Improve networking

common/mod_loader.ts

@@ -20,15 +20,25 @@ export interface ModData {
 	ores: OreJson[];
 }
 
-// a mod as the server lists it to clients, in load order. paths are relative to the site root
+// a mod as the server lists it to clients, in load order. paths are relative to the server's root
 export interface ModListing {
 	id: string;
 	name: string;
 	version: string;
+	// short hash of everything public, the folder it's served from
 	hash: string;
 	data: string;
 	client?: string;
 	worldgen?: string;
+	// sha-256 in hex of each file, clients check these before using them
+	sha256: { data: string; client?: string; worldgen?: string };
+}
+
+// the texture atlas with every mod's textures, built by the server
+export interface AtlasListing {
+	png: string;
+	json: string;
+	sha256: { png: string; json: string };
 }
 
 export class RecipeBook {

common/protocol.ts

@@ -1,10 +1,14 @@
 // messages sent between the client and the server, as json over a websocket
 import type { Faces } from "./constants.ts";
 import type { ItemData } from "./inventory.ts";
-import type { ModListing } from "./mod_loader.ts";
+import type { AtlasListing, ModListing } from "./mod_loader.ts";
 
 export const AIR_ID = "bworld:air";
 
+// bump when a client and server of different versions can't play together.
+// the server rejects a different version before the client downloads anything
+export const PROTOCOL_VERSION = 1;
+
 export interface PlayerInfo {
 	id: string;
 	name: string;
@@ -44,7 +48,9 @@ export interface ScreenLayout {
 
 // clients send what the player is trying to do, the server decides what happens
 export type ClientMessage =
-	| { type: "hello"; name: string }
+	| { type: "hello"; name: string; protocol: number }
+	// sent once the client has downloaded, checked and loaded everything in welcome
+	| { type: "ready" }
 	| { type: "move"; x: number; y: number; z: number; yaw: number; pitch: number }
 	| { type: "break_block"; x: number; y: number; z: number }
 	// right click on a block: interact with it, or place the held block against `face`
@@ -56,14 +62,23 @@ export type ClientMessage =
 	| { type: "chat"; text: string };
 
 export type ServerMessage =
+	// what to download before joining, see "Delivery to clients" in MODS.md
 	| {
 		type: "welcome";
+		protocol: number;
+		seed: string;
+		atlas: AtlasListing;
+		// in load order, the client loads them before joining the world
+		mods: ModListing[];
+	}
+	// the connection is closed right after
+	| { type: "rejected"; reason: string }
+	// answers ready, the player is in the world from here
+	| {
+		type: "join";
 		id: string;
 		// the server may change the name asked for, like alice to alice2
 		name: string;
-		seed: string;
-		// in load order, the client loads them before joining the world
-		mods: ModListing[];
 		players: PlayerInfo[];
 		changes: BlockChange[];
 		spawn: { x: number; y: number; z: number; yaw: number; pitch: number };