1 files changed, 43 insertions, 0 deletions
diff --git a/packages/integrations/node/src/middleware.ts b/packages/integrations/node/src/middleware.ts
new file mode 100644
index 000000000..5bb104914
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+++ b/packages/integrations/node/src/middleware.ts
@@ -0,0 +1,43 @@
+import type { NodeApp } from 'astro/app/node';
+import { createAppHandler } from './serve-app.js';
+import type { RequestHandler } from './types.js';
+
+/**
+ * Creates a middleware that can be used with Express, Connect, etc.
+ *
+ * Similar to `createAppHandler` but can additionally be placed in the express
+ * chain as an error middleware.
+ *
+ * https://expressjs.com/en/guide/using-middleware.html#middleware.error-handling
+ */
+export default function createMiddleware(app: NodeApp): RequestHandler {
+	const handler = createAppHandler(app);
+	const logger = app.getAdapterLogger();
+	// using spread args because express trips up if the function's
+	// stringified body includes req, res, next, locals directly
+	return async (...args) => {
+		// assume normal invocation at first
+		const [req, res, next, locals] = args;
+		// short circuit if it is an error invocation
+		if (req instanceof Error) {
+			const error = req;
+			if (next) {
+				return next(error);
+				// biome-ignore lint/style/noUselessElse: <explanation>
+			} else {
+				throw error;
+			}
+		}
+		try {
+			await handler(req, res, next, locals);
+		} catch (err) {
+			logger.error(`Could not render ${req.url}`);
+			console.error(err);
+			if (!res.headersSent) {
+				// biome-ignore lint/style/noUnusedTemplateLiteral: <explanation>
+				res.writeHead(500, `Server error`);
+				res.end();
+			}
+		}
+	};
+}