protocols/identify/: Add example (#2689)

examples/README.md

@@ -27,6 +27,10 @@ A set of examples showcasing how to use rust-libp2p.
 
   A basic key value store demonstrating libp2p and the mDNS and Kademlia protocol.
 
+- [Identify](../protocols/identify/examples/identify.rs)
+
+  Demonstrates how to use identify protocol to query peer information.
+
 - [IPFS Kademlia](ipfs-kad.rs)
 
   Demonstrates how to perform Kademlia queries on the IPFS network.

protocols/identify/Cargo.toml

@@ -27,6 +27,7 @@ void = "1.0"
 [dev-dependencies]
 async-std = "1.6.2"
 env_logger = "0.9"
+libp2p = { path = "../..", default-features = false, features = ["identify", "tcp-async-io"] }
 libp2p-mplex = { path = "../../muxers/mplex" }
 libp2p-noise = { path = "../../transports/noise" }
 libp2p-tcp = { path = "../../transports/tcp" }

protocols/identify/examples/identify.rs

@@ -0,0 +1,87 @@
+// Copyright 2018 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.
+
+//! identify example
+//!
+//! In the first terminal window, run:
+//!
+//! ```sh
+//! cargo run --example identify
+//! ```
+//! It will print the [`PeerId`] and the listening addresses, e.g. `Listening on
+//! "/ip4/127.0.0.1/tcp/24915"`
+//!
+//! In the second terminal window, start a new instance of the example with:
+//!
+//! ```sh
+//! cargo run --example identify -- /ip4/127.0.0.1/tcp/24915
+//! ```
+//! The two nodes establish a connection, negotiate the identify protocol
+//! and will send each other identify info which is then printed to the console.
+
+use futures::prelude::*;
+use libp2p::{identity, Multiaddr, PeerId};
+use libp2p_identify::{Identify, IdentifyConfig, IdentifyEvent};
+use libp2p_swarm::{Swarm, SwarmEvent};
+use std::error::Error;
+
+#[async_std::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    let local_key = identity::Keypair::generate_ed25519();
+    let local_peer_id = PeerId::from(local_key.public());
+    println!("Local peer id: {:?}", local_peer_id);
+
+    let transport = libp2p::development_transport(local_key.clone()).await?;
+
+    // Create a identify network behaviour.
+    let behaviour = Identify::new(IdentifyConfig::new(
+        "/ipfs/id/1.0.0".to_string(),
+        local_key.public(),
+    ));
+
+    let mut swarm = Swarm::new(transport, behaviour, local_peer_id);
+
+    // Tell the swarm to listen on all interfaces and a random, OS-assigned
+    // port.
+    swarm.listen_on("/ip4/0.0.0.0/tcp/0".parse()?)?;
+
+    // Dial the peer identified by the multi-address given as the second
+    // command-line argument, if any.
+    if let Some(addr) = std::env::args().nth(1) {
+        let remote: Multiaddr = addr.parse()?;
+        swarm.dial(remote)?;
+        println!("Dialed {}", addr)
+    }
+
+    loop {
+        match swarm.select_next_some().await {
+            SwarmEvent::NewListenAddr { address, .. } => println!("Listening on {:?}", address),
+            // Prints peer id identify info is being sent to.
+            SwarmEvent::Behaviour(IdentifyEvent::Sent { peer_id, .. }) => {
+                println!("Sent identify info to {:?}", peer_id)
+            }
+            // Prints out the info received via the identify event
+            SwarmEvent::Behaviour(IdentifyEvent::Received { info, .. }) => {
+                println!("Received {:?}", info)
+            }
+            _ => {}
+        }
+    }
+}