chat_example/
main.rs

1// Copyright 2018 Parity Technologies (UK) Ltd.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a
4// copy of this software and associated documentation files (the "Software"),
5// to deal in the Software without restriction, including without limitation
6// the rights to use, copy, modify, merge, publish, distribute, sublicense,
7// and/or sell copies of the Software, and to permit persons to whom the
8// Software is furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
14// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
19// DEALINGS IN THE SOFTWARE.
20
21#![doc = include_str!("../README.md")]
22
23use std::{
24    collections::hash_map::DefaultHasher,
25    error::Error,
26    hash::{Hash, Hasher},
27    time::Duration,
28};
29
30use futures::stream::StreamExt;
31use libp2p::{
32    gossipsub, mdns, noise,
33    swarm::{NetworkBehaviour, SwarmEvent},
34    tcp, yamux,
35};
36use tokio::{io, io::AsyncBufReadExt, select};
37use tracing_subscriber::EnvFilter;
38
39// We create a custom network behaviour that combines Gossipsub and Mdns.
40#[derive(NetworkBehaviour)]
41struct MyBehaviour {
42    gossipsub: gossipsub::Behaviour,
43    mdns: mdns::tokio::Behaviour,
44}
45
46#[tokio::main]
47async fn main() -> Result<(), Box<dyn Error>> {
48    let _ = tracing_subscriber::fmt()
49        .with_env_filter(EnvFilter::from_default_env())
50        .try_init();
51
52    let mut swarm = libp2p::SwarmBuilder::with_new_identity()
53        .with_tokio()
54        .with_tcp(
55            tcp::Config::default(),
56            noise::Config::new,
57            yamux::Config::default,
58        )?
59        .with_quic()
60        .with_behaviour(|key| {
61            // To content-address message, we can take the hash of message and use it as an ID.
62            let message_id_fn = |message: &gossipsub::Message| {
63                let mut s = DefaultHasher::new();
64                message.data.hash(&mut s);
65                gossipsub::MessageId::from(s.finish().to_string())
66            };
67
68            // Set a custom gossipsub configuration
69            let gossipsub_config = gossipsub::ConfigBuilder::default()
70                .heartbeat_interval(Duration::from_secs(10)) // This is set to aid debugging by not cluttering the log space
71                .validation_mode(gossipsub::ValidationMode::Strict) // This sets the kind of message validation. The default is Strict (enforce message
72                // signing)
73                .message_id_fn(message_id_fn) // content-address messages. No two messages of the same content will be propagated.
74                .build()
75                .map_err(|msg| io::Error::new(io::ErrorKind::Other, msg))?; // Temporary hack because `build` does not return a proper `std::error::Error`.
76
77            // build a gossipsub network behaviour
78            let gossipsub = gossipsub::Behaviour::new(
79                gossipsub::MessageAuthenticity::Signed(key.clone()),
80                gossipsub_config,
81            )?;
82
83            let mdns =
84                mdns::tokio::Behaviour::new(mdns::Config::default(), key.public().to_peer_id())?;
85            Ok(MyBehaviour { gossipsub, mdns })
86        })?
87        .build();
88
89    // Create a Gossipsub topic
90    let topic = gossipsub::IdentTopic::new("test-net");
91    // subscribes to our topic
92    swarm.behaviour_mut().gossipsub.subscribe(&topic)?;
93
94    // Read full lines from stdin
95    let mut stdin = io::BufReader::new(io::stdin()).lines();
96
97    // Listen on all interfaces and whatever port the OS assigns
98    swarm.listen_on("/ip4/0.0.0.0/udp/0/quic-v1".parse()?)?;
99    swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?)?;
100
101    println!("Enter messages via STDIN and they will be sent to connected peers using Gossipsub");
102
103    // Kick it off
104    loop {
105        select! {
106            Ok(Some(line)) = stdin.next_line() => {
107                if let Err(e) = swarm
108                    .behaviour_mut().gossipsub
109                    .publish(topic.clone(), line.as_bytes()) {
110                    println!("Publish error: {e:?}");
111                }
112            }
113            event = swarm.select_next_some() => match event {
114                SwarmEvent::Behaviour(MyBehaviourEvent::Mdns(mdns::Event::Discovered(list))) => {
115                    for (peer_id, _multiaddr) in list {
116                        println!("mDNS discovered a new peer: {peer_id}");
117                        swarm.behaviour_mut().gossipsub.add_explicit_peer(&peer_id);
118                    }
119                },
120                SwarmEvent::Behaviour(MyBehaviourEvent::Mdns(mdns::Event::Expired(list))) => {
121                    for (peer_id, _multiaddr) in list {
122                        println!("mDNS discover peer has expired: {peer_id}");
123                        swarm.behaviour_mut().gossipsub.remove_explicit_peer(&peer_id);
124                    }
125                },
126                SwarmEvent::Behaviour(MyBehaviourEvent::Gossipsub(gossipsub::Event::Message {
127                    propagation_source: peer_id,
128                    message_id: id,
129                    message,
130                })) => println!(
131                        "Got message: '{}' with id: {id} from peer: {peer_id}",
132                        String::from_utf8_lossy(&message.data),
133                    ),
134                SwarmEvent::NewListenAddr { address, .. } => {
135                    println!("Local node is listening on {address}");
136                }
137                _ => {}
138            }
139        }
140    }
141}
chat_example/main.rs

chat_example/
main.rs
