actix.rs

// [dependencies]
// actix-web = "4"
// serde = "1.0.202"
// serde_derive = "1.0.202"

use actix_web::{get, post, web, App, HttpRequest, HttpResponse, HttpServer, Responder};
use serde_derive::Deserialize;

#[derive(Deserialize)]
struct Info {
    username: String,
}

// get query params
#[get("/")]
async fn index(req: HttpRequest) -> impl Responder {
    let params =
        web::Query::<Info>::from_query(req.query_string()).unwrap_or(actix_web::web::Query(Info {
            username: "Anonymous".into(),
        }));

    HttpResponse::Ok().body(format!("Hello, {}!", params.username))
}

#[post("/echo")]
async fn echo(req_body: String) -> impl Responder {
    HttpResponse::Ok().body(req_body)
}

async fn manual_hello() -> impl Responder {
    HttpResponse::Ok().body("Hey there!")
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    HttpServer::new(|| {
        App::new()
            .service(index)
            .service(echo)
            .route("/hey", web::get().to(manual_hello))
    })
    .bind(("127.0.0.1", 8080))?
    .run()
    .await
}