docs(examples): update echo example to use async/await
This commit is contained in:
Fuyang Liu
committed by
Sean McArthur
Sean McArthur
parent
22142943f4
commit
7ff8fccced
@@ -1,80 +1,80 @@
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#![feature(async_await)]
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#![deny(warnings)]
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#![deny(warnings)]
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extern crate futures;
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extern crate hyper;
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extern crate hyper;
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use futures::future;
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use hyper::rt::{Future, Stream};
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use hyper::service::service_fn;
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use hyper::{Body, Method, Request, Response, Server, StatusCode};
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use hyper::{Body, Method, Request, Response, Server, StatusCode};
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use hyper::service::{make_service_fn, service_fn};
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/// We need to return different futures depending on the route matched,
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use futures_util::TryStreamExt;
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/// and we can do that with an enum, such as `futures::Either`, or with
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/// trait objects.
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///
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/// A boxed Future (trait object) is used as it is easier to understand
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/// and extend with more types. Advanced users could switch to `Either`.
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type BoxFut = Box<dyn Future<Item = Response<Body>, Error = hyper::Error> + Send>;
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/// This is our service handler. It receives a Request, routes on its
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/// This is our service handler. It receives a Request, routes on its
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/// path, and returns a Future of a Response.
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/// path, and returns a Future of a Response.
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fn echo(req: Request<Body>) -> BoxFut {
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async fn echo(req: Request<Body>) -> Result<Response<Body>, hyper::Error> {
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let mut response = Response::new(Body::empty());
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match (req.method(), req.uri().path()) {
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match (req.method(), req.uri().path()) {
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// Serve some instructions at /
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// Serve some instructions at /
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(&Method::GET, "/") => {
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(&Method::GET, "/") => {
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*response.body_mut() = Body::from("Try POSTing data to /echo");
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Ok(Response::new(Body::from("Try POSTing data to /echo such as: `curl localhost:3000/echo -XPOST -d 'hello world'`")))
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}
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}
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// Simply echo the body back to the client.
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// Simply echo the body back to the client.
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(&Method::POST, "/echo") => {
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(&Method::POST, "/echo") => {
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*response.body_mut() = req.into_body();
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Ok(Response::new(req.into_body()))
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}
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}
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// Convert to uppercase before sending back to client.
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// Convert to uppercase before sending back to client using a stream.
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(&Method::POST, "/echo/uppercase") => {
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(&Method::POST, "/echo/uppercase") => {
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let mapping = req.into_body().map(|chunk| {
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let chunk_stream = req.into_body().map_ok(|chunk| {
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chunk
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chunk
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.iter()
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.iter()
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.map(|byte| byte.to_ascii_uppercase())
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.map(|byte| byte.to_ascii_uppercase())
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.collect::<Vec<u8>>()
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.collect::<Vec<u8>>()
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});
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});
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Ok(Response::new(Body::wrap_stream(chunk_stream)))
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*response.body_mut() = Body::wrap_stream(mapping);
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}
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}
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// Reverse the entire body before sending back to the client.
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// Reverse the entire body before sending back to the client.
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//
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//
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// Since we don't know the end yet, we can't simply stream
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// Since we don't know the end yet, we can't simply stream
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// the chunks as they arrive. So, this returns a different
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// the chunks as they arrive as we did with the above uppercase endpoint.
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// future, waiting on concatenating the full body, so that
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// So here we do `.await` on the future, waiting on concatenating the full body,
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// it can be reversed. Only then can we return a `Response`.
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// then afterwards the content can be reversed. Only then can we return a `Response`.
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(&Method::POST, "/echo/reversed") => {
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(&Method::POST, "/echo/reversed") => {
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let reversed = req.into_body().concat2().map(move |chunk| {
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let whole_chunk = req.into_body().try_concat().await;
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let body = chunk.iter().rev().cloned().collect::<Vec<u8>>();
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*response.body_mut() = Body::from(body);
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response
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});
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return Box::new(reversed);
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let reversed_chunk = whole_chunk.map(move |chunk| {
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chunk.iter().rev().cloned().collect::<Vec<u8>>()
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})?;
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Ok(Response::new(Body::from(reversed_chunk)))
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}
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}
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// The 404 Not Found route...
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// Return the 404 Not Found for other routes.
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_ => {
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_ => {
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*response.status_mut() = StatusCode::NOT_FOUND;
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let mut not_found = Response::default();
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*not_found.status_mut() = StatusCode::NOT_FOUND;
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Ok(not_found)
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}
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}
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}
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};
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Box::new(future::ok(response))
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}
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}
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fn main() {
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#[tokio::main]
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async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
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let addr = ([127, 0, 0, 1], 3000).into();
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let addr = ([127, 0, 0, 1], 3000).into();
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let service = make_service_fn(|_| {
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async {
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Ok::<_, hyper::Error>(service_fn(echo))
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}
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});
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let server = Server::bind(&addr)
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let server = Server::bind(&addr)
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.serve(|| service_fn(echo))
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.serve(service);
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.map_err(|e| eprintln!("server error: {}", e));
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println!("Listening on http://{}", addr);
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println!("Listening on http://{}", addr);
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hyper::rt::run(server);
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server.await?;
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Ok(())
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}
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}
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