tiddlywiki-plugin-dev/dist/js/dev-ws-server.js

[](https://github.com/tiddly-gittly)

import { WebSocketServer, WebSocket } from "ws";
const refreshHeartBeat = (ws) => {
  ws.isAlive = true;
  if (ws.heartBeatInterval) {
    clearInterval(ws.heartBeatInterval);
  }
  ws.heartBeatInterval = setInterval(() => {
    if (ws.isAlive === false) {
      clearInterval(ws.heartBeatInterval);
      delete ws.heartBeatInterval;
      return ws.terminate();
    }
    ws.isAlive = false;
    ws.ping();
  }, 5e3);
};
const DEV_WS_PATHNAME = "/__dev_ws";
const parseClientGeneration = (url) => {
  if (!url) {
    return 0;
  }
  try {
    const generation = Number(
      new URL(url, "http://localhost").searchParams.get("gen")
    );
    return Number.isFinite(generation) ? generation : 0;
  } catch {
    return 0;
  }
};
const parseRequestPathname = (url) => {
  if (!url) {
    return "";
  }
  try {
    return new URL(url, "http://localhost").pathname;
  } catch {
    return url;
  }
};
const createNotifyServer = async () => {
  const server = new WebSocketServer({ noServer: true });
  let connectionCount = 0;
  let currentGeneration = 0;
  let saveBusy = false;
  const saveBusyCallbacks = [];
  server.on("connection", (ws, request) => {
    connectionCount++;
    const clientId = connectionCount;
    const clientGeneration = parseClientGeneration(request?.url);
    console.log(
      `[Modern.TiddlyDev] [ws] Client #${clientId} connected (total: ${server.clients.size})`
    );
    refreshHeartBeat(ws);
    ws.ping();
    ws.on("pong", () => refreshHeartBeat(ws));
    ws.on("message", (data) => {
      const msg = String(data);
      if (msg === "save-start") {
        if (!saveBusy) {
          saveBusy = true;
          saveBusyCallbacks.forEach((cb) => cb(true));
        }
        return;
      }
      if (msg === "save-end") {
        if (saveBusy) {
          saveBusy = false;
          saveBusyCallbacks.forEach((cb) => cb(false));
        }
        return;
      }
    });
    ws.on("close", () => {
      if (ws.heartBeatInterval) {
        clearInterval(ws.heartBeatInterval);
      }
      const remaining = server.clients?.size ?? 0;
      console.log(
        `[Modern.TiddlyDev] [ws] Client #${clientId} disconnected (total: ${remaining})`
      );
    });
    if (currentGeneration > 0 && clientGeneration < currentGeneration && ws.readyState === WebSocket.OPEN) {
      console.log(
        `[Modern.TiddlyDev] [refresh] Client #${clientId} is from build ${clientGeneration} (current ${currentGeneration}) — telling it to refresh`
      );
      ws.send("refresh");
    }
  });
  const onUpgrade = (request, socket, head) => {
    if (parseRequestPathname(request.url) === DEV_WS_PATHNAME) {
      server.handleUpgrade(request, socket, head, (ws) => {
        server.emit("connection", ws, request);
      });
    }
  };
  const attachToHttpServer = (httpServer) => {
    httpServer.on("upgrade", onUpgrade);
    return () => {
      httpServer.removeListener("upgrade", onUpgrade);
    };
  };
  const notifyRefresh = () => {
    const count = server.clients.size;
    if (count === 0) {
      console.log(
        `[Modern.TiddlyDev] [refresh] No clients connected — skipping browser notification`
      );
    } else {
      console.log(
        `[Modern.TiddlyDev] [refresh] Notifying ${count} client(s) to refresh`
      );
      server.clients.forEach((ws) => {
        if (ws.readyState === WebSocket.OPEN) {
          ws.send("refresh");
        }
      });
    }
  };
  const closeAllClients = () => {
    for (const ws of server.clients) {
      ws.terminate();
    }
  };
  const setBuildGeneration = (generation) => {
    if (Number.isFinite(generation)) {
      currentGeneration = generation;
    }
  };
  return {
    server,
    attachToHttpServer,
    closeAllClients,
    notifyRefresh,
    setBuildGeneration,
    onSaveBusyChange: (cb) => {
      saveBusyCallbacks.push(cb);
      return () => {
        const i = saveBusyCallbacks.indexOf(cb);
        if (i !== -1)
          saveBusyCallbacks.splice(i, 1);
      };
    }
  };
};
export {
  createNotifyServer
};