Node.js standalone mode + support for astro preview (#5056)

* wip

* Deprecate buildConfig and move to config.build

* Implement the standalone server

* Stay backwards compat

* Add changesets

* correctly merge URLs

* Get config earlier

* update node tests

* Return the preview server

* update remaining tests

* swap usage and config ordering

* Update packages/astro/src/@types/astro.ts

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

* Update .changeset/metal-pumas-walk.md

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

* Update .changeset/metal-pumas-walk.md

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

* Update .changeset/stupid-points-refuse.md

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

* Update .changeset/stupid-points-refuse.md

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

* Link to build.server config

Co-authored-by: Fred K. Schott <fkschott@gmail.com>
Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

1 files changed, 53 insertions, 0 deletions

diff --git a/packages/integrations/node/src/standalone.ts b/packages/integrations/node/src/standalone.ts
new file mode 100644
index 000000000..8fef96ed5
--- /dev/null
+++ b/packages/integrations/node/src/standalone.ts
@@ -0,0 +1,53 @@
+import type { NodeApp } from 'astro/app/node';
+import type { Options } from './types';
+import path from 'path';
+import { fileURLToPath } from 'url';
+import middleware from './middleware.js';
+import { createServer } from './http-server.js';
+
+function resolvePaths(options: Options) {
+	const clientURLRaw = new URL(options.client);
+	const serverURLRaw = new URL(options.server);
+	const rel = path.relative(fileURLToPath(serverURLRaw), fileURLToPath(clientURLRaw));
+	
+	const serverEntryURL = new URL(import.meta.url);
+	const clientURL = new URL(appendForwardSlash(rel), serverEntryURL);
+
+	return {
+		client: clientURL,
+	};
+}
+
+function appendForwardSlash(pth: string) {
+	return pth.endsWith('/') ? pth : pth + '/';
+}
+
+export function getResolvedHostForHttpServer(host: string | boolean) {
+	if (host === false) {
+		// Use a secure default
+		return '127.0.0.1';
+	} else if (host === true) {
+		// If passed --host in the CLI without arguments
+		return undefined; // undefined typically means 0.0.0.0 or :: (listen on all IPs)
+	} else {
+		return host;
+	}
+}
+
+export default function startServer(app: NodeApp, options: Options) {
+	const port = process.env.PORT ? Number(process.env.port) : (options.port ?? 8080);
+	const { client } = resolvePaths(options);
+	const handler = middleware(app);
+
+	const host = getResolvedHostForHttpServer(options.host);
+	const server = createServer({
+		client,
+		port,
+		host,
+	}, handler);
+
+	// eslint-disable-next-line no-console
+	console.log(`Server listening on http://${host}:${port}`);
+
+	return server.closed();
+}