Get the protocol version to send from the ping packet (#20)

The first step of https://github.com/iceiix/steven/issues/18 Enhance protocol support,
instead of hardcoding a fixed version, the client now matches whatever the server sent.

* Get the protocol version to send from the ping packet

* Save/load server protocol versions to disk, server_versions.json

* Fallback to default SUPPORTED_PROTOCOL if no ping response

src/main.rs

@@ -15,7 +15,7 @@
 #![recursion_limit="300"]
 
 use std::time::{Instant, Duration};
-use log::info;
+use log::{info, warn};
 extern crate steven_shared as shared;
 
 #[macro_use]
@@ -73,6 +73,8 @@ pub struct Game {
     chunk_builder: chunk_builder::ChunkBuilder,
 
     connect_reply: Option<mpsc::Receiver<Result<server::Server, protocol::Error>>>,
+    protocol_version: i32,
+
     dpi_factor: f64,
     last_mouse_x: f64,
     last_mouse_y: f64,
@@ -83,6 +85,23 @@ pub struct Game {
 
 impl Game {
     pub fn connect_to(&mut self, address: &str) {
+        // Read saved server protocol version from ping response TODO: get from memory?
+        use std::fs;
+        let file = match fs::File::open("server_versions.json") {
+            Ok(val) => val,
+            Err(_) => return,
+        };
+        let server_versions_info: serde_json::Value = serde_json::from_reader(file).unwrap();
+        let protocol_version = {
+            if let Some(v) = server_versions_info.get(address) {
+                v.as_i64().unwrap() as i32
+            } else {
+                warn!("Server protocol version not known for {} (no ping response?), defaulting to {}", address, protocol::SUPPORTED_PROTOCOL);
+                protocol::SUPPORTED_PROTOCOL
+            }
+        };
+
+        self.protocol_version = protocol_version;
         let (tx, rx) = mpsc::channel();
         self.connect_reply = Some(rx);
         let address = address.to_owned();
@@ -93,7 +112,7 @@ impl Game {
             access_token: self.vars.get(auth::AUTH_TOKEN).clone(),
         };
         thread::spawn(move || {
-            tx.send(server::Server::connect(resources, profile, &address)).unwrap();
+            tx.send(server::Server::connect(resources, profile, &address, protocol_version)).unwrap();
         });
     }
 
@@ -211,6 +230,7 @@ fn main() {
         should_close: false,
         chunk_builder: chunk_builder::ChunkBuilder::new(resource_manager, textures),
         connect_reply: None,
+        protocol_version: protocol::SUPPORTED_PROTOCOL,
         dpi_factor,
         last_mouse_x: 0.0,
         last_mouse_y: 0.0,

src/screen/server_list.rs

@@ -17,6 +17,7 @@ use std::thread;
 use std::sync::mpsc;
 use std::rc::Rc;
 use std::cell::RefCell;
+use std::collections::HashMap;
 
 use crate::ui;
 use crate::render;
@@ -36,6 +37,7 @@ pub struct ServerList {
     disconnect_reason: Option<Component>,
 
     needs_reload: Rc<RefCell<bool>>,
+    server_protocol_versions: HashMap<String, i32>,
 }
 
 struct UIElements {
@@ -68,6 +70,7 @@ struct Server {
 }
 
 struct PingInfo {
+    address: String, 
     motd: format::Component,
     ping: Duration,
     exists: bool,
@@ -94,6 +97,7 @@ impl ServerList {
             elements: None,
             disconnect_reason,
             needs_reload: Rc::new(RefCell::new(false)),
+            server_protocol_versions: HashMap::new(),
         }
     }
 
@@ -271,6 +275,7 @@ impl ServerList {
                             None
                         };
                         drop(send.send(PingInfo {
+                            address,
                             motd: desc,
                             ping: res.1,
                             exists: true,
@@ -286,6 +291,7 @@ impl ServerList {
                         let mut msg = TextComponent::new(&e);
                         msg.modifier.color = Some(format::Color::Red);
                         let _ = send.send(PingInfo {
+                            address,
                             motd: Component::Text(msg),
                             ping: Duration::new(99999, 0),
                             exists: false,
@@ -488,6 +494,11 @@ impl super::Screen for ServerList {
                                     format!("Out of date {}/{}", res.online, res.max)
                                 };
                                 players.text = txt;
+
+                                // TODO: store in memory instead of disk? but where?
+                                self.server_protocol_versions.insert(res.address, res.protocol_version);
+                                let mut out = fs::File::create("server_versions.json").unwrap();
+                                serde_json::to_writer_pretty(&mut out, &self.server_protocol_versions).unwrap();
                             }
                             let mut txt = TextComponent::new(&res.protocol_name);
                             txt.modifier.color = Some(format::Color::Yellow);

src/server/mod.rs

@@ -103,13 +103,13 @@ macro_rules! handle_packet {
 
 impl Server {
 
-    pub fn connect(resources: Arc<RwLock<resources::Manager>>, profile: mojang::Profile, address: &str) -> Result<Server, protocol::Error> {
+    pub fn connect(resources: Arc<RwLock<resources::Manager>>, profile: mojang::Profile, address: &str, protocol_version: i32) -> Result<Server, protocol::Error> {
         let mut conn = protocol::Conn::new(address)?;
 
         let host = conn.host.clone();
         let port = conn.port;
         conn.write_packet(protocol::packet::handshake::serverbound::Handshake {
-             protocol_version: protocol::VarInt(protocol::SUPPORTED_PROTOCOL),
+             protocol_version: protocol::VarInt(protocol_version),
              host,
              port,
              next: protocol::VarInt(2),