Added a simple handshake example.

examples/handshake.rs

@@ -0,0 +1,102 @@
+use rand::Rng;
+use std::io::Write;
+use std::net::{IpAddr, Ipv4Addr, Shutdown, SocketAddr, TcpStream};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use bitcoin::consensus::encode;
+use bitcoin::network::address;
+use bitcoin::network::constants;
+use bitcoin::network::message;
+use bitcoin::network::message_network;
+use bitcoin::network::stream_reader::StreamReader;
+
+fn main() {
+    // This example establishes a connection to a Bitcoin node, sends the intial
+    // "version" message, waits for the reply, and finally closes the connection.
+
+    let address = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(130, 149, 80, 221)), 8333);
+
+    let version_message = build_version_message(address.clone());
+
+    let first_message = message::RawNetworkMessage {
+        magic: constants::Network::Bitcoin.magic(),
+        payload: version_message,
+    };
+
+    if let Ok(mut stream) = TcpStream::connect(address) {
+        // Send the message
+        let _ = stream.write(encode::serialize(&first_message).as_slice());
+        println!("Sent version message");
+
+        // Wait for reply and close stream
+
+        loop {
+            let reply = StreamReader::new(&mut stream, None).read_next();
+            let unwrapped: message::RawNetworkMessage = reply.unwrap();
+            match unwrapped.payload {
+                message::NetworkMessage::Version(_) => {
+                    println!("Received version message: {:?}", unwrapped.payload);
+
+                    let second_message = message::RawNetworkMessage {
+                        magic: constants::Network::Bitcoin.magic(),
+                        payload: message::NetworkMessage::Verack,
+                    };
+
+                    let _ = stream.write(encode::serialize(&second_message).as_slice());
+                    println!("Sent verack message");
+                }
+                message::NetworkMessage::Verack => {
+                    println!("Received verack message: {:?}", unwrapped.payload);
+                    break;
+                }
+                _ => {
+                    println!("Received unknown message: {:?}", unwrapped.payload);
+                    break;
+                }
+            }
+        }
+        let _ = stream.shutdown(Shutdown::Both);
+    } else {
+        eprintln!("Failed to open connection");
+    }
+}
+
+fn build_version_message(address: SocketAddr) -> message::NetworkMessage {
+    // Building version message, see https://en.bitcoin.it/wiki/Protocol_documentation#version
+    let my_address = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(0, 0, 0, 0)), 0);
+
+    // "bitfield of features to be enabled for this connection"
+    let services = constants::ServiceFlags::NONE;
+
+    // "standard UNIX timestamp in seconds"
+    let timestamp = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("Time error")
+        .as_secs();
+
+    // "The network address of the node receiving this message"
+    let addr_recv = address::Address::new(&address, constants::ServiceFlags::NONE);
+
+    // "The network address of the node emitting this message"
+    let addr_from = address::Address::new(&my_address, constants::ServiceFlags::NONE);
+
+    // "Node random nonce, randomly generated every time a version packet is sent. This nonce is used to detect connections to self."
+    let nonce: u64 = rand::thread_rng().gen();
+
+    // "User Agent (0x00 if string is 0 bytes long)"
+    let user_agent = String::from("rust-example");
+
+    // "The last block received by the emitting node"
+    let start_height: i32 = 0;
+
+    // Construct the message
+    message::NetworkMessage::Version(message_network::VersionMessage::new(
+        services,
+        timestamp as i64,
+        addr_recv,
+        addr_from,
+        nonce,
+        user_agent,
+        start_height,
+    ))
+}