies, each middleware pass the request among /// themselves to do processing. If any of them returns `Err(Response)`, the /// rest of the middlewares are skipped as well as the route handler. /// /// /// ```rust,ignore /// use arc_reactor::prelude::*; /// /// //#### #[middleware(Request)] /// fn middleware1(req: Request) { /// println!("will be executed"); /// return Ok(req) /// } /// /// //#### #[middleware(Request)] /// fn middleware2(req: Request) { /// println!("will always be called, because middleware1 always returns Ok(request)"); /// return Err(Response::new().with_status(401)) /// } /// /// //#### #[middleware(Request)] /// fn middleware3(req: Request) { /// println!("will never be called"); /// return Ok(req) /// } /// /// //#### #[service] /// fn TestService(req: Request, res: Response) { /// println!("Will never be called, because middleware 2 returns an Err(response)") /// ...... /// } /// /// /// fn main() { /// let router = Router::new() /// .get2("/user", mw![middleware1, middleware2, middleware3], TestService); // note that the order of middlewares matter! /// ..... /// // start the server mount the routes. /// /// } /// /// ``` /// /// # Note /// Please note that you would probably never have a reason to implement this /// trait on your type directly. /// /// Instead you'll use the middleware proc_macro /// [`#[middleware]`](../impl_service/fn.middleware.html) to decorate your /// functions. The proc_macro makes `MiddleWare`'s aasynchronous by default. so /// you can `await!()` on futures. pub trait MiddleWare<T: Sized>: MiddleWareClone<T> + Sync + Send { fn call(&self, param: T) -> MiddleWareFuture<T>; } impl<T> MiddleWare<Request> for T where T: Fn(Request) -> MiddleWareFuture<Request> + Send + Sync + Clone + 'static, { fn call(&self, req: Request) -> MiddleWareFuture<Request> { (self)(req) } } #[cfg(not(feature = "unstable"))] impl<T> MiddleWare<Response> for T where T: Fn(Response) -> MiddleWareFuture<Response> + Send + Sync + Clone + 'static, { fn call(&self, res: Response) -> MiddleWareFuture<Response> { (self)(res) } } #[doc(hidden)] pub trait MiddleWareClone<D> { fn clone_middleware(&self) -> Box<MiddleWare<D>>; } impl<T, D> MiddleWareClone<D> for T where T: 'static + MiddleWare<D> + Clone, { fn clone_middleware(&self) -> Box<MiddleWare<D>> { Box::new(self.clone()) } } impl<T: 'static> Clone for Box<MiddleWare<T>> { fn clone(&self) -> Self { self.clone_middleware() } } /// This enables a vector of `MiddleWare<Request>` to behave like a single /// `MiddleWare<Request>` returning `Err(Response)` in any of the /// `MiddleWare<Request>` will cause the rest of the middlewares to be skipped. /// Note that there's a conveinience macro `mw` that allows you not write boxes /// everywhere. /// impl MiddleWare<Request> for Vec<Box<MiddleWare<Request>>> { fn call(&self, request: Request) -> MiddleWareFuture<Request> { self.iter() .fold(Box::new(future::ok(request)), |request, middleware| { let middleware = middleware.clone(); Box::new(request.and_then(move |req| middleware.call(req))) }) } } /// This enables a vector of `MiddleWare<Request>` to behave like a single /// `MiddleWare<Request>` returning `Err(Response)` in any of the /// `MiddleWare<Request>` will cause the rest of the middlewares to be skipped. /// Note that there's a conveinient macro `mw` that allows you not write /// boxes everywhere. /// impl MiddleWare<Response> for Vec<Box<MiddleWare<Response>>> { fn call(&self, response: Response) -> MiddleWareFuture<Response> { self.iter() .fold(Box::new(future::ok(response)), |response, middleware| { let middleware = middleware.clone(); Box::new(response.and_then(move |res| middleware.call(res))) }) } } impl MiddleWare<Request> for Box<MiddleWare<Request>> { fn call(&self, item: Request) -> MiddleWareFuture<Request> { (**self).call(item) } } impl MiddleWare<Response> for Box<MiddleWare<Response>> { fn call(&self, item: Response) -> MiddleWareFuture<Response> { (**self).call(item) } } /// Set middlewares that should be executed on a request. /// /// # Example /// /// ```rust, ignore /// #![feature(proc_macro, generators, specialization, proc_macro_non_items)] /// #[macro_use] /// extern crate arc_reactor; /// use arc_reactor::{prelude::*, routing::Router}; /// /// fn get_main_routes() -> Router { /// let app_middlewares = mw![checkIfAuth]; /// /// // Feel free to use pre-configured app middleware /// } /// /// #[middleware(Request)] /// fn checkIfAuth(req: Request) { /// if req.body().is_empty() { /// return Err((401, "You need to include some data to access this route!").into()); /// } /// /// Ok(req) /// } /// ``` #[macro_export] macro_rules! mw { ($($middlewares:expr), +) => {{ use $crate::proto::MiddleWare; let middleWares: Vec<Box<MiddleWare<_>>> = vec![$(Box::new($middlewares)), +]; Box::new(middleWares) as Box<MiddleWare<_>> }}; }