refactor(build): don't emit middleware.mjs (#12479)

Author: ematipico

packages/astro/src/core/build/generate.ts

@@ -33,6 +33,7 @@ import { getOutputDirectory } from '../../prerender/utils.js';
 import type { SSRManifestI18n } from '../app/types.js';
 import { NoPrerenderedRoutesWithDomains } from '../errors/errors-data.js';
 import { AstroError, AstroErrorData } from '../errors/index.js';
+import { NOOP_MIDDLEWARE_FN } from '../middleware/noop-middleware.js';
 import { getRedirectLocationOrThrow, routeIsRedirect } from '../redirects/index.js';
 import { RenderContext } from '../render-context.js';
 import { callGetStaticPaths } from '../render/route-cache.js';
@@ -65,14 +66,9 @@ export async function generatePages(options: StaticBuildOptions, internals: Buil
 		const baseDirectory = getOutputDirectory(options.settings.config);
 		const renderersEntryUrl = new URL('renderers.mjs', baseDirectory);
 		const renderers = await import(renderersEntryUrl.toString());
-		let middleware: MiddlewareHandler = (_, next) => next();
-		try {
-			// middleware.mjs is not emitted if there is no user middleware
-			// in which case the import fails with ERR_MODULE_NOT_FOUND, and we fall back to a no-op middleware
-			middleware = await import(new URL('middleware.mjs', baseDirectory).toString()).then(
-				(mod) => mod.onRequest,
-			);
-		} catch {}
+		const middleware: MiddlewareHandler = internals.middlewareEntryPoint
+			? await import(internals.middlewareEntryPoint.toString()).then((mod) => mod.onRequest)
+			: NOOP_MIDDLEWARE_FN;
 		manifest = createBuildManifest(
 			options.settings,
 			internals,

packages/astro/src/core/build/pipeline.ts

@@ -137,15 +137,13 @@ export class BuildPipeline extends Pipeline {
 		const renderersEntryUrl = new URL(`renderers.mjs?time=${Date.now()}`, baseDirectory);
 		const renderers = await import(renderersEntryUrl.toString());
 
-		const middleware = await import(new URL('middleware.mjs', baseDirectory).toString())
-			.then((mod) => {
-				return function () {
-					return { onRequest: mod.onRequest };
-				};
-			})
-			// middleware.mjs is not emitted if there is no user middleware
-			// in which case the import fails with ERR_MODULE_NOT_FOUND, and we fall back to a no-op middleware
-			.catch(() => manifest.middleware);
+		const middleware = internals.middlewareEntryPoint
+			? await import(internals.middlewareEntryPoint.toString()).then((mod) => {
+					return function () {
+						return { onRequest: mod.onRequest };
+					};
+				})
+			: manifest.middleware;
 
 		if (!renderers) {
 			throw new Error(

packages/astro/src/core/middleware/vite-plugin.ts

@@ -13,17 +13,13 @@ export const MIDDLEWARE_MODULE_ID = '\0astro-internal:middleware';
 const NOOP_MIDDLEWARE = '\0noop-middleware';
 
 export function vitePluginMiddleware({ settings }: { settings: AstroSettings }): VitePlugin {
-	let isCommandBuild = false;
 	let resolvedMiddlewareId: string | undefined = undefined;
 	const hasIntegrationMiddleware =
 		settings.middlewares.pre.length > 0 || settings.middlewares.post.length > 0;
 	let userMiddlewareIsPresent = false;
 
 	return {
 		name: '@astro/plugin-middleware',
-		config(_, { command }) {
-			isCommandBuild = command === 'build';
-		},
 		async resolveId(id) {
 			if (id === MIDDLEWARE_MODULE_ID) {
 				const middlewareId = await this.resolve(
@@ -53,15 +49,6 @@ export function vitePluginMiddleware({ settings }: { settings: AstroSettings }):
 				if (!userMiddlewareIsPresent && settings.config.i18n?.routing === 'manual') {
 					throw new AstroError(MissingMiddlewareForInternationalization);
 				}
-				// In the build, tell Vite to emit this file
-				if (isCommandBuild) {
-					this.emitFile({
-						type: 'chunk',
-						preserveSignature: 'strict',
-						fileName: 'middleware.mjs',
-						id,
-					});
-				}
 
 				const preMiddleware = createMiddlewareImports(settings.middlewares.pre, 'pre');
 				const postMiddleware = createMiddlewareImports(settings.middlewares.post, 'post');
@@ -124,7 +111,7 @@ export function vitePluginMiddlewareBuild(
 
 		writeBundle(_, bundle) {
 			for (const [chunkName, chunk] of Object.entries(bundle)) {
-				if (chunk.type !== 'asset' && chunk.fileName === 'middleware.mjs') {
+				if (chunk.type !== 'asset' && chunk.facadeModuleId === MIDDLEWARE_MODULE_ID) {
 					const outputDirectory = getOutputDirectory(opts.settings.config);
 					internals.middlewareEntryPoint = new URL(chunkName, outputDirectory);
 				}