feat: support middlewares in SSG for endpoints and pages

Author: ematipico

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

@@ -1391,11 +1391,6 @@ interface AstroSharedContext<Props extends Record<string, any> = Record<string,
 	 * TODO documentation
 	 */
 	locals: Locals;
-
-	/**
-	 * TODO documentation
-	 */
-	setLocal: (key: string, value: any) => void;
 }
 
 export interface APIContext<Props extends Record<string, any> = Record<string, any>>
@@ -1562,14 +1557,16 @@ export interface AstroIntegration {
 	};
 }
 
-export type MiddlewareResolve = (context: APIContext) => Promise<Response>;
-export type MiddlewareHandler = (
+export type MiddlewareResolve<R> = (context: APIContext) => Promise<R>;
+export type MiddlewareHandler<R> = (
 	context: Readonly<APIContext>,
-	response: MiddlewareResolve
-) => Promise<Response>;
+	response: MiddlewareResolve<R>
+) => Promise<R>;
 
-export type AstroMiddlewareInstance = {
-	onRequest?: MiddlewareHandler;
+// NOTE: when updating this file with other functions,
+// remember to update `plugin-page.ts` too, to add that function as a no-op function.
+export type AstroMiddlewareInstance<R> = {
+	onRequest?: MiddlewareHandler<R>;
 };
 
 export interface AstroPluginOptions {

packages/astro/src/core/app/index.ts

@@ -231,7 +231,8 @@ export class App {
 			status,
 		});
 
-		const result = await callEndpoint(handler, this.#env, ctx, this.#logging);
+		// TODO PLT-104 add adapter middleware here
+		const result = await callEndpoint(handler, this.#env, ctx, this.#logging, undefined);
 
 		if (result.type === 'response') {
 			if (result.response.headers.get('X-Astro-Response') === 'Not-Found') {

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

@@ -6,13 +6,16 @@ import type { OutputAsset, OutputChunk } from 'rollup';
 import { fileURLToPath } from 'url';
 import type {
 	AstroConfig,
+	AstroMiddlewareInstance,
 	AstroSettings,
 	ComponentInstance,
 	EndpointHandler,
 	ImageTransform,
+	MiddlewareHandler,
 	RouteType,
 	SSRError,
 	SSRLoadedRenderer,
+	EndpointOutput,
 } from '../../@types/astro';
 import {
 	generateImage as generateImageInternal,
@@ -27,10 +30,20 @@ import {
 } from '../../core/path.js';
 import { runHookBuildGenerated } from '../../integrations/index.js';
 import { BEFORE_HYDRATION_SCRIPT_ID, PAGE_SCRIPT_ID } from '../../vite-plugin-scripts/index.js';
-import { call as callEndpoint, throwIfRedirectNotAllowed } from '../endpoint/index.js';
-import { AstroError } from '../errors/index.js';
+import {
+	call as callEndpoint,
+	createAPIContext,
+	throwIfRedirectNotAllowed,
+} from '../endpoint/index.js';
+import { AstroError, AstroErrorData } from '../errors/index.js';
 import { debug, info } from '../logger/core.js';
-import { createEnvironment, createRenderContext, renderPage } from '../render/index.js';
+import {
+	createEnvironment,
+	createRenderContext,
+	getParamsAndProps,
+	GetParamsAndPropsError,
+	renderPage,
+} from '../render/index.js';
 import { callGetStaticPaths } from '../render/route-cache.js';
 import { createLinkStylesheetElementSet, createModuleScriptsSet } from '../render/ssr-element.js';
 import { createRequest } from '../request.js';
@@ -45,6 +58,7 @@ import {
 } from './internal.js';
 import type { PageBuildData, SingleFileBuiltModule, StaticBuildOptions } from './types';
 import { getTimeStat } from './util.js';
+import { callMiddleware } from '../middleware/index.js';
 
 function shouldSkipDraft(pageModule: ComponentInstance, settings: AstroSettings): boolean {
 	return (
@@ -168,6 +182,7 @@ async function generatePage(
 	const scripts = pageInfo?.hoistedScript ?? null;
 
 	const pageModule = ssrEntry.pageMap?.get(pageData.component);
+	const middleware = ssrEntry.middleware;
 
 	if (!pageModule) {
 		throw new Error(
@@ -197,7 +212,7 @@ async function generatePage(
 
 	for (let i = 0; i < paths.length; i++) {
 		const path = paths[i];
-		await generatePath(path, opts, generationOptions);
+		await generatePath(path, opts, generationOptions, middleware);
 		const timeEnd = performance.now();
 		const timeChange = getTimeStat(timeStart, timeEnd);
 		const timeIncrease = `(+${timeChange})`;
@@ -339,7 +354,8 @@ function getUrlForPath(
 async function generatePath(
 	pathname: string,
 	opts: StaticBuildOptions,
-	gopts: GeneratePathOptions
+	gopts: GeneratePathOptions,
+	middleware: AstroMiddlewareInstance<unknown>
 ) {
 	const { settings, logging, origin, routeCache } = opts;
 	const { mod, internals, linkIds, scripts: hoistedScripts, pageData, renderers } = gopts;
@@ -412,6 +428,7 @@ async function generatePath(
 		ssr,
 		streaming: true,
 	});
+
 	const ctx = createRenderContext({
 		origin,
 		pathname,
@@ -426,7 +443,14 @@ async function generatePath(
 	let encoding: BufferEncoding | undefined;
 	if (pageData.route.type === 'endpoint') {
 		const endpointHandler = mod as unknown as EndpointHandler;
-		const result = await callEndpoint(endpointHandler, env, ctx, logging);
+
+		const result = await callEndpoint(
+			endpointHandler,
+			env,
+			ctx,
+			logging,
+			middleware as AstroMiddlewareInstance<Response | EndpointOutput>
+		);
 
 		if (result.type === 'response') {
 			throwIfRedirectNotAllowed(result.response, opts.settings.config);
@@ -441,7 +465,39 @@ async function generatePath(
 	} else {
 		let response: Response;
 		try {
-			response = await renderPage(mod, ctx, env);
+			const paramsAndPropsResp = await getParamsAndProps({
+				mod: mod as any,
+				route: ctx.route,
+				routeCache: env.routeCache,
+				pathname: ctx.pathname,
+				logging: env.logging,
+				ssr: env.ssr,
+			});
+
+			if (paramsAndPropsResp === GetParamsAndPropsError.NoMatchingStaticPath) {
+				throw new AstroError({
+					...AstroErrorData.NoMatchingStaticPathFound,
+					message: AstroErrorData.NoMatchingStaticPathFound.message(ctx.pathname),
+					hint: ctx.route?.component
+						? AstroErrorData.NoMatchingStaticPathFound.hint([ctx.route?.component])
+						: '',
+				});
+			}
+			const [params, props] = paramsAndPropsResp;
+
+			const context = createAPIContext({
+				request: ctx.request,
+				params,
+				props,
+				site: env.site,
+				adapterName: env.adapterName,
+			});
+			// If the user doesn't configure a middleware, the rollup plugin emits a no-op function,
+			// so it's safe to use `callMiddleware` regardless
+			let onRequest = middleware.onRequest as MiddlewareHandler<Response>;
+			response = await callMiddleware<Response>(onRequest, context, () => {
+				return renderPage(mod, ctx, env, context);
+			});
 		} catch (err) {
 			if (!AstroError.is(err) && !(err as SSRError).id && typeof err === 'object') {
 				(err as SSRError).id = pageData.component;

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

@@ -78,6 +78,8 @@ export interface BuildInternals {
 	// The SSR entry chunk. Kept in internals to share between ssr/client build steps
 	ssrEntryChunk?: OutputChunk;
 	componentMetadata: SSRResult['componentMetadata'];
+
+	middleware?: ViteID;
 }
 
 /**

packages/astro/src/core/build/plugins/plugin-pages.ts

@@ -1,10 +1,10 @@
 import type { Plugin as VitePlugin } from 'vite';
 import type { AstroBuildPlugin } from '../plugin';
 import type { StaticBuildOptions } from '../types';
-
 import { pagesVirtualModuleId, resolvedPagesVirtualModuleId } from '../../app/index.js';
 import { addRollupInput } from '../add-rollup-input.js';
 import { eachPageData, hasPrerenderedPages, type BuildInternals } from '../internal.js';
+import { MIDDLEWARE_PATH_SEGMENT_NAME } from '../../constants.js';
 
 export function vitePluginPages(opts: StaticBuildOptions, internals: BuildInternals): VitePlugin {
 	return {
@@ -22,8 +22,10 @@ export function vitePluginPages(opts: StaticBuildOptions, internals: BuildIntern
 			}
 		},
 
-		load(id) {
+		async load(id) {
 			if (id === resolvedPagesVirtualModuleId) {
+				const middlewareId = await this.resolve(`./src/${MIDDLEWARE_PATH_SEGMENT_NAME}`);
+
 				let importMap = '';
 				let imports = [];
 				let i = 0;
@@ -47,8 +49,12 @@ export function vitePluginPages(opts: StaticBuildOptions, internals: BuildIntern
 
 				const def = `${imports.join('\n')}
 
+${middlewareId ? `import * as _middleware from "${middlewareId.id}";` : ''}
+
 export const pageMap = new Map([${importMap}]);
-export const renderers = [${rendererItems}];`;
+export const renderers = [${rendererItems}];
+export const middleware = ${middlewareId ? '_middleware' : '{ onRequest() {} }'};
+`;
 
 				return def;
 			}

packages/astro/src/core/build/static-build.ts

@@ -12,7 +12,7 @@ import {
 } from '../../core/build/internal.js';
 import { emptyDir, removeEmptyDirs } from '../../core/fs/index.js';
 import { appendForwardSlash, prependForwardSlash } from '../../core/path.js';
-import { isModeServerWithNoAdapter } from '../../core/util.js';
+import { isModeServerWithNoAdapter, viteID } from '../../core/util.js';
 import { runHookBuildSetup } from '../../integrations/index.js';
 import { PAGE_SCRIPT_ID } from '../../vite-plugin-scripts/index.js';
 import { resolvedPagesVirtualModuleId } from '../app/index.js';
@@ -25,6 +25,7 @@ import { createPluginContainer, type AstroBuildPluginContainer } from './plugin.
 import { registerAllPlugins } from './plugins/index.js';
 import type { PageBuildData, StaticBuildOptions } from './types';
 import { getTimeStat } from './util.js';
+import { MIDDLEWARE_PATH_SEGMENT_NAME } from '../constants.js';
 
 export async function viteBuild(opts: StaticBuildOptions) {
 	const { allPages, settings } = opts;
@@ -57,6 +58,11 @@ export async function viteBuild(opts: StaticBuildOptions) {
 		facadeIdToPageDataMap.set(fileURLToPath(astroModuleURL), pageData);
 	}
 
+	// track middleware
+
+	const middlewareURL = new URL('./src/' + MIDDLEWARE_PATH_SEGMENT_NAME, settings.config.root);
+	internals.middleware = viteID(middlewareURL);
+
 	// Empty out the dist folder, if needed. Vite has a config for doing this
 	// but because we are running 2 vite builds in parallel, that would cause a race
 	// condition, so we are doing it ourselves
@@ -114,7 +120,7 @@ export async function staticBuild(opts: StaticBuildOptions, internals: BuildInte
 		case 'static': {
 			settings.timer.start('Static generate');
 			await generatePages(opts, internals);
-			await cleanServerOutput(opts);
+			// await cleanServerOutput(opts);
 			settings.timer.end('Static generate');
 			return;
 		}

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

@@ -1,6 +1,7 @@
 import type { default as vite, InlineConfig } from 'vite';
 import type {
 	AstroConfig,
+	AstroMiddlewareInstance,
 	AstroSettings,
 	BuildConfig,
 	ComponentInstance,
@@ -44,6 +45,7 @@ export interface StaticBuildOptions {
 
 export interface SingleFileBuiltModule {
 	pageMap: Map<ComponentPath, ComponentInstance>;
+	middleware: AstroMiddlewareInstance<unknown>;
 	renderers: SSRLoadedRenderer[];
 }
 

packages/astro/src/core/endpoint/dev/index.ts

@@ -1,4 +1,8 @@
-import type { EndpointHandler } from '../../../@types/astro';
+import type {
+	AstroMiddlewareInstance,
+	EndpointHandler,
+	EndpointOutput,
+} from '../../../@types/astro';
 import type { LogOptions } from '../../logger/core';
 import type { SSROptions } from '../../render/dev';
 import { createRenderContext } from '../../render/index.js';
@@ -8,6 +12,7 @@ export async function call(options: SSROptions, logging: LogOptions) {
 	const {
 		env,
 		preload: [, mod],
+		middleware,
 	} = options;
 	const endpointHandler = mod as unknown as EndpointHandler;
 
@@ -18,5 +23,11 @@ export async function call(options: SSROptions, logging: LogOptions) {
 		route: options.route,
 	});
 
-	return await callEndpoint(endpointHandler, env, ctx, logging);
+	return await callEndpoint(
+		endpointHandler,
+		env,
+		ctx,
+		logging,
+		middleware as AstroMiddlewareInstance<Response | EndpointOutput>
+	);
 }

packages/astro/src/core/endpoint/index.ts

@@ -1,4 +1,12 @@
-import type { APIContext, AstroConfig, EndpointHandler, Params } from '../../@types/astro';
+import type {
+	APIContext,
+	AstroConfig,
+	AstroMiddlewareInstance,
+	EndpointHandler,
+	EndpointOutput,
+	MiddlewareHandler,
+	Params,
+} from '../../@types/astro';
 import type { Environment, RenderContext } from '../render/index';
 
 import { renderEndpoint } from '../../runtime/server/index.js';
@@ -7,6 +15,7 @@ import { AstroCookies, attachToResponse } from '../cookies/index.js';
 import { AstroError, AstroErrorData } from '../errors/index.js';
 import { warn, type LogOptions } from '../logger/core.js';
 import { getParamsAndProps, GetParamsAndPropsError } from '../render/core.js';
+import { callMiddleware } from '../middleware/index.js';
 
 const clientAddressSymbol = Symbol.for('astro.clientAddress');
 const clientLocalsSymbol = Symbol.for('astro.locals');
@@ -75,7 +84,8 @@ export async function call(
 	mod: EndpointHandler,
 	env: Environment,
 	ctx: RenderContext,
-	logging: LogOptions
+	logging: LogOptions,
+	middleware: AstroMiddlewareInstance<Response | EndpointOutput> | undefined
 ): Promise<EndpointCallResult> {
 	const paramsAndPropsResp = await getParamsAndProps({
 		mod: mod as any,
@@ -105,7 +115,15 @@ export async function call(
 		adapterName: env.adapterName,
 	});
 
-	const response = await renderEndpoint(mod, context, env.ssr);
+	let response;
+	if (middleware && middleware.onRequest) {
+		const onRequest = middleware.onRequest as MiddlewareHandler<Response | EndpointOutput>;
+		response = await callMiddleware<Response | EndpointOutput>(onRequest, context, () => {
+			return renderEndpoint(mod, context, env.ssr);
+		});
+	} else {
+		response = await renderEndpoint(mod, context, env.ssr);
+	}
 
 	if (response instanceof Response) {
 		attachToResponse(response, context.cookies);