Connect to server over websocket for live cloud sync

Desktop app now holds a persistent websocket to the server and syncs
on push notifications instead of a fixed timer, falling back to the
old polling interval only when the socket is down. Cloud folder/file
listings are cached locally so the browser stays usable offline.

Claude-Session: https://claude.ai/code/session_01PoLmSR1pFVyHf8i5b1rNWk

src-tauri/Cargo.lock

@@ -947,6 +947,12 @@ dependencies = [
  "syn 2.0.119",
 ]
 
+[[package]]
+name = "data-encoding"
+version = "2.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4ae5f15dda3c708c0ade84bfee31ccab44a3da4f88015ed22f63732abe300c8"
+
 [[package]]
 name = "data-url"
 version = "0.3.2"
@@ -3889,6 +3895,8 @@ version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "22f6172bdec972074665ed81ed53b71da00bfc44b65a753cfde883ec4c702a1a"
 dependencies = [
+ "libc",
+ "rand_chacha",
  "rand_core",
 ]
 
@@ -3907,6 +3915,9 @@ name = "rand_core"
 version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom 0.2.17",
+]
 
 [[package]]
 name = "raw-window-handle"
@@ -4558,6 +4569,17 @@ dependencies = [
  "stable_deref_trait",
 ]
 
+[[package]]
+name = "sha1"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a978451301f4db1d02937a4ab3ccce137717b81826e79b7d49ffe3244a13c3b8"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
 [[package]]
 name = "sha2"
 version = "0.10.9"
@@ -5705,6 +5727,25 @@ dependencies = [
  "core_maths",
 ]
 
+[[package]]
+name = "tungstenite"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18e5b8366ee7a95b16d32197d0b2604b43a0be89dc5fac9f8e96ccafbaedda8a"
+dependencies = [
+ "byteorder",
+ "bytes",
+ "data-encoding",
+ "http",
+ "httparse",
+ "log",
+ "native-tls",
+ "rand",
+ "sha1",
+ "thiserror 1.0.69",
+ "utf-8",
+]
+
 [[package]]
 name = "two-face"
 version = "0.4.5"
@@ -5778,6 +5819,7 @@ dependencies = [
  "tauri-plugin-clipboard-manager",
  "tauri-plugin-dialog",
  "tauri-plugin-opener",
+ "tungstenite",
  "typst",
  "typst-assets",
  "typst-html",
@@ -6345,6 +6387,12 @@ dependencies = [
  "xmlwriter",
 ]
 
+[[package]]
+name = "utf-8"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09cc8ee72d2a9becf2f2febe0205bbed8fc6615b7cb429ad062dc7b7ddd036a9"
+
 [[package]]
 name = "utf16_iter"
 version = "1.0.5"

src-tauri/Cargo.toml

@@ -42,4 +42,5 @@ base64 = "0.22"
 diffy = "0.4"
 walkdir = "2"
 ureq = { version = "2.12", features = ["json"] }
+tungstenite = { version = "0.24", features = ["native-tls"] }
 

src-tauri/src/db.rs

@@ -19,7 +19,7 @@ pub struct DocumentLink {
     pub synced_at: Option<String>,
 }
 
-const SCHEMA: [&str; 5] = [
+const SCHEMA: [&str; 6] = [
     "CREATE TABLE IF NOT EXISTS settings (
         key TEXT PRIMARY KEY,
         value TEXT NOT NULL
@@ -51,6 +51,11 @@ const SCHEMA: [&str; 5] = [
         data TEXT NOT NULL,
         source_modified INTEGER NOT NULL
     )",
+    "CREATE TABLE IF NOT EXISTS cloud_cache (
+        key TEXT PRIMARY KEY,
+        payload TEXT NOT NULL,
+        cached_at TEXT NOT NULL
+    )",
 ];
 
 const MIGRATIONS: [&str; 2] = [
@@ -416,4 +421,30 @@ impl Store {
             Ok(())
         })
     }
+
+    pub fn cloud_cache(&self, key: &str) -> Result<Option<String>, String> {
+        self.with(|connection| {
+            connection
+                .query_row(
+                    "SELECT payload FROM cloud_cache WHERE key = ?1",
+                    params![key],
+                    |row| row.get(0),
+                )
+                .optional()
+        })
+    }
+
+    pub fn save_cloud_cache(&self, key: &str, payload: &str) -> Result<(), String> {
+        self.with(|connection| {
+            connection.execute(
+                "INSERT INTO cloud_cache (key, payload, cached_at)
+                 VALUES (?1, ?2, ?3)
+                 ON CONFLICT(key) DO UPDATE SET
+                   payload = excluded.payload,
+                   cached_at = excluded.cached_at",
+                params![key, payload, chrono::Utc::now().to_rfc3339()],
+            )?;
+            Ok(())
+        })
+    }
 }

src-tauri/src/lib.rs

@@ -6,6 +6,7 @@ mod sync;
 mod thumbnails;
 mod workspace;
 mod world;
+mod ws;
 
 use base64::{engine::general_purpose::STANDARD as BASE64, Engine as _};
 use serde::{Deserialize, Serialize};
@@ -16,6 +17,7 @@ use assets::Asset;
 use db::Store;
 use compiler::{CompileResult, Diagnostic};
 use lsp::{LspHandle, LspState};
+use ws::WsState;
 use sync::{Account, ProjectSummary, SyncReport};
 use workspace::{
     browse, is_project_dir, is_text_file, list_files, load_settings, project_file_path,
@@ -535,6 +537,16 @@ fn clear_thumbnails(store: State<'_, Store>) -> Result<(), String> {
     store.clear_thumbnails()
 }
 
+#[tauri::command]
+fn get_cloud_cache(store: State<'_, Store>, key: String) -> Result<Option<String>, String> {
+    store.cloud_cache(&key)
+}
+
+#[tauri::command]
+fn save_cloud_cache(store: State<'_, Store>, key: String, payload: String) -> Result<(), String> {
+    store.save_cloud_cache(&key, &payload)
+}
+
 #[tauri::command]
 fn list_assets(app: AppHandle, store: State<'_, Store>) -> Result<Vec<Asset>, String> {
     assets::list_assets(&app, &store)
@@ -703,6 +715,7 @@ fn cloud_check_compatibility(server_url: String) -> sync::CompatibilityStatus {
 fn cloud_login(
     app: AppHandle,
     store: State<'_, Store>,
+    ws_state: State<'_, WsState>,
     server_url: String,
     email: String,
     password: String,
@@ -712,12 +725,14 @@ fn cloud_login(
     let response = sync::login(&server_url, &email, &password, &device_name)?;
 
     let mut settings = load_settings(&app, &store)?;
-    settings.server_url = server_url;
+    settings.server_url = server_url.clone();
-    settings.device_token = Some(response.token);
+    settings.device_token = Some(response.token.clone());
     settings.account_email = Some(response.email.clone());
     settings.account_username = Some(response.username.clone());
     save_settings(&store, &settings)?;
 
+    ws_state.start(app, server_url, response.token);
+
     Ok(Account {
         user_id: response.user_id,
         username: response.username,
@@ -726,7 +741,11 @@ fn cloud_login(
 }
 
 #[tauri::command]
-fn cloud_logout(app: AppHandle, store: State<'_, Store>) -> Result<(), String> {
+fn cloud_logout(
+    app: AppHandle,
+    store: State<'_, Store>,
+    ws_state: State<'_, WsState>,
+) -> Result<(), String> {
     let mut settings = load_settings(&app, &store)?;
     if let Some(token) = &settings.device_token {
         let _ = sync::logout(&settings.server_url, token);
@@ -735,7 +754,31 @@ fn cloud_logout(app: AppHandle, store: State<'_, Store>) -> Result<(), String> {
     settings.device_token = None;
     settings.account_email = None;
     settings.account_username = None;
-    save_settings(&store, &settings)
+    save_settings(&store, &settings)?;
+
+    ws_state.stop(&app);
+
+    Ok(())
+}
+
+#[tauri::command]
+fn cloud_ws_start(app: AppHandle, store: State<'_, Store>, ws_state: State<'_, WsState>) -> Result<(), String> {
+    let settings = load_settings(&app, &store)?;
+    if let Some(token) = settings.device_token {
+        ws_state.start(app, settings.server_url, token);
+    }
+    Ok(())
+}
+
+#[tauri::command]
+fn cloud_ws_stop(app: AppHandle, ws_state: State<'_, WsState>) -> Result<(), String> {
+    ws_state.stop(&app);
+    Ok(())
+}
+
+#[tauri::command]
+fn cloud_ws_status(ws_state: State<'_, WsState>) -> Result<String, String> {
+    Ok(ws_state.status())
 }
 
 #[tauri::command]
@@ -1311,6 +1354,7 @@ pub fn run() {
             Ok(())
         })
         .manage(LspState::default())
+        .manage(WsState::default())
         .on_window_event(|window, event| {
             if matches!(event, tauri::WindowEvent::Destroyed) {
                 if let Some(state) = window.app_handle().try_state::<LspState>() {
@@ -1342,6 +1386,8 @@ pub fn run() {
             thumbnail,
             read_image,
             clear_thumbnails,
+            get_cloud_cache,
+            save_cloud_cache,
             list_assets,
             list_resources,
             list_font_families,
@@ -1357,6 +1403,9 @@ pub fn run() {
             cloud_login,
             cloud_logout,
             cloud_account,
+            cloud_ws_start,
+            cloud_ws_stop,
+            cloud_ws_status,
             cloud_list_projects,
             cloud_list_folders,
             cloud_create_folder,

src-tauri/src/ws.rs

@@ -0,0 +1,156 @@
+use serde::{Deserialize, Serialize};
+use std::net::TcpStream;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::Mutex;
+use std::time::Duration;
+use tauri::{AppHandle, Emitter, Manager};
+use tungstenite::client::IntoClientRequest;
+use tungstenite::stream::MaybeTlsStream;
+use tungstenite::Message;
+
+pub const STATUS_EVENT: &str = "cloud://ws-status";
+pub const SYNC_EVENT: &str = "cloud://sync-event";
+
+const READ_TIMEOUT: Duration = Duration::from_secs(10);
+const RECONNECT_DELAY: Duration = Duration::from_secs(5);
+
+#[derive(Deserialize, Serialize, Clone)]
+pub struct DeviceEvent {
+    pub kind: String,
+    pub project_id: Option<String>,
+    pub document_id: Option<String>,
+}
+
+pub struct WsState {
+    generation: AtomicU64,
+    status: Mutex<String>,
+}
+
+impl Default for WsState {
+    fn default() -> Self {
+        Self {
+            generation: AtomicU64::new(0),
+            status: Mutex::new("offline".to_string()),
+        }
+    }
+}
+
+impl WsState {
+    pub fn status(&self) -> String {
+        self.status
+            .lock()
+            .map(|slot| slot.clone())
+            .unwrap_or_else(|_| "offline".to_string())
+    }
+
+    fn set_status(&self, app: &AppHandle, status: &str) {
+        if let Ok(mut slot) = self.status.lock() {
+            *slot = status.to_string();
+        }
+        let _ = app.emit(STATUS_EVENT, status);
+    }
+
+    pub fn start(&self, app: AppHandle, server_url: String, token: String) {
+        let generation = self.generation.fetch_add(1, Ordering::SeqCst) + 1;
+        self.set_status(&app, "connecting");
+
+        std::thread::spawn(move || run_loop(app, server_url, token, generation));
+    }
+
+    pub fn stop(&self, app: &AppHandle) {
+        self.generation.fetch_add(1, Ordering::SeqCst);
+        self.set_status(app, "offline");
+    }
+}
+
+fn still_current(app: &AppHandle, generation: u64) -> bool {
+    app.state::<WsState>().generation.load(Ordering::SeqCst) == generation
+}
+
+fn ws_url(server_url: &str) -> String {
+    let trimmed = server_url.trim_end_matches('/');
+    if let Some(rest) = trimmed.strip_prefix("https://") {
+        format!("wss://{}/api/desktop/ws", rest)
+    } else if let Some(rest) = trimmed.strip_prefix("http://") {
+        format!("ws://{}/api/desktop/ws", rest)
+    } else {
+        format!("ws://{}/api/desktop/ws", trimmed)
+    }
+}
+
+fn configure_read_timeout(stream: &MaybeTlsStream<TcpStream>) {
+    let tcp = match stream {
+        MaybeTlsStream::Plain(stream) => Some(stream),
+        MaybeTlsStream::NativeTls(stream) => Some(stream.get_ref()),
+        _ => None,
+    };
+
+    if let Some(tcp) = tcp {
+        let _ = tcp.set_read_timeout(Some(READ_TIMEOUT));
+    }
+}
+
+fn is_timeout(error: &tungstenite::Error) -> bool {
+    matches!(
+        error,
+        tungstenite::Error::Io(io_error)
+            if io_error.kind() == std::io::ErrorKind::WouldBlock
+                || io_error.kind() == std::io::ErrorKind::TimedOut
+    )
+}
+
+fn connect_and_listen(app: &AppHandle, url: &str, token: &str, generation: u64) -> Result<(), String> {
+    let mut request = url
+        .into_client_request()
+        .map_err(|e| e.to_string())?;
+    let header_value = format!("Bearer {}", token)
+        .parse()
+        .map_err(|_| "Invalid device token".to_string())?;
+    request.headers_mut().insert("Authorization", header_value);
+
+    let (mut socket, _response) = tungstenite::connect(request).map_err(|e| e.to_string())?;
+    configure_read_timeout(socket.get_ref());
+
+    app.state::<WsState>().set_status(app, "connected");
+
+    loop {
+        if !still_current(app, generation) {
+            let _ = socket.close(None);
+            return Ok(());
+        }
+
+        match socket.read() {
+            Ok(Message::Text(text)) => {
+                if let Ok(event) = serde_json::from_str::<DeviceEvent>(text.as_ref()) {
+                    let _ = app.emit(SYNC_EVENT, event);
+                }
+            }
+            Ok(Message::Ping(_)) => {
+                let _ = socket.flush();
+            }
+            Ok(Message::Close(_)) => return Ok(()),
+            Ok(_) => {}
+            Err(ref error) if is_timeout(error) => continue,
+            Err(error) => return Err(error.to_string()),
+        }
+    }
+}
+
+fn run_loop(app: AppHandle, server_url: String, token: String, generation: u64) {
+    let url = ws_url(&server_url);
+
+    loop {
+        if !still_current(&app, generation) {
+            return;
+        }
+
+        let _ = connect_and_listen(&app, &url, &token, generation);
+
+        if !still_current(&app, generation) {
+            return;
+        }
+
+        app.state::<WsState>().set_status(&app, "offline");
+        std::thread::sleep(RECONNECT_DELAY);
+    }
+}

src/lib/components/FileViewer.svelte

@@ -947,6 +947,13 @@
           {/if}
         </div>
 
+        {#if app.cloudOffline}
+          <div class="mb-3 flex items-center gap-2 rounded-lg border border-[var(--color-line)] bg-[var(--color-surface-muted)] px-3 py-2 text-xs text-[var(--color-ink-muted)]">
+            <Icon icon="ph:wifi-slash" class="text-base" />
+            Offline — showing last synced data
+          </div>
+        {/if}
+
         {#if cloudTrail.length > 0}
           <div class="mb-3 flex flex-wrap items-center gap-1 text-xs">
             <button

src/lib/components/SettingsModal.svelte

@@ -454,8 +454,9 @@
               {/each}
             </select>
             <span class="text-[var(--color-ink-muted)]">
-              Pulls and pushes cloud-linked projects on a timer. Conflicts pause
+              Pulls and pushes cloud-linked projects on a timer. Used as a
-              syncing until they are resolved.
+              fallback when live sync (websocket) is unavailable. Conflicts
+              pause syncing until they are resolved.
             </span>
           </div>
         </div>

src/lib/ts/api.ts

@@ -277,6 +277,24 @@ export const cloudLogout = () => invoke<void>("cloud_logout");
 
 export const cloudAccount = () => invoke<Account | null>("cloud_account");
 
+export const cloudWsStart = () => invoke<void>("cloud_ws_start");
+
+export const cloudWsStop = () => invoke<void>("cloud_ws_stop");
+
+export const cloudWsStatus = () => invoke<string>("cloud_ws_status");
+
+export interface DeviceEvent {
+  kind: "project" | "document" | "structure";
+  project_id: string | null;
+  document_id: string | null;
+}
+
+export const getCloudCache = (key: string) =>
+  invoke<string | null>("get_cloud_cache", { key });
+
+export const saveCloudCache = (key: string, payload: string) =>
+  invoke<void>("save_cloud_cache", { key, payload });
+
 export const cloudListProjects = () =>
   invoke<ProjectSummary[]>("cloud_list_projects");
 

src/lib/ts/state.svelte.ts

@@ -1,3 +1,4 @@
+import { listen } from "@tauri-apps/api/event";
 import * as api from "./api";
 import type {
   Account,
@@ -7,6 +8,7 @@ import type {
   CloudFolder,
   CompileResult,
   Conflict,
+  DeviceEvent,
   Diagnostic,
   DocumentLink,
   LinkedDocument,
@@ -47,6 +49,8 @@ interface AppState {
   cloudDocuments: CloudDocument[];
   cloudFiles: CloudFile[];
   cloudLoading: boolean;
+  cloudOffline: boolean;
+  wsStatus: string;
   linkedDocuments: LinkedDocument[];
   linkedProjects: LinkedProject[];
   documentLink: DocumentLink | null;
@@ -89,6 +93,8 @@ export const app = $state<AppState>({
   cloudDocuments: [],
   cloudFiles: [],
   cloudLoading: false,
+  cloudOffline: false,
+  wsStatus: "offline",
   linkedDocuments: [],
   linkedProjects: [],
   documentLink: null,
@@ -340,6 +346,10 @@ export async function bootstrap() {
   try {
     app.settings = await api.getSettings();
     restartAutoSync();
+    await initWsSync();
+    if (app.settings?.device_token) {
+      api.cloudWsStart().catch(() => {});
+    }
     await browseTo("");
     await refreshAccount();
   } catch (error) {
@@ -347,6 +357,37 @@ export async function bootstrap() {
   }
 }
 
+async function initWsSync() {
+  await listen<string>("cloud://ws-status", (event) => {
+    app.wsStatus = event.payload;
+  });
+
+  await listen<DeviceEvent>("cloud://sync-event", (event) => {
+    handleDeviceEvent(event.payload);
+  });
+
+  app.wsStatus = await api.cloudWsStatus().catch(() => "offline");
+}
+
+function handleDeviceEvent(event: DeviceEvent) {
+  const linkedProject = app.target?.cloud_project_id;
+  const linkedDocument = app.documentLink?.document_id;
+
+  const matchesOpenTarget =
+    (event.kind === "project" &&
+      event.project_id &&
+      event.project_id === linkedProject) ||
+    (event.kind === "document" &&
+      event.document_id &&
+      event.document_id === linkedDocument);
+
+  if (matchesOpenTarget) {
+    autoSync();
+  } else if (app.scope === "cloud") {
+    refreshCloud();
+  }
+}
+
 export async function browseTo(path: string) {
   try {
     app.entries = await api.browseWorkspace(path);
@@ -382,20 +423,52 @@ export async function refreshCloudProjects() {
   }
 }
 
+interface CloudSnapshot {
+  folders: CloudFolder[];
+  documents: CloudDocument[];
+  projects: ProjectSummary[];
+  files: CloudFile[];
+}
+
+function cloudCacheKey() {
+  return `cloud:${app.cloudFolder ?? "root"}`;
+}
+
+function applyCloudSnapshot(snapshot: CloudSnapshot) {
+  if (app.cloudFolder === "shared") {
+    app.cloudDocuments = snapshot.documents;
+    app.cloudProjects = snapshot.projects;
+    app.cloudFolders = [];
+    app.cloudFiles = [];
+  } else {
+    app.cloudFolderTree = snapshot.folders;
+    app.cloudFolders = snapshot.folders.filter(
+      (folder) => (folder.parent_id ?? null) === app.cloudFolder,
+    );
+    app.cloudDocuments = snapshot.documents;
+    app.cloudProjects = snapshot.projects.filter(
+      (project) =>
+        project.role !== "owner" ||
+        (project.folder_id ?? null) === app.cloudFolder,
+    );
+    app.cloudFiles = snapshot.files;
+  }
+}
+
 export async function refreshCloud() {
   if (!app.account) return;
 
   app.cloudLoading = true;
+  const cacheKey = cloudCacheKey();
+
   try {
     app.linkedDocuments = await api.cloudLinkedDocuments().catch(() => []);
     app.linkedProjects = await api.cloudLinkedProjects().catch(() => []);
 
+    let snapshot: CloudSnapshot;
     if (app.cloudFolder === "shared") {
       const shared = await api.cloudListShared();
-      app.cloudDocuments = shared.documents;
+      snapshot = { folders: [], documents: shared.documents, projects: shared.projects, files: [] };
-      app.cloudProjects = shared.projects;
-      app.cloudFolders = [];
-      app.cloudFiles = [];
     } else {
       const [folders, documents, projects, files] = await Promise.all([
         api.cloudListFolders(),
@@ -403,20 +476,20 @@ export async function refreshCloud() {
         api.cloudListProjects(),
         api.cloudListFiles(app.cloudFolder),
       ]);
-      app.cloudFolderTree = folders;
+      snapshot = { folders, documents, projects, files };
-      app.cloudFolders = folders.filter(
-        (folder) => (folder.parent_id ?? null) === app.cloudFolder,
-      );
-      app.cloudDocuments = documents;
-      app.cloudProjects = projects.filter(
-        (project) =>
-          project.role !== "owner" ||
-          (project.folder_id ?? null) === app.cloudFolder,
-      );
-      app.cloudFiles = files;
     }
+
+    applyCloudSnapshot(snapshot);
+    app.cloudOffline = false;
+    api.saveCloudCache(cacheKey, JSON.stringify(snapshot)).catch(() => {});
   } catch (error) {
-    setError(error);
+    const cached = await api.getCloudCache(cacheKey).catch(() => null);
+    if (cached) {
+      applyCloudSnapshot(JSON.parse(cached));
+      app.cloudOffline = true;
+    } else {
+      setError(error);
+    }
   } finally {
     app.cloudLoading = false;
   }
@@ -668,7 +741,7 @@ export function restartAutoSync() {
   if (seconds <= 0) return;
 
   syncTimer = setInterval(() => {
-    autoSync();
+    if (app.wsStatus !== "connected") autoSync();
   }, seconds * 1000);
 }
 

src/routes/+page.svelte

@@ -512,6 +512,12 @@
     on: "LSP ready",
     unavailable: "LSP unavailable",
   };
+
+  const wsLabel: Record<string, string> = {
+    connected: "Live sync",
+    connecting: "Connecting…",
+    offline: "Offline (polling)",
+  };
 </script>
 
 <svelte:window on:keydown={handleKeydown} />
@@ -588,6 +594,23 @@
         {lspLabel[app.lspStatus]}
       </span>
 
+      {#if app.account}
+        <span
+          class="flex items-center gap-1 text-[10px] text-[var(--color-ink-muted)]"
+          title="Cloud sync connection"
+        >
+          <span
+            class="h-1.5 w-1.5 rounded-full
+              {app.wsStatus === 'connected'
+              ? 'bg-[var(--color-success)]'
+              : app.wsStatus === 'connecting'
+                ? 'bg-[var(--color-accent)]'
+                : 'bg-[var(--color-ink-muted)]'}"
+          ></span>
+          {wsLabel[app.wsStatus] ?? "Offline (polling)"}
+        </span>
+      {/if}
+
       <button
         class="flex items-center gap-1.5 rounded-md px-2.5 py-1.5 text-xs text-[var(--color-ink-muted)] transition hover:bg-[var(--color-surface-muted)] hover:text-[var(--color-ink)]"
         onclick={saveAndCompile}