Share State using Hyper

Really need help my use case, any suggestion or comment.

I have been seeking a way to find have a variable in the main function and allow the variable change any request comes in.

No necessary for the following code, but any method using Hyper that can fulfill the upper requirement is what I am looking for.

extern crate futures;
extern crate hyper;

use futures::future;
use hyper::rt::{Future, Stream};
use hyper::service::service_fn;
use hyper::{Body, Method, Request, Response, Server, StatusCode};

/// We need to return different futures depending on the route matched,
/// and we can do that with an enum, such as `futures::Either`, or with
/// trait objects.
/// A boxed Future (trait object) is used as it is easier to understand
/// and extend with more types. Advanced users could switch to `Either`.
type BoxFut = Box<Future<Item = Response<Body>, Error = hyper::Error> + Send>;

/// This is our service handler. It receives a Request, routes on its
/// path, and returns a Future of a Response.
fn echo(req: Request<Body>) -> BoxFut {
    let mut response = Response::new(Body::empty());

    match (req.method(), req.uri().path()) {
        // Serve some instructions at /
        (&Method::GET, "/") => {
            *response.body_mut() = Body::from("Try POSTing data to /echo");

        // Simply echo the body back to the client.
        (&Method::POST, "/echo") => {
            *response.body_mut() = req.into_body();

        // Convert to uppercase before sending back to client.
        (&Method::POST, "/echo/uppercase") => {
            let mapping = req.into_body().map(|chunk| {
                    .map(|byte| byte.to_ascii_uppercase())

            *response.body_mut() = Body::wrap_stream(mapping);

        // Reverse the entire body before sending back to the client.
        // Since we don't know the end yet, we can't simply stream
        // the chunks as they arrive. So, this returns a different
        // future, waiting on concatenating the full body, so that
        // it can be reversed. Only then can we return a `Response`.
        (&Method::POST, "/echo/reversed") => {
            let reversed = req.into_body().concat2().map(move |chunk| {
                let body = chunk.iter().rev().cloned().collect::<Vec<u8>>();
                *response.body_mut() = Body::from(body);

            return Box::new(reversed);

        // The 404 Not Found route...
        _ => {
            *response.status_mut() = StatusCode::NOT_FOUND;


fn main() {
    let addr = ([127, 0, 0, 1], 3000).into();

    let server = Server::bind(&addr)
        .serve(|| service_fn(echo))
        .map_err(|e| eprintln!("server error: {}", e));

    println!("Listening on http://{}", addr);


Greetings Leonjia,

In order for us to help you, can you please elaborate on what you want the variable to do? Is it a filter of sorts? You mentioned you wanted to “allow the variable change any request comes in”

So, we asynchronously have the service_fn(echo) being called each time information comes in. Okay, so if you want a filter, you can create a function and call it inside the echo function at the very beginning of it.

What exactly do you want the “variable” to do? Is it not a function?

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