feat(astro): experimental middleware (#6721)

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

1 files changed, 64 insertions, 0 deletions

diff --git a/packages/integrations/node/src/nodeMiddleware.ts b/packages/integrations/node/src/nodeMiddleware.ts
new file mode 100644
index 000000000..c23cdb89c
--- /dev/null
+++ b/packages/integrations/node/src/nodeMiddleware.ts
@@ -0,0 +1,64 @@
+import type { NodeApp } from 'astro/app/node';
+import type { IncomingMessage, ServerResponse } from 'http';
+import type { Readable } from 'stream';
+import { responseIterator } from './response-iterator';
+import type { Options } from './types';
+
+export default function (app: NodeApp, mode: Options['mode']) {
+	return async function (
+		req: IncomingMessage,
+		res: ServerResponse,
+		next?: (err?: unknown) => void
+	) {
+		try {
+			const route =
+				mode === 'standalone' ? app.match(req, { matchNotFound: true }) : app.match(req);
+			if (route) {
+				try {
+					const response = await app.render(req);
+					await writeWebResponse(app, res, response);
+				} catch (err: unknown) {
+					if (next) {
+						next(err);
+					} else {
+						throw err;
+					}
+				}
+			} else if (next) {
+				return next();
+			} else {
+				res.writeHead(404);
+				res.end('Not found');
+			}
+		} catch (err: unknown) {
+			if (!res.headersSent) {
+				res.writeHead(500, `Server error`);
+				res.end();
+			}
+		}
+	};
+}
+
+async function writeWebResponse(app: NodeApp, res: ServerResponse, webResponse: Response) {
+	const { status, headers } = webResponse;
+
+	if (app.setCookieHeaders) {
+		const setCookieHeaders: Array<string> = Array.from(app.setCookieHeaders(webResponse));
+		if (setCookieHeaders.length) {
+			res.setHeader('Set-Cookie', setCookieHeaders);
+		}
+	}
+
+	res.writeHead(status, Object.fromEntries(headers.entries()));
+	if (webResponse.body) {
+		try {
+			for await (const chunk of responseIterator(webResponse) as unknown as Readable) {
+				res.write(chunk);
+			}
+		} catch (err: any) {
+			console.error(err?.stack || err?.message || String(err));
+			res.write('Internal server error');
+		}
+	}
+	res.end();
+}