How to get tokio::net::TcpStream out of hyper::upgraded::Upgraded?

[ncihnegn]

Want to use the raw TcpStream.

[seanmonstar]

You can make use of Upgraded::downcast().

[ncihnegn]

error[E0277]: the trait bound `tokio::net::TcpStream: hyper::rt::Read` is not satisfied
   --> src/main.rs:18:42
    |
18  |     let mut stream = upgraded.downcast::<TcpStream>();
    |                               --------   ^^^^^^^^^ the trait `hyper::rt::Read` is not implemented for `tokio::net::TcpStream`
    |                               |
    |                               required by a bound introduced by this call
    |
    = help: the following other types implement trait `hyper::rt::Read`:
              TokioIo<T>
              Box<T>
              Upgraded
              Pin<P>
              &mut T
note: required by a bound in `Upgraded::downcast`

[seanmonstar]

You need to use the same type as that wich you used for the handshake(io)/serve_connection(io). Did you wrap it in a TokioIo?

[ncihnegn]

Yes. But I can't use handshake(TcpStream).

error[E0277]: the trait bound `tokio::net::TcpStream: hyper::rt::Read` is not satisfied
   --> src/main.rs:41:68
    |
41  | ... conn) = hyper::client::conn::http1::handshake(stream).await?;
    |             ------------------------------------- ^^^^^^ the trait `hyper::rt::Read` is not implemented for `tokio::net::TcpStream`

[kitty-eu-org]

@ncihnegn Have you solved this problem?

[ncihnegn]

Not really, but using tokio::io::copy_bidirectional is good enough for me.

[ncihnegn]

Or how can I separate the reader and writer like TcpStream::into_split()?

[maxim-arcsec]

I ran into this and couldn't get Upgraded::downcast<T> to work. Turns out the upgraded connection is wrapped inside a Rewind<T> which is private so it's impossible to provide the correct T for Upgraded::downcast<T> to succeed.

Instead you need to use the downcast function from hyper_util.

use tokio::net::TcpStream;
use hyper_util::TokioIo;
use hyper_util::server::conn::auto::upgrade::downcast;

let tokio_io_stream: TokioIo<TcpStream> = downcast(upgraded).unwrap().io;
let tcp_stream: TcpStream = tokio_io_stream.into_inner();

This issue is mentioned here