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#1663 in Asynchronous

BSD-2-Clause OR Apache-2.0

3.5K SLoC

Docs.rs Tests


Rust implementation of the Fizyr RPC procotol.

The Fizyr RPC protocol is a request/response protocol, with bi-directional feedback as long as a request is open. Additionally, you can send individual stream messages that do not initiate a request.


Peer and PeerHandle

As a user of the library, you will mostly be using the PeerHandle object. The PeerHandle is used to interact with a remote peer. It is used to send and receive requests and stream messages. It can also be split in a PeerReadHandle and a PeerWriteHandle, to allow moving the handles into different tasks. The write handle can also be cloned and used in multiple tasks.

To obtain a PeerHandle, you can call Peer::connect(). This will connect to a remote listener and spawn a background task to read and write messages over the connection. If you need full control over tasks, you can instead create a Peer object and call Peer::run() manually.


The Listener struct is used to accept incoming connections and gives you a PeerHandle for each incoming connection. You can then use the handle to process incoming messages and to send messages to the peer. Usually, you will want to spawn a task for each accepted connection that handles the communication.


Each peer internally uses a Transport. The transport is responsible for reading and writing raw messages. By abstracting away the message transport, the library can expose a single generic Peer and Listener struct.

There are different transports for different socket types. Different transports may also use different types as message body. For example, the TcpTransport and UnixStreamTransport use messages with a StreamBody. This StreamBody body type contains raw bytes.

The UnixSeqpacketTransport has messages with a UnixBody, which allows you to embed file descriptors with each message.


The library uses features to avoid unnecessarily large dependency trees. Each feature corresponds to a different transport type. None of the features are enabled by default. Currently, the library has these features:


use fizyr_rpc::{TcpPeer, StreamConfig};

let (peer, info) = TcpPeer::connect("localhost:1337", StreamConfig::default()).await?;
eprintln!("Connected to: {}", info.remote_address());
let mut request = peer.send_request(1, &b"Hello World!"[..]).await?;

while let Some(update) = request.recv_update().await {
    let body = std::str::from_utf8(&update.body)?;
    eprintln!("Received update: {}", body);

let response = request.recv_response().await?;
let body = std::str::from_utf8(&response.body)?;
eprintln!("Received response: {}", body);


~104K SLoC