feat: add share API endpoints and in-memory rate limiting

- POST/DELETE /api/notes/[id]/share for creating/revoking public links
- GET /api/shared/[token] for fetching shared note data (no auth)
- GET /api/shared/[token]/attachment/[attachmentId] for public images
- Add /s/ and /api/shared to PUBLIC_PATHS in auth middleware
- Add IP-based rate limiter (60 req/min) for public endpoints

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/hooks.server.ts

@@ -8,7 +8,9 @@ const PUBLIC_PATHS = [
 	'/setup',
 	'/api/auth/login',
 	'/api/auth/setup',
-	'/api/auth/oauth'
+	'/api/auth/oauth',
+	'/s/',
+	'/api/shared'
 ];
 
 export const handle: Handle = async ({ event, resolve }) => {

src/lib/server/ip-rate-limit.ts

@@ -0,0 +1,14 @@
+const store = new Map<string, { count: number; windowStart: number }>();
+const WINDOW_MS = 60_000; // 1 minute
+const MAX_REQUESTS = 60;
+
+export function checkIpRateLimit(ip: string): boolean {
+	const now = Date.now();
+	const entry = store.get(ip);
+	if (!entry || now - entry.windowStart > WINDOW_MS) {
+		store.set(ip, { count: 1, windowStart: now });
+		return true;
+	}
+	entry.count++;
+	return entry.count <= MAX_REQUESTS;
+}

src/routes/api/notes/[id]/share/+server.ts

@@ -0,0 +1,17 @@
+import { json } from '@sveltejs/kit';
+import type { RequestHandler } from './$types.js';
+import { getUserId } from '$lib/server/api-utils.js';
+import { createShare, revokeShare } from '$lib/server/shares-service.js';
+import { db } from '$lib/server/db/index.js';
+
+export const POST: RequestHandler = async ({ params, url, ...event }) => {
+	const userId = getUserId(event);
+	const { token } = createShare(db, params.id, userId);
+	return json({ token, url: `${url.origin}/s/${token}` }, { status: 201 });
+};
+
+export const DELETE: RequestHandler = async ({ params, ...event }) => {
+	const userId = getUserId(event);
+	revokeShare(db, params.id, userId);
+	return new Response(null, { status: 204 });
+};

src/routes/api/shared/[token]/+server.ts

@@ -0,0 +1,20 @@
+import { json, error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types.js';
+import { getSharedNote } from '$lib/server/shares-service.js';
+import { checkIpRateLimit } from '$lib/server/ip-rate-limit.js';
+import { db } from '$lib/server/db/index.js';
+
+export const GET: RequestHandler = async ({ params, getClientAddress }) => {
+	const ip = getClientAddress();
+	if (!checkIpRateLimit(ip)) {
+		throw error(429, 'Too many requests');
+	}
+
+	const data = getSharedNote(db, params.token);
+	if (!data) {
+		throw error(404, 'Not found');
+	}
+
+	const { noteId: _, ...publicData } = data;
+	return json(publicData);
+};

src/routes/api/shared/[token]/attachment/[attachmentId]/+server.ts

@@ -0,0 +1,37 @@
+import { error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types.js';
+import { getSharedNote } from '$lib/server/shares-service.js';
+import { getAttachment } from '$lib/server/attachments.js';
+import { checkIpRateLimit } from '$lib/server/ip-rate-limit.js';
+import { db } from '$lib/server/db/index.js';
+import { readFile } from 'fs/promises';
+
+export const GET: RequestHandler = async ({ params, url, getClientAddress }) => {
+	const ip = getClientAddress();
+	if (!checkIpRateLimit(ip)) {
+		throw error(429, 'Too many requests');
+	}
+
+	const data = getSharedNote(db, params.token);
+	if (!data) {
+		throw error(404, 'Not found');
+	}
+
+	const attachment = await getAttachment(db, params.attachmentId, data.noteId);
+	if (!attachment) {
+		throw error(404, 'Attachment not found');
+	}
+
+	const wantThumb = url.searchParams.get('thumb') === '1';
+	const filePath = wantThumb && attachment.thumbnailPath ? attachment.thumbnailPath : attachment.path;
+	const mimeType = wantThumb && attachment.thumbnailPath ? 'image/webp' : attachment.mimeType;
+
+	const buffer = await readFile(filePath);
+	return new Response(buffer, {
+		headers: {
+			'Content-Type': mimeType,
+			'Content-Disposition': `inline; filename="${attachment.filename}"`,
+			'Cache-Control': 'public, max-age=31536000, immutable'
+		}
+	});
+};