v3: a performance pass over both halves — indexed queries, streamed files, cached previews, and feeds that stop re-rendering on every tick — a review turned up whole-file reads, unindexed scans and render storms; each fix comes with a test. Database: migration 0016 adds the indexes the hot queries lacked — dumps by created_at, (user_id, created_at) and slug, votes by (user_id, created_at), playlists by slug, users by lower(username) for @mentions, and the child side of every cascading foreign key (comment replies, a user's comments, follows both ways, chat messages, invites, reset tokens); the feeds, dump and playlist pages, upvotes and follower fan-out all plan as index searches now, with no temp-table sort. SQLite runs in WAL with synchronous=NORMAL and a busy timeout, and a transaction() helper wraps the multi-row writes (a dump and its categories, category sets, backlinks, attachment links, playlist reorders, follower notifications) so they commit once instead of once a row. Lists no longer run a COUNT(*) per page: they fetch limit + 1 rows and hasMore comes from the extra one; total stays only on search, the one place it's shown. Files: /api/files read the whole upload (up to 50 MB) for every range request a player makes while seeking; api/lib/serve-file.ts streams the requested bytes from disk, with an ETag and 304s, and serves avatars, attachments, covers and thumbnails too. File and thumbnail URLs carry the file's version (size and last change), so the current one is cached for a year and anything else revalidates — a same-size replacement used to stay stale, and a video's still was cached immutable forever under a URL that never changed. Feeds showed image dumps at full size: /api/thumbnails now makes a 960px preview with ffmpeg (GIFs and unreadable images go out as they are), one run per output however many cards ask at once, and ffmpeg is probed once per process instead of spawned per request. Uploads stream to disk; replacing a file writes beside it and renames over, a hard link keeping the old one for rollback instead of holding both in memory; generated stills and previews go when the file is replaced or the dump deleted, and a custom thumbnail with its dump. Outbound: fetchWithTimeout's deadline now covers the body — a server that answered at once and then dripped could hold a create open indefinitely — and pages are read to 4 MB at most; metadata is cached five minutes so the create form's preview and the post that follows share one fetch (refresh-metadata still goes to the page); proxied images sit in a 32 MB LRU. Broadcasts serialize once rather than per socket, and index.html is kept in memory until the file changes. Frontend: currentTime lived in PlayerContext, so every card re-rendered — and re-parsed its Markdown — four times a second while anything played; the playhead has its own PlayerTimeContext now. The socket context is split three ways (feed, chat via useWSChat, presence via useWSPresence), so typing, presence and chat messages leave the feeds alone. DumpCard, JournalCard and Markdown are memoized; card images use the server preview and load lazily; the feed cache is written when the page is left rather than after every pause in scrolling; the theme context value is memoized.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/services/rich-content-service.ts

@@ -70,6 +70,8 @@ async function fetchViaCurl(
         `${url.hostname.replace(/^\[(.*)\]$/, "$1")}:${port}:${pinned}`,
         "--max-time",
         String(Math.ceil(timeoutMs / 1000)),
+        "--max-filesize",
+        String(2 * MAX_PAGE_BYTES),
         "--user-agent",
         FETCH_HEADERS["User-Agent"],
         "--header",
@@ -118,7 +120,78 @@ async function fetchViaCurl(
   }
 }
 
-/** One request, no redirects followed. */
+/**
+ * Most bytes of a fetched page that are read. Metadata lives in the <head>,
+ * and a "page" past this is a download, not something to scrape.
+ */
+export const MAX_PAGE_BYTES = 4 * 1024 * 1024;
+
+/**
+ * Hands `body` on, and clears the request's deadline once it has been read to
+ * the end or cancelled. Until then the deadline still applies: a server that
+ * answers at once and then drips its body can't hold the request open.
+ */
+function withDeadline(
+  body: ReadableStream<Uint8Array>,
+  timer: ReturnType<typeof setTimeout>,
+): ReadableStream<Uint8Array> {
+  const reader = body.getReader();
+  return new ReadableStream({
+    async pull(controller) {
+      try {
+        const { done, value } = await reader.read();
+        if (done) {
+          clearTimeout(timer);
+          controller.close();
+        } else {
+          controller.enqueue(value);
+        }
+      } catch (err) {
+        clearTimeout(timer);
+        controller.error(err);
+      }
+    },
+    cancel(reason) {
+      clearTimeout(timer);
+      return reader.cancel(reason);
+    },
+  });
+}
+
+/**
+ * Reads a response's body as text, stopping at `maxBytes` (the rest is
+ * cancelled, never downloaded).
+ */
+export async function readTextCapped(
+  res: Response,
+  maxBytes = MAX_PAGE_BYTES,
+): Promise<string> {
+  if (!res.body) return "";
+  const reader = res.body.getReader();
+  const chunks: Uint8Array[] = [];
+  let size = 0;
+  try {
+    while (size < maxBytes) {
+      const { done, value } = await reader.read();
+      if (done) break;
+      chunks.push(value);
+      size += value.byteLength;
+    }
+  } finally {
+    await reader.cancel().catch(() => {});
+  }
+  const bytes = new Uint8Array(Math.min(size, maxBytes));
+  let offset = 0;
+  for (const chunk of chunks) {
+    const part = chunk.subarray(0, bytes.byteLength - offset);
+    bytes.set(part, offset);
+    offset += part.byteLength;
+    if (offset >= bytes.byteLength) break;
+  }
+  return new TextDecoder().decode(bytes);
+}
+
+/** One request, no redirects followed. The timeout covers the body too. */
 async function fetchOnce(
   url: URL,
   address: string,
@@ -126,13 +199,15 @@ async function fetchOnce(
 ): Promise<Response> {
   const controller = new AbortController();
   const timer = setTimeout(() => controller.abort(), timeoutMs);
+  let res: Response;
   try {
-    return await fetch(url, {
+    res = await fetch(url, {
       signal: controller.signal,
       headers: FETCH_HEADERS,
       redirect: "manual",
     });
   } catch (err) {
+    clearTimeout(timer);
     if (!(err instanceof TypeError && err.message.includes("certificate"))) {
       throw err;
     }
@@ -145,9 +220,16 @@ async function fetchOnce(
     if (curlRes) return curlRes;
 
     throw err;
-  } finally {
-    clearTimeout(timer);
   }
+  if (!res.body) {
+    clearTimeout(timer);
+    return res;
+  }
+  return new Response(withDeadline(res.body, timer), {
+    status: res.status,
+    statusText: res.statusText,
+    headers: res.headers,
+  });
 }
 
 /**
@@ -606,7 +688,45 @@ export interface FetchRichContentResult {
  * On failure it still yields a minimal stub so a *new* dump has something
  * displayable, but `ok: false` lets callers with existing metadata keep it.
  */
-export async function tryFetchRichContent(
+// Metadata fetched in the last few minutes, by URL. The create form previews a
+// link and then posts it; without this the page was fetched twice, and the
+// second fetch was the slow part of posting. Only successes are kept, and a
+// metadata refresh (`fresh`) always goes to the page.
+const RECENT_TTL_MS = 5 * 60 * 1000;
+const RECENT_MAX = 200;
+const recent = new Map<
+  string,
+  { at: number; result: Promise<FetchRichContentResult> }
+>();
+
+/** Forget every cached result (tests). */
+export function clearRichContentCache(): void {
+  recent.clear();
+}
+
+export function tryFetchRichContent(
+  url: string,
+  { fresh = false }: { fresh?: boolean } = {},
+): Promise<FetchRichContentResult> {
+  const hit = recent.get(url);
+  if (!fresh && hit && Date.now() - hit.at < RECENT_TTL_MS) return hit.result;
+  recent.delete(url);
+
+  // Stored while in flight too, so a preview and a post racing share a fetch.
+  const result = fetchRichContentUncached(url);
+  if (recent.size >= RECENT_MAX) {
+    const oldest = recent.keys().next().value;
+    if (oldest !== undefined) recent.delete(oldest);
+  }
+  const entry = { at: Date.now(), result };
+  recent.set(url, entry);
+  result.then(({ ok }) => {
+    if (!ok && recent.get(url) === entry) recent.delete(url);
+  });
+  return result;
+}
+
+async function fetchRichContentUncached(
   url: string,
 ): Promise<FetchRichContentResult> {
   try {