review handlers section

content/docs/handlers.md

@@ -6,12 +6,12 @@ weight: 160
 
 # Request Handlers
 
-A request handler is a function that accepts zero or more parameters that can be extracted
+A request handler is an async function that accepts zero or more parameters that can be extracted
 from a request (ie, [*impl FromRequest*][implfromrequest]) and returns a type that can
 be converted into an HttpResponse (ie, [*impl Responder*][implresponder]).
 
 Request handling happens in two stages. First the handler object is called, returning any
-object that implements the [*Responder*][respondertrait] trait.  Then, `respond_to()` is
+object that implements the [*Responder*][respondertrait] trait. Then, `respond_to()` is
 called on the returned object, converting itself to a `HttpResponse` or `Error`.
 
 By default actix-web provides `Responder` implementations for some standard types,
@@ -22,13 +22,13 @@ such as `&'static str`, `String`, etc.
 Examples of valid handlers:
 
 ```rust
-fn index(_req: HttpRequest) -> &'static str {
+async fn index(_req: HttpRequest) -> &'static str {
     "Hello world!"
 }
 ```
 
 ```rust
-fn index(_req: HttpRequest) -> String {
+async fn index(_req: HttpRequest) -> String {
     "Hello world!".to_owned()
 }
 ```
@@ -37,13 +37,13 @@ You can also change the signature to return `impl Responder` which works well if
 complex types are involved.
 
 ```rust
-fn index(_req: HttpRequest) -> impl Responder {
+async fn index(_req: HttpRequest) -> impl Responder {
     Bytes::from_static(b"Hello world!")
 }
 ```
 
 ```rust
-fn index(req: HttpRequest) -> Box<Future<Item=HttpResponse, Error=Error>> {
+async fn index(req: HttpRequest) -> Box<Future<Item=HttpResponse, Error=Error>> {
     ...
 }
 ```
@@ -56,28 +56,13 @@ Let's create a response for a custom type that serializes to an `application/jso
 
 {{< include-example example="responder-trait" file="main.rs" section="responder-trait" >}}
 
-## Async handlers
+## Streaming response body
 
-There are two different types of async handlers. Response objects can be generated asynchronously
+Response body can be generated asynchronously. In this case, body must implement
-or more precisely, any type that implements the [*Responder*][respondertrait] trait.
-
-In this case, the handler must return a `Future` object that resolves to the *Responder* type, i.e:
-
-{{< include-example example="async-handlers" file="main.rs" section="async-responder" >}}
-
-Or the response body can be generated asynchronously. In this case, body must implement
 the stream trait `Stream<Item=Bytes, Error=Error>`, i.e:
 
 {{< include-example example="async-handlers" file="stream.rs" section="stream" >}}
 
-Both methods can be combined. (i.e Async response with streaming body)
-
-It is possible to return a `Result` where the `Result::Item` type can be `Future`.  In
-this example, the `index` handler can return an error immediately or return a future
-that resolves to a `HttpResponse`.
-
-{{< include-example example="async-handlers" file="async_stream.rs" section="async-stream" >}}
-
 ## Different return types (Either)
 
 Sometimes, you need to return different types of responses. For example, you can error

examples/async-handlers/Cargo.toml

@@ -1,9 +1,10 @@
 [package]
 name = "async-handlers"
-version = "1.0.0"
+version = "2.0.0"
 edition = "2018"
 
 [dependencies]
-actix-web = "1.0"
+actix-web = "2.0"
-futures = "0.1"
+actix-rt = "1.0"
-bytes = "0.4"
+futures = "0.3.1"
+bytes = "0.5"

examples/async-handlers/src/async_stream.rs

@@ -1,28 +0,0 @@
-fn is_error() -> bool {
-    false
-}
-
-// <async-stream>
-use actix_web::{error, Error, HttpResponse};
-use futures::future::{result, Future};
-
-fn index() -> Result<Box<dyn Future<Item = HttpResponse, Error = Error>>, Error> {
-    if is_error() {
-        Err(error::ErrorBadRequest("bad request"))
-    } else {
-        Ok(Box::new(result(Ok(HttpResponse::Ok()
-            .content_type("text/html")
-            .body("Hello!")))))
-    }
-}
-// </async-stream>
-
-pub fn main() {
-    use actix_web::{web, App, HttpServer};
-
-    HttpServer::new(|| App::new().route("/", web::to_async(index)))
-        .bind("127.0.0.1:8088")
-        .unwrap()
-        .run()
-        .unwrap();
-}

examples/async-handlers/src/main.rs

@@ -1,30 +1,3 @@
-pub mod async_stream;
 pub mod stream;
-// <async-responder>
-use actix_web::{Error, HttpResponse};
-use futures::future::{ok, Future};
 
-fn index() -> Box<dyn Future<Item = HttpResponse, Error = Error>> {
+fn main() {}
-    Box::new(ok::<_, Error>(
-        HttpResponse::Ok().content_type("text/html").body("Hello!"),
-    ))
-}
-
-fn index2() -> Box<dyn Future<Item = &'static str, Error = Error>> {
-    Box::new(ok::<_, Error>("Welcome!"))
-}
-
-fn main() {
-    use actix_web::{web, App, HttpServer};
-
-    HttpServer::new(|| {
-        App::new()
-            .route("/async", web::to_async(index))
-            .route("/", web::to_async(index2))
-    })
-    .bind("127.0.0.1:8088")
-    .unwrap()
-    .run()
-    .unwrap();
-}
-// </async-responder>

examples/async-handlers/src/stream.rs

@@ -1,23 +1,22 @@
 // <stream>
-use actix_web::{Error, HttpResponse};
+use actix_web::{web, App, HttpServer, Error, HttpResponse};
 use bytes::Bytes;
 use futures::stream::once;
+use futures::future::ok;
 
-fn index() -> HttpResponse {
+async fn index() -> HttpResponse {
-    let body = once::<Bytes, Error>(Ok(Bytes::from_static(b"test")));
+    let body = once(ok::<_, Error>(Bytes::from_static(b"test")));
 
     HttpResponse::Ok()
         .content_type("application/json")
-        .streaming(Box::new(body))
+        .streaming(body)
 }
 
-pub fn main() {
+#[actix_rt::main]
-    use actix_web::{web, App, HttpServer};
+async fn main() -> std::io::Result<()> {
-
+    HttpServer::new(|| App::new().route("/async", web::to(index)))
-    HttpServer::new(|| App::new().route("/async", web::to_async(index)))
+        .bind("127.0.0.1:8088")?
-        .bind("127.0.0.1:8088")
-        .unwrap()
         .run()
-        .unwrap();
+        .await
 }
 // </stream>

examples/either/src/main.rs

@@ -1,23 +1,18 @@
 // <either>
 use actix_web::{Either, Error, HttpResponse};
-use futures::future::{ok, Future};
 
-type RegisterResult =
+type RegisterResult = Either<HttpResponse, Result<&'static str, Error>>;
-    Either<HttpResponse, Box<dyn Future<Item = HttpResponse, Error = Error>>>;
 
 fn index() -> RegisterResult {
     if is_a_variant() {
         // <- choose variant A
         Either::A(HttpResponse::BadRequest().body("Bad data"))
     } else {
-        Either::B(
+        // <- variant B
-            // <- variant B
+        Either::B(Ok("Hello!"))
-            Box::new(ok(HttpResponse::Ok()
-                .content_type("text/html")
-                .body("Hello!".to_string()))),
-        )
     }
 }
+// </either>
 
 fn main() {
     use actix_web::{web, App, HttpServer};
@@ -28,7 +23,6 @@ fn main() {
         .run()
         .unwrap();
 }
-// </either>
 
 fn is_a_variant() -> bool {
     true