First pass at Middlewares.

content/docs/middleware.md

@@ -21,48 +21,14 @@ Typically, middleware is involved in the following actions:
 
 Middleware is registered for each application and executed in same order as
 registration. In general, a *middleware* is a type that implements the
-[*Middleware trait*](../../actix-web/actix_web/middleware/trait.Middleware.html).
+[*Service trait*](../../actix-web/actix_web/dev/trait.Service.html) and
-Each method in this trait has a default implementation. Each method can return
+[*Transform trait*](../../actix-web/actix_web/dev/trait.Transform.html).
+Each method in the traits has a default implementation. Each method can return
 a result immediately or a *future* object.
 
-The following demonstrates using middleware to add request and response headers:
+The following demonstrates creating a simple middleware:
 
-```rust
+{{< include-example example="middleware" file="main.rs" section="main" >}}
-use http::{header, HttpTryFrom};
-use actix_web::{App, HttpRequest, HttpResponse, Result};
-use actix_web::middleware::{Middleware, Started, Response};
-
-struct Headers;  // <- Our middleware
-
-/// Middleware implementation, middlewares are generic over application state,
-/// so you can access state with `HttpRequest::state()` method.
-impl<S> Middleware<S> for Headers {
-
-    /// Method is called when request is ready. It may return
-    /// future, which should resolve before next middleware get called.
-    fn start(&self, req: &HttpRequest<S>) -> Result<Started> {
-        Ok(Started::Done)
-    }
-
-    /// Method is called when handler returns response,
-    /// but before sending http message to peer.
-    fn response(&self, req: &HttpRequest<S>, mut resp: HttpResponse)
-        -> Result<Response>
-    {
-        resp.headers_mut().insert(
-            header::HeaderName::try_from("X-VERSION").unwrap(),
-            header::HeaderValue::from_static("0.2"));
-        Ok(Response::Done(resp))
-    }
-}
-
-fn main() {
-    App::new()
-       // Register middleware, this method can be called multiple times
-       .middleware(Headers)
-       .resource("/", |r| r.f(|_| HttpResponse::Ok()));
-}
-```
 
 > Actix provides several useful middlewares, such as *logging*, *user sessions*, etc.
 
@@ -85,21 +51,7 @@ Default `Logger` can be created with `default` method, it uses the default forma
   %a %t "%r" %s %b "%{Referer}i" "%{User-Agent}i" %T
 ```
 
-```rust
+{{< include-example example="middleware" file="logger.rs" section="logger" >}}
-extern crate env_logger;
-use actix_web::App;
-use actix_web::middleware::Logger;
-
-fn main() {
-    std::env::set_var("RUST_LOG", "actix_web=info");
-    env_logger::init();
-
-    App::new()
-       .middleware(Logger::default())
-       .middleware(Logger::new("%a %{User-Agent}i"))
-       .finish();
-}
-```
 
 The following is an example of the default logging format:
 
@@ -140,37 +92,23 @@ To set default response headers, the `DefaultHeaders` middleware can be used. Th
 *DefaultHeaders* middleware does not set the header if response headers already contain
 a specified header.
 
-```rust
+{{< include-example example="middleware" file="default_headers.rs" section="default-headers" >}}
-use actix_web::{http, middleware, App, HttpResponse};
-
-fn main() {
-    let app = App::new()
-        .middleware(
-            middleware::DefaultHeaders::new()
-                .header("X-Version", "0.2"))
-        .resource("/test", |r| {
-             r.method(http::Method::GET).f(|req| HttpResponse::Ok());
-             r.method(http::Method::HEAD).f(|req| HttpResponse::MethodNotAllowed());
-        })
-       .finish();
-}
-```
 
 ## User sessions
 
 Actix provides a general solution for session management. The
-[**SessionStorage**](../../actix-web/actix_web/middleware/session/struct.SessionStorage.html) middleware can be
+[**actix-session**](https://docs.rs/actix-session/0.1.1/actix_session/) middleware can be
 used with different backend types to store session data in different backends.
 
 > By default, only cookie session backend is implemented. Other backend implementations
 > can be added.
 
-[**CookieSessionBackend**](../../actix-web/actix_web/middleware/session/struct.CookieSessionBackend.html)
+[**CookieSession**](../../actix-web/actix_web/middleware/session/struct.CookieSessionBackend.html)
 uses cookies as session storage. `CookieSessionBackend` creates sessions which
 are limited to storing fewer than 4000 bytes of data, as the payload must fit into a
 single cookie. An internal server error is generated if a session contains more than 4000 bytes.
 
-A cookie may have a security policy of *signed* or *private*. Each has a respective `CookieSessionBackend` constructor.
+A cookie may have a security policy of *signed* or *private*. Each has a respective `CookieSession` constructor.
 
 A *signed* cookie may be viewed but not modified by the client. A *private* cookie may neither be viewed nor modified by the client.
 
@@ -178,41 +116,13 @@ The constructors take a key as an argument. This is the private key for cookie s
 
 In general, you create a
 `SessionStorage` middleware and initialize it with specific backend implementation,
-such as a `CookieSessionBackend`. To access session data,
+such as a `CookieSession`. To access session data,
 [*HttpRequest::session()*](../../actix-web/actix_web/middleware/session/trait.RequestSession.html#tymethod.session)
  must be used. This method returns a
 [*Session*](../../actix-web/actix_web/middleware/session/struct.Session.html) object, which allows us to get or set
 session data.
 
-```rust
+{{< include-example example="middleware" file="user_sessions.rs" section="user-session" >}}
-use actix_web::{server, App, HttpRequest, Result};
-use actix_web::middleware::session::{RequestSession, SessionStorage, CookieSessionBackend};
-
-fn index(req: &HttpRequest) -> Result<&'static str> {
-    // access session data
-    if let Some(count) = req.session().get::<i32>("counter")? {
-        println!("SESSION value: {}", count);
-        req.session().set("counter", count+1)?;
-    } else {
-        req.session().set("counter", 1)?;
-    }
-
-    Ok("Welcome!")
-}
-
-fn main() {
-    let sys = actix::System::new("basic-example");
-    server::new(
-        || App::new().middleware(
-           SessionStorage::new(
-             CookieSessionBackend::signed(&[0; 32])
-                .secure(false)
-            )))
-        .bind("127.0.0.1:59880").unwrap()
-        .start();
-    let _ = sys.run();
-}
-```
 
 # Error handlers
 
@@ -223,26 +133,4 @@ for a specific status code. You can modify an existing response or create a comp
 one. The error handler can return a response immediately or return a future that resolves
 into a response.
 
-```rust
+{{< include-example example="middleware" file="errorhandler.rs" section="error-handler" >}}
-use actix_web::{
-    App, HttpRequest, HttpResponse, Result,
-    http, middleware::Response, middleware::ErrorHandlers};
-
-fn render_500<S>(_: &HttpRequest<S>, resp: HttpResponse) -> Result<Response> {
-   let mut builder = resp.into_builder();
-   builder.header(http::header::CONTENT_TYPE, "application/json");
-   Ok(Response::Done(builder.into()))
-}
-
-fn main() {
-    let app = App::new()
-        .middleware(
-            ErrorHandlers::new()
-                .handler(http::StatusCode::INTERNAL_SERVER_ERROR, render_500))
-        .resource("/test", |r| {
-             r.method(http::Method::GET).f(|_| HttpResponse::Ok());
-             r.method(http::Method::HEAD).f(|_| HttpResponse::MethodNotAllowed());
-        })
-        .finish();
-}
-```

examples/Cargo.toml

@@ -21,4 +21,5 @@ exclude = [
   "requests",
   "responses",
   "testing",
+  "middleware",
 ]

examples/middleware/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "middleware"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+actix-web = "1.0"
+actix-service = "0.4"
+actix-session = "0.1"
+futures = "0.1"
+env_logger = "0.6"

examples/middleware/src/default_headers.rs

@@ -0,0 +1,16 @@
+// <default-headers>
+use actix_web::{http, middleware, web, App, HttpResponse};
+
+fn main() {
+    App::new()
+        .wrap(middleware::DefaultHeaders::new().header("X-Version", "0.2"))
+        .service(
+            web::resource("/test")
+                .route(web::get().to(|| HttpResponse::Ok()))
+                .route(
+                    web::method(http::Method::HEAD)
+                        .to(|| HttpResponse::MethodNotAllowed()),
+                ),
+        );
+}
+// </default-headers>

examples/middleware/src/errorhandler.rs

@@ -0,0 +1,25 @@
+// <error-handler>
+use actix_web::middleware::errhandlers::{ErrorHandlerResponse, ErrorHandlers};
+use actix_web::{dev, http, web, App, HttpResponse, Result};
+
+fn render_500<B>(mut res: dev::ServiceResponse<B>) -> Result<ErrorHandlerResponse<B>> {
+    res.response_mut().headers_mut().insert(
+        http::header::CONTENT_TYPE,
+        http::HeaderValue::from_static("Error"),
+    );
+    Ok(ErrorHandlerResponse::Response(res))
+}
+
+fn main() {
+    App::new()
+        .wrap(
+            ErrorHandlers::new()
+                .handler(http::StatusCode::INTERNAL_SERVER_ERROR, render_500),
+        )
+        .service(
+            web::resource("/test")
+                .route(web::get().to(|| HttpResponse::Ok()))
+                .route(web::head().to(|| HttpResponse::MethodNotAllowed())),
+        );
+}
+// </error-handler>

examples/middleware/src/logger.rs

@@ -0,0 +1,14 @@
+// <logger>
+use actix_web::middleware::Logger;
+use actix_web::App;
+use env_logger;
+
+fn main() {
+    std::env::set_var("RUST_LOG", "actix_web=info");
+    env_logger::init();
+
+    App::new()
+        .wrap(Logger::default())
+        .wrap(Logger::new("%a %{User-Agent}i"));
+}
+// </logger>

examples/middleware/src/main.rs

@@ -0,0 +1,72 @@
+mod default_headers;
+mod errorhandler;
+mod logger;
+mod user_sessions;
+// <main>
+use actix_service::{Service, Transform};
+use actix_web::{dev::ServiceRequest, dev::ServiceResponse, web, App, Error};
+use futures::future::{ok, FutureResult};
+use futures::{Future, Poll};
+
+// There are two steps in middleware processing.
+// 1. Middleware initialization, middleware factory gets called with
+//    next service in chain as parameter.
+// 2. Middleware's call method gets called with normal request.
+pub struct SayHi;
+
+// Middleware factory is `Transform` trait from actix-service crate
+// `S` - type of the next service
+// `B` - type of response's body
+impl<S, B> Transform<S> for SayHi
+where
+    S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Request = ServiceRequest;
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type InitError = ();
+    type Transform = SayHiMiddleware<S>;
+    type Future = FutureResult<Self::Transform, Self::InitError>;
+
+    fn new_transform(&self, service: S) -> Self::Future {
+        ok(SayHiMiddleware { service })
+    }
+}
+
+pub struct SayHiMiddleware<S> {
+    service: S,
+}
+
+impl<S, B> Service for SayHiMiddleware<S>
+where
+    S: Service<Request = ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Request = ServiceRequest;
+    type Response = ServiceResponse<B>;
+    type Error = Error;
+    type Future = Box<Future<Item = Self::Response, Error = Self::Error>>;
+
+    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
+        self.service.poll_ready()
+    }
+
+    fn call(&mut self, req: ServiceRequest) -> Self::Future {
+        println!("Hi from start. You requested: {}", req.path());
+
+        Box::new(self.service.call(req).and_then(|res| {
+            println!("Hi from response");
+            Ok(res)
+        }))
+    }
+}
+// </main>
+fn main() {
+    App::new().wrap(SayHi).service(
+        web::resource("/")
+            .to(|| "Hello, middleware! Check the console where the server is run."),
+    );
+}

examples/middleware/src/user_sessions.rs

@@ -0,0 +1,37 @@
+// <user-session>
+use actix_session::{CookieSession, Session};
+use actix_web::{middleware::Logger, web, App, HttpRequest, HttpServer, Result};
+
+/// simple index handler with session
+fn index(session: Session, req: HttpRequest) -> Result<&'static str> {
+    println!("{:?}", req);
+
+    // RequestSession trait is used for session access
+    let mut counter = 1;
+    if let Some(count) = session.get::<i32>("counter")? {
+        println!("SESSION value: {}", count);
+        counter = count + 1;
+        session.set("counter", counter)?;
+    } else {
+        session.set("counter", counter)?;
+    }
+
+    Ok("welcome!")
+}
+
+fn main() -> std::io::Result<()> {
+    std::env::set_var("RUST_LOG", "actix_web=info");
+    env_logger::init();
+
+    HttpServer::new(|| {
+        App::new()
+            // enable logger
+            .wrap(Logger::default())
+            // cookie session middleware
+            .wrap(CookieSession::signed(&[0; 32]).secure(false))
+            .service(web::resource("/").to(index))
+    })
+    .bind("127.0.0.1:8080")?
+    .run()
+}
+// </user-session>