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a tool for shared writing and social publishing forked from leaflet.pub/leaflet
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235import { AtUri } from "@atproto/syntax";import { createClient } from "@supabase/supabase-js";import { getCache } from "@vercel/functions";import { NextRequest, NextResponse } from "next/server";import { Database } from "supabase/database.types";
export const config = { matcher: [ /* * Match all paths except for: * 1. /api routes * 2. /_next (Next.js internals) * 3. /_static (inside /public) * 4. all root files inside /public (e.g. /favicon.ico) */ "/((?!api/|_next/|_static/|_vercel|[\\w-]+\\.\\w+).*)", ],};
let supabase = createClient<Database>( process.env.NEXT_PUBLIC_SUPABASE_API_URL as string, process.env.SUPABASE_SERVICE_ROLE_KEY as string,);
const cache = getCache();
async function getDomainRoutes(hostname: string) { let { data } = await supabase .from("custom_domains") .select( "*, custom_domain_routes(*), publication_domains(*, publications(*))", ) .eq("domain", hostname) .single(); return data;}type DomainRoutes = Awaited<ReturnType<typeof getDomainRoutes>>;
const auth_callback_route = "/auth_callback";const receive_auth_callback_route = "/receive_auth_callback";
const botUserAgentRegex = /bot|crawler|spider|crawling|facebookexternalhit|facebookcatalog|whatsapp|telegram|slackbot|discordbot|linkedinbot|twitterbot|embedly|quora link preview|pinterest|redditbot|applebot|duckduckbot|baiduspider|yandex|bingpreview|vkshare|w3c_validator|mastodon|pleroma|misskey|iframely|skypeuripreview|google-inspectiontool|chrome-lighthouse/i;
function isBot(req: NextRequest) { let ua = req.headers.get("user-agent"); if (!ua) return false; return botUserAgentRegex.test(ua);}function isMainSiteHost(hostname: string): boolean { return ( hostname === "leaflet.pub" || hostname.startsWith("localhost") || hostname.startsWith("127.0.0.1") || hostname.endsWith(".vercel.app") );}
export default async function middleware(req: NextRequest) { let hostname = req.headers.get("host")!; if (req.nextUrl.pathname === auth_callback_route) return authCallback(req); if (req.nextUrl.pathname === receive_auth_callback_route) return receiveAuthCallback(req);
if (req.nextUrl.pathname === "/" && isMainSiteHost(hostname)) { let hasAuth = req.cookies.has("auth_token") || req.cookies.has("external_auth_token"); if (hasAuth) { let navState = req.cookies.get("nav-state")?.value; let target = navState === "reader" ? "/reader" : "/home"; return NextResponse.redirect(new URL(target, req.url)); } }
if (hostname === "leaflet.pub") return; if (req.nextUrl.pathname === "/not-found") return; let routes: DomainRoutes = null; try { routes = (await cache.get(`domain:${hostname}`)) as DomainRoutes; } catch {} if (!routes) { routes = await getDomainRoutes(hostname); if (routes) { try { await cache.set(`domain:${hostname}`, routes, { ttl: 60, tags: [`domain:${hostname}`], }); } catch {} } }
let pub = routes?.publication_domains[0]?.publications; if (pub) { if (req.nextUrl.pathname.startsWith("/lish")) return; let cookie = req.cookies.get("external_auth_token"); let isStaticReq = req.nextUrl.pathname.includes("/rss") || req.nextUrl.pathname.includes("/atom") || req.nextUrl.pathname.includes("/json");
// Check if we've already completed auth (prevents redirect loop when cookies are disabled) let authCompleted = req.nextUrl.searchParams.has("auth_completed");
if ( !isStaticReq && !isBot(req) && (!cookie || req.nextUrl.searchParams.has("refreshAuth")) && !authCompleted && !hostname.includes("leaflet.pub") ) { return initiateAuthCallback(req); }
// If auth was completed but we still don't have a cookie, cookies might be disabled // Continue without auth rather than looping if (authCompleted && !cookie) { console.warn( "Auth completed but no cookie set - cookies may be disabled", ); } let aturi = new AtUri(pub?.uri); return NextResponse.rewrite( new URL( `/lish/${aturi.host}/${aturi.rkey}${req.nextUrl.pathname}`, req.url, ), ); } if (routes) { let route = routes.custom_domain_routes.find( (r) => r.route === req.nextUrl.pathname, ); if (route) return NextResponse.rewrite( new URL(`/${route.view_permission_token}`, req.url), ); else { return NextResponse.redirect(new URL("/not-found", req.url)); } }}
type CROSS_SITE_AUTH_REQUEST = { redirect: string; ts: string };type CROSS_SITE_AUTH_RESPONSE = { redirect: string; auth_token: string | null; ts: string;};async function initiateAuthCallback(req: NextRequest) { let redirectUrl = new URL(req.url); redirectUrl.searchParams.delete("refreshAuth"); let token: CROSS_SITE_AUTH_REQUEST = { redirect: redirectUrl.toString(), ts: new Date().toISOString(), }; let payload = btoa(JSON.stringify(token)); let signature = await signCrossSiteToken(payload); return NextResponse.redirect( `https://leaflet.pub${auth_callback_route}?payload=${encodeURIComponent(payload)}&signature=${encodeURIComponent(signature)}`, );}
async function authCallback(req: NextRequest) { let payload = req.nextUrl.searchParams.get("payload"); let signature = req.nextUrl.searchParams.get("signature");
if (typeof payload !== "string" || typeof signature !== "string") return new NextResponse("Payload or Signature not string", { status: 401 });
payload = decodeURIComponent(payload); signature = decodeURIComponent(signature);
let verifySig = await signCrossSiteToken(payload); if (verifySig !== signature) return new NextResponse("Incorrect Signature", { status: 401 });
let token: CROSS_SITE_AUTH_REQUEST = JSON.parse(atob(payload)); let auth_token = req.cookies.get("auth_token")?.value || null; let redirect_url = new URL(token.redirect); let response_token: CROSS_SITE_AUTH_RESPONSE = { redirect: token.redirect, auth_token, ts: new Date().toISOString(), };
let response_payload = btoa(JSON.stringify(response_token)); let sig = await signCrossSiteToken(response_payload); return NextResponse.redirect( `https://${redirect_url.host}${receive_auth_callback_route}?payload=${encodeURIComponent(response_payload)}&signature=${encodeURIComponent(sig)}`, );}
async function receiveAuthCallback(req: NextRequest) { let payload = req.nextUrl.searchParams.get("payload"); let signature = req.nextUrl.searchParams.get("signature");
if (typeof payload !== "string" || typeof signature !== "string") return new NextResponse(null, { status: 401 }); payload = decodeURIComponent(payload); signature = decodeURIComponent(signature);
let verifySig = await signCrossSiteToken(payload); if (verifySig !== signature) return new NextResponse(null, { status: 401 });
let token: CROSS_SITE_AUTH_RESPONSE = JSON.parse(atob(payload));
let url = new URL(token.redirect); url.searchParams.set("auth_completed", "true"); let response = NextResponse.redirect(url.toString()); response.cookies.set("external_auth_token", token.auth_token || "null"); return response;}
const signCrossSiteToken = async (input: string) => { if (!process.env.CROSS_SITE_AUTH_SECRET) throw new Error("Environment variable CROSS_SITE_AUTH_SECRET not set "); const encoder = new TextEncoder(); const data = encoder.encode(input); const secretKey = process.env.CROSS_SITE_AUTH_SECRET; const keyData = encoder.encode(secretKey);
const key = await crypto.subtle.importKey( "raw", keyData, { name: "HMAC", hash: "SHA-256" }, false, ["sign"], );
const signature = await crypto.subtle.sign("HMAC", key, data);
return btoa(String.fromCharCode(...new Uint8Array(signature)));};