godot-webrtc-mplayer-testing/server.ts

// import { randomInt } from "./deps.ts";

const SERVER_VERSION = "0.1.0";
// TODO: version comparison

type ID = string;

// app state
const allLobbies = new Map<ID, Lobby>();
const allClients = new Map<ID, Client>();
// TODO: client index by id

interface DataMessage {
  type: string;
}

type ServerDataObject = Record<string, string | number | symbol | null>;
type ServerData = ServerDataObject | string;
type Message = string | DataMessage;

const broadcast = (message: Message) =>
  allClients.forEach((client) => client.send(message));

const buildMessage = (
  type: string,
  data: ServerData | ServerData[],
) =>
  Object.assign(
    { type },
    Array.isArray(data)
      ? { data }
      : (typeof data === "object" ? data : { data }),
  );

class Client {
  id: ID;
  peerId: number | null;
  name: string;
  socket: WebSocket;
  lobby: Lobby | null;

  constructor(socket: WebSocket) {
    this.id = crypto.randomUUID();
    this.socket = socket;
    this.peerId = null;
    this.name = "Client";
    this.lobby = null;

    allClients.set(this.id, this);
  }

  isConnected() {
    return this.socket.readyState == WebSocket.OPEN;
  }

  remove() {
    this.lobbyLeave();
    if (this.isConnected()) {
      this.socket.close();
    }
    allClients.delete(this.id);
  }

  send(message: Message) {
    try {
      if (this.isConnected()) {
        this.socket.send(
          typeof message === "object"
            ? ("json:" + JSON.stringify(message))
            : message,
        );
      }
    } catch (e) {
      console.error(
        `Failed to send on socket ${this.socket} to client ${this.id}. Disconnecting and removing...`,
      );
    }
  }

  clientList() {
    if (!this.lobby) return;
    const netClients: { id: ID; name: string; peerId: number | null }[] = [];
    this.lobby.clients.forEach(({ id, name, peerId }) =>
      netClients.push({ id, name, peerId })
    );
    // TODO: chunk async?
  }

  lobbyList() {
    const netLobbies: { id: ID; name: string }[] = [];
    allLobbies.forEach(({ id, name }) => netLobbies.push({ id, name }));
    // TODO: chunk async?
    this.send(buildMessage("lobby_list", netLobbies));
  }

  lobbyNew({ id, name }: Lobby) {
    // if the client is already in a lobby, we don't care about new lobbies
    if (this.lobby) return;
    this.send(buildMessage("lobby_new", { id, name }));
  }

  lobbyDelete({ id }: Lobby) {
    if (this.lobby) return;
    this.send(buildMessage("lobby_delete", { id }));
  }

  lobbyCreate() {
    if (this.lobby) {
      this.send(
        `[info] cannot create lobby (already in lobby ${this.lobby.id})`,
      );
      return;
    }
    new Lobby(this);
  }

  lobbyJoin(lobby: Lobby) {
    if (this.lobby) {
      this.send(`[info] cannot join lobby (already in lobby ${this.lobby.id})`);
      return;
    }
    this.lobby = lobby;
    lobby.addClient(this);
    this.send(
      buildMessage("lobby_joined", { id: lobby.id, peerId: this.peerId }),
    );
  }

  lobbyLeave() {
    const leavingLobby = this.lobby;
    if (!leavingLobby) {
      this.send(`[info] cannot leave lobby (not in a lobby)`);
      return;
    }
    this.peerId = null;
    this.lobby = null;
    if (this.isConnected()) {
      this.send(buildMessage("lobby_left", { id: leavingLobby.id }));
    }
    leavingLobby.removeClient(this);
  }
}

class Lobby {
  id: ID;
  name: string;
  clients: Map<ID, Client>;
  hostClientId: ID;

  constructor(host: Client, name?: string) {
    this.id = crypto.randomUUID();
    this.hostClientId = host.id;
    this.clients = new Map<ID, Client>();
    this.name = name || this.id;

    allLobbies.set(this.id, this);
    host.peerId = 1;
    host.lobbyJoin(this);
    allClients.forEach((client) => client.lobbyNew(this));
  }

  remove() {
    allClients.forEach((client) => client.lobbyDelete(this));
    this.clients.forEach((client) => {
      client.lobbyLeave();
    });
    allLobbies.delete(this.id);
  }

  broadcast(message: Message) {
    this.clients.forEach((client) => client.send(message));
  }

  addClient(client: Client) {
    if (!client.peerId) {
      const arr = new Int32Array(1);
      crypto.getRandomValues(arr);
      client.peerId = Math.abs(arr[0]);
    }
    client.send(buildMessage("your_peer_id", client.peerId.toString()));
    this.broadcast(
      buildMessage("peer_joined", {
        id: client.id,
        name: client.name,
        peerId: client.peerId,
      }),
    );
    this.clients.forEach((c) =>
      client.send(buildMessage("peer_joined", {
        id: c.id,
        name: c.name,
        peerId: c.peerId,
      }))
    );
    this.clients.set(client.id, client);
  }

  removeClient({ id }: Client) {
    this.clients.delete(id);
    this.broadcast(buildMessage("peer_left", { id }));
    if (id === this.hostClientId) {
      console.warn("Host left!");
      this.remove();
    }
  }
}

interface ClientMessage {
  type: "candidate" | "offer" | "answer";
  data: ServerDataObject;
}

// events
function onMessage(client: Client, ev: MessageEvent) {
  // TODO: log who from?
  const msg = ev.data.trim();
  console.log("Client Message Received", msg);
  if (msg === "init") client.send(buildMessage("your_id", client.id));
  if (msg === "lobby_create") client.lobbyCreate();
  if (msg === "lobby_leave") client.lobbyLeave();
  if (msg === "request_lobby_list") client.lobbyList();
  if (msg.startsWith("lobby_join:")) {
    const id = msg.substr(11);
    const lobby = allLobbies.get(id);
    if (lobby) {
      client.lobbyJoin(lobby);
      client.clientList();
    } else client.send(`[info] could not find lobby ${id}`);
  }
  if (msg.startsWith("json:")) {
    const data: ClientMessage = JSON.parse(msg.substr(5));
    if (["candidate", "answer", "offer"].includes(data.type)) {
      console.log("Received WebRTC Negotiation Message...");
      if (typeof data.data === "object") {
        const subdata = data.data;
        if (typeof subdata["peerId"] === "number") {
          const destPeerId: number = subdata["peerId"];
          for (const iClient of client.lobby?.clients.values() || []) {
            if (iClient.peerId == destPeerId) {
              const payload = Object.assign({}, data);
              const srcPeerId = client.peerId;
              payload.data.peerId = srcPeerId;
              console.log(
                `Forwarding WebRTC Negotiation Message from peer ${srcPeerId} to peer ${destPeerId}...`,
              );
              iClient.send(payload);
              break;
            }
          }
        }
      }
    }
  }
}

function onSocketOpen(client: Client, _ev: Event) {
  console.log("New Client", client.id);
}

function onClientLeave(client: Client) {
  client.remove();
}

function onSocketClose(client: Client, _ev: Event) {
  console.log("Client Close");
  onClientLeave(client);
}

function onSocketError(client: Client, _ev: Event) {
  console.log("Client Error");
  onClientLeave(client);
}

const PORT = parseInt(Deno.env.get("PORT") || "80");
console.log("Listening on port", PORT);
const listener = Deno.listen({ port: PORT });
for await (const conn of listener) {
  // console.debug("Connection received:", conn);
  (async () => {
    const server = Deno.serveHttp(conn);
    for await (const { respondWith, request } of server) {
      // console.debug("HTTP Request Received", request);
      try {
        // console.warn(JSON.stringify([allClients, allLobbies]));
        const { socket, response } = Deno.upgradeWebSocket(request);
        const client = new Client(socket);
        socket.onmessage = (ev) => onMessage(client, ev);
        socket.onopen = (ev) => onSocketOpen(client, ev);
        socket.onclose = (ev) => onSocketClose(client, ev);
        socket.onerror = (ev) => onSocketError(client, ev);
        respondWith(response);
      } catch (e) {
        console.log("Could not add client for unhandled reason:", e);
        respondWith(
          new Response("400 Bad Request", {
            status: 400,
            headers: { "content-type": "text/html" },
          }),
        );
      }
    }
  })();
}