fix: prerendering encodes url multiple times

.changeset/green-rings-pump.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[fix] don't encode redirects multiple times

.prettierrc

@@ -21,6 +21,14 @@
 			"options": {
 				"requirePragma": true
 			}
+		},
+		{
+			"files": [
+				"packages/kit/src/core/adapt/test/fixtures/**/*.html"
+			],
+			"options": {
+				"requirePragma": true
+			}
 		}
 	]
 }

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

@@ -98,6 +98,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 
 	/**
 	 * @param {string} path
+	 * @returns string
 	 */
 	function normalize(path) {
 		if (config.kit.trailingSlash === 'always') {
@@ -109,19 +110,39 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 		return path;
 	}
 
+	/**
+	 * @param {string} path
+	 * @returns string
+	 */
+	function remove_query_string(path) {
+		return path.split('?')[0];
+	}
+
+	/** @type {(location: string) => string} */
+	function encode_location(location) {
+		const is_relative_url = location.startsWith('.') || location.startsWith('/');
+		if (is_relative_url) {
+			const protocol = 'http://';
+			return new URL(protocol + location).toString().substring(protocol.length);
+		}
+
+		return new URL(location).toString();
+	}
+
 	const q = queue(config.kit.prerender.concurrency);
 
 	/**
 	 * @param {string} decoded_path
 	 * @param {string?} referrer
 	 */
 	function enqueue(decoded_path, referrer) {
-		const path = encodeURI(normalize(decoded_path));
+		const decoded_path_without_query_string = remove_query_string(decoded_path);
+		const path = encodeURI(normalize(decoded_path_without_query_string));
 
 		if (seen.has(path)) return;
 		seen.add(path);
 
-		return q.add(() => visit(path, decoded_path, referrer));
+		return q.add(() => visit(path, decoded_path_without_query_string, referrer));
 	}
 
 	/**
@@ -167,8 +188,10 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 				if (location) {
 					mkdirp(dirname(file));
 
+					const encoded_location = encode_location(location);
+
 					log.warn(`${rendered.status} ${decoded_path} -> ${location}`);
-					writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${encodeURI(location)}">`);
+					writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${encoded_location}">`);
 
 					const resolved = resolve(path, location);
 					if (is_root_relative(resolved)) {
@@ -206,7 +229,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 
 				if (result.body) {
 					writeFileSync(file, result.body);
-					paths.push(dependency_path);
+					paths.push(normalize(dependency_path));
 				}
 
 				if (response_type === OK) {

packages/kit/src/core/adapt/test/fixtures/prerender/.svelte-kit/output/server/app.js

@@ -1,5 +1,34 @@
+function get_redirect_response(url) {
+	const [, , , , url_type, encoding_style] = url.split('/');
+
+	const base_url = (() => {
+		switch (url_type) {
+			case 'absolute-url':
+				return 'https://my.server.com/';
+			case 'path-url':
+				return './../../redirected';
+			case 'relative-url':
+				return '/redirected';
+		}
+	})();
+
+	const search_params =
+		encoding_style === 'encoding'
+			? new URLSearchParams({ redirect: 'https://kit.svelte.dev/docs' }).toString()
+			: 'redirect=https://kit.svelte.dev/docs';
+
+	return {
+		status: 302,
+		headers: {
+			location: `${base_url}?${search_params}`
+		}
+	};
+}
+
 export class App {
-	render() {
+	render({ url }) {
+		if (url.startsWith('http://prerender/redirects/')) return get_redirect_response(url);
+
 		return {
 			status: 200,
 			headers: {

packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/encoding/index.html

@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=https://my.server.com/?redirect=https%3A%2F%2Fkit.svelte.dev%2Fdocs">

packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/absolute-url/no-encoding/index.html

@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=https://my.server.com/?redirect=https://kit.svelte.dev/docs">

packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/encoding/index.html

@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=./redirected?redirect=https%3A%2F%2Fkit.svelte.dev%2Fdocs">

packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/path-url/no-encoding/index.html

@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=./redirected?redirect=https://kit.svelte.dev/docs">

packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/encoding/index.html

@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=redirected/?redirect=https%3A%2F%2Fkit.svelte.dev%2Fdocs">

packages/kit/src/core/adapt/test/fixtures/prerender/build/redirects/relative-url/no-encoding/index.html

@@ -0,0 +1 @@
+<meta http-equiv="refresh" content="0;url=redirected/?redirect=https://kit.svelte.dev/docs">

packages/kit/src/core/adapt/test/index.js

@@ -1,4 +1,4 @@
-import { rmSync } from 'fs';
+import { readFileSync, rmSync } from 'fs';
 import { join } from 'path';
 import * as uvu from 'uvu';
 import * as assert from 'uvu/assert';
@@ -112,7 +112,15 @@ suite('prerender', async () => {
 		// @ts-expect-error
 		server: { chunks: [] },
 		static: [],
-		entries: ['/nested']
+		entries: [
+			'/nested',
+			'/redirects/absolute-url/no-encoding',
+			'/redirects/absolute-url/encoding',
+			'/redirects/path-url/no-encoding',
+			'/redirects/path-url/encoding',
+			'/redirects/relative-url/no-encoding',
+			'/redirects/relative-url/encoding'
+		]
 	};
 
 	const builder = create_builder({
@@ -130,7 +138,23 @@ suite('prerender', async () => {
 		dest
 	});
 
-	assert.equal(glob('**', { cwd: prerendered_files }), glob('**', { cwd: dest }));
+	const expected = glob('**', { cwd: prerendered_files });
+	const files = glob('**', { cwd: dest });
+
+	// test if all files are present
+	assert.equal(files, expected);
+
+	// check each file if content is correct
+	for (const file of expected.filter((file) => file.endsWith('.html'))) {
+		const expected_content = readFileSync(join(prerendered_files, file));
+		const actual_content = readFileSync(join(dest, file));
+
+		assert.equal(
+			actual_content.toString(),
+			expected_content.toString(),
+			`content of '${file}' is not equal`
+		);
+	}
 
 	rmSync(dest, { recursive: true, force: true });
 });