Using macros for JSON serialization

JSON serialization is directly supported via the Actix-web crate. We can demonstrate this by creating a GET view that returns all our to do items in the views/to_do/get.rs file:

use actix_web::{web, Responder};
use serde_json::value::Value;
use serde_json::Map;
use crate::state::read_file;
pub async fn get() -> impl Responder {
    let state: Map<String, Value> = read_file(String::from(        "./state.json"));
    return web::Json(state);
}

Here, we simply read our JSON file and return it, we pass it into the web::Json struct, and then we return it. The web::Json struct implements the Responder trait. We have to define this new view by adding the module definition to the views/to_do/mod.rs file, and then add the route definition to the factory function:

Mod get 
. . . 
app.route(&base_path.define(String::from("/get")),
 ...