v3: fix the privacy and security findings of the comment pass — private dumps' broadcasts, mentions and attachments reached people who can't see them, and a few smaller holes. A dump's every write now goes through ws-service's broadcastDumpChange(before, after), which decides the audience: a private dump's creation, edits and deletion reach its owner's sockets alone (its deletion id went to everyone before), going private is dump_deleted for everyone else and dump_updated for the owner (whose other tabs dropped it), going public dump_created for everyone else. Mentions in a private dump, a comment on one, or a private playlist's description notify no one until it goes public (mentions are deduplicated per context, so going public notifies them once), and a moderator's edit of a comment, chat message or playlist mentions in the author's name. A link preview of a private playlist is refused, as one of a private dump already was: the preview is stored in the linking dump, which others may see. Attachments record the type of the resource that links them (migration 0018 backfills it); one linked by a private dump or playlist, or a comment on a private dump, is served only with its owner's media token, which Markdown now adds to attachment URLs, and one whose resource is gone answers 404 and is purged at startup. The Bandcamp provider claimed bandcamp.com.evil.example (the pattern wasn't anchored) and now reuses bandcamp-tralbum's anchored one; the YouTube provider took any site's ?list= for a YouTube playlist and missed m., music., youtube-nocookie and /live/ links, and now shares canonical-url's rules. Sign-in does the same scrypt work for an unknown username as for a wrong password, so timing no longer tells which exist. Usernames and emails are unique regardless of case (migration 0017, which refuses to run over existing clashes and names them): "Bob" and "bob" could both sign up and a mention picked one, emails had no constraint, and a reset request in another case silently sent nothing. The Open Graph tags escape the site name and build their URLs on PUBLIC_URL and FRONTEND_URL instead of the request's origin, which a proxy may rewrite.

Error statuses follow one rule: APIException takes a status and derives the code from it (BAD_REQUEST 400, UNAUTHORIZED 401, FORBIDDEN 403, NOT_FOUND 404, CONFLICT 409, RATE_LIMITED 429, SERVER_ERROR 500, BAD_GATEWAY 502), so a code can't contradict its status. That fixed real bugs: a wrong current password on change-password answered 401, on which authFetch signs the user out; editing or deleting someone else's comment or chat message answered 401 rather than 403; one invalid dump edit answered 422. A taken username is 409, like a taken email.

Along the way: the database is created from schema.sql by connection.ts when the file doesn't exist, so every task works on a fresh checkout (dev and serve never ran db/init.ts, which is gone); the startup purge compared ISO dates with SQLite's datetime() as text and kept anything from the current UTC day, and now compares ISO cutoffs; the seeded admin's hash comes from lib/password.ts (split out of jwt.ts, which needs the JWT secret) rather than a copy of its format; avatar, thumbnail and playlist-cover uploads go through replaceUploadedFile, which writes beside the old file and renames over it before the record announces it (a failed avatar write lost the old avatar; a thumbnail was announced before it existed); upload.ts derives its size message from MAX_IMAGE_SIZE_BYTES and stops re-exporting the upload folders; ALLOWED_IMAGE_MIMES, which duplicated detectImageMime, is gone; the SPA fallback no longer calls next() after answering; a reply must answer a comment on the same dump (a foreign or unknown parent was a 500 or a cross-dump thread). 211 backend and 628 frontend tests pass.

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

api/db/migrations/0017_case_insensitive_users.ts

@@ -0,0 +1,36 @@
+/**
+ * Makes usernames and emails unique regardless of case. Usernames were unique
+ * only as typed, so "Bob" and "bob" could both sign up, and a mention, which
+ * looks names up in lower case, then reached one of them at random. Emails
+ * had no constraint at all: two sign-ups racing past the service's check could
+ * share an address, and password resets are looked up by address.
+ *
+ * @module
+ */
+
+import type { DatabaseSync } from "node:sqlite";
+
+/**
+ * Run once by `runMigrations`. It refuses to run, naming the clashes, when two
+ * accounts already share a name or an address in some case: which one keeps
+ * it is for whoever runs the site to decide, by editing one of them.
+ */
+export function up(db: DatabaseSync): void {
+  for (const column of ["username", "email"]) {
+    const clashes = db.prepare(
+      `SELECT lower(${column}) AS value FROM users GROUP BY lower(${column}) HAVING COUNT(*) > 1;`,
+    ).all() as { value: string }[];
+    if (clashes.length > 0) {
+      throw new Error(
+        `Several accounts share a ${column} in different cases: ${
+          clashes.map((c) => c.value).join(", ")
+        }. Change all but one of each, then restart.`,
+      );
+    }
+  }
+  db.exec(`
+    DROP INDEX IF EXISTS idx_users_username_lower;
+    CREATE UNIQUE INDEX IF NOT EXISTS idx_users_username_lower ON users(lower(username));
+    CREATE UNIQUE INDEX IF NOT EXISTS idx_users_email_lower    ON users(lower(email));
+  `);
+}

api/db/migrations/0018_attachment_resource_type.ts

@@ -0,0 +1,34 @@
+/**
+ * Adds `attachments.resource_type`, the kind of thing an attachment's
+ * `resource_id` names. Without it, an attachment couldn't tell whose it was:
+ * one pasted into a private dump was served to anyone with its URL, and one
+ * whose dump, comment or message was deleted was kept for good.
+ *
+ * @module
+ */
+
+import type { DatabaseSync } from "node:sqlite";
+
+/**
+ * Run once by `runMigrations`. Existing bound attachments get the type of the
+ * table that holds their resource; one whose resource is gone gets none, and
+ * the startup purge deletes it. A database made from schema.sql already has
+ * the column.
+ */
+export function up(db: DatabaseSync): void {
+  const cols = db.prepare(`PRAGMA table_info(attachments);`).all() as {
+    name: string;
+  }[];
+  if (cols.some((c) => c.name === "resource_type")) return;
+  db.exec(`
+    ALTER TABLE attachments ADD COLUMN resource_type TEXT;
+    UPDATE attachments SET resource_type = CASE
+      WHEN resource_id IN (SELECT id FROM dumps)         THEN 'dump'
+      WHEN resource_id IN (SELECT id FROM comments)      THEN 'comment'
+      WHEN resource_id IN (SELECT id FROM playlists)     THEN 'playlist'
+      WHEN resource_id IN (SELECT id FROM chat_messages) THEN 'chat'
+      WHEN resource_id IN (SELECT id FROM users)         THEN 'user'
+    END
+    WHERE resource_id IS NOT NULL;
+  `);
+}