fix(exit-node): support Deno fetch export

Author: therealaleph

assets/exit_node/exit_node.ts

@@ -81,7 +81,7 @@ function sanitizeHeaders(h: unknown): Record<string, string> {
   return out;
 }
 
-export default async function (req: Request): Promise<Response> {
+export async function handleExitNodeRequest(req: Request): Promise<Response> {
   // Fail closed on the placeholder PSK so a fresh deploy without setup
   // can't accidentally serve as an open relay.
   if (PSK === "CHANGE_ME_TO_A_STRONG_SECRET") {
@@ -173,3 +173,7 @@ export default async function (req: Request): Promise<Response> {
     return Response.json({ e: message }, { status: 500 });
   }
 }
+
+export default {
+  fetch: handleExitNodeRequest,
+};

assets/exit_node/wrapper.ts

@@ -36,7 +36,22 @@
 // secret. The wrapper imports the handler from exit_node.ts directly,
 // so changing the constant in exit_node.ts is all you need.
 
-import handler from "./exit_node.ts";
+import exitNode from "./exit_node.ts";
+
+const handler =
+  typeof exitNode === "function" ? exitNode : exitNode.fetch.bind(exitNode);
+
+function concatChunks(chunks: Uint8Array[]): Blob | undefined {
+  if (!chunks.length) return undefined;
+  const len = chunks.reduce((sum, chunk) => sum + chunk.length, 0);
+  const out = new Uint8Array(len);
+  let offset = 0;
+  for (const chunk of chunks) {
+    out.set(chunk, offset);
+    offset += chunk.length;
+  }
+  return new Blob([out.buffer as ArrayBuffer]);
+}
 
 // Deno (preferred)
 if (typeof (globalThis as any).Deno !== "undefined") {
@@ -94,7 +109,7 @@ else if (typeof (globalThis as any).process !== "undefined") {
     // Build a web-standard Request from Node's IncomingMessage.
     const chunks: Uint8Array[] = [];
     for await (const c of req) chunks.push(c as Uint8Array);
-    const body = chunks.length ? Buffer.concat(chunks) : undefined;
+    const body = concatChunks(chunks);
 
     const url = `http://${req.headers.host ?? hostname}${req.url ?? "/"}`;
     const webReq = new Request(url, {