@needle-tools/networking/src/networking_utils.js

Networking backend functionality for Needle Engine

(() => {

  const Storage = require("./storage");

  module.exports.loadState = async function (roomName) {
    const res = await Storage.loadRoomState(roomName);
    if ("state" in res) {
      return res.state;
    }
    return {};
  };

  module.exports.saveState = async function (roomName, state) {
    if (!roomName || !state) {
      console.warn("Invalid room or state, can not persist data");
      return;
    }
    await Storage.saveRoomState(roomName, state);
    return;
  };

  // notification event that someone joined their room
  module.exports.sendUpdate_UserJoinedRoom = function (ws, data) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(JSON.stringify({ key: "user-joined-room", data: data }));
  };

  // notification event that someone left their room
  module.exports.sendUpdate_UserLeftRoom = function (ws, data) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(JSON.stringify({ key: "user-left-room", data: data }));
  };

  // notification event that current user (you) joined room
  module.exports.sendUpdate_JoinedRoom = function (ws, roomName, inRoomIds, viewId, allowEditing) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    console.log("send joined room", roomName);
    ws.send(
      JSON.stringify({ key: "joined-room", room: roomName, inRoom: inRoomIds, viewId: viewId, allowEditing: allowEditing })
    );
  };

  // notification event that user (you) left a room
  module.exports.sendUpdate_LeftRoom = function (ws, roomName) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(JSON.stringify({ key: "left-room", room: roomName }));
  };

  module.exports.sendUpdate_RoomStateSent = function (ws, roomName) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(
      JSON.stringify({ key: "room-state-sent", room: roomName })
    );
  };

  module.exports.sendUpdate_GainedOwnershipBroadcast = function (
    ws,
    ownerId,
    guid
  ) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(
      JSON.stringify({
        key: "gained-ownership-broadcast",
        data: { guid: guid, owner: ownerId },
      })
    );
  };

  module.exports.sendUpdate_LostOwnershipBroadcast = function (
    ws,
    prevOwner,
    guid
  ) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(
      JSON.stringify({
        key: "lost-ownership-broadcast",
        data: { guid: guid, owner: prevOwner },
      })
    );
  };

  module.exports.sendUpdate_LostOwnership = function (ws, guid) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    console.log(`User ${ws.id} lost ownership ${guid}`);
    ws.send(JSON.stringify({ key: "lost-ownership", data: guid }));
  };

  module.exports.sendUpdate_GainedOwnership = function (ws, guid) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    console.log(ws.id + " gained ownership " + guid);
    ws.send(JSON.stringify({ key: "gained-ownership", data: guid }));
  };

  module.exports.sendUpdate_IsOwner = function (ws, guid, bool) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(
      JSON.stringify({
        key: "response-is-owner",
        data: { guid: guid, value: bool },
      })
    );
  };

  module.exports.sendUpdate_HasOwner = function (ws, guid, bool) {
    if (!ws || ws.readyState !== ws.OPEN) return;
    ws.send(
      JSON.stringify({
        key: "response-has-owner",
        data: { guid: guid, value: bool },
      })
    );
  };

  module.exports.getUniqueID = function () {
    function s4() {
      return Math.floor((1 + Math.random()) * 0x10000)
        .toString(16)
        .substring(1);
    }
    return s4() + s4() + "-" + s4();
  };


  // this is used to generate view-only guid from room id and secret
  // we also need to decrypt to get the original room name from the generated id
  // this is necessary so a viewer can also open a room and the server knows which room to open/load from this id
  const crypto = require("crypto");
  // make buffer constant so it doesnt change when server reloads (instead of 16 random bytes)
  const iv = Buffer.from([0xe6, 0x4d, 0xf7, 0x25, 0x4d, 0x50, 0xbe, 0x5b, 0xf8, 0x79, 0x0b, 0xf6, 0x16, 0x07, 0x71, 0x82]);
  const algorithm = 'aes-256-ctr';
  const fallbackKey = "40edb098f15eac40920111a4e50b0d15";

  module.exports.getUniqueIDWithSalt = function (key) {
    let salt = process.env.VIEW_ONLY_SALT;
    if (!salt) {
      console.error("Missing VIEW_ONLY_SALT environment variable");
      salt = fallbackKey;
    }
    const cipher = crypto.createCipheriv(algorithm, salt, iv);
    const encrypted = Buffer.concat([cipher.update(key), cipher.final()]);
    return encrypted.toString("hex");
  };

  module.exports.decryptID = function (id) {
    let salt = process.env.VIEW_ONLY_SALT;
    if (!salt) {
      console.error("Missing VIEW_ONLY_SALT environment variable");
      salt = fallbackKey;
    }
    const decipher = crypto.createDecipheriv(algorithm, salt, iv);
    const decrpyted = Buffer.concat([decipher.update(Buffer.from(id, 'hex')), decipher.final()]);
    return decrpyted.toString();
  }
})();