How to get the response body inside a wrap_fn middleware

[Franzx41]

Hi, guys. How I can get the response body string from the middleware inside wrap_fn?

use actix_web::{ web, App, HttpServer, Responder, dev::Service as _ };

async fn index() -> impl Responder {
    "API is up"
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {

    HttpServer::new(move || {
        App::new()
            .wrap_fn(|req, srv| {
                let fut = srv.call(req);
                async {
                    let res = fut.await?;
                    // How to get the response body here?
                    Ok(res)
                }
            })
            .route("/", web::get().to(index))
    })
    .bind("0.0.0.0:7878")?
    .run()
    .await
}

[robjtede]

The highlighted lines from this example show how to read the response body: https://github.com/actix/examples/blob/master/middleware/encrypted-payloads/src/main.rs#L127-L136

Though it's important to put a body back into the response so it actually gets sent out as well: https://github.com/actix/examples/blob/master/middleware/encrypted-payloads/src/main.rs#L153-L155

I'd also recommend using from_fn() from actix-web-lab which is a much better developer experience than wrap_fn.