feat(comments) : filter abusive language and prevent spam

README.md

@@ -208,6 +208,16 @@ selected guide (or all guides) read for that admin. Hiding a root also hides its
 are recorded in the activity log. Comment reads and legacy attachment redirects
 are not cached; guide content caches are independent of discussions.
 
+Comment writes (including replies and edits) are limited per account across all
+guides to one every 5 seconds, 5 per minute, and 30 per hour using shared Redis.
+New text comments cannot repeat the same normalized text within 5 minutes;
+failed uploads or saves release that duplicate reservation. Edits and image-only
+comments still use the write limits. Before uploading images or saving, the server
+rejects a focused Thai/English abusive-term list, common English spelling
+obfuscations, more than 3 links, 20 identical consecutive characters, and a word
+or short phrase repeated 8 times. The rules live in `lib/comments/moderation.ts`;
+they are heuristic text filters, not image moderation or an automated review queue.
+
 The comment migration must run before deploying these pages. For PostgreSQL
 integration verification, point `DATABASE_INTEGRATION_URL` at a migrated test or
 development database and run `bun run test tests/comments.integration.test.ts`.

components/comments/client.ts

@@ -1,6 +1,9 @@
 export const COMMENT_ERRORS: Record<string, string> = {
   "sign-in-required": "กรุณาเข้าสู่ระบบเพื่อแสดงความคิดเห็น",
   "too-many-requests": "ทำรายการบ่อยเกินไป กรุณารอสักครู่แล้วลองใหม่",
+  "comment-abusive-language": "ความคิดเห็นมีคำหยาบหรือคำดูหมิ่น กรุณาแก้ไขข้อความก่อนส่ง",
+  "comment-spam": "ความคิดเห็นมีลิงก์หรือข้อความซ้ำมากเกินไป กรุณาแก้ไขข้อความก่อนส่ง",
+  "comment-duplicate": "คุณส่งข้อความนี้แล้ว กรุณารอ 5 นาทีก่อนส่งข้อความเดิมอีกครั้ง",
   "uploads-busy": "ระบบอัปโหลดกำลังใช้งานมาก กรุณาลองใหม่อีกครั้ง",
   "image-too-large": "รูปภาพแต่ละรูปต้องมีขนาดไม่เกิน 10 MiB",
   "body-too-large": "แนบรูปภาพได้สูงสุด 5 รูป รูปละไม่เกิน 10 MiB",

lib/comments/moderation.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+import { checkCommentContent, normalizeCommentText } from "./moderation";
+
+describe("comment content moderation", () => {
+  it.each(["fuck you", "F U C K", "f.u.c.k", "f\u200buck", "ｆｕｃｋ", "sh1t", "b!tch", "ไอ้เหี้ย", "เย็ดแม่", "ควย"])("rejects abusive language: %s", (text) => {
+    expect(() => checkCommentContent(text)).toThrow("comment-abusive-language");
+  });
+  it.each(["", "This weapon has classic passive stats", "Scunthorpe", "The boss has an assassin phase", "ทีมนี้ใช้กล้วยได้ไหม", "ขอบคุณสำหรับไกด์ครับ", "https://example.com/guide", "https://a.test https://b.test https://c.test", "ha ha ha", "Crit rate 100%!"])("allows ordinary discussion: %s", (text) => {
+    expect(() => checkCommentContent(text)).not.toThrow();
+  });
+  it.each(["https://a.test https://b.test https://c.test https://d.test", "www.a.test www.b.test www.c.test www.d.test", "a".repeat(20), "🔥".repeat(20), "buy now ".repeat(8), "spam ".repeat(8)])("rejects spam: %s", (text) => {
+    expect(() => checkCommentContent(text)).toThrow("comment-spam");
+  });
+  it("normalizes casing, whitespace, invisible characters and compatibility forms for duplicates", () => {
+    expect(normalizeCommentText("  Ｈello\u200b\n WORLD  ")).toBe("hello world");
+  });
+  it("rejects text containing only invisible characters", () => {
+    expect(() => checkCommentContent("\u200b\u200d")).toThrow("empty-comment");
+  });
+});

lib/comments/moderation.ts

@@ -0,0 +1,26 @@
+import { HttpError } from "@/lib/security/http";
+
+// Keep the list focused: broad substring matches reject ordinary game discussion.
+const englishTerms = ["fuck", "fucking", "fucker", "motherfucker", "shit", "bullshit", "bitch", "cunt", "asshole", "nigger", "nigga", "faggot"];
+const substitutions: Record<string, string> = { a: "[a@4]", e: "[e3]", i: "[i1!]", o: "[o0]", s: "[s$5]", t: "[t7]" };
+const abusiveEnglish = new RegExp(
+  `(?<![\\p{L}\\p{N}])(?:${englishTerms.map((term) => [...term].map((letter) => substitutions[letter] ?? letter).join("[\\s\\p{P}\\p{S}]*")).join("|")})(?![\\p{L}\\p{N}])`,
+  "u",
+);
+const abusiveThai = /(?:ไอ้เหี้ย|อีเหี้ย|ไอ้สัส|อีสัส|เย็ดแม่|ควย)/u;
+
+export function normalizeCommentText(text: string) {
+  return text.normalize("NFKC").toLowerCase().replace(/\p{Cf}/gu, "").replace(/\s+/gu, " ").trim();
+}
+
+export function checkCommentContent(text: string) {
+  const normalized = normalizeCommentText(text);
+  if (text && !normalized) throw new HttpError(400, "empty-comment");
+  if (abusiveEnglish.test(normalized) || abusiveThai.test(normalized))
+    throw new HttpError(400, "comment-abusive-language");
+  if ((normalized.match(/(?:https?:\/\/|www\.)[^\s]+/gu)?.length ?? 0) > 3 ||
+      /(.)\1{19,}/u.test(normalized) ||
+      /(?:^|\s)(\S+(?:\s+\S+){0,4})(?:\s+\1){7,}(?=\s|$)/u.test(normalized))
+    throw new HttpError(400, "comment-spam");
+  return normalized;
+}

lib/comments/publish.ts

@@ -11,6 +11,7 @@ import { boundedBody, HttpError, withUploadSlot } from "@/lib/security/http";
 import { authorizeComment, commentId, ensureCommentThread, getCommentTarget, withCommentLock } from "./repository";
 import { MAX_COMMENT_BODY_BYTES, parseCommentForm } from "./validation";
 import type { CommentViewer } from "./types";
+import { withCommentSpamProtection } from "./spam";
 
 type ParsedForm = ReturnType<typeof parseCommentForm>;
 type Upload = { id: string; objectKey: string; mimeType: string; byteSize: number };
@@ -54,6 +55,7 @@ export async function publishComment(request: Request, viewer: CommentViewer, op
   const destination = initial?.destination ?? await getCommentTarget(options.target!, viewer);
   const result = await withUploadSlot(async () => {
     const form = parseCommentForm(await boundedBody(request, MAX_COMMENT_BODY_BYTES).formData(), Boolean(options.id));
+    return withCommentSpamProtection(viewer.id, form.text, Boolean(options.id), async () => {
       const uploaded: Upload[] = [];
       try {
         const storage = form.files.length ? await getMediaStorage() : null;
@@ -101,6 +103,7 @@ export async function publishComment(request: Request, viewer: CommentViewer, op
         throw cause;
       }
     });
+  });
   await notifyCommentChange(destination.target);
   return result;
 }

lib/comments/spam.test.ts

@@ -0,0 +1,68 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("server-only", () => ({}));
+const mocks = vi.hoisted(() => ({ limit: vi.fn(), set: vi.fn(), eval: vi.fn() }));
+vi.mock("@/lib/security/rate-limit", () => ({ limitRequest: mocks.limit }));
+vi.mock("@/lib/redis/client", () => ({ getRedisClient: async () => ({ set: mocks.set, eval: mocks.eval }) }));
+import { withCommentSpamProtection } from "./spam";
+import { HttpError } from "@/lib/security/http";
+
+describe("comment spam protection", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mocks.limit.mockResolvedValue(undefined);
+    mocks.set.mockResolvedValue("OK");
+    mocks.eval.mockResolvedValue(1);
+  });
+  it("limits all writes and retains the duplicate reservation on success", async () => {
+    const publish = vi.fn().mockResolvedValue({ id: "saved" });
+    await expect(withCommentSpamProtection("author", "Hello", false, publish)).resolves.toEqual({ id: "saved" });
+    expect(mocks.limit.mock.calls).toEqual([
+      ["comment-write-hour", "author", 30, 3600],
+      ["comment-write-minute", "author", 5],
+      ["comment-write-cooldown", "author", 1, 5],
+    ]);
+    expect(mocks.set).toHaveBeenCalledWith(expect.any(String), expect.any(String), "EX", 300, "NX");
+    expect(mocks.eval).not.toHaveBeenCalled();
+  });
+  it("uses the same private duplicate key for normalized text across targets", async () => {
+    await withCommentSpamProtection("author", " HELLO\u200b\n world", false, async () => undefined);
+    await withCommentSpamProtection("author", "hello world", false, async () => undefined);
+    expect(mocks.set.mock.calls[0][0]).toBe(mocks.set.mock.calls[1][0]);
+    expect(mocks.set.mock.calls[0][0]).not.toContain("hello");
+    await withCommentSpamProtection("other", "hello world", false, async () => undefined);
+    expect(mocks.set.mock.calls[2][0]).not.toBe(mocks.set.mock.calls[0][0]);
+  });
+  it("rejects simultaneous or recent duplicate posts before uploading or saving", async () => {
+    mocks.set.mockResolvedValue(null);
+    const publish = vi.fn();
+    await expect(withCommentSpamProtection("author", "Hello", false, publish)).rejects.toMatchObject({ status: 429, message: "comment-duplicate", retryAfter: 300 });
+    expect(publish).not.toHaveBeenCalled();
+  });
+  it("releases only its own reservation when publication fails", async () => {
+    const failure = new Error("upload failed");
+    await expect(withCommentSpamProtection("author", "Hello", false, async () => { throw failure; })).rejects.toBe(failure);
+    const [key, token] = mocks.set.mock.calls[0];
+    expect(mocks.eval).toHaveBeenCalledWith(expect.stringContaining("ARGV[1]"), 1, key, token);
+  });
+  it("blocks abuse in edits and leaves persistence untouched", async () => {
+    const publish = vi.fn();
+    await expect(withCommentSpamProtection("author", "fuck you", true, publish)).rejects.toMatchObject({ status: 400, message: "comment-abusive-language" });
+    expect(publish).not.toHaveBeenCalled();
+    expect(mocks.set).not.toHaveBeenCalled();
+  });
+  it.each([true, false])("keeps edits and image-only comments usable while rate limiting them (editing=%s)", async (editing) => {
+    const publish = vi.fn().mockResolvedValue("saved");
+    await expect(withCommentSpamProtection("author", editing ? "same text" : "", editing, publish)).resolves.toBe("saved");
+    expect(mocks.limit).toHaveBeenCalledTimes(3);
+    expect(mocks.set).not.toHaveBeenCalled();
+  });
+  it("stops publication if the shared rate limit or Redis is unavailable", async () => {
+    const publish = vi.fn();
+    mocks.limit.mockRejectedValueOnce(new HttpError(429, "too-many-requests", 5));
+    await expect(withCommentSpamProtection("author", "Hello", false, publish)).rejects.toMatchObject({ status: 429 });
+    mocks.set.mockRejectedValueOnce(new Error("Redis unavailable"));
+    await expect(withCommentSpamProtection("author", "Hello", false, publish)).rejects.toThrow("Redis unavailable");
+    expect(publish).not.toHaveBeenCalled();
+  });
+});

lib/comments/spam.ts

@@ -0,0 +1,37 @@
+import "server-only";
+
+import { createHash, randomUUID } from "node:crypto";
+import { getRedisClient } from "@/lib/redis/client";
+import { HttpError } from "@/lib/security/http";
+import { limitRequest } from "@/lib/security/rate-limit";
+import { checkCommentContent } from "./moderation";
+
+const duplicateWindow = 300;
+const releaseScript = `
+if redis.call('GET', KEYS[1]) == ARGV[1] then
+  return redis.call('DEL', KEYS[1])
+end
+return 0
+`;
+
+export async function withCommentSpamProtection<T>(authorId: string, text: string, editing: boolean, publish: () => Promise<T>): Promise<T> {
+  const normalized = checkCommentContent(text);
+  await limitRequest("comment-write-hour", authorId, 30, 3600);
+  await limitRequest("comment-write-minute", authorId, 5);
+  await limitRequest("comment-write-cooldown", authorId, 1, 5);
+  // Edits may retain their text while changing images; image-only posts use the rate limits.
+  if (editing || !normalized) return publish();
+  const digest = createHash("sha256").update(JSON.stringify([authorId, normalized])).digest("hex");
+  const key = `${process.env.REDIS_SECURITY_PREFIX || "buzz:security"}:comment-duplicate:${digest}`;
+  const token = randomUUID();
+  const redis = await getRedisClient();
+  if (await redis.set(key, token, "EX", duplicateWindow, "NX") !== "OK")
+    throw new HttpError(429, "comment-duplicate", duplicateWindow);
+  try {
+    return await publish();
+  } catch (cause) {
+    // Failed uploads/saves can be retried; never remove a newer writer's reservation.
+    await redis.eval(releaseScript, 1, key, token).catch(() => undefined);
+    throw cause;
+  }
+}

tests/comments.integration.test.ts

@@ -14,6 +14,7 @@ vi.mock("@/lib/comments/events", () => ({ notifyCommentChange: notify }));
 const storage = vi.hoisted(() => ({ write: vi.fn(), delete: vi.fn() }));
 const rateLimit = vi.hoisted(() => vi.fn());
 vi.mock("@/lib/security/rate-limit", () => ({ limitRequest: rateLimit }));
+vi.mock("@/lib/redis/client", () => ({ getRedisClient: async () => ({ set: async () => "OK", eval: async () => 1 }) }));
 const session = vi.hoisted(() => ({ get: vi.fn() }));
 vi.mock("@/lib/media/storage", () => ({ getMediaStorage: async () => storage, publicMediaUrl: (key: string) => `https://storage.example.test/${key}` }));
 vi.mock("@/lib/auth/server", () => ({ getCustomerSession: session.get }));
@@ -380,6 +381,29 @@ describeDatabase("guide comments against PostgreSQL", { timeout: 30000 }, () =>
     expect(read.status).toBe(200); expect(read.headers.get("cache-control")).toContain("no-store");
     expect((await read.json()).items).toHaveLength(1);
   });
+  it("rejects abusive posts, replies and edits before uploads, revisions or notifications", async () => {
+    session.get.mockResolvedValue({ user: { id: author.id }, session: { id: "session" } });
+    const url = `https://guide.example.test/api/comments?target=${target}`;
+    const blocked = await commentsRoute.POST(request("f.u.c.k", { images: [png] }, url));
+    expect(blocked.status).toBe(400);
+    expect(await blocked.json()).toEqual({ error: "comment-abusive-language" });
+    expect((await page()).items).toHaveLength(0);
+    expect(storage.write).not.toHaveBeenCalled();
+    expect(notify).not.toHaveBeenCalled();
+    const root = await post("Normal discussion");
+    notify.mockClear();
+    vi.mocked(after).mockClear();
+    const reply = await commentsRoute.POST(request("ไอ้เหี้ย", { reply: root.id }, url));
+    expect(reply.status).toBe(400);
+    const edited = await itemRoute.PATCH(request("buy now ".repeat(8), { version: 1, images: [png] }), { params: Promise.resolve({ id: root.id }) });
+    expect(edited.status).toBe(400);
+    expect(await edited.json()).toEqual({ error: "comment-spam" });
+    expect((await page()).items).toHaveLength(1);
+    expect((await commentHistory(root.id, author)).items).toHaveLength(1);
+    expect(storage.write).not.toHaveBeenCalled();
+    expect(notify).not.toHaveBeenCalled();
+    expect(after).not.toHaveBeenCalled();
+  });
   it("enforces author and admin rights through mutation endpoints", async () => {
     const root = await post();
     session.get.mockResolvedValue({ user: { id: other.id }, session: { id: "session" } });