Hyper cannot find Server module - http

Question

I'm writing a "hello world" HTTP server with Hyper, however I am not able to find the Server and rt modules when trying to import them.
When invoking cargo run, then I see this error message:
26 | let server = hyper::Server::bind(&addr).serve(router);
| ^^^^^^ could not find `Server` in `hyper`
I must be missing something obvious about Rust and Hyper. What I am trying to do is writing something as dry/simple as possible with just the HTTP layer and some basic routes. I would like to include as little as possible 3rd party dependencies e.g avoiding Tokio which I think involves async behavior, but I am not sure about the context as I am new to Rust.
Looks like I must use futures, so I included this dependency and perhaps futures only work with the async reserved word (which I am not sure if it comes from Tokio or Rust itself).
What confuses me is that in the Hyper examples I do see imports like use hyper::{Body, Request, Response, Server};, so that Server thing must be there, somewhere.
These are the dependencies in Cargo.toml:
hyper = "0.14.12"
serde_json = "1.0.67"
futures = "0.3.17"
This is the code in main.rs:
use futures::future;
use hyper::service::service_fn;
use hyper::{Body, Method, Response, StatusCode};
use serde_json::json;
fn main() {
let router = || {
service_fn(|req| match (req.method(), req.uri().path()) {
(&Method::GET, "/foo") => {
let mut res = Response::new(
Body::from(json!({"message": "bar"}).to_string())
);
future::ok(res)
},
(_, _) => {
let mut res = Response::new(
Body::from(json!({"content": "route not found"}).to_string())
);
*res.status_mut() = StatusCode::NOT_FOUND;
future::ok(res)
}
})
};
let addr = "127.0.0.1:8080".parse::<std::net::SocketAddr>().unwrap();
let server = hyper::Server::bind(&addr).serve(router); // <== this line fails to compile
// hyper::rt::run(server.map_err(|e| {
// eprintln!("server error: {}", e);
// }));
}
How do I make the code above compile and run?

Answer 1

According to documentation, you are missing one module namespace in your call hyper::server::Server:
let server = hyper::server::Server::bind(&addr).serve(router)
In order to use server you need to activate the feature flag in cargo:
hyper = { version = "0.14.12", features = ["server"] }