1 files changed, 69 insertions, 0 deletions
diff --git a/packages/integrations/node/src/preview.ts b/packages/integrations/node/src/preview.ts
new file mode 100644
index 000000000..94a81bfdb
--- /dev/null
+++ b/packages/integrations/node/src/preview.ts
@@ -0,0 +1,69 @@
+import { fileURLToPath } from 'node:url';
+import type { CreatePreviewServer } from 'astro';
+import { AstroError } from 'astro/errors';
+import { logListeningOn } from './log-listening-on.js';
+import type { createExports } from './server.js';
+import { createServer } from './standalone.js';
+
+type ServerModule = ReturnType<typeof createExports>;
+type MaybeServerModule = Partial<ServerModule>;
+
+const createPreviewServer: CreatePreviewServer = async (preview) => {
+	let ssrHandler: ServerModule['handler'];
+	let options: ServerModule['options'];
+	try {
+		process.env.ASTRO_NODE_AUTOSTART = 'disabled';
+		const ssrModule: MaybeServerModule = await import(preview.serverEntrypoint.toString());
+		if (typeof ssrModule.handler === 'function') {
+			ssrHandler = ssrModule.handler;
+			// biome-ignore lint/style/noNonNullAssertion: <explanation>
+			options = ssrModule.options!;
+		} else {
+			throw new AstroError(
+				`The server entrypoint doesn't have a handler. Are you sure this is the right file?`
+			);
+		}
+	} catch (err) {
+		if ((err as any).code === 'ERR_MODULE_NOT_FOUND') {
+			throw new AstroError(
+				`The server entrypoint ${fileURLToPath(
+					preview.serverEntrypoint
+				)} does not exist. Have you ran a build yet?`
+			);
+			// biome-ignore lint/style/noUselessElse: <explanation>
+		} else {
+			throw err;
+		}
+	}
+	// If the user didn't specify a host, it will already have been defaulted to
+	// "localhost" by getResolvedHostForHttpServer in astro core/preview/util.ts.
+	// The value `undefined` actually means that either the user set `options.server.host`
+	// to `true`, or they passed `--host` without an argument. In that case, we
+	// should listen on all IPs.
+	const host = process.env.HOST ?? preview.host ?? '0.0.0.0';
+
+	const port = preview.port ?? 4321;
+	const server = createServer(ssrHandler, host, port);
+
+	// If user specified custom headers append a listener
+	// to the server to add those headers to response
+	if (preview.headers) {
+		server.server.addListener('request', (_, res) => {
+			if (res.statusCode === 200) {
+				for (const [name, value] of Object.entries(preview.headers ?? {})) {
+					if (value) res.setHeader(name, value);
+				}
+			}
+		});
+	}
+
+	logListeningOn(preview.logger, server.server, host);
+	await new Promise<void>((resolve, reject) => {
+		server.server.once('listening', resolve);
+		server.server.once('error', reject);
+		server.server.listen(port, host);
+	});
+	return server;
+};
+
+export { createPreviewServer as default };