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Add libp2p-request-response protocol. #1596

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Jun 29, 2020
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1 change: 1 addition & 0 deletions Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -107,6 +107,7 @@ members = [
"protocols/noise",
"protocols/ping",
"protocols/plaintext",
"protocols/request-response",
"protocols/secio",
"swarm",
"transports/dns",
Expand Down
13 changes: 8 additions & 5 deletions core/src/upgrade.rs
Original file line number Diff line number Diff line change
Expand Up @@ -87,12 +87,12 @@ pub use self::{
///
/// # Context
///
/// In situations where we provide a list of protocols that we support, the elements of that list are required to
/// implement the [`ProtocolName`] trait.
/// In situations where we provide a list of protocols that we support,
/// the elements of that list are required to implement the [`ProtocolName`] trait.
///
/// Libp2p will call the [`ProtocolName::protocol_name`] trait method on each element of that list, and transmit the
/// returned value on the network. If the remote accepts a given protocol, the element serves as the return value of
/// the function that performed the negotiation.
/// Libp2p will call [`ProtocolName::protocol_name`] on each element of that list, and transmit the
/// returned value on the network. If the remote accepts a given protocol, the element
/// serves as the return value of the function that performed the negotiation.
///
/// # Example
///
Expand All @@ -118,6 +118,9 @@ pub use self::{
///
pub trait ProtocolName {
/// The protocol name as bytes. Transmitted on the network.
///
/// **Note:** Valid protocol names must start with `/` and
/// not exceed 140 bytes in length.
fn protocol_name(&self) -> &[u8];
}

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11 changes: 6 additions & 5 deletions protocols/floodsub/src/layer.rs
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ use libp2p_swarm::{
NetworkBehaviourAction,
PollParameters,
ProtocolsHandler,
OneShotEvent,
OneShotHandler,
NotifyHandler,
DialPeerCondition,
Expand Down Expand Up @@ -237,7 +238,7 @@ impl Floodsub {
}

impl NetworkBehaviour for Floodsub {
type ProtocolsHandler = OneShotHandler<FloodsubProtocol, FloodsubRpc, InnerMessage>;
type ProtocolsHandler = OneShotHandler<FloodsubProtocol, FloodsubRpc, InnerMessage, ()>;
type OutEvent = FloodsubEvent;

fn new_handler(&mut self) -> Self::ProtocolsHandler {
Expand Down Expand Up @@ -287,12 +288,12 @@ impl NetworkBehaviour for Floodsub {
&mut self,
propagation_source: PeerId,
_connection: ConnectionId,
event: InnerMessage,
event: OneShotEvent<InnerMessage, ()>,
) {
// We ignore successful sends event.
// We ignore successful sends or timeouts.
let event = match event {
InnerMessage::Rx(event) => event,
InnerMessage::Sent => return,
OneShotEvent::Success(InnerMessage::Rx(event)) => event,
OneShotEvent::Success(InnerMessage::Sent) | OneShotEvent::Timeout(()) => return,
};

// Update connected peers topics
Expand Down
24 changes: 24 additions & 0 deletions protocols/request-response/Cargo.toml
Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
[package]
name = "libp2p-request-response"
edition = "2018"
description = "Generic Request/Response Protocols"
version = "0.19.0"
authors = ["Parity Technologies <admin@parity.io>"]
license = "MIT"
repository = "https://github.com/libp2p/rust-libp2p"
keywords = ["peer-to-peer", "libp2p", "networking"]
categories = ["network-programming", "asynchronous"]

[dependencies]
futures = "0.3.1"
libp2p-core = { version = "0.19.0", path = "../../core" }
libp2p-swarm = { version = "0.19.0", path = "../../swarm" }
smallvec = "1.4"
wasm-timer = "0.2"

[dev-dependencies]
async-std = "1.6.2"
libp2p-noise = { version = "0.19.0", path = "../noise" }
libp2p-tcp = { version = "0.19.0", path = "../../transports/tcp", features = ["async-std"] }
libp2p-yamux = { version = "0.19.0", path = "../../muxers/yamux" }
rand = "0.7"
64 changes: 64 additions & 0 deletions protocols/request-response/src/codec.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,64 @@
// Copyright 2020 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

pub use libp2p_core::ProtocolName;

use futures::{prelude::*, future::BoxFuture};
use std::io;

/// A `RequestResponseCodec` defines the request and response types
/// for a [`RequestResponse`](crate::RequestResponse) protocol or
/// protocol family and how they are encoded / decoded on an I/O stream.
pub trait RequestResponseCodec {
/// The type of protocol(s) or protocol versions being negotiated.
type Protocol: ProtocolName + Send + Sync + Clone;
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/// The type of inbound and outbound requests.
type Request: Send;
/// The type of inbound and outbound responses.
type Response: Send;

/// Reads a request from the given I/O stream according to the
/// negotiated protocol.
fn read_request<'a, T>(&mut self, protocol: &Self::Protocol, io: &'a mut T)
-> BoxFuture<'a, Result<Self::Request, io::Error>>
where
T: AsyncRead + Unpin + Send;

/// Reads a response from the given I/O stream according to the
/// negotiated protocol.
fn read_response<'a, T>(&mut self, protocol: &Self::Protocol, io: &'a mut T)
-> BoxFuture<'a, Result<Self::Response, io::Error>>
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How about using async-trait for this trait and writing:

async fn read_response<T>(&mut self, protocol: &Self::Protocol, io: &mut T) -> io::Result<Self::Response>

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@tomaka tomaka Jun 25, 2020

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I'm personally not a fan of async-trait. It hides things from you for a very minimal gain. No strong opinion on this however.

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Thanks for the suggestion. I wasn't sure how controversial it would be and was even curious if someone would suggest it. While I have no strong preference and it is a relatively small convenience, I do see the appeal in getting syntactic uniformity for async (i.e. future-returning) methods, whether in traits or not. In terms of hiding things I personally don't think it makes the situation worse because the code expands in a very similar way to that of the existing built-in async fns for non-trait methods (subject to the inherent limitations, of course), which one needs to understand in any case. So I have async-trait a try: 9c6e6b4. If there are strong objections, please let me know.

where
T: AsyncRead + Unpin + Send;

/// Writes a request to the given I/O stream according to the
/// negotiated protocol.
fn write_request<'a, T>(&mut self, protocol: &Self::Protocol, io: &'a mut T, req: Self::Request)
-> BoxFuture<'a, Result<(), io::Error>>
where
T: AsyncWrite + Unpin + Send;

/// Writes a response to the given I/O stream according to the
/// negotiated protocol.
fn write_response<'a, T>(&mut self, protocol: &Self::Protocol, io: &'a mut T, res: Self::Response)
-> BoxFuture<'a, Result<(), io::Error>>
where
T: AsyncWrite + Unpin + Send;
}