Redirects

.changeset/chatty-actors-stare.md

@@ -0,0 +1,33 @@
+---
+'astro': minor
+---
+
+Experimental redirects support
+
+This change adds support for the redirects RFC, currently in stage 3: https://github.com/withastro/roadmap/pull/587
+
+Now you can specify redirects in your Astro config:
+
+```js
+import { defineConfig } from 'astro/config';
+
+export defineConfig({
+  redirects: {
+    '/blog/old-post': '/blog/new-post'
+  }
+});
+```
+
+You can also specify spread routes using the same syntax as in file-based routing:
+
+```js
+import { defineConfig } from 'astro/config';
+
+export defineConfig({
+  redirects: {
+    '/blog/[...slug]': '/articles/[...slug]'
+  }
+});
+```
+
+By default Astro will build HTML files that contain the `<meta http-equiv="refresh">` tag. Adapters can also support redirect routes and create configuration for real HTTP-level redirects in production.

.changeset/fuzzy-ladybugs-jump.md

@@ -0,0 +1,7 @@
+---
+'@astrojs/cloudflare': minor
+---
+
+Support for experimental redirects
+
+This adds support for the redirects RFC in the Cloudflare adapter. No changes are necessary, simply use configured redirects and the adapter will update your `_redirects` file.

.changeset/hip-news-clean.md

@@ -0,0 +1,7 @@
+---
+'@astrojs/vercel': minor
+---
+
+Support for experimental redirects
+
+This adds support for the redirects RFC in the Vercel adapter. No changes are necessary, simply use configured redirects and the adapter will output the vercel.json file with the configuration values.

.changeset/twenty-suns-vanish.md

@@ -0,0 +1,9 @@
+---
+'@astrojs/netlify': minor
+---
+
+Support for experimental redirects
+
+This adds support for the redirects RFC in the Netlify adapter, including a new `@astrojs/netlify/static` adapter for static sites. 
+
+No changes are necessary when using SSR. Simply use configured redirects and the adapter will update your `_redirects` file.

packages/astro/package.json

@@ -113,6 +113,7 @@
   },
   "dependencies": {
     "@astrojs/compiler": "^1.4.0",
+    "@astrojs/internal-helpers": "^0.1.0",
     "@astrojs/language-server": "^1.0.0",
     "@astrojs/markdown-remark": "^2.2.1",
     "@astrojs/telemetry": "^2.1.1",

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

@@ -109,6 +109,7 @@ export interface CLIFlags {
 	open?: boolean;
 	experimentalAssets?: boolean;
 	experimentalMiddleware?: boolean;
+	experimentalRedirects?: boolean;
 }
 
 export interface BuildConfig {
@@ -452,6 +453,53 @@ export interface AstroUserConfig {
 	 */
 	cacheDir?: string;
 
+
+
+	/**
+	 * @docs
+	 * @name redirects (Experimental)
+	 * @type {RedirectConfig}
+	 * @default `{}`
+	 * @version 2.6.0
+	 * @description Specify a mapping of redirects where the key is the route to match
+	 * and the value is the path to redirect to. 
+	 *
+	 * You can redirect both static and dynamic routes, but only to the same kind of route.
+	 * For example you cannot have a `'/article': '/blog/[...slug]'` redirect.
+	 * 
+	 * 
+	 * ```js
+	 * {
+	 *   redirects: {
+	 *     '/old': '/new',
+	 *     '/blog/[...slug]': '/articles/[...slug]',
+	 *   }
+	 * }
+	 * ```
+	 *
+	 *  
+	 * For statically-generated sites with no adapter installed, this will produce a client redirect using a [`<meta http-equiv="refresh">` tag](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/meta#http-equiv) and does not support status codes.
+	 *
+	 * When using SSR or with a static adapter in `output: static`
+	 * mode, status codes are supported.
+	 * Astro will serve redirected GET requests with a status of `301`
+	 * and use a status of `308` for any other request method.
+	 * 
+	 * You can customize the [redirection status code](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status#redirection_messages) using an object in the redirect config:
+	 * 
+	 * ```js
+	 * {
+	 *   redirects: {
+	 *     '/other': {
+	 *       status: 302,
+	 *       destination: '/place',
+	 *     },
+	 *   }
+	 * }
+	 * ```
+	 */
+	redirects?: RedirectConfig;
+
 	/**
 	 * @docs
 	 * @name site
@@ -733,6 +781,29 @@ export interface AstroUserConfig {
 		 * ```
 		 */
 		serverEntry?: string;
+		/**
+		 * @docs
+		 * @name build.redirects
+		 * @type {boolean}
+		 * @default `true`
+		 * @version 2.6.0
+		 * @description
+		 * Specifies whether redirects will be output to HTML during the build.
+		 * This option only applies to `output: 'static'` mode; in SSR redirects
+		 * are treated the same as all responses.
+		 * 
+		 * This option is mostly meant to be used by adapters that have special 
+		 * configuration files for redirects and do not need/want HTML based redirects.
+		 *
+		 * ```js
+		 * {
+		 *   build: {
+		 *     redirects: false
+		 *   }
+		 * }
+		 * ```
+		 */
+		redirects?: boolean;
 	};
 
 	/**
@@ -1179,6 +1250,27 @@ export interface AstroUserConfig {
 		 * ```
 		 */
 		hybridOutput?: boolean;
+
+		/**
+		 * @docs
+		 * @name experimental.redirects
+		 * @type {boolean}
+		 * @default `false`
+		 * @version 2.6.0
+		 * @description
+		 * Enable experimental support for redirect configuration. With this enabled
+		 * you can set redirects via the top-level `redirects` property. To enable
+		 * this feature, set `experimental.redirects` to `true`.
+		 *
+		 * ```js
+		 * {
+		 * 	experimental: {
+		 *		redirects: true,
+		 * 	},
+		 * }
+		 * ```
+		 */
+		 redirects?: boolean;
 	};
 
 	// Legacy options to be removed
@@ -1578,6 +1670,8 @@ export interface AstroAdapter {
 
 type Body = string;
 
+export type ValidRedirectStatus = 300 | 301 | 302 | 303 | 304 | 307 | 308;
+
 // Shared types between `Astro` global and API context object
 interface AstroSharedContext<Props extends Record<string, any> = Record<string, any>> {
 	/**
@@ -1607,7 +1701,7 @@ interface AstroSharedContext<Props extends Record<string, any> = Record<string,
 	/**
 	 * Redirect to another page (**SSR Only**).
 	 */
-	redirect(path: string, status?: 301 | 302 | 303 | 307 | 308): Response;
+	redirect(path: string, status?: ValidRedirectStatus): Response;
 
 	/**
 	 * Object accessed via Astro middleware
@@ -1805,7 +1899,7 @@ export type MiddlewareNext<R> = () => Promise<R>;
 export type MiddlewareHandler<R> = (
 	context: APIContext,
 	next: MiddlewareNext<R>
-) => Promise<R> | Promise<void> | void;
+) => Promise<R> | R | Promise<void> | void;
 
 export type MiddlewareResponseHandler = MiddlewareHandler<Response>;
 export type MiddlewareEndpointHandler = MiddlewareHandler<Response | EndpointOutput>;
@@ -1822,14 +1916,19 @@ export interface AstroPluginOptions {
 	logging: LogOptions;
 }
 
-export type RouteType = 'page' | 'endpoint';
+export type RouteType = 'page' | 'endpoint' | 'redirect';
 
 export interface RoutePart {
 	content: string;
 	dynamic: boolean;
 	spread: boolean;
 }
 
+type RedirectConfig = string | {
+	status: ValidRedirectStatus;
+	destination: string;
+}
+
 export interface RouteData {
 	route: string;
 	component: string;
@@ -1842,6 +1941,12 @@ export interface RouteData {
 	segments: RoutePart[][];
 	type: RouteType;
 	prerender: boolean;
+	redirect?: RedirectConfig;
+	redirectRoute?: RouteData;
+}
+
+export type RedirectRouteData = RouteData & {
+	redirect: string;
 }
 
 export type SerializedRouteData = Omit<RouteData, 'generate' | 'pattern'> & {

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

@@ -28,6 +28,7 @@ import {
 	createStylesheetElementSet,
 } from '../render/ssr-element.js';
 import { matchRoute } from '../routing/match.js';
+import { RedirectComponentInstance } from '../redirects/index.js';
 export { deserializeManifest } from './common.js';
 
 const clientLocalsSymbol = Symbol.for('astro.locals');
@@ -137,22 +138,20 @@ export class App {
 			defaultStatus = 404;
 		}
 
-		let page = await this.#manifest.pageMap.get(routeData.component)!();
-		let mod = await page.page();
+		let mod = await this.#getModuleForRoute(routeData);
 
-		if (routeData.type === 'page') {
+		if (routeData.type === 'page' || routeData.type === 'redirect') {
 			let response = await this.#renderPage(request, routeData, mod, defaultStatus);
 
 			// If there was a known error code, try sending the according page (e.g. 404.astro / 500.astro).
 			if (response.status === 500 || response.status === 404) {
-				const errorPageData = matchRoute('/' + response.status, this.#manifestData);
-				if (errorPageData && errorPageData.route !== routeData.route) {
-					page = await this.#manifest.pageMap.get(errorPageData.component)!();
-					mod = await page.page();
+				const errorRouteData = matchRoute('/' + response.status, this.#manifestData);
+				if (errorRouteData && errorRouteData.route !== routeData.route) {
+					mod = await this.#getModuleForRoute(errorRouteData);
 					try {
 						let errorResponse = await this.#renderPage(
 							request,
-							errorPageData,
+							errorRouteData,
 							mod,
 							response.status
 						);
@@ -172,6 +171,19 @@ export class App {
 		return getSetCookiesFromResponse(response);
 	}
 
+	async #getModuleForRoute(route: RouteData): Promise<ComponentInstance> {
+		if(route.type === 'redirect') {
+			return RedirectComponentInstance;
+		} else {
+			const importComponentInstance = this.#manifest.pageMap.get(route.component);
+			if(!importComponentInstance) {
+				throw new Error(`Unexpectedly unable to find a component instance for route ${route.route}`);
+			}
+			const built = await importComponentInstance();
+			return built.page();
+		}
+	}
+
 	async #renderPage(
 		request: Request,
 		routeData: RouteData,

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

@@ -26,6 +26,7 @@ export function getOutFolder(
 		case 'endpoint':
 			return new URL('.' + appendForwardSlash(npath.dirname(pathname)), outRoot);
 		case 'page':
+		case 'redirect':
 			switch (astroConfig.build.format) {
 				case 'directory': {
 					if (STATUS_CODE_PAGES.has(pathname)) {
@@ -51,6 +52,7 @@ export function getOutFile(
 		case 'endpoint':
 			return new URL(npath.basename(pathname), outFolder);
 		case 'page':
+		case 'redirect':
 			switch (astroConfig.build.format) {
 				case 'directory': {
 					if (STATUS_CODE_PAGES.has(pathname)) {