singularity-forge/web/proxy.ts
2026-05-05 14:46:18 +02:00

77 lines
2.6 KiB
TypeScript

import { type NextRequest, NextResponse } from "next/server";
/**
* Next.js proxy — validates bearer token and origin on all API routes.
*
* The SF_WEB_AUTH_TOKEN env var is set at server launch. Every /api/* request
* must carry a matching `Authorization: Bearer <token>` header. EventSource
* (SSE) connections may use the `_token` query parameter instead since the
* EventSource API cannot set custom headers.
*
* Additionally, if an `Origin` header is present, it must match the expected
* localhost origin to prevent cross-site request forgery.
*/
export function proxy(request: NextRequest): NextResponse | undefined {
const { pathname } = request.nextUrl;
// Only gate API routes
if (!pathname.startsWith("/api/")) return NextResponse.next();
const expectedToken = process.env.SF_WEB_AUTH_TOKEN;
if (!expectedToken) {
// If no token was configured (e.g. dev mode without launch harness),
// allow everything — the server didn't opt into auth.
return NextResponse.next();
}
// ── Origin / CORS check ────────────────────────────────────────────
const origin = request.headers.get("origin");
if (origin) {
const host = process.env.SF_WEB_HOST || "127.0.0.1";
const port = process.env.SF_WEB_PORT || "3000";
// Default: localhost origin for the launched host:port
const allowed = new Set([`http://${host}:${port}`]);
// SF_WEB_ALLOWED_ORIGINS lets users whitelist additional origins for
// secure tunnel setups (Tailscale Serve, Cloudflare Tunnel, ngrok, etc.)
const extra = process.env.SF_WEB_ALLOWED_ORIGINS;
if (extra) {
for (const entry of extra.split(",")) {
const trimmed = entry.trim();
if (trimmed) allowed.add(trimmed);
}
}
if (!allowed.has(origin)) {
return NextResponse.json(
{ error: "Forbidden: origin mismatch" },
{ status: 403 },
);
}
}
// ── Bearer token check ─────────────────────────────────────────────
let token: string | null = null;
// 1. Authorization header (preferred)
const authHeader = request.headers.get("authorization");
if (authHeader?.startsWith("Bearer ")) {
token = authHeader.slice(7);
}
// 2. Query parameter fallback for EventSource / SSE
if (!token) {
token = request.nextUrl.searchParams.get("_token");
}
if (!token || token !== expectedToken) {
return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
}
return NextResponse.next();
}
export const config = {
matcher: "/api/:path*",
};