diff options
Diffstat (limited to 'packages/meshbay-hub/src')
3 files changed, 239 insertions, 2 deletions
diff --git a/packages/meshbay-hub/src/meshbay_hub/api/webapp.py b/packages/meshbay-hub/src/meshbay_hub/api/webapp.py index 6ac5cdb..3e23961 100644 --- a/packages/meshbay-hub/src/meshbay_hub/api/webapp.py +++ b/packages/meshbay-hub/src/meshbay_hub/api/webapp.py @@ -180,6 +180,10 @@ _HTML = """\ and app.js's own relative imports inherit the prefix, which is the only way the module graph is guaranteed not to be a mixture of two builds. See _asset_version() and VersionedStatics. --> + <!-- First, and not a module: if the graph below never links, no module code + runs at all, and this is what keeps the page from being silently blank. + It draws nothing unless #app is still empty ten seconds from now. --> + <script src="/a/{v}/boot-guard.js"></script> <!-- Argon2id (WebAssembly, inlined) — WebCrypto has no memory-hard KDF, and the keypair bundle needs one: it is protected by the passphrase alone and sits on every node its owner joins (C4). Vendored, see static/vendor/PROVENANCE.md --> diff --git a/packages/meshbay-hub/src/meshbay_hub/static/boot-guard.js b/packages/meshbay-hub/src/meshbay_hub/static/boot-guard.js new file mode 100644 index 0000000..f5e3aa1 --- /dev/null +++ b/packages/meshbay-hub/src/meshbay_hub/static/boot-guard.js @@ -0,0 +1,200 @@ +/** + * The page can never stay silently blank. + * + * A reader once had nothing but white for an evening: the shell arrived, the + * modules were served from the browser's own store so not one request reached + * the hub, and nothing ever rendered. No message, no error on screen, nothing + * in the server's log to look at — the same account worked in a private window + * and in another browser, which is the signature of something wrong in this + * origin's stored state rather than in what was deployed. Clearing the site's + * data fixed it. Clearing the *cache*, three times, had not: a service worker + * and IndexedDB are not the cache, and nothing on screen said so. + * + * This answers the *silence*, not whatever caused it. A blank page is a bug + * report nobody can write, and a phone has no console to open. + * + * **A classic script, deliberately, and first.** The failure it guards against + * includes the module graph never linking — one bad module and no module code + * runs at all, so a guard inside `app.js` would be part of what failed. This + * one has no imports and cannot be stopped by them. + * + * It does nothing when the application mounts, which is the ordinary case: it + * looks once, late, and speaks only to a reader already staring at nothing. + */ +(function () { + 'use strict'; + + // Long enough that a cold phone on a slow network is never interrupted — + // argon2's wasm, forty modules and a catalogue — and short enough that + // nobody sits in front of white wondering. The app mounts in well under two + // seconds when it mounts at all. + var GIVE_UP_MS = 10000; + var problems = []; + + function note(what) { + if (problems.length < 5) problems.push(String(what).slice(0, 200)); + } + + // Capture phase: a `<script>` or stylesheet that fails to load fires `error` + // at the element, and that one does not bubble. + window.addEventListener('error', function (e) { + if (e && e.target && e.target !== window && e.target.src) { + note('could not load ' + String(e.target.src).replace(/^https?:\/\/[^/]+/, '')); + } else if (e && e.message) { + note(e.message); + } + }, true); + + window.addEventListener('unhandledrejection', function (e) { + var r = e && e.reason; + note((r && (r.message || r)) || 'a promise rejected'); + }); + + var FR = (navigator.language || '').toLowerCase().indexOf('fr') === 0; + var TEXT = FR ? { + title: 'MeshBay n’a pas pu démarrer', + body: 'L’application s’est arrêtée avant d’afficher quoi que ce soit. ' + + 'Cela vient presque toujours des données que ce navigateur garde pour ce site.', + retry: 'Réessayer', + reset: 'Réinitialiser les données de ce site', + warn: 'Vous devrez vous reconnecter. Vos fichiers et vos groupes ne sont pas ' + + 'touchés : ils vivent sur les nœuds, pas ici.', + doing: 'Réinitialisation…', + blocked: 'Un autre onglet de ce site garde la base ouverte. Fermez les autres ' + + 'onglets meshbay, puis réessayez.', + } : { + title: 'MeshBay could not start', + body: 'The application stopped before it drew anything. This is almost always ' + + 'the data this browser keeps for this site.', + retry: 'Try again', + reset: 'Reset this site’s data', + warn: 'You will have to sign in again. Your files and groups are untouched: ' + + 'they live on the nodes, not here.', + doing: 'Resetting…', + blocked: 'Another tab of this site is holding the database open. Close the ' + + 'other meshbay tabs, then try again.', + }; + + /** + * Deleting a database waits for every connection to it to close, and another + * tab of this site is a connection. Unwatched, `deleteDatabase` then does + * nothing at all and says nothing — so this page would reload into the state + * it had just promised to clear, which is the bug this file exists to end. + * Blocked deletions are named and handed back. + */ + function dropDatabase(name) { + return new Promise(function (res) { + var req; + try { req = indexedDB.deleteDatabase(name); } catch (e) { return res(null); } + var settled = false; + var end = function (v) { if (!settled) { settled = true; res(v); } }; + req.onsuccess = function () { end(null); }; + req.onerror = function () { end(null); }; + req.onblocked = function () { end(name); }; + setTimeout(function () { end(name); }, 2500); + return undefined; + }); + } + + /** Everything this origin holds, and the service worker with it. */ + function resetSiteData(done) { + var waiting = []; + var blocked = []; + try { localStorage.clear(); } catch (e) { /* private mode */ } + try { sessionStorage.clear(); } catch (e) { /* private mode */ } + + if (window.indexedDB) { + var names = indexedDB.databases + ? indexedDB.databases().then(function (dbs) { + return (dbs || []).map(function (d) { return d && d.name; }).filter(Boolean); + }).catch(function () { return ['meshbay', 'meshbay_keys']; }) + // Safari and older engines have no `databases()`; these are ours. + : Promise.resolve(['meshbay', 'meshbay_keys']); + waiting.push(names.then(function (list) { + return Promise.all(list.map(dropDatabase)).then(function (results) { + results.forEach(function (n) { if (n) blocked.push(n); }); + }); + }).catch(function () {})); + } + + if (window.caches && caches.keys) { + waiting.push(caches.keys().then(function (keys) { + return Promise.all((keys || []).map(function (k) { return caches.delete(k); })); + }).catch(function () {})); + } + + if (navigator.serviceWorker && navigator.serviceWorker.getRegistrations) { + waiting.push(navigator.serviceWorker.getRegistrations().then(function (regs) { + return Promise.all((regs || []).map(function (r) { return r.unregister(); })); + }).catch(function () {})); + } + + // Bounded: a hung unregister must not leave the reader on "Resetting…" for + // ever, which would be this bug wearing a different hat. + var fired = false; + var finish = function () { if (!fired) { fired = true; done(blocked); } }; + Promise.all(waiting).then(finish).catch(finish); + setTimeout(finish, 4000); + } + + function el(tag, style, text) { + var n = document.createElement(tag); + if (style) n.setAttribute('style', style); + if (text) n.textContent = text; + return n; + } + + function show(root) { + var BTN = 'display:block;width:100%;margin:8px 0;padding:12px 16px;font:inherit;' + + 'font-size:15px;border-radius:8px;border:1px solid #c9ccd1;background:#fff;' + + 'color:#111;cursor:pointer'; + var box = el('div', 'max-width:34em;margin:12vh auto;padding:0 20px;' + + 'font:15px/1.55 system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:#111'); + + box.appendChild(el('h1', 'font-size:20px;margin:0 0 12px', TEXT.title)); + box.appendChild(el('p', 'margin:0 0 16px;color:#444', TEXT.body)); + + var retry = el('button', BTN, TEXT.retry); + retry.addEventListener('click', function () { location.reload(); }); + box.appendChild(retry); + + var reset = el('button', BTN + ';border-color:#b23;color:#b23', TEXT.reset); + reset.addEventListener('click', function () { + reset.disabled = true; + reset.textContent = TEXT.doing; + resetSiteData(function (blocked) { + if (!blocked.length) { location.reload(); return; } + // Reloading here would be a lie: the database is still there, held by + // another tab, and the page would come back exactly as broken. + reset.disabled = false; + reset.textContent = TEXT.reset; + var why = el('p', 'margin:12px 0 0;color:#b23;font-size:13px', + TEXT.blocked + ' (' + blocked.join(', ') + ')'); + why.setAttribute('data-blocked', blocked.join(',')); + box.appendChild(why); + }); + }); + box.appendChild(reset); + + box.appendChild(el('p', 'margin:12px 0 0;color:#666;font-size:13px', TEXT.warn)); + + if (problems.length) { + // Verbatim, and on screen. Nothing else reaches a reader who cannot open + // a console, and it is the first thing anybody diagnosing this will ask. + var pre = el('pre', 'margin:16px 0 0;padding:10px;background:#f3f4f6;' + + 'border-radius:6px;font-size:12px;white-space:pre-wrap;word-break:break-word;' + + 'color:#333', problems.join('\n')); + box.appendChild(pre); + } + + root.appendChild(box); + } + + setTimeout(function () { + var root = document.getElementById('app'); + // Mounted, which is the ordinary case and the end of this script's + // involvement. A later render replaces whatever is here anyway. + if (!root || root.firstChild) return; + show(root); + }, GIVE_UP_MS); +}()); diff --git a/packages/meshbay-hub/src/meshbay_hub/static/hub-client.js b/packages/meshbay-hub/src/meshbay_hub/static/hub-client.js index dbd5037..eead457 100644 --- a/packages/meshbay-hub/src/meshbay_hub/static/hub-client.js +++ b/packages/meshbay-hub/src/meshbay_hub/static/hub-client.js @@ -18,6 +18,7 @@ const IDB_NAME = 'meshbay'; // disagreeing about the version is a `VersionError` thrown at whichever of // them happens to run second. const IDB_VERSION = 2; +const OPEN_DB_TIMEOUT_MS = 5000; const IDB_STORE = 'group_indexes'; const IDB_PLAYLISTS = 'playlists'; @@ -27,9 +28,32 @@ function navigate(path) { // ── IndexedDB cache ───────────────────────────────────────────────────────── +/** + * The database, opened — or refused, but never left hanging. + * + * A version upgrade waits for every other connection to this database to + * close. A second tab of this site holding version 1 open is enough to stop + * it, and `indexedDB.open` then fires **neither** `success` nor `error`: it + * fires `blocked`, and if nothing handles that the promise never settles. Every + * `await openDB()` behind it waits for ever, which reads as a feature that + * silently does nothing rather than as a failure anybody can see. + * + * So `blocked` is heard, and a deadline covers the rest. Callers already treat + * a rejection as "no local cache this time" and carry on. + */ function openDB() { return new Promise((resolve, reject) => { const req = indexedDB.open(IDB_NAME, IDB_VERSION); + let settled = false; + const done = (fn, arg) => { if (!settled) { settled = true; fn(arg); } }; + // Generous: the other tab is asked to close and usually does within a + // frame. This is the backstop for the one that cannot — a page suspended + // on a phone, say — not a latency budget. + const deadline = setTimeout(() => done(reject, new Error( + 'IndexedDB open timed out (another tab may hold an older version open)')), + OPEN_DB_TIMEOUT_MS); + req.onblocked = () => done(reject, new Error( + 'IndexedDB upgrade blocked by another tab of this site')); req.onupgradeneeded = () => { const db = req.result; if (!db.objectStoreNames.contains(IDB_STORE)) { @@ -43,8 +67,17 @@ function openDB() { db.createObjectStore(IDB_PLAYLISTS); } }; - req.onsuccess = () => resolve(req.result); - req.onerror = () => reject(req.error); + req.onsuccess = () => { + clearTimeout(deadline); + // Giving up does not cancel the request: the other tab eventually closes, + // the upgrade goes through, and this fires with a live connection nobody + // is waiting for. Left open it squats the database — blocking the next + // upgrade *and* any attempt to delete it, which is the failure this + // whole guard exists to end, arriving through the back door. + if (settled) { try { req.result.close(); } catch { /* already gone */ } return; } + done(resolve, req.result); + }; + req.onerror = () => { clearTimeout(deadline); done(reject, req.error); }; }); } |