minecraft-rs/minecraft-protocol/examples/ping.rs

use std::{env, io::Cursor, net::TcpStream};

use minecraft_protocol::{types::VarInt, v1_18::{serverbound::Handshake, PROTOCOL_VERSION}, PacketContent};

use log::debug;

struct Packet<T>
where
    T: PacketContent,
{
    packet_id: VarInt,
    content: T,
}

impl<T> Packet<T>
where
    T: PacketContent,
{
    fn read_from<R>(reader: &mut R) -> Result<Self, minecraft_protocol::Error>
    where
        R: std::io::Read,
    {
        let mut packet = Vec::new();
        let mut buffer = [0u8; 8092];

        let size = reader.read(&mut buffer).unwrap();

        let packet_size = {
            let mut cursor = Cursor::new(&buffer);
            let packet_size = VarInt::read_from(&mut cursor).unwrap();
            packet.extend_from_slice(&buffer[cursor.position() as usize..size]);
            packet_size
        };

        while packet.len() < packet_size.0 as usize {
            let size = reader.read(&mut buffer).unwrap();
            packet.extend_from_slice(&buffer[0..size]);
        }

        let mut cursor = Cursor::new(&packet);
        let packet_id = VarInt::read_from(&mut cursor).unwrap();

        let content = T::read_from(&mut cursor)?;

        Ok(Packet { packet_id, content })
    }

    fn write_to<W>(&self, writer: &mut W) -> Result<(), minecraft_protocol::Error>
    where
        W: std::io::Write,
    {
        let mut write_buffer = Cursor::new(Vec::new());
        self.packet_id.write_to(&mut write_buffer)?;
        self.content.write_to(&mut write_buffer)?;

        let write_buffer = write_buffer.get_ref();

        VarInt(write_buffer.len() as i32).write_to(writer)?;
        writer.write_all(write_buffer)?;

        Ok(())
    }
}

fn main() {
    env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("info")).init();
    let mut args = env::args().skip(1);

    let address = if let Some(ad) = args.next() {
        ad
    } else {
        panic!("missing server address")
    };

    let port = if let Some(port) = args.next() {
        port.parse::<u16>().expect("failed to get port")
    } else {
        25565
    };

    ping(&address, port);
}

fn ping(address: &str, port: u16) {
    let mut stream = TcpStream::connect(format!("{}:{}", address, port)).unwrap();

    {
        debug!("writting ...");

        let packet = Packet {
            packet_id: VarInt(0x00),
            content: Handshake {
                protocol_version: VarInt(PROTOCOL_VERSION),
                server_address: String::from(address),
                server_port: port,
                next_state: VarInt(1),
            },
        };
        packet.write_to(&mut stream).unwrap();

        let packet = Packet {
            packet_id: VarInt(0x00),
            content: (),
        };
        packet.write_to(&mut stream).unwrap();
    }

    let ping_value: serde_json::Value = {
        debug!("reading ...");

        let p: Packet<String> = Packet::read_from(&mut stream).unwrap();
        log::trace!("{}", p.content);

        serde_json::from_str(&p.content).expect("failed to decode as json")
    };

    debug!("{:#?}", ping_value);

    println!("result for {}:{}", address, port);
    let ping_value = ping_value.as_object().unwrap();
    if let Some(version) = ping_value.get("version").and_then(|s| s.as_object()) {
        println!(
            "\tversion: {} ({})",
            version
                .get("name")
                .and_then(|m| m.as_str())
                .expect("failed to get version name"),
            version
                .get("protocol")
                .and_then(|m| m.as_i64())
                .expect("failed to get protocol")
        );
    }

    if let Some(description) = ping_value.get("description") {
        println!(
            "\tdescription : {}",
            description.get("text").unwrap().as_str().unwrap()
        );
    }

    if let Some(players) = ping_value.get("players").and_then(|o| o.as_object()) {
        println!("\tplayers");
        println!(
            "\t\tnumbers : {}/{}",
            players
                .get("online")
                .and_then(|m| m.as_i64())
                .expect("failed to get online players count"),
            players
                .get("max")
                .and_then(|m| m.as_i64())
                .expect("failed to get max player")
        );

        if let Some(sample) = players.get("sample").and_then(|s| s.as_array()) {
            println!("\t\tsample:");
            for player in sample {
                println!(
                    "\t\t\t- {}",
                    player
                        .get("name")
                        .and_then(|m| m.as_str())
                        .expect("failed to get name of player")
                );
            }
        }
    }
}