Please add caching example about examples HOT 4 OPEN

use actix_http::header::CONTENT_TYPE;
use actix_session::SessionExt;
use actix_web::{
    body::{self, MessageBody},
    dev::{ServiceRequest, ServiceResponse},
    http::{
        header::{HeaderValue, CACHE_CONTROL},
        Method, StatusCode,
    },
    Error, HttpResponse,
};

use actix_web_lab::middleware::Next;

pub async fn cache_middleware(
    req: ServiceRequest,
    next: Next<impl MessageBody>,
) -> Result<ServiceResponse<impl MessageBody>, Error> {
    let key = format!("{}{}", req.path(), req.query_string());
    let session = req.get_session();

    if let Ok(cached_response) = session.get::<String>(&key) {
        //println!("{:?}", cached_response);
        if cached_response.is_some() {
            let res = HttpResponse::new(StatusCode::OK).set_body(cached_response.unwrap());
            let mut res = ServiceResponse::new(req.request().to_owned(), res);

            res.headers_mut()
                .append(CONTENT_TYPE, HeaderValue::from_static("application/json"));
            res.headers_mut()
                .append(CACHE_CONTROL, HeaderValue::from_static("max-age=86400"));

            return Ok(res);
        }
    }
    // Call the next service
    let res = next.call(req).await?;

    // deconstruct response into parts
    let (req, res) = res.into_parts();
    let (res, body) = res.into_parts();

    // Convert body to Bytes
    let body = body::to_bytes(body).await.ok().unwrap();
    // Use bytes directly for caching instead of converting to a String
    let res_body_enc = std::str::from_utf8(&body).unwrap();

    let res = res.set_body(res_body_enc.to_owned());
    let mut res = ServiceResponse::new(req.to_owned(), res);

    println!("{}, {}", req.method(), res.status());
    if req.method() == Method::GET && StatusCode::is_success(&res.status()) {
        println!("caching");
        res.headers_mut()
            .append(CACHE_CONTROL, HeaderValue::from_static("max-age=86400"));
        if let Err(e) = session.insert(key, res_body_enc) {
            println!("cache insert error: {}", e);
        }
    } else {
        println!("not caching");
    }
    Ok(res)
}