Use Cloudflare Pages to serve static assets and support _headers, _redirects and _routes.json (#5347)

Co-authored-by: AirBorne04 <unknown>
Co-authored-by: Chris Swithinbank <swithinbank@gmail.com>

.changeset/quick-items-jog.md

@@ -0,0 +1,6 @@
+---
+'@astrojs/cloudflare': minor
+---
+
+Now building for Cloudflare directory mode takes advantage of the standard asset handling from Cloudflare Pages, and therefore does not call a function script to deliver static assets anymore.
+Also supports the use of `_routes.json`, `_redirects` and `_headers` files when placed into the `public` folder.

packages/integrations/cloudflare/README.md

@@ -66,7 +66,7 @@ In order for preview to work you must install `wrangler`
 $ pnpm install wrangler --save-dev
 ```
 
-It's then possible to update the preview script in your `package.json` to `"preview": "wrangler pages dev ./dist"`.This will allow you run your entire application locally with [Wrangler](https://github.com/cloudflare/wrangler2), which supports secrets, environment variables, KV namespaces, Durable Objects and [all other supported Cloudflare bindings](https://developers.cloudflare.com/pages/platform/functions/#adding-bindings).
+It's then possible to update the preview script in your `package.json` to `"preview": "wrangler pages dev ./dist"`. This will allow you run your entire application locally with [Wrangler](https://github.com/cloudflare/wrangler2), which supports secrets, environment variables, KV namespaces, Durable Objects and [all other supported Cloudflare bindings](https://developers.cloudflare.com/pages/platform/functions/#adding-bindings).
 
 ## Access to the Cloudflare runtime
 
@@ -107,6 +107,14 @@ export function get({ params }) {
 }
 ```
 
+## Headers, Redirects and function invocation routes
+
+Cloudflare has support for adding custom [headers](https://developers.cloudflare.com/pages/platform/headers/), configuring static [redirects](https://developers.cloudflare.com/pages/platform/redirects/) and defining which routes should [invoke functions](https://developers.cloudflare.com/pages/platform/functions/routing/#function-invocation-routes). Cloudflare looks for `_headers`, `_redirects`, and `_routes.json` files in your build output directory to configure these features. This means they should be placed in your Astro project’s `public/` directory.
+
+### Custom `_routes.json`
+
+By default, `@astrojs/cloudflare` will generate a `_routes.json` file that lists all files from your `dist/` folder and redirects from the `_redirects` file in the `exclude` array. This will enable Cloudflare to serve files and process static redirects without a function invocation. Creating a custom `_routes.json` will override this automatic optimization and, if not configured manually, cause function invocations that will count against the request limits of your Cloudflare plan.
+
 ## Troubleshooting
 
 For help, check out the `#support` channel on [Discord](https://astro.build/chat). Our friendly Support Squad members are here to help!

packages/integrations/cloudflare/package.json

@@ -34,7 +34,8 @@
     "test": "mocha --exit --timeout 30000 test/"
   },
   "dependencies": {
-    "esbuild": "^0.14.42"
+    "esbuild": "^0.14.42",
+    "tiny-glob": "^0.2.9"
   },
   "peerDependencies": {
     "astro": "^1.6.10"

packages/integrations/cloudflare/src/index.ts

@@ -1,6 +1,8 @@
 import type { AstroAdapter, AstroConfig, AstroIntegration } from 'astro';
 import esbuild from 'esbuild';
 import * as fs from 'fs';
+import * as os from 'os';
+import glob from 'tiny-glob';
 import { fileURLToPath } from 'url';
 
 type Options = {
@@ -32,6 +34,8 @@ const SHIM = `globalThis.process = {
 	env: {},
 };`;
 
+const SERVER_BUILD_FOLDER = '/$server_build/';
+
 export default function createIntegration(args?: Options): AstroIntegration {
 	let _config: AstroConfig;
 	let _buildConfig: BuildConfig;
@@ -45,8 +49,8 @@ export default function createIntegration(args?: Options): AstroIntegration {
 				needsBuildConfig = !config.build.client;
 				updateConfig({
 					build: {
-						client: new URL('./static/', config.outDir),
+						client: new URL(`.${config.base}`, config.outDir),
-						server: new URL('./', config.outDir),
+						server: new URL(`.${SERVER_BUILD_FOLDER}`, config.outDir),
 						serverEntry: '_worker.js',
 					},
 				});
@@ -62,6 +66,11 @@ export default function createIntegration(args?: Options): AstroIntegration {
 
 `);
 				}
+
+				if (config.base === SERVER_BUILD_FOLDER) {
+					throw new Error(`
+  [@astrojs/cloudflare] \`base: "${SERVER_BUILD_FOLDER}"\` is not allowed. Please change your \`base\` config to something else.`);
+				}
 			},
 			'astro:build:setup': ({ vite, target }) => {
 				if (target === 'server') {
@@ -84,19 +93,20 @@ export default function createIntegration(args?: Options): AstroIntegration {
 			'astro:build:start': ({ buildConfig }) => {
 				// Backwards compat
 				if (needsBuildConfig) {
-					buildConfig.client = new URL('./static/', _config.outDir);
+					buildConfig.client = new URL(`.${_config.base}`, _config.outDir);
-					buildConfig.server = new URL('./', _config.outDir);
+					buildConfig.server = new URL(`.${SERVER_BUILD_FOLDER}`, _config.outDir);
 					buildConfig.serverEntry = '_worker.js';
 				}
 			},
 			'astro:build:done': async () => {
-				const entryUrl = new URL(_buildConfig.serverEntry, _buildConfig.server);
+				const entryPath = fileURLToPath(new URL(_buildConfig.serverEntry, _buildConfig.server)),
-				const pkg = fileURLToPath(entryUrl);
+					entryUrl = new URL(_buildConfig.serverEntry, _config.outDir),
+					buildPath = fileURLToPath(entryUrl);
 				await esbuild.build({
 					target: 'es2020',
 					platform: 'browser',
-					entryPoints: [pkg],
+					entryPoints: [entryPath],
-					outfile: pkg,
+					outfile: buildPath,
 					allowOverwrite: true,
 					format: 'esm',
 					bundle: true,
@@ -107,8 +117,90 @@ export default function createIntegration(args?: Options): AstroIntegration {
 				});
 
 				// throw the server folder in the bin
-				const chunksUrl = new URL('./chunks', _buildConfig.server);
+				const serverUrl = new URL(_buildConfig.server);
-				await fs.promises.rm(chunksUrl, { recursive: true, force: true });
+				await fs.promises.rm(serverUrl, { recursive: true, force: true });
+
+				// move cloudflare specific files to the root
+				const cloudflareSpecialFiles = ['_headers', '_redirects', '_routes.json'];
+				if (_config.base !== '/') {
+					for (const file of cloudflareSpecialFiles) {
+						try {
+							await fs.promises.rename(
+								new URL(file, _buildConfig.client),
+								new URL(file, _config.outDir)
+							);
+						} catch (e) {
+							// ignore
+						}
+					}
+				}
+
+				const routesExists = await fs.promises
+					.stat(new URL('./_routes.json', _config.outDir))
+					.then((stat) => stat.isFile())
+					.catch(() => false);
+
+				// this creates a _routes.json, in case there is none present to enable
+				// cloudflare to handle static files and support _redirects configuration
+				// (without calling the function)
+				if (!routesExists) {
+					const staticPathList: Array<string> = (
+						await glob(`${fileURLToPath(_buildConfig.client)}/**/*`, {
+							cwd: fileURLToPath(_config.outDir),
+							filesOnly: true,
+						})
+					)
+						.filter((file: string) => cloudflareSpecialFiles.indexOf(file) < 0)
+						.map((file: string) => `/${file}`);
+
+					const redirectsExists = await fs.promises
+						.stat(new URL('./_redirects', _config.outDir))
+						.then((stat) => stat.isFile())
+						.catch(() => false);
+
+          // convert all redirect source paths into a list of routes
+          // and add them to the static path
+					if (redirectsExists) {
+						const redirects = (
+							await fs.promises.readFile(new URL('./_redirects', _config.outDir), 'utf-8')
+						)
+							.split(os.EOL)
+							.map((line) => {
+								const parts = line.split(' ');
+								if (parts.length < 2) {
+									return null;
+								} else {
+									// convert /products/:id to /products/*
+									return (
+										parts[0]
+											.replace(/\/:.*?(?=\/|$)/g, '/*')
+											// remove query params as they are not supported by cloudflare
+											.replace(/\?.*$/, '')
+									);
+								}
+							})
+							.filter(
+								(line, index, arr) => line !== null && arr.indexOf(line) === index
+							) as string[];
+
+						if (redirects.length > 0) {
+							staticPathList.push(...redirects);
+						}
+					}
+
+					await fs.promises.writeFile(
+						new URL('./_routes.json', _config.outDir),
+						JSON.stringify(
+							{
+								version: 1,
+								include: ['/*'],
+								exclude: staticPathList,
+							},
+							null,
+							2
+						)
+					);
+				}
 
 				if (isModeDirectory) {
 					const functionsUrl = new URL(`file://${process.cwd()}/functions/`);

packages/integrations/cloudflare/src/server.advanced.ts

@@ -15,12 +15,11 @@ export function createExports(manifest: SSRManifest) {
 	const fetch = async (request: Request, env: Env, context: any) => {
 		process.env = env as any;
 
-		const { origin, pathname } = new URL(request.url);
+		const { pathname } = new URL(request.url);
 
-		// static assets
+		// static assets fallback, in case default _routes.json is not used
 		if (manifest.assets.has(pathname)) {
-			const assetRequest = new Request(`${origin}/static/${app.removeBase(pathname)}`, request);
+			return env.ASSETS.fetch(request);
-			return env.ASSETS.fetch(assetRequest);
 		}
 
 		let routeData = app.match(request, { matchNotFound: true });

packages/integrations/cloudflare/src/server.directory.ts

@@ -17,11 +17,10 @@ export function createExports(manifest: SSRManifest) {
 	} & Record<string, unknown>) => {
 		process.env = runtimeEnv.env as any;
 
-		const { origin, pathname } = new URL(request.url);
+		const { pathname } = new URL(request.url);
-		// static assets
+		// static assets fallback, in case default _routes.json is not used
 		if (manifest.assets.has(pathname)) {
-			const assetRequest = new Request(`${origin}/static/${app.removeBase(pathname)}`, request);
+			return next(request);
-			return next(assetRequest);
 		}
 
 		let routeData = app.match(request, { matchNotFound: true });

pnpm-lock.yaml

@@ -2554,9 +2554,11 @@ importers:
       cheerio: ^1.0.0-rc.11
       esbuild: ^0.14.42
       mocha: ^9.2.2
+      tiny-glob: ^0.2.9
       wrangler: ^2.0.23
     dependencies:
       esbuild: 0.14.54
+      tiny-glob: 0.2.9
     devDependencies:
       astro: link:../../astro
       astro-scripts: link:../../../scripts