feat: use config.kit.paths.base for static assets

fixes sveltejs#4442, fixes sveltejs#2843

- add manifest.prefix and builder.getAppPrefixDirectory()
- adapter-cloudflare*: use manifest.prefix instead of manifest.appDir
- adapter-netlify: use prefixed appDir for cache headers
- adapter-vercel: use prefixed appDir for routes.json
- adapter-cloudflare, adapter-cloudflare-workers, adapter-netlify: write static assets to "$dest/$base"

Author: hmnd

.changeset/smooth-waves-accept.md

@@ -0,0 +1,9 @@
+---
+'@sveltejs/adapter-cloudflare': patch
+'@sveltejs/adapter-cloudflare-workers': patch
+'@sveltejs/adapter-netlify': patch
+'@sveltejs/adapter-vercel': patch
+'@sveltejs/kit': patch
+---
+
+Use config.kit.paths.base prefix for static assets

packages/adapter-cloudflare-workers/files/entry.js

@@ -4,7 +4,7 @@ import { getAssetFromKV } from '@cloudflare/kv-asset-handler';
 
 const server = new Server(manifest);
 
-const prefix = `/${manifest.appDir}/`;
+const { prefix } = manifest;
 
 addEventListener('fetch', (/** @type {FetchEvent} */ event) => {
 	event.respondWith(handle(event));

packages/adapter-cloudflare-workers/index.js

@@ -60,9 +60,11 @@ export default function () {
 			writeFileSync(`${entrypoint}/package.json`, JSON.stringify({ main: 'index.js' }));
 
 			builder.log.minor('Copying assets...');
-			builder.writeClient(bucket);
-			builder.writeStatic(bucket);
-			builder.writePrerendered(bucket);
+
+			const prefixedBucket = `${bucket}${builder.config.kit.paths.base}`;
+			builder.writeClient(prefixedBucket);
+			builder.writeStatic(prefixedBucket);
+			builder.writePrerendered(prefixedBucket);
 		}
 	};
 }

packages/adapter-cloudflare/files/worker.js

@@ -3,7 +3,7 @@ import { manifest, prerendered } from 'MANIFEST';
 
 const server = new Server(manifest);
 
-const prefix = `/${manifest.appDir}/`;
+const { prefix } = manifest;
 
 export default {
 	/**

packages/adapter-cloudflare/index.js

@@ -16,9 +16,10 @@ export default function (options = {}) {
 			builder.rimraf(tmp);
 			builder.mkdirp(tmp);
 
-			builder.writeStatic(dest);
-			builder.writeClient(dest);
-			builder.writePrerendered(dest);
+			const prefixedDest = `${dest}${builder.config.kit.paths.base}`;
+			builder.writeStatic(prefixedDest);
+			builder.writeClient(prefixedDest);
+			builder.writePrerendered(prefixedDest);
 
 			const relativePath = posix.relative(tmp, builder.getServerDirectory());
 

packages/adapter-netlify/index.js

@@ -122,9 +122,11 @@ export default function ({ split = false } = {}) {
 			}
 
 			builder.log.minor('Copying assets...');
-			builder.writeStatic(publish);
-			builder.writeClient(publish);
-			builder.writePrerendered(publish);
+
+			const prefixedPublish = `${publish}${builder.config.kit.paths.base}`;
+			builder.writeStatic(prefixedPublish);
+			builder.writeClient(prefixedPublish);
+			builder.writePrerendered(prefixedPublish);
 
 			builder.log.minor('Writing redirects...');
 			const redirect_file = join(publish, '_redirects');
@@ -136,7 +138,7 @@ export default function ({ split = false } = {}) {
 			builder.copy('_headers', headers_file);
 			appendFileSync(
 				headers_file,
-				`\n\n/${builder.config.kit.appDir}/*\n  cache-control: public\n  cache-control: immutable\n  cache-control: max-age=31536000\n`
+				`\n\n${builder.getPrefixedAppDirectory()}*\n  cache-control: public\n  cache-control: immutable\n  cache-control: max-age=31536000\n`
 			);
 		}
 	};

packages/adapter-vercel/index.js

@@ -162,7 +162,7 @@ export default function ({ external = [] } = {}) {
 					...prerendered_pages,
 					...prerendered_redirects,
 					{
-						src: `/${builder.config.kit.appDir}/.+`,
+						src: `/${builder.getPrefixedAppDirectory()}/.+`,
 						headers: {
 							'cache-control': 'public, immutable, max-age=31536000'
 						}

packages/kit/src/core/adapt/builder.js

@@ -119,6 +119,10 @@ export function create_builder({ config, build_data, prerendered, log }) {
 			return config.kit.files.assets;
 		},
 
+		getPrefixedAppDirectory() {
+			return build_data.prefix;
+		},
+
 		writeClient(dest) {
 			return copy(`${config.kit.outDir}/output/client`, dest, {
 				filter: (file) => file[0] !== '.'

packages/kit/src/core/build/index.js

@@ -26,6 +26,7 @@ export async function build(config, { log }) {
 
 	const { manifest_data } = sync.all(config);
 
+	const assets_prefix = `${config.kit.paths.assets || config.kit.paths.base}/${config.kit.appDir}/`;
 	const options = {
 		cwd,
 		config,
@@ -34,7 +35,7 @@ export async function build(config, { log }) {
 		// during `svelte-kit preview`, because we use a local asset path. If Vite
 		// used relative paths, I _think_ this could get fixed. Issue here:
 		// https://github.com./vitejs/vite/issues/2009
-		assets_base: `${config.kit.paths.assets || config.kit.paths.base}/${config.kit.appDir}/`,
+		assets_base: assets_prefix,
 		manifest_data,
 		output_dir,
 		client_entry_file: path.relative(cwd, `${get_runtime_path(config)}/client/start.js`),
@@ -48,6 +49,7 @@ export async function build(config, { log }) {
 	/** @type {import('types').BuildData} */
 	const build_data = {
 		app_dir: config.kit.appDir,
+		prefix: assets_prefix,
 		manifest_data: options.manifest_data,
 		service_worker: options.service_worker_entry_file ? 'service-worker.js' : null, // TODO make file configurable?
 		client,

packages/kit/src/core/dev/plugin.js

@@ -49,6 +49,7 @@ export async function create_plugin(config, cwd) {
 
 				manifest = {
 					appDir: config.kit.appDir,
+					prefix: config.kit.appDir,
 					assets: new Set(manifest_data.assets.map((asset) => asset.file)),
 					mimeTypes: get_mime_lookup(manifest_data),
 					_: {

packages/kit/src/core/generate_manifest/index.js

@@ -63,6 +63,7 @@ export function generate_manifest({ build_data, relative_path, routes, format =
 	// prettier-ignore
 	return `{
 		appDir: ${s(build_data.app_dir)},
+		prefix: ${s(build_data.prefix)},
 		assets: new Set(${s(assets)}),
 		mimeTypes: ${s(get_mime_lookup(build_data.manifest_data))},
 		_: {

packages/kit/types/index.d.ts

@@ -49,6 +49,7 @@ export interface Builder {
 	getClientDirectory(): string;
 	getServerDirectory(): string;
 	getStaticDirectory(): string;
+	getPrefixedAppDirectory(): string;
 
 	/**
 	 * @param dest the destination folder to which files should be copied
@@ -245,6 +246,7 @@ export class Server {
 
 export interface SSRManifest {
 	appDir: string;
+	prefix: string;
 	assets: Set<string>;
 	mimeTypes: Record<string, string>;
 

packages/kit/types/internal.d.ts

@@ -43,6 +43,7 @@ export interface Asset {
 
 export interface BuildData {
 	app_dir: string;
+	prefix: string;
 	manifest_data: ManifestData;
 	service_worker: string | null;
 	client: {