initial commit

src/main.ts

@@ -0,0 +1,81 @@
+import type { ServerWebSocket } from "bun";
+
+interface Event {
+  kind: number;
+  tags: string[][];
+  content: string;
+  created_at: number;
+  pubkey: string;
+  id: string;
+  sig: string;
+}
+
+type Nip42ProxySocketData = {
+  authenticated: boolean;
+  authToken: string;
+  remoteWs: WebSocket;
+};
+
+async function validateAuthEvent(event: Event, challenge: string): boolean {
+  if (event.kind !== 22242) return false;
+  const last30Seconds = Math.floor(Date.now() / 1000) - 30;
+  if (event.created_at < last30Seconds) return false;
+  const challengeTag = event.tags.find(tag => tag[0] === 'challange')?.[1];
+  if (challengeTag !== challenge) return false;
+  const file = Bun.file("./allowed-pubkeys.json");
+  if (!file.exists()) return true;
+  const allowedPubkeys = JSON.parse(await file.text());
+  if (!allowedPubkeys.includes(event.pubkey)) return false;
+  return true;
+}
+
+const sendMessage = (ws: ServerWebSocket<Nip42ProxySocketData>, message: any[]) => ws.send(JSON.stringify(message), true);
+const sendAuth = (ws: ServerWebSocket<Nip42ProxySocketData>) => sendMessage(ws, ["AUTH", ws.data.authToken, "This is an authenticated relay."]);
+
+export function main(mainRelayUrl: string) {
+  const server = Bun.serve<Nip42ProxySocketData, {}>({
+    fetch(req, server) {
+      const upgrade = server.upgrade(req, {
+        data: {
+          authenticated: false,
+          authToken: Bun.randomUUIDv7()
+        }
+      });
+      if (!upgrade) console.log(`http request`)
+      return new Response("this is a proxy. Use http to access it");
+    },
+    websocket: {
+      async message(ws, msg) {
+        const [command, ...data] = JSON.parse(msg);
+        if (!ws.data.authenticated) {
+          if (command === "REQ") {
+            const [name, ...filters] = data;
+            sendMessage(ws, ["CLOSED", name, 'auth-required: you must authenticate first']);
+          }
+          if (command === "EVENT") {
+            const [event] = data;
+            sendMessage(ws, ["OK", event.id, false, 'auth-required: you must authenticate first']);
+          }
+          if (command === "AUTH") {
+            const [event] = data;
+            const valid = await validateAuthEvent(event, ws.data.authToken);
+            if (!valid) return sendMessage(ws, ['NOTICE', "Invalid auth event"]);
+            ws.data.authenticated = true;
+            return;
+          }
+          return sendAuth(ws);
+        }
+        ws.data.remoteWs.send(msg);
+      },
+      open(ws) {
+        sendAuth(ws);
+        ws.data.remoteWs = new WebSocket(mainRelayUrl);
+        ws.data.remoteWs.onmessage = (data) => ws.send(data.data, true);
+      },
+      perMessageDeflate: true,
+      perMessageDeflateCompressionLevel: 9
+    }
+  })
+  console.log('Server listening @', server.url.host)
+}
+