1 files changed, 95 insertions, 0 deletions
diff --git a/packages/integrations/vercel/src/serverless/request-transform.ts b/packages/integrations/vercel/src/serverless/request-transform.ts
new file mode 100644
index 000000000..7cdb2550a
--- /dev/null
+++ b/packages/integrations/vercel/src/serverless/request-transform.ts
@@ -0,0 +1,95 @@
+import { Readable } from 'node:stream';
+import type { IncomingMessage, ServerResponse } from 'node:http';
+
+/*
+  Credits to the SvelteKit team
+	https://github.com/sveltejs/kit/blob/69913e9fda054fa6a62a80e2bb4ee7dca1005796/packages/kit/src/node.js
+*/
+
+function get_raw_body(req: IncomingMessage) {
+	return new Promise<Uint8Array | null>((fulfil, reject) => {
+		const h = req.headers;
+
+		if (!h['content-type']) {
+			return fulfil(null);
+		}
+
+		req.on('error', reject);
+
+		const length = Number(h['content-length']);
+
+		// https://github.com/jshttp/type-is/blob/c1f4388c71c8a01f79934e68f630ca4a15fffcd6/index.js#L81-L95
+		if (isNaN(length) && h['transfer-encoding'] == null) {
+			return fulfil(null);
+		}
+
+		let data = new Uint8Array(length || 0);
+
+		if (length > 0) {
+			let offset = 0;
+			req.on('data', (chunk) => {
+				const new_len = offset + Buffer.byteLength(chunk);
+
+				if (new_len > length) {
+					return reject({
+						status: 413,
+						reason: 'Exceeded "Content-Length" limit',
+					});
+				}
+
+				data.set(chunk, offset);
+				offset = new_len;
+			});
+		} else {
+			req.on('data', (chunk) => {
+				const new_data = new Uint8Array(data.length + chunk.length);
+				new_data.set(data, 0);
+				new_data.set(chunk, data.length);
+				data = new_data;
+			});
+		}
+
+		req.on('end', () => {
+			fulfil(data);
+		});
+	});
+}
+
+export async function getRequest(base: string, req: IncomingMessage): Promise<Request> {
+	let headers = req.headers as Record<string, string>;
+	if (req.httpVersionMajor === 2) {
+		// we need to strip out the HTTP/2 pseudo-headers because node-fetch's
+		// Request implementation doesn't like them
+		headers = Object.assign({}, headers);
+		delete headers[':method'];
+		delete headers[':path'];
+		delete headers[':authority'];
+		delete headers[':scheme'];
+	}
+	return new Request(base + req.url, {
+		method: req.method,
+		headers,
+		body: await get_raw_body(req), // TODO stream rather than buffer
+	});
+}
+
+export async function setResponse(res: ServerResponse, response: Response): Promise<void> {
+	const headers = Object.fromEntries(response.headers);
+
+	if (response.headers.has('set-cookie')) {
+		// @ts-expect-error (headers.raw() is non-standard)
+		headers['set-cookie'] = response.headers.raw()['set-cookie'];
+	}
+
+	res.writeHead(response.status, headers);
+
+	if (response.body instanceof Readable) {
+		response.body.pipe(res);
+	} else {
+		if (response.body) {
+			res.write(await response.arrayBuffer());
+		}
+
+		res.end();
+	}
+}