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docs(examples): Update params example to use async await
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‎examples/params.rs

+66-61
Original file line numberDiff line numberDiff line change
@@ -1,96 +1,101 @@
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#![deny(warnings)]
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extern crate futures;
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#![feature(async_await)]
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// #![deny(warnings)] // FIXME: https://github.com/rust-lang/rust/issues/62411
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extern crate hyper;
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extern crate pretty_env_logger;
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extern crate url;
66

7-
use futures::{future, Future, Stream};
8-
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use hyper::{Body, Method, Request, Response, Server, StatusCode};
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use hyper::service::service_fn;
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use hyper::service::{service_fn, make_service_fn};
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use std::collections::HashMap;
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use url::form_urlencoded;
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use futures_util::TryStreamExt;
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1514
static INDEX: &[u8] = b"<html><body><form action=\"post\" method=\"post\">Name: <input type=\"text\" name=\"name\"><br>Number: <input type=\"text\" name=\"number\"><br><input type=\"submit\"></body></html>";
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static MISSING: &[u8] = b"Missing field";
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static NOTNUMERIC: &[u8] = b"Number field is not numeric";
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// Using service_fn, we can turn this function into a `Service`.
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fn param_example(req: Request<Body>) -> Box<dyn Future<Item=Response<Body>, Error=hyper::Error> + Send> {
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async fn param_example(req: Request<Body>) -> Result<Response<Body>, hyper::Error> {
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match (req.method(), req.uri().path()) {
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(&Method::GET, "/") | (&Method::GET, "/post") => {
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Box::new(future::ok(Response::new(INDEX.into())))
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Ok(Response::new(INDEX.into()))
2423
},
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(&Method::POST, "/post") => {
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Box::new(req.into_body().concat2().map(|b| {
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// Parse the request body. form_urlencoded::parse
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// always succeeds, but in general parsing may
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// fail (for example, an invalid post of json), so
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// returning early with BadRequest may be
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// necessary.
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//
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// Warning: this is a simplified use case. In
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// principle names can appear multiple times in a
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// form, and the values should be rolled up into a
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// HashMap<String, Vec<String>>. However in this
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// example the simpler approach is sufficient.
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let params = form_urlencoded::parse(b.as_ref()).into_owned().collect::<HashMap<String, String>>();
25+
let b = req.into_body().try_concat().await?;
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// Parse the request body. form_urlencoded::parse
27+
// always succeeds, but in general parsing may
28+
// fail (for example, an invalid post of json), so
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// returning early with BadRequest may be
30+
// necessary.
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//
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// Warning: this is a simplified use case. In
33+
// principle names can appear multiple times in a
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// form, and the values should be rolled up into a
35+
// HashMap<String, Vec<String>>. However in this
36+
// example the simpler approach is sufficient.
37+
let params = form_urlencoded::parse(b.as_ref()).into_owned().collect::<HashMap<String, String>>();
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40-
// Validate the request parameters, returning
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// early if an invalid input is detected.
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let name = if let Some(n) = params.get("name") {
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n
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} else {
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return Response::builder()
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.status(StatusCode::UNPROCESSABLE_ENTITY)
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.body(MISSING.into())
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.unwrap();
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};
50-
let number = if let Some(n) = params.get("number") {
51-
if let Ok(v) = n.parse::<f64>() {
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v
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} else {
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return Response::builder()
55-
.status(StatusCode::UNPROCESSABLE_ENTITY)
56-
.body(NOTNUMERIC.into())
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.unwrap();
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}
39+
// Validate the request parameters, returning
40+
// early if an invalid input is detected.
41+
let name = if let Some(n) = params.get("name") {
42+
n
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} else {
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return Ok(Response::builder()
45+
.status(StatusCode::UNPROCESSABLE_ENTITY)
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.body(MISSING.into())
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.unwrap());
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};
49+
let number = if let Some(n) = params.get("number") {
50+
if let Ok(v) = n.parse::<f64>() {
51+
v
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} else {
60-
return Response::builder()
53+
return Ok(Response::builder()
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.status(StatusCode::UNPROCESSABLE_ENTITY)
62-
.body(MISSING.into())
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.unwrap();
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};
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.body(NOTNUMERIC.into())
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.unwrap());
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}
58+
} else {
59+
return Ok(Response::builder()
60+
.status(StatusCode::UNPROCESSABLE_ENTITY)
61+
.body(MISSING.into())
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.unwrap());
63+
};
6564

66-
// Render the response. This will often involve
67-
// calls to a database or web service, which will
68-
// require creating a new stream for the response
69-
// body. Since those may fail, other error
70-
// responses such as InternalServiceError may be
71-
// needed here, too.
72-
let body = format!("Hello {}, your number is {}", name, number);
73-
Response::new(body.into())
74-
}))
65+
// Render the response. This will often involve
66+
// calls to a database or web service, which will
67+
// require creating a new stream for the response
68+
// body. Since those may fail, other error
69+
// responses such as InternalServiceError may be
70+
// needed here, too.
71+
let body = format!("Hello {}, your number is {}", name, number);
72+
Ok(Response::new(body.into()))
7573
},
7674
_ => {
77-
Box::new(future::ok(Response::builder()
78-
.status(StatusCode::NOT_FOUND)
79-
.body(Body::empty())
80-
.unwrap()))
75+
Ok(Response::builder()
76+
.status(StatusCode::NOT_FOUND)
77+
.body(Body::empty())
78+
.unwrap())
8179
}
8280
}
83-
8481
}
8582

86-
fn main() {
83+
#[hyper::rt::main]
84+
async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
8785
pretty_env_logger::init();
8886

8987
let addr = ([127, 0, 0, 1], 1337).into();
9088

9189
let server = Server::bind(&addr)
92-
.serve(|| service_fn(param_example))
93-
.map_err(|e| eprintln!("server error: {}", e));
90+
.serve(make_service_fn(|_| {
91+
async {
92+
Ok::<_, hyper::Error>(service_fn(param_example))
93+
}
94+
}));
95+
96+
println!("Listening on http://{}", addr);
97+
98+
server.await?;
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95-
hyper::rt::run(server);
100+
Ok(())
96101
}

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