basic filewatcher using websocket

src/shims/fs/watcher-client.js

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+// Client-side WebSocket file watcher.
+// Connects to the server's /ws endpoint, receives file change events,
+// updates the metadata/content caches, and dispatches to fs.watch listeners
+// so Obsidian's vault picks them up automatically.
+
+import { isRecentLocalOp } from "./echo-guard.js";
+
+const RECONNECT_DELAY = 2000;
+
+export function createWatcherClient(metadataCache, contentCache, fsWatch) {
+  let ws = null;
+  let vaultId = null;
+  let reconnectTimer = null;
+
+  function connect(vault) {
+    vaultId = vault;
+
+    if (!vaultId) {
+      console.warn("[watcher] No vault ID, skipping WebSocket connection");
+      return;
+    }
+
+    const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
+    const url = `${protocol}//${window.location.host}/ws?vault=${encodeURIComponent(vaultId)}`;
+
+    try {
+      ws = new WebSocket(url);
+    } catch (e) {
+      console.error("[watcher] Failed to create WebSocket:", e);
+      scheduleReconnect();
+      return;
+    }
+
+    ws.onopen = () => {
+      console.log("[watcher] Connected to file watcher");
+    };
+
+    ws.onmessage = (event) => {
+      try {
+        const msg = JSON.parse(event.data);
+        handleEvent(msg);
+      } catch (e) {
+        console.error("[watcher] Failed to parse message:", e);
+      }
+    };
+
+    ws.onclose = () => {
+      console.log("[watcher] Disconnected");
+      ws = null;
+      scheduleReconnect();
+    };
+
+    ws.onerror = (e) => {
+      console.error("[watcher] WebSocket error:", e);
+    };
+  }
+
+  function scheduleReconnect() {
+    if (reconnectTimer) return;
+
+    reconnectTimer = setTimeout(() => {
+      reconnectTimer = null;
+
+      if (vaultId) {
+        console.log("[watcher] Reconnecting...");
+        connect(vaultId);
+      }
+    }, RECONNECT_DELAY);
+  }
+
+  function handleEvent(msg) {
+    const { type, path, stat } = msg;
+
+    if (!type || !path) return;
+
+    // Suppress echo from our own operations
+    if (isRecentLocalOp(path)) {
+      return;
+    }
+
+    switch (type) {
+      case "created":
+        if (stat) {
+          metadataCache.set(path, {
+            type: "file",
+            size: stat.size,
+            mtime: stat.mtime,
+            ctime: stat.ctime,
+          });
+        }
+        contentCache.invalidate(path);
+        fsWatch._dispatch("created", path);
+        break;
+
+      case "folder-created":
+        metadataCache.set(path, { type: "directory" });
+        fsWatch._dispatch("folder-created", path);
+        break;
+
+      case "modified":
+        if (stat) {
+          metadataCache.set(path, {
+            type: "file",
+            size: stat.size,
+            mtime: stat.mtime,
+            ctime: stat.ctime,
+          });
+        }
+        contentCache.invalidate(path);
+        fsWatch._dispatch("modified", path);
+        break;
+
+      case "deleted":
+        metadataCache.delete(path);
+        contentCache.invalidate(path);
+        fsWatch._dispatch("deleted", path);
+        break;
+
+      default:
+        console.warn("[watcher] Unknown event type:", type);
+    }
+  }
+
+  function disconnect() {
+    if (reconnectTimer) {
+      clearTimeout(reconnectTimer);
+      reconnectTimer = null;
+    }
+
+    if (ws) {
+      ws.onclose = null; // prevent reconnect
+      ws.close();
+      ws = null;
+    }
+  }
+
+  return {
+    connect,
+    disconnect,
+  };
+}