Rocket - Single hit-counter using a text file


examples/rocket/single-counter-in-text-file/Cargo.toml
[package]
name = "single-counter-in-text-file"
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"
tempdir = "0.3"

examples/rocket/single-counter-in-text-file/src/main.rs
#[macro_use]
extern crate rocket;

use std::fs::File;
use std::io::Write;

#[get("/")]
fn index() -> String {
    let file = match std::env::var("COUNTER_PATH") {
        Ok(val) => std::path::PathBuf::from(val),
        Err(_) => {
            let current_dir = std::env::current_dir().unwrap();
            current_dir.join("counter.txt")
        }
    };

    let counter: u32 = if file.exists() {
        std::fs::read_to_string(&file)
            .unwrap()
            .trim_end()
            .parse()
            .unwrap()
    } else {
        0
    };
    let counter = counter + 1;

    let mut fh = File::create(file).unwrap();
    writeln!(&mut fh, "{}", counter).unwrap();

    format!("Counter is {}", counter)
}

#[launch]
fn rocket() -> _ {
    rocket::build().mount("/", routes![index])
}

#[cfg(test)]
mod tests;

examples/rocket/single-counter-in-text-file/src/tests.rs
use rocket::http::Status;
use rocket::local::blocking::Client;
use tempdir::TempDir;

#[test]
fn test_counte() {
    let tmp_dir = TempDir::new("counter").unwrap();
    std::env::set_var("COUNTER_PATH", tmp_dir.path().join("counter.txt"));

    let client = Client::tracked(super::rocket()).unwrap();
    let response = client.get("/").dispatch();

    assert_eq!(response.status(), Status::Ok);
    assert_eq!(response.into_string(), Some("Counter is 1".into()));

    let response = client.get("/").dispatch();
    assert_eq!(response.status(), Status::Ok);
    assert_eq!(response.into_string(), Some("Counter is 2".into()));
}