Rust Rocket: In memory hit counter using state

Based on the managed state example.

Dependencies

examples/rocket/in-memory-hit-counter-state/Cargo.toml

[package]
name = "rocket-sessions"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
rocket = "0.5.0"

Code

examples/rocket/in-memory-hit-counter-state/src/main.rs

#[macro_use]
extern crate rocket;

use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering;

use rocket::response::content;
use rocket::State;

struct HitCount {
    count: AtomicUsize
}

#[get("/")]
fn index(hit_count: &State<HitCount>) -> content::RawHtml<String> {
    //let current_count = hit_count.count.load(Ordering::Relaxed);
    let current_count = hit_count.count.fetch_add(1, Ordering::Relaxed);

    content::RawHtml(format!("Rocket Counter: {current_count}"))
}

#[launch]
fn rocket() -> _ {
    rocket::build()
        .mount("/", routes![index])
        .manage(HitCount { count: AtomicUsize::new(0) })
}

#[cfg(test)]
mod tests;

Test

examples/rocket/in-memory-hit-counter-state/src/tests.rs

use rocket::http::Status;
use rocket::local::blocking::Client;

#[test]
fn counter() {
    let client = Client::tracked(super::rocket()).unwrap();
    let response = client.get("/").dispatch();

    assert_eq!(response.status(), Status::Ok);
    assert_eq!(
        response.headers().get_one("Content-Type").unwrap(),
        "text/html; charset=utf-8"
    );
    assert_eq!(response.into_string().unwrap(), "Rocket Counter: 0");


    let response = client.get("/").dispatch();
    assert_eq!(response.into_string().unwrap(), "Rocket Counter: 1");

    let response = client.get("/").dispatch();
    assert_eq!(response.into_string().unwrap(), "Rocket Counter: 2");
}

#[test]
fn _another_counter() {
    let client = Client::tracked(super::rocket()).unwrap();
    let response = client.get("/").dispatch();

    assert_eq!(response.status(), Status::Ok);
    assert_eq!(
        response.headers().get_one("Content-Type").unwrap(),
        "text/html; charset=utf-8"
    );
    assert_eq!(response.into_string().unwrap(), "Rocket Counter: 0");


    let response = client.get("/").dispatch();
    assert_eq!(response.into_string().unwrap(), "Rocket Counter: 1");
}