From 1c6067e5de00c9d8b5b2e19dc3eaef08bde13987 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 17:42:58 +0000
Subject: [PATCH 01/14] Saving progress on websockets for discussion

---
 packages/kit/src/exports/public.d.ts          |  52 +++--
 packages/kit/src/exports/vite/dev/index.js    |  84 ++++++--
 packages/kit/src/runtime/app/server/index.js  |   1 +
 packages/kit/src/runtime/server/endpoint.js   |  49 +++--
 packages/kit/src/runtime/server/index.js      |   5 +-
 packages/kit/src/runtime/server/respond.js    |  26 ++-
 packages/kit/src/types/internal.d.ts          |  19 +-
 packages/kit/src/utils/exports.js             |   1 +
 packages/kit/test/apps/ws/README.md           |   1 +
 packages/kit/test/apps/ws/package.json        |  27 +++
 .../kit/test/apps/ws/playwright.config.js     |   1 +
 packages/kit/test/apps/ws/src/app.html        |  11 +
 .../kit/test/apps/ws/src/routes/+page.svelte  |  29 +++
 .../kit/test/apps/ws/src/routes/ws/+server.ts |  18 ++
 packages/kit/test/apps/ws/svelte.config.js    |   6 +
 packages/kit/test/apps/ws/test/test.js        |  89 ++++++++
 packages/kit/test/apps/ws/tsconfig.json       |   8 +
 packages/kit/test/apps/ws/vite.config.js      |  14 ++
 pnpm-lock.yaml                                | 200 ++++++++++++++++++
 19 files changed, 570 insertions(+), 71 deletions(-)
 create mode 100644 packages/kit/test/apps/ws/README.md
 create mode 100644 packages/kit/test/apps/ws/package.json
 create mode 100644 packages/kit/test/apps/ws/playwright.config.js
 create mode 100644 packages/kit/test/apps/ws/src/app.html
 create mode 100644 packages/kit/test/apps/ws/src/routes/+page.svelte
 create mode 100644 packages/kit/test/apps/ws/src/routes/ws/+server.ts
 create mode 100644 packages/kit/test/apps/ws/svelte.config.js
 create mode 100644 packages/kit/test/apps/ws/test/test.js
 create mode 100644 packages/kit/test/apps/ws/tsconfig.json
 create mode 100644 packages/kit/test/apps/ws/vite.config.js

diff --git a/packages/kit/src/exports/public.d.ts b/packages/kit/src/exports/public.d.ts
index 77be062a3163..a8357260f964 100644
--- a/packages/kit/src/exports/public.d.ts
+++ b/packages/kit/src/exports/public.d.ts
@@ -19,6 +19,8 @@ import {
 } from '../types/private.js';
 import { BuildData, SSRNodeLoader, SSRRoute, ValidatedConfig } from 'types';
 import type { PluginOptions } from '@sveltejs/vite-plugin-svelte';
+import type { IncomingMessage } from 'node:http';
+import type { Duplex } from 'node:stream';
 
 export { PrerenderOption } from '../types/private.js';
 
@@ -315,7 +317,7 @@ export interface KitConfig {
 	/**
 	 * The directory where SvelteKit keeps its stuff, including static assets (such as JS and CSS) and internally-used routes.
 	 *
-	 * If `paths.assets` is specified, there will be two app directories — `${paths.assets}/${appDir}` and `${paths.base}/${appDir}`.
+	 * If `paths.assets` is specified, there will be two app directories - `${paths.assets}/${appDir}` and `${paths.base}/${appDir}`.
 	 * @default "_app"
 	 */
 	appDir?: string;
@@ -548,10 +550,10 @@ export interface KitConfig {
 		/**
 		 * How to respond to HTTP errors encountered while prerendering the app.
 		 *
-		 * - `'fail'` — fail the build
+		 * - `'fail'` - fail the build
 		 * - `'ignore'` - silently ignore the failure and continue
-		 * - `'warn'` — continue, but print a warning
-		 * - `(details) => void` — a custom error handler that takes a `details` object with `status`, `path`, `referrer`, `referenceType` and `message` properties. If you `throw` from this function, the build will fail
+		 * - `'warn'` - continue, but print a warning
+		 * - `(details) => void` - a custom error handler that takes a `details` object with `status`, `path`, `referrer`, `referenceType` and `message` properties. If you `throw` from this function, the build will fail
 		 *
 		 * ```js
 		 * /// file: svelte.config.js
@@ -580,10 +582,10 @@ export interface KitConfig {
 		/**
 		 * How to respond when hash links from one prerendered page to another don't correspond to an `id` on the destination page.
 		 *
-		 * - `'fail'` — fail the build
+		 * - `'fail'` - fail the build
 		 * - `'ignore'` - silently ignore the failure and continue
-		 * - `'warn'` — continue, but print a warning
-		 * - `(details) => void` — a custom error handler that takes a `details` object with `path`, `id`, `referrers` and `message` properties. If you `throw` from this function, the build will fail
+		 * - `'warn'` - continue, but print a warning
+		 * - `(details) => void` - a custom error handler that takes a `details` object with `path`, `id`, `referrers` and `message` properties. If you `throw` from this function, the build will fail
 		 *
 		 * @default "fail"
 		 * @since 1.15.7
@@ -592,10 +594,10 @@ export interface KitConfig {
 		/**
 		 * How to respond when an entry generated by the `entries` export doesn't match the route it was generated from.
 		 *
-		 * - `'fail'` — fail the build
+		 * - `'fail'` - fail the build
 		 * - `'ignore'` - silently ignore the failure and continue
-		 * - `'warn'` — continue, but print a warning
-		 * - `(details) => void` — a custom error handler that takes a `details` object with `generatedFromId`, `entry`, `matchedId` and `message` properties. If you `throw` from this function, the build will fail
+		 * - `'warn'` - continue, but print a warning
+		 * - `(details) => void` - a custom error handler that takes a `details` object with `generatedFromId`, `entry`, `matchedId` and `message` properties. If you `throw` from this function, the build will fail
 		 *
 		 * @default "fail"
 		 * @since 1.16.0
@@ -685,8 +687,8 @@ export interface KitConfig {
  */
 export type Handle = (input: {
 	event: RequestEvent;
-	resolve(event: RequestEvent, opts?: ResolveOptions): MaybePromise<Response>;
-}) => MaybePromise<Response>;
+	resolve(event: RequestEvent, opts?: ResolveOptions): MaybePromise<void | Response>;
+}) => MaybePromise<void | Response>;
 
 /**
  * The server-side [`handleError`](https://svelte.dev/docs/kit/hooks#shared-hooks-handleError) hook runs when an unexpected error is thrown while responding to a request.
@@ -785,9 +787,9 @@ export interface LoadEvent<
 	 *	}
 	 *	```
 	 *
-	 * Setting the same header multiple times (even in separate `load` functions) is an error — you can only set a given header once.
+	 * Setting the same header multiple times (even in separate `load` functions) is an error - you can only set a given header once.
 	 *
-	 * You cannot add a `set-cookie` header with `setHeaders` — use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API in a server-only `load` function instead.
+	 * You cannot add a `set-cookie` header with `setHeaders` - use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API in a server-only `load` function instead.
 	 *
 	 * `setHeaders` has no effect when a `load` function runs in the browser.
 	 */
@@ -802,7 +804,7 @@ export interface LoadEvent<
 	/**
 	 * This function declares that the `load` function has a _dependency_ on one or more URLs or custom identifiers, which can subsequently be used with [`invalidate()`](https://svelte.dev/docs/kit/$app-navigation#invalidate) to cause `load` to rerun.
 	 *
-	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf — it's only necessary if you're using a custom API client that bypasses `fetch`.
+	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf - it's only necessary if you're using a custom API client that bypasses `fetch`.
 	 *
 	 * URLs can be absolute or relative to the page being loaded, and must be [encoded](https://developer.mozilla.org/en-US/docs/Glossary/percent-encoding).
 	 *
@@ -1076,6 +1078,10 @@ export interface RequestEvent<
 	 * The original request object
 	 */
 	request: Request;
+		/**
+	 * The upgrade request object
+	 */
+	upgrade?: {request: IncomingMessage, socket: Duplex, head: Buffer}
 	/**
 	 * Info about the current route
 	 */
@@ -1103,9 +1109,9 @@ export interface RequestEvent<
 	 *	}
 	 *	```
 	 *
-	 * Setting the same header multiple times (even in separate `load` functions) is an error — you can only set a given header once.
+	 * Setting the same header multiple times (even in separate `load` functions) is an error - you can only set a given header once.
 	 *
-	 * You cannot add a `set-cookie` header with `setHeaders` — use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API instead.
+	 * You cannot add a `set-cookie` header with `setHeaders` - use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API instead.
 	 */
 	setHeaders(headers: Record<string, string>): void;
 	/**
@@ -1133,6 +1139,16 @@ export type RequestHandler<
 	RouteId extends string | null = string | null
 > = (event: RequestEvent<Params, RouteId>) => MaybePromise<Response>;
 
+/**
+ * A `(event: UpgradeEvent) => void` function exported from a `+server.js` file with the name UPGRADE and handles server upgrade requests.
+ *
+ * It receives `Params` as the first generic argument, which you can skip by using [generated types](https://svelte.dev/docs/kit/types#Generated-types) instead.
+ */
+export type UpgradeHandler<
+	Params extends Partial<Record<string, string>> = Partial<Record<string, string>>,
+	RouteId extends string | null = string | null
+> = (event: RequestEvent<Params, RouteId>) => MaybePromise<void>;
+
 export interface ResolveOptions {
 	/**
 	 * Applies custom transforms to HTML. If `done` is true, it's the final chunk. Chunks are not guaranteed to be well-formed HTML
@@ -1226,7 +1242,7 @@ export interface ServerLoadEvent<
 	/**
 	 * This function declares that the `load` function has a _dependency_ on one or more URLs or custom identifiers, which can subsequently be used with [`invalidate()`](https://svelte.dev/docs/kit/$app-navigation#invalidate) to cause `load` to rerun.
 	 *
-	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf — it's only necessary if you're using a custom API client that bypasses `fetch`.
+	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf - it's only necessary if you're using a custom API client that bypasses `fetch`.
 	 *
 	 * URLs can be absolute or relative to the page being loaded, and must be [encoded](https://developer.mozilla.org/en-US/docs/Glossary/percent-encoding).
 	 *
diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index 0dbc912940a2..6f92ae590ada 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -43,7 +43,7 @@ export async function dev(vite, vite_config, svelte_config) {
 	globalThis.fetch = (info, init) => {
 		if (typeof info === 'string' && !SCHEME.test(info)) {
 			throw new Error(
-				`Cannot use relative URL (${info}) with global fetch — use \`event.fetch\` instead: https://svelte.dev/docs/kit/web-standards#fetch-apis`
+				`Cannot use relative URL (${info}) with global fetch - use \`event.fetch\` instead: https://svelte.dev/docs/kit/web-standards#fetch-apis`
 			);
 		}
 
@@ -431,6 +431,52 @@ export async function dev(vite, vite_config, svelte_config) {
 		// serving routes with those names. See https://github.com/vitejs/vite/issues/7363
 		remove_static_middlewares(vite.middlewares);
 
+		vite.httpServer?.on('upgrade', async (req, socket, head) => {
+			const base = `${vite.config.server.https ? 'wss' : 'ws'}://${
+				req.headers[':authority'] || req.headers.host
+			}`;
+
+			// we have to import `Server` before calling `set_assets`
+			const { Server } = /** @type {import('types').ServerModule} */ (
+				await vite.ssrLoadModule(`${runtime_base}/server/index.js`, { fixStacktrace: true })
+			);
+
+			const server = new Server(manifest);
+
+			await server.init({
+				env,
+				read: (file) => createReadableStream(from_fs(file))
+			});
+
+			const request = await getRequest({
+				base,
+				request: req
+			});
+
+			await server.respond(
+				request,
+				{
+					getClientAddress: () => {
+						const { remoteAddress } = req.socket;
+						if (remoteAddress) return remoteAddress;
+						throw new Error('Could not determine clientAddress');
+					},
+					read: (file) => {
+						if (file in manifest._.server_assets) {
+							return fs.readFileSync(from_fs(file));
+						}
+
+						return fs.readFileSync(path.join(svelte_config.kit.files.assets, file));
+					},
+					before_handle: (event, config, prerender) => {
+						async_local_storage.enterWith({ event, config, prerender });
+					},
+					emulator
+				},
+				{ request: req, socket, head }
+			);
+		});
+
 		vite.middlewares.use(async (req, res) => {
 			// Vite's base middleware strips out the base path. Restore it
 			const original_url = req.url;
@@ -521,24 +567,28 @@ export async function dev(vite, vite_config, svelte_config) {
 					return;
 				}
 
-				const rendered = await server.respond(request, {
-					getClientAddress: () => {
-						const { remoteAddress } = req.socket;
-						if (remoteAddress) return remoteAddress;
-						throw new Error('Could not determine clientAddress');
-					},
-					read: (file) => {
-						if (file in manifest._.server_assets) {
-							return fs.readFileSync(from_fs(file));
-						}
+				const rendered = await server.respond(
+					request,
+					{
+						getClientAddress: () => {
+							const { remoteAddress } = req.socket;
+							if (remoteAddress) return remoteAddress;
+							throw new Error('Could not determine clientAddress');
+						},
+						read: (file) => {
+							if (file in manifest._.server_assets) {
+								return fs.readFileSync(from_fs(file));
+							}
 
-						return fs.readFileSync(path.join(svelte_config.kit.files.assets, file));
+							return fs.readFileSync(path.join(svelte_config.kit.files.assets, file));
+						},
+						before_handle: (event, config, prerender) => {
+							async_local_storage.enterWith({ event, config, prerender });
+						},
+						emulator
 					},
-					before_handle: (event, config, prerender) => {
-						async_local_storage.enterWith({ event, config, prerender });
-					},
-					emulator
-				});
+					undefined
+				);
 
 				if (rendered.status === 404) {
 					// @ts-expect-error
diff --git a/packages/kit/src/runtime/app/server/index.js b/packages/kit/src/runtime/app/server/index.js
index 33c9b0a0d1ba..8a3c7283d6a8 100644
--- a/packages/kit/src/runtime/app/server/index.js
+++ b/packages/kit/src/runtime/app/server/index.js
@@ -71,3 +71,4 @@ export function read(asset) {
 
 	throw new Error(`Asset does not exist: ${file}`);
 }
+
diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index 55bcd87807b9..162e774474ff 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -7,9 +7,10 @@ import { method_not_allowed } from './utils.js';
  * @param {import('@sveltejs/kit').RequestEvent} event
  * @param {import('types').SSREndpoint} mod
  * @param {import('types').SSRState} state
- * @returns {Promise<Response>}
+ * @returns {Promise<Response | void>}
  */
 export async function render_endpoint(event, mod, state) {
+	console.log(event);
 	const method = /** @type {import('types').HttpMethod} */ (event.request.method);
 
 	let handler = mod[method] || mod.fallback;
@@ -40,28 +41,36 @@ export async function render_endpoint(event, mod, state) {
 	}
 
 	try {
-		let response = await handler(
-			/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
-		);
-
-		if (!(response instanceof Response)) {
-			throw new Error(
-				`Invalid response from route ${event.url.pathname}: handler should return a Response object`
+		if (method === 'GET' && event.request.headers.has('upgrade') && event.upgrade && mod.UPGRADE) {
+			console.log('upgrade');
+			await mod.UPGRADE(/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event));
+		} else {
+			console.log('not upgrade');
+			let response = await handler(
+				/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
 			);
-		}
 
-		if (state.prerendering) {
-			// the returned Response might have immutable Headers
-			// so we should clone them before trying to mutate them
-			response = new Response(response.body, {
-				status: response.status,
-				statusText: response.statusText,
-				headers: new Headers(response.headers)
-			});
-			response.headers.set('x-sveltekit-prerender', String(prerender));
+			if (!(response instanceof Response)) {
+				throw new Error(
+					`Invalid response from route ${event.url.pathname}: handler should return a Response object`
+				);
+			}
+
+			if (state.prerendering) {
+				// the returned Response might have immutable Headers
+				// so we should clone them before trying to mutate them
+				response = new Response(response.body, {
+					status: response.status,
+					statusText: response.statusText,
+					headers: new Headers(response.headers)
+				});
+				response.headers.set('x-sveltekit-prerender', String(prerender));
+			}
+
+			console.log(response);
+
+			return response;
 		}
-
-		return response;
 	} catch (e) {
 		if (e instanceof Redirect) {
 			return new Response(undefined, {
diff --git a/packages/kit/src/runtime/server/index.js b/packages/kit/src/runtime/server/index.js
index 36cbd04be16f..53c22589a5dd 100644
--- a/packages/kit/src/runtime/server/index.js
+++ b/packages/kit/src/runtime/server/index.js
@@ -92,13 +92,14 @@ export class Server {
 
 	/**
 	 * @param {Request} request
+	 * @param {{request: import('http').IncomingMessage, socket: import('stream').Duplex , head: Buffer}?} webhookRequest
 	 * @param {import('types').RequestOptions} options
 	 */
-	async respond(request, options) {
+	async respond(request, webhookRequest, options) {
 		return respond(request, this.#options, this.#manifest, {
 			...options,
 			error: false,
 			depth: 0
-		});
+		}, webhookRequest);
 	}
 }
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
index f81f52ef2557..a26bd2c18e92 100644
--- a/packages/kit/src/runtime/server/respond.js
+++ b/packages/kit/src/runtime/server/respond.js
@@ -54,10 +54,12 @@ const allowed_page_methods = new Set(['GET', 'HEAD', 'OPTIONS']);
  * @param {import('types').SSROptions} options
  * @param {import('@sveltejs/kit').SSRManifest} manifest
  * @param {import('types').SSRState} state
- * @returns {Promise<Response>}
+ * @param {{request: import('http').IncomingMessage, socket: import('stream').Duplex , head: Buffer}?} upgradeRequest
+ * @returns {Promise<void | Response>}
  */
-export async function respond(request, options, manifest, state) {
+export async function respond(request, options, manifest, state, upgradeRequest) {
 	/** URL but stripped from the potential `/__data.json` suffix and its search param  */
+	console.log('hit respond');
 	const url = new URL(request.url);
 
 	if (options.csrf_check_origin) {
@@ -81,6 +83,7 @@ export async function respond(request, options, manifest, state) {
 		}
 	}
 
+	console.log('hit reroute');
 	// reroute could alter the given URL, so we pass a copy
 	let rerouted_path;
 	try {
@@ -91,6 +94,7 @@ export async function respond(request, options, manifest, state) {
 		});
 	}
 
+	console.log('hit decode');
 	let decoded;
 	try {
 		decoded = decode_pathname(rerouted_path);
@@ -139,7 +143,7 @@ export async function respond(request, options, manifest, state) {
 	}
 
 	if (!state.prerendering?.fallback) {
-		// TODO this could theoretically break — should probably be inside a try-catch
+		// TODO this could theoretically break - should probably be inside a try-catch
 		const matchers = await manifest._.matchers();
 
 		for (const candidate of manifest._.routes) {
@@ -206,6 +210,12 @@ export async function respond(request, options, manifest, state) {
 		isDataRequest: is_data_request,
 		isSubRequest: state.depth > 0
 	};
+	console.log('hit create event');
+
+	if(upgradeRequest) {
+		console.log('hit upgrade event');
+		event.upgrade = upgradeRequest;
+	}
 
 	/** @type {import('types').RequiredResolveOptions} */
 	let resolve_opts = {
@@ -324,10 +334,12 @@ export async function respond(request, options, manifest, state) {
 
 		if (state.prerendering && !state.prerendering.fallback) disable_search(url);
 
+		console.log('hit handle');
 		const response = await options.hooks.handle({
 			event,
 			resolve: (event, opts) =>
 				resolve(event, opts).then((response) => {
+					if(!response) return;
 					// add headers/cookies here, rather than inside `resolve`, so that we
 					// can do it once for all responses instead of once per `return`
 					for (const key in headers) {
@@ -346,7 +358,7 @@ export async function respond(request, options, manifest, state) {
 		});
 
 		// respond with 304 if etag matches
-		if (response.status === 200 && response.headers.has('etag')) {
+		if (response?.status === 200 && response?.headers.has('etag')) {
 			let if_none_match_value = request.headers.get('if-none-match');
 
 			// ignore W/ prefix https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-None-Match#directives
@@ -381,7 +393,7 @@ export async function respond(request, options, manifest, state) {
 
 		// Edge case: If user does `return Response(30x)` in handle hook while processing a data request,
 		// we need to transform the redirect response to a corresponding JSON response.
-		if (is_data_request && response.status >= 300 && response.status <= 308) {
+		if (is_data_request && response && response.status >= 300 && response.status <= 308) {
 			const location = response.headers.get('location');
 			if (location) {
 				return redirect_json_response(new Redirect(/** @type {any} */ (response.status), location));
@@ -434,7 +446,7 @@ export async function respond(request, options, manifest, state) {
 			if (route) {
 				const method = /** @type {import('types').HttpMethod} */ (event.request.method);
 
-				/** @type {Response} */
+				/** @type {void | Response} */
 				let response;
 
 				if (is_data_request) {
@@ -484,7 +496,7 @@ export async function respond(request, options, manifest, state) {
 
 				// If the route contains a page and an endpoint, we need to add a
 				// `Vary: Accept` header to the response because of browser caching
-				if (request.method === 'GET' && route.page && route.endpoint) {
+				if (request.method === 'GET' && route.page && route.endpoint && response) {
 					const vary = response.headers
 						.get('vary')
 						?.split(',')
diff --git a/packages/kit/src/types/internal.d.ts b/packages/kit/src/types/internal.d.ts
index c9dbb51ce007..d60972a97447 100644
--- a/packages/kit/src/types/internal.d.ts
+++ b/packages/kit/src/types/internal.d.ts
@@ -17,7 +17,8 @@ import {
 	RequestEvent,
 	SSRManifest,
 	Emulator,
-	Adapter
+	Adapter,
+	UpgradeHandler
 } from '@sveltejs/kit';
 import {
 	HttpMethod,
@@ -26,6 +27,8 @@ import {
 	RequestOptions,
 	TrailingSlash
 } from './private.js';
+import type { IncomingMessage } from 'node:http';
+import type { Duplex } from 'node:stream';
 
 export interface ServerModule {
 	Server: typeof InternalServer;
@@ -131,7 +134,8 @@ export class InternalServer extends Server {
 			/** A hook called before `handle` during dev, so that `AsyncLocalStorage` can be populated */
 			before_handle?: (event: RequestEvent, config: any, prerender: PrerenderOption) => void;
 			emulator?: Emulator;
-		}
+		},
+		webhookRequest?: {request: IncomingMessage, socket: Duplex, head: Buffer},
 	): Promise<Response>;
 }
 
@@ -386,11 +390,12 @@ export interface PageNodeIndexes {
 export type PrerenderEntryGenerator = () => MaybePromise<Array<Record<string, string>>>;
 
 export type SSREndpoint = Partial<Record<HttpMethod, RequestHandler>> & {
-	prerender?: PrerenderOption;
-	trailingSlash?: TrailingSlash;
-	config?: any;
-	entries?: PrerenderEntryGenerator;
-	fallback?: RequestHandler;
+  UPGRADE?: UpgradeHandler;
+  prerender?: PrerenderOption;
+  trailingSlash?: TrailingSlash;
+  config?: any;
+  entries?: PrerenderEntryGenerator;
+  fallback?: RequestHandler;
 };
 
 export interface SSRRoute {
diff --git a/packages/kit/src/utils/exports.js b/packages/kit/src/utils/exports.js
index ed685edb7ded..93860c5b5377 100644
--- a/packages/kit/src/utils/exports.js
+++ b/packages/kit/src/utils/exports.js
@@ -72,6 +72,7 @@ const valid_page_exports = new Set([...valid_layout_exports, 'entries']);
 const valid_layout_server_exports = new Set([...valid_layout_exports]);
 const valid_page_server_exports = new Set([...valid_layout_server_exports, 'actions', 'entries']);
 const valid_server_exports = new Set([
+	'UPGRADE',
 	'GET',
 	'POST',
 	'PATCH',
diff --git a/packages/kit/test/apps/ws/README.md b/packages/kit/test/apps/ws/README.md
new file mode 100644
index 000000000000..dddfaa2ca89c
--- /dev/null
+++ b/packages/kit/test/apps/ws/README.md
@@ -0,0 +1 @@
+This app exists to test websocket implementations.
diff --git a/packages/kit/test/apps/ws/package.json b/packages/kit/test/apps/ws/package.json
new file mode 100644
index 000000000000..20d0a22b928b
--- /dev/null
+++ b/packages/kit/test/apps/ws/package.json
@@ -0,0 +1,27 @@
+{
+	"name": "test-ws",
+	"private": true,
+	"version": "0.0.1",
+	"scripts": {
+		"dev": "vite dev",
+		"build": "vite build",
+		"preview": "vite preview",
+		"check": "svelte-kit sync && tsc && svelte-check",
+		"test": "pnpm test:dev && pnpm test:build",
+		"test:dev": "cross-env DEV=true playwright test",
+		"test:build": "playwright test"
+	},
+	"devDependencies": {
+		"@sveltejs/adapter-node": "workspace:^",
+		"@sveltejs/kit": "workspace:^",
+		"@sveltejs/vite-plugin-svelte": "^3.0.1",
+		"cross-env": "^7.0.3",
+		"socket.io": "^4.8.1",
+		"svelte": "^4.2.10",
+		"svelte-check": "^4.0.1",
+		"typescript": "^5.3.3",
+		"vite": "^5.3.2",
+		"ws": "^8.18.0"
+	},
+	"type": "module"
+}
diff --git a/packages/kit/test/apps/ws/playwright.config.js b/packages/kit/test/apps/ws/playwright.config.js
new file mode 100644
index 000000000000..33d36b651014
--- /dev/null
+++ b/packages/kit/test/apps/ws/playwright.config.js
@@ -0,0 +1 @@
+export { config as default } from '../../utils.js';
diff --git a/packages/kit/test/apps/ws/src/app.html b/packages/kit/test/apps/ws/src/app.html
new file mode 100644
index 000000000000..b8ba4699b2ba
--- /dev/null
+++ b/packages/kit/test/apps/ws/src/app.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		%sveltekit.head%
+	</head>
+	<body>
+		<div style="display: contents">%sveltekit.body%</div>
+	</body>
+</html>
diff --git a/packages/kit/test/apps/ws/src/routes/+page.svelte b/packages/kit/test/apps/ws/src/routes/+page.svelte
new file mode 100644
index 000000000000..e83274902d05
--- /dev/null
+++ b/packages/kit/test/apps/ws/src/routes/+page.svelte
@@ -0,0 +1,29 @@
+<script>
+	import { browser } from '$app/environment';
+
+	const events = [];
+	if (browser) {
+		console.log('connecting');
+		const websocket = new WebSocket('/ws');
+
+		console.log(websocket);
+
+		websocket.onopen = () => {
+			console.log('connected');
+			websocket.send('hello');
+		};
+
+		websocket.onmessage = (event) => {
+			events.push(event.data);
+			console.log(event.data);
+		};
+	}
+</script>
+
+<h1>Hello</h1>
+
+<div>
+	{#each events as event}
+		<p>{event}</p>
+	{/each}
+</div>
diff --git a/packages/kit/test/apps/ws/src/routes/ws/+server.ts b/packages/kit/test/apps/ws/src/routes/ws/+server.ts
new file mode 100644
index 000000000000..b15fdc03a0f9
--- /dev/null
+++ b/packages/kit/test/apps/ws/src/routes/ws/+server.ts
@@ -0,0 +1,18 @@
+import { WebSocketServer } from 'ws';
+// import { Server } from "socket.io";
+
+const wss = new WebSocketServer({ noServer: true });
+// const io = new Server();
+
+export function UPGRADE({upgrade}) {
+		console.log(request);
+			wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
+				wss.emit('connection', ws, request);
+			});
+}
+
+export function GET({request}) {
+	console.log(request);
+
+	return new Response('ok');
+}
diff --git a/packages/kit/test/apps/ws/svelte.config.js b/packages/kit/test/apps/ws/svelte.config.js
new file mode 100644
index 000000000000..821c14379ec8
--- /dev/null
+++ b/packages/kit/test/apps/ws/svelte.config.js
@@ -0,0 +1,6 @@
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
+	kit: {}
+};
+
+export default config;
diff --git a/packages/kit/test/apps/ws/test/test.js b/packages/kit/test/apps/ws/test/test.js
new file mode 100644
index 000000000000..1633e55d28b4
--- /dev/null
+++ b/packages/kit/test/apps/ws/test/test.js
@@ -0,0 +1,89 @@
+import process from 'node:process';
+import { expect } from '@playwright/test';
+import { test } from '../../../utils.js';
+
+/** @typedef {import('@playwright/test').Response} Response */
+
+test.describe.configure({ mode: 'parallel' });
+
+test.describe('env', () => {
+	test('resolves upwards', async ({ page }) => {
+		await page.goto('/basepath/env');
+		expect(await page.textContent('[data-testid="static"]')).toBe('static: resolves upwards!');
+		expect(await page.textContent('[data-testid="dynamic"]')).toBe('dynamic: resolves upwards!');
+	});
+});
+
+test.describe('paths', () => {
+	test('serves /basepath', async ({ page }) => {
+		await page.goto('/basepath');
+		expect(await page.textContent('h1')).toBe('Hello');
+	});
+
+	test('serves assets from /basepath', async ({ request }) => {
+		const response = await request.get('/basepath/answer.txt');
+		expect(await response.text()).toBe('42');
+	});
+
+	test('uses relative paths during SSR', async ({ page, javaScriptEnabled }) => {
+		await page.goto('/basepath');
+
+		let base = javaScriptEnabled ? '/basepath' : '.';
+		expect(await page.textContent('[data-testid="base"]')).toBe(`base: ${base}`);
+		expect(await page.textContent('[data-testid="assets"]')).toBe(`assets: ${base}`);
+
+		await page.goto('/basepath/deeply/nested/page');
+
+		base = javaScriptEnabled ? '/basepath' : '../..';
+		expect(await page.textContent('[data-testid="base"]')).toBe(`base: ${base}`);
+		expect(await page.textContent('[data-testid="assets"]')).toBe(`assets: ${base}`);
+	});
+
+	test('serves /basepath with trailing slash always', async ({ page }) => {
+		await page.goto('/basepath');
+		expect(new URL(page.url()).pathname).toBe('/basepath/');
+	});
+
+	test('respects trailing slash option when navigating from /basepath', async ({
+		page,
+		clicknav
+	}) => {
+		await page.goto('/basepath');
+		expect(new URL(page.url()).pathname).toBe('/basepath/');
+		await clicknav('[data-testid="link"]');
+		expect(new URL(page.url()).pathname).toBe('/basepath/hello');
+	});
+});
+
+test.describe('Service worker', () => {
+	if (process.env.DEV) return;
+
+	test('build /basepath/service-worker.js', async ({ baseURL, request }) => {
+		const response = await request.get('/basepath/service-worker.js');
+		const content = await response.text();
+
+		const fn = new Function('self', 'location', content);
+
+		const self = {
+			addEventListener: () => {},
+			base: null,
+			build: null
+		};
+
+		const pathname = '/basepath/service-worker.js';
+
+		fn(self, {
+			href: baseURL + pathname,
+			pathname
+		});
+
+		expect(self.base).toBe('/basepath');
+		expect(self.build[0]).toMatch(/\/basepath\/_app\/immutable\/entry\/start\.[\w-]+\.js/);
+		expect(self.image_src).toMatch(/\/basepath\/_app\/immutable\/assets\/image\.[\w-]+\.jpg/);
+	});
+
+	test('does not register /basepath/service-worker.js', async ({ page }) => {
+		await page.goto('/basepath');
+		expect(await page.content()).not.toMatch(/navigator\.serviceWorker/);
+	});
+});
diff --git a/packages/kit/test/apps/ws/tsconfig.json b/packages/kit/test/apps/ws/tsconfig.json
new file mode 100644
index 000000000000..b1096bf168cd
--- /dev/null
+++ b/packages/kit/test/apps/ws/tsconfig.json
@@ -0,0 +1,8 @@
+{
+	"compilerOptions": {
+		"allowJs": true,
+		"checkJs": true,
+		"noEmit": true
+	},
+	"extends": "./.svelte-kit/tsconfig.json"
+}
diff --git a/packages/kit/test/apps/ws/vite.config.js b/packages/kit/test/apps/ws/vite.config.js
new file mode 100644
index 000000000000..8e2cdfd37133
--- /dev/null
+++ b/packages/kit/test/apps/ws/vite.config.js
@@ -0,0 +1,14 @@
+import { sveltekit } from '@sveltejs/kit/vite';
+import path from 'path';
+
+/** @type {import('vite').UserConfig} */
+const config = {
+	plugins: [sveltekit()],
+	server: {
+		fs: {
+			allow: [path.resolve('../../../src')]
+		}
+	},
+};
+
+export default config;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0a360411ab50..0496bf454bfc 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -644,6 +644,39 @@ importers:
         specifier: ^5.3.2
         version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
 
+  packages/kit/test/apps/ws:
+    devDependencies:
+      '@sveltejs/adapter-node':
+        specifier: workspace:^
+        version: link:../../../../adapter-node
+      '@sveltejs/kit':
+        specifier: workspace:^
+        version: link:../../..
+      '@sveltejs/vite-plugin-svelte':
+        specifier: ^3.0.1
+        version: 3.1.0(svelte@4.2.19)(vite@5.3.6(@types/node@18.19.50)(lightningcss@1.24.1))
+      cross-env:
+        specifier: ^7.0.3
+        version: 7.0.3
+      socket.io:
+        specifier: ^4.8.1
+        version: 4.8.1
+      svelte:
+        specifier: ^4.2.10
+        version: 4.2.19
+      svelte-check:
+        specifier: ^4.0.1
+        version: 4.0.1(picomatch@4.0.2)(svelte@4.2.19)(typescript@5.6.3)
+      typescript:
+        specifier: ^5.3.3
+        version: 5.6.3
+      vite:
+        specifier: ^5.3.2
+        version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
+      ws:
+        specifier: ^8.18.0
+        version: 8.18.0
+
   packages/kit/test/build-errors:
     devDependencies:
       vitest:
@@ -1911,6 +1944,9 @@ packages:
   '@sinclair/typebox@0.27.8':
     resolution: {integrity: sha512-+Fj43pSMwJs4KRrH/938Uf+uAELIgVBmQzg/q1YG10djyfA3TnrU8N8XzqCh/okZdszqBQTZf96idMfE5lnwTA==}
 
+  '@socket.io/component-emitter@3.1.2':
+    resolution: {integrity: sha512-9BCxFwvbGg/RsZK9tjXd8s4UcwR0MWeFQ1XEKIQVVvAGJyINdrqKMcTRyLoK8Rse1GjzLV9cwjWV1olXRWEXVA==}
+
   '@stylistic/eslint-plugin-js@2.1.0':
     resolution: {integrity: sha512-gdXUjGNSsnY6nPyqxu6lmDTtVrwCOjun4x8PUn0x04d5ucLI74N3MT1Q0UhdcOR9No3bo5PGDyBgXK+KmD787A==}
     engines: {node: ^18.18.0 || ^20.9.0 || >=21.1.0}
@@ -1962,9 +1998,15 @@ packages:
   '@types/connect@3.4.38':
     resolution: {integrity: sha512-K6uROf1LD88uDQqJCktA4yzL1YYAK6NgfsI0v/mTgyPKWsX1CnJ0XPSDhViejru1GcRkLWb8RlzFYJRqGUbaug==}
 
+  '@types/cookie@0.4.1':
+    resolution: {integrity: sha512-XW/Aa8APYr6jSVVA1y/DEIZX0/GMKLEVekNG727R8cs56ahETkRAy/3DR7+fJyh7oUgGwNQaRfXCun0+KbWY7Q==}
+
   '@types/cookie@0.6.0':
     resolution: {integrity: sha512-4Kh9a6B2bQciAhf7FSuMRRkUWecJgJu9nPnx3yzpsfXX/c50REIqpHY4C82bXP90qrLtXtkDxTZosYO3UpOwlA==}
 
+  '@types/cors@2.8.17':
+    resolution: {integrity: sha512-8CGDvrBj1zgo2qE+oS3pOCyYNqCPryMWY2bGfwA0dcfopWGgxs+78df0Rs3rc9THP4JkOhLsAa+15VdpAqkcUA==}
+
   '@types/eslint@8.56.12':
     resolution: {integrity: sha512-03ruubjWyOHlmljCVoxSuNDdmfZDzsrrz0P2LeJsOXr+ZwFQ+0yQIwNCwt/GYhV7Z31fgtXJTAEs+FYlEL851g==}
 
@@ -2078,6 +2120,10 @@ packages:
   abbrev@1.1.1:
     resolution: {integrity: sha512-nne9/IiQ/hzIhY6pdDnbBtz7DjPTKrY00P/zvPSm5pOFkl6xuGrGnXn/VtTNNfNtAfZ9/1RtehkszU9qcTii0Q==}
 
+  accepts@1.3.8:
+    resolution: {integrity: sha512-PYAthTa2m2VKxuvSD3DPC/Gy+U+sOA1LAuT8mkmRuvw+NACSaeXEQ+NHcVF7rONl6qcaxV3Uuemwawk+7+SJLw==}
+    engines: {node: '>= 0.6'}
+
   acorn-import-attributes@1.9.5:
     resolution: {integrity: sha512-n02Vykv5uA3eHGM/Z2dQrcD56kL8TyDb2p1+0P83PClMnC/nc+anbQRhIOWnSq4Ke/KvDPrY3C9hDtC/A3eHnQ==}
     peerDependencies:
@@ -2168,6 +2214,10 @@ packages:
   balanced-match@1.0.2:
     resolution: {integrity: sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw==}
 
+  base64id@2.0.0:
+    resolution: {integrity: sha512-lGe34o6EHj9y3Kts9R4ZYs/Gr+6N7MCaMlIFA3F1R2O5/m7K06AxfSeO5530PEERE6/WyEg3lsuyw4GHlPZHog==}
+    engines: {node: ^4.5.0 || >= 5.9}
+
   better-path-resolve@1.0.0:
     resolution: {integrity: sha512-pbnl5XzGBdrFU/wT4jqmJVPn2B6UHPBOhzMQkY/SPUPB6QtUXtmBHBIwCbXJol93mOpGMnQyP/+BB19q04xj7g==}
     engines: {node: '>=4'}
@@ -2283,6 +2333,14 @@ packages:
     resolution: {integrity: sha512-U71cyTamuh1CRNCfpGY6to28lxvNwPG4Guz/EVjgf3Jmzv0vlDp1atT9eS5dDjMYHucpHbWns6Lwf3BKz6svdw==}
     engines: {node: '>= 0.6'}
 
+  cookie@0.7.2:
+    resolution: {integrity: sha512-yki5XnKuf750l50uGTllt6kKILY4nQ1eNIQatoXEByZ5dWgnKqbnqmTrBE5B4N7lrMJKQ2ytWMiTO2o0v6Ew/w==}
+    engines: {node: '>= 0.6'}
+
+  cors@2.8.5:
+    resolution: {integrity: sha512-KIHbLJqu73RGr/hnbrO9uBeixNGuvSQjul/jdFvS/KFSIH1hWVd1ng7zOHx+YrEfInLG7q4n6GHQ9cDtxv/P6g==}
+    engines: {node: '>= 0.10'}
+
   cross-env@7.0.3:
     resolution: {integrity: sha512-+/HKd6EgcQCJGh2PSjZuUitQBQynKor4wrFbRg4DtAgS1aWO+gU52xpH7M9ScGgXSYmAVS9bIJ8EzuaGw0oNAw==}
     engines: {node: '>=10.14', npm: '>=6', yarn: '>=1'}
@@ -2393,6 +2451,14 @@ packages:
   emoji-regex@8.0.0:
     resolution: {integrity: sha512-MSjYzcWNOA0ewAHpz0MxpYFvwg6yjy1NG3xteoqz644VCo/RPgnr1/GGt+ic3iJTzQ8Eu3TdM14SawnVUmGE6A==}
 
+  engine.io-parser@5.2.3:
+    resolution: {integrity: sha512-HqD3yTBfnBxIrbnM1DoD6Pcq8NECnh8d4As1Qgh0z5Gg3jRRIqijury0CL3ghu/edArpUYiYqQiDUQBIs4np3Q==}
+    engines: {node: '>=10.0.0'}
+
+  engine.io@6.6.2:
+    resolution: {integrity: sha512-gmNvsYi9C8iErnZdVcJnvCpSKbWTt1E8+JZo8b+daLninywUWi5NQ5STSHZ9rFjFO7imNcvb8Pc5pe/wMR5xEw==}
+    engines: {node: '>=10.2.0'}
+
   enhanced-resolve@5.17.1:
     resolution: {integrity: sha512-LMHl3dXhTcfv8gM4kEzIUeTQ+7fpdA0l2tUf34BddXPkz2A5xJ5L/Pchd5BL6rdccM9QGvu0sWZzK1Z1t4wwyg==}
     engines: {node: '>=10.13.0'}
@@ -2954,6 +3020,14 @@ packages:
     resolution: {integrity: sha512-PXwfBhYu0hBCPw8Dn0E+WDYb7af3dSLVWKi3HGv84IdF4TyFoC0ysxFd0Goxw7nSv4T/PzEJQxsYsEiFCKo2BA==}
     engines: {node: '>=8.6'}
 
+  mime-db@1.52.0:
+    resolution: {integrity: sha512-sPU4uV7dYlvtWJxwwxHD0PuihVNiE7TyAbQ5SWxDCB9mUYvOgroQOwYQQOKPJ8CIbE+1ETVlOoK1UC2nU3gYvg==}
+    engines: {node: '>= 0.6'}
+
+  mime-types@2.1.35:
+    resolution: {integrity: sha512-ZDY+bPm5zTTF+YpCrAU9nK0UgICYPT0QtT1NZWFv4s++TNkcgVaT0g6+4R2uI4MjQjzysHB1zxuWL50hzaeXiw==}
+    engines: {node: '>= 0.6'}
+
   mime@3.0.0:
     resolution: {integrity: sha512-jSCU7/VB1loIWBZe14aEYHU/+1UMEHoaO7qxCOVJOw9GgH72VAWppxNcjU+x9a2k3GSIBXNKxXQFqRvvZ7vr3A==}
     engines: {node: '>=10.0.0'}
@@ -3023,6 +3097,10 @@ packages:
   natural-compare@1.4.0:
     resolution: {integrity: sha512-OWND8ei3VtNC9h7V60qff3SVobHr996CTwgxubgyQYEpg290h9J0buyECNNJexkFm5sOajh5G116RYA1c8ZMSw==}
 
+  negotiator@0.6.3:
+    resolution: {integrity: sha512-+EUsqGPLsM+j/zdChZjsnX51g4XrHFOIXwfnCVPGlQk/k5giakcKsuxCObBRu6DSm9opw/O6slWbJdghQM4bBg==}
+    engines: {node: '>= 0.6'}
+
   no-case@3.0.4:
     resolution: {integrity: sha512-fgAN3jGAh+RoxUGZHTSOLJIqUc2wmoBwGR4tbpNAKmmovFoWq0OdRkb0VkldReO2a2iBT/OEulG9XSUc10r3zg==}
 
@@ -3436,6 +3514,17 @@ packages:
     resolution: {integrity: sha512-g9Q1haeby36OSStwb4ntCGGGaKsaVSjQ68fBxoQcutl5fS1vuY18H3wSt3jFyFtrkx+Kz0V1G85A4MyAdDMi2Q==}
     engines: {node: '>=8'}
 
+  socket.io-adapter@2.5.5:
+    resolution: {integrity: sha512-eLDQas5dzPgOWCk9GuuJC2lBqItuhKI4uxGgo9aIV7MYbk2h9Q6uULEh8WBzThoI7l+qU9Ast9fVUmkqPP9wYg==}
+
+  socket.io-parser@4.2.4:
+    resolution: {integrity: sha512-/GbIKmo8ioc+NIWIhwdecY0ge+qVBSMdgxGygevmdHj24bsfgtCmcUUcQ5ZzcylGFHsN3k4HB4Cgkl96KVnuew==}
+    engines: {node: '>=10.0.0'}
+
+  socket.io@4.8.1:
+    resolution: {integrity: sha512-oZ7iUCxph8WYRHHcjBEc9unw3adt5CmSNlppj/5Q4k2RIrhl8Z5yY2Xr4j9zj0+wzVZ0bxmYoGSzKJnRl6A4yg==}
+    engines: {node: '>=10.2.0'}
+
   source-map-js@1.2.1:
     resolution: {integrity: sha512-UXWMKhLOwVKb728IUtQPXxfYU+usdybtUrK/8uGE8CQMvrhOpwvzDBwj0QhSL7MQc7vIsISBG8VQ8+IDQxpfQA==}
     engines: {node: '>=0.10.0'}
@@ -3703,6 +3792,10 @@ packages:
     engines: {node: '>=8'}
     hasBin: true
 
+  vary@1.1.2:
+    resolution: {integrity: sha512-BNGbWLfd0eUPabhkXUVm0j8uuvREyTh5ovRa/dyow/BqAbZJyC+5fU+IzQOzmAKzYqYRAISoRhdQr3eIZ/PXqg==}
+    engines: {node: '>= 0.8'}
+
   vite-imagetools@7.0.1:
     resolution: {integrity: sha512-23jnLhkTH0HR9Vd9LxMYnajOLeo0RJNEAHhtlsQP6kfPuOBoTzt54rWbEWB9jmhEXAOflLQpM+FrmilVPAoyGA==}
     engines: {node: '>=18.0.0'}
@@ -3818,6 +3911,18 @@ packages:
   wrappy@1.0.2:
     resolution: {integrity: sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==}
 
+  ws@8.17.1:
+    resolution: {integrity: sha512-6XQFvXTkbfUOZOKKILFG1PDK2NDQs4azKQl26T0YS5CxqWLgXajbPZ+h4gZekJyRqFU8pvnbAbbs/3TgRPy+GQ==}
+    engines: {node: '>=10.0.0'}
+    peerDependencies:
+      bufferutil: ^4.0.1
+      utf-8-validate: '>=5.0.2'
+    peerDependenciesMeta:
+      bufferutil:
+        optional: true
+      utf-8-validate:
+        optional: true
+
   ws@8.18.0:
     resolution: {integrity: sha512-8VbfWfHLbbwu3+N6OKsOMpBdT4kXPDDB9cJk2bJ6mh9ucxdlnNvH1e+roYkKmN9Nxw2yjz7VzeO9oOz2zJ04Pw==}
     engines: {node: '>=10.0.0'}
@@ -4493,6 +4598,8 @@ snapshots:
 
   '@sinclair/typebox@0.27.8': {}
 
+  '@socket.io/component-emitter@3.1.2': {}
+
   '@stylistic/eslint-plugin-js@2.1.0(eslint@9.6.0)':
     dependencies:
       '@types/eslint': 8.56.12
@@ -4593,8 +4700,14 @@ snapshots:
     dependencies:
       '@types/node': 18.19.50
 
+  '@types/cookie@0.4.1': {}
+
   '@types/cookie@0.6.0': {}
 
+  '@types/cors@2.8.17':
+    dependencies:
+      '@types/node': 18.19.50
+
   '@types/eslint@8.56.12':
     dependencies:
       '@types/estree': 1.0.6
@@ -4760,6 +4873,11 @@ snapshots:
 
   abbrev@1.1.1: {}
 
+  accepts@1.3.8:
+    dependencies:
+      mime-types: 2.1.35
+      negotiator: 0.6.3
+
   acorn-import-attributes@1.9.5(acorn@8.12.1):
     dependencies:
       acorn: 8.12.1
@@ -4833,6 +4951,8 @@ snapshots:
 
   balanced-match@1.0.2: {}
 
+  base64id@2.0.0: {}
+
   better-path-resolve@1.0.0:
     dependencies:
       is-windows: 1.0.2
@@ -4948,6 +5068,13 @@ snapshots:
 
   cookie@0.6.0: {}
 
+  cookie@0.7.2: {}
+
+  cors@2.8.5:
+    dependencies:
+      object-assign: 4.1.1
+      vary: 1.1.2
+
   cross-env@7.0.3:
     dependencies:
       cross-spawn: 7.0.3
@@ -5033,6 +5160,25 @@ snapshots:
 
   emoji-regex@8.0.0: {}
 
+  engine.io-parser@5.2.3: {}
+
+  engine.io@6.6.2:
+    dependencies:
+      '@types/cookie': 0.4.1
+      '@types/cors': 2.8.17
+      '@types/node': 18.19.50
+      accepts: 1.3.8
+      base64id: 2.0.0
+      cookie: 0.7.2
+      cors: 2.8.5
+      debug: 4.3.5
+      engine.io-parser: 5.2.3
+      ws: 8.17.1
+    transitivePeerDependencies:
+      - bufferutil
+      - supports-color
+      - utf-8-validate
+
   enhanced-resolve@5.17.1:
     dependencies:
       graceful-fs: 4.2.11
@@ -5638,6 +5784,12 @@ snapshots:
       braces: 3.0.3
       picomatch: 2.3.1
 
+  mime-db@1.52.0: {}
+
+  mime-types@2.1.35:
+    dependencies:
+      mime-db: 1.52.0
+
   mime@3.0.0: {}
 
   mimic-fn@4.0.0: {}
@@ -5700,6 +5852,8 @@ snapshots:
 
   natural-compare@1.4.0: {}
 
+  negotiator@0.6.3: {}
+
   no-case@3.0.4:
     dependencies:
       lower-case: 2.0.2
@@ -6089,6 +6243,36 @@ snapshots:
 
   slash@3.0.0: {}
 
+  socket.io-adapter@2.5.5:
+    dependencies:
+      debug: 4.3.5
+      ws: 8.17.1
+    transitivePeerDependencies:
+      - bufferutil
+      - supports-color
+      - utf-8-validate
+
+  socket.io-parser@4.2.4:
+    dependencies:
+      '@socket.io/component-emitter': 3.1.2
+      debug: 4.3.5
+    transitivePeerDependencies:
+      - supports-color
+
+  socket.io@4.8.1:
+    dependencies:
+      accepts: 1.3.8
+      base64id: 2.0.0
+      cors: 2.8.5
+      debug: 4.3.5
+      engine.io: 6.6.2
+      socket.io-adapter: 2.5.5
+      socket.io-parser: 4.2.4
+    transitivePeerDependencies:
+      - bufferutil
+      - supports-color
+      - utf-8-validate
+
   source-map-js@1.2.1: {}
 
   source-map@0.6.1: {}
@@ -6155,6 +6339,18 @@ snapshots:
     transitivePeerDependencies:
       - picomatch
 
+  svelte-check@4.0.1(picomatch@4.0.2)(svelte@4.2.19)(typescript@5.6.3):
+    dependencies:
+      '@jridgewell/trace-mapping': 0.3.25
+      chokidar: 3.6.0
+      fdir: 6.3.0(picomatch@4.0.2)
+      picocolors: 1.1.0
+      sade: 1.8.1
+      svelte: 4.2.19
+      typescript: 5.6.3
+    transitivePeerDependencies:
+      - picomatch
+
   svelte-eslint-parser@0.39.2(svelte@5.1.9):
     dependencies:
       eslint-scope: 7.2.2
@@ -6344,6 +6540,8 @@ snapshots:
       kleur: 4.1.5
       sade: 1.8.1
 
+  vary@1.1.2: {}
+
   vite-imagetools@7.0.1(rollup@4.24.0):
     dependencies:
       '@rollup/pluginutils': 5.1.0(rollup@4.24.0)
@@ -6478,6 +6676,8 @@ snapshots:
 
   wrappy@1.0.2: {}
 
+  ws@8.17.1: {}
+
   ws@8.18.0: {}
 
   xxhash-wasm@1.0.2: {}

From ffe1eadf0d6b15de9f24589ee0a1ad1a09176315 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 18:07:13 +0000
Subject: [PATCH 02/14] functional implementation

---
 packages/kit/src/runtime/server/endpoint.js   |  1 -
 packages/kit/src/runtime/server/index.js      |  4 ++--
 packages/kit/src/runtime/server/respond.js    |  1 +
 .../kit/test/apps/ws/src/routes/ws/+server.ts | 20 +++++++++++++------
 4 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index 162e774474ff..cb5c8bed0ea6 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -10,7 +10,6 @@ import { method_not_allowed } from './utils.js';
  * @returns {Promise<Response | void>}
  */
 export async function render_endpoint(event, mod, state) {
-	console.log(event);
 	const method = /** @type {import('types').HttpMethod} */ (event.request.method);
 
 	let handler = mod[method] || mod.fallback;
diff --git a/packages/kit/src/runtime/server/index.js b/packages/kit/src/runtime/server/index.js
index 53c22589a5dd..655159a2e567 100644
--- a/packages/kit/src/runtime/server/index.js
+++ b/packages/kit/src/runtime/server/index.js
@@ -92,10 +92,10 @@ export class Server {
 
 	/**
 	 * @param {Request} request
-	 * @param {{request: import('http').IncomingMessage, socket: import('stream').Duplex , head: Buffer}?} webhookRequest
 	 * @param {import('types').RequestOptions} options
+	 * @param {{request: import('http').IncomingMessage, socket: import('stream').Duplex , head: Buffer}?} webhookRequest
 	 */
-	async respond(request, webhookRequest, options) {
+	async respond(request, options, webhookRequest) {
 		return respond(request, this.#options, this.#manifest, {
 			...options,
 			error: false,
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
index a26bd2c18e92..b6a425189df3 100644
--- a/packages/kit/src/runtime/server/respond.js
+++ b/packages/kit/src/runtime/server/respond.js
@@ -214,6 +214,7 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 
 	if(upgradeRequest) {
 		console.log('hit upgrade event');
+		console.log(upgradeRequest);
 		event.upgrade = upgradeRequest;
 	}
 
diff --git a/packages/kit/test/apps/ws/src/routes/ws/+server.ts b/packages/kit/test/apps/ws/src/routes/ws/+server.ts
index b15fdc03a0f9..9003acc299f3 100644
--- a/packages/kit/test/apps/ws/src/routes/ws/+server.ts
+++ b/packages/kit/test/apps/ws/src/routes/ws/+server.ts
@@ -4,14 +4,22 @@ import { WebSocketServer } from 'ws';
 const wss = new WebSocketServer({ noServer: true });
 // const io = new Server();
 
-export function UPGRADE({upgrade}) {
-		console.log(request);
-			wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
-				wss.emit('connection', ws, request);
-			});
+wss.on('connection', (ws) => {
+	ws.on('error', console.error);
+
+	ws.on('message', (message) => {
+		console.log('received: %s', message);
+	});
+});
+
+export function UPGRADE({ upgrade }) {
+	wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
+		console.log('UPGRADED');
+		wss.emit('connection', ws, upgrade.request);
+	});
 }
 
-export function GET({request}) {
+export function GET({ request }) {
 	console.log(request);
 
 	return new Response('ok');

From b0f2ee13852d75c640749c3d23af075bd994496e Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 18:52:21 +0000
Subject: [PATCH 03/14] cleaned logs

---
 packages/kit/src/runtime/server/endpoint.js | 4 ----
 packages/kit/src/runtime/server/respond.js  | 7 -------
 2 files changed, 11 deletions(-)

diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index cb5c8bed0ea6..ba0f10c9e10c 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -41,10 +41,8 @@ export async function render_endpoint(event, mod, state) {
 
 	try {
 		if (method === 'GET' && event.request.headers.has('upgrade') && event.upgrade && mod.UPGRADE) {
-			console.log('upgrade');
 			await mod.UPGRADE(/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event));
 		} else {
-			console.log('not upgrade');
 			let response = await handler(
 				/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
 			);
@@ -66,8 +64,6 @@ export async function render_endpoint(event, mod, state) {
 				response.headers.set('x-sveltekit-prerender', String(prerender));
 			}
 
-			console.log(response);
-
 			return response;
 		}
 	} catch (e) {
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
index b6a425189df3..3b013d32ac8a 100644
--- a/packages/kit/src/runtime/server/respond.js
+++ b/packages/kit/src/runtime/server/respond.js
@@ -59,7 +59,6 @@ const allowed_page_methods = new Set(['GET', 'HEAD', 'OPTIONS']);
  */
 export async function respond(request, options, manifest, state, upgradeRequest) {
 	/** URL but stripped from the potential `/__data.json` suffix and its search param  */
-	console.log('hit respond');
 	const url = new URL(request.url);
 
 	if (options.csrf_check_origin) {
@@ -83,7 +82,6 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 		}
 	}
 
-	console.log('hit reroute');
 	// reroute could alter the given URL, so we pass a copy
 	let rerouted_path;
 	try {
@@ -94,7 +92,6 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 		});
 	}
 
-	console.log('hit decode');
 	let decoded;
 	try {
 		decoded = decode_pathname(rerouted_path);
@@ -210,11 +207,8 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 		isDataRequest: is_data_request,
 		isSubRequest: state.depth > 0
 	};
-	console.log('hit create event');
 
 	if(upgradeRequest) {
-		console.log('hit upgrade event');
-		console.log(upgradeRequest);
 		event.upgrade = upgradeRequest;
 	}
 
@@ -335,7 +329,6 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 
 		if (state.prerendering && !state.prerendering.fallback) disable_search(url);
 
-		console.log('hit handle');
 		const response = await options.hooks.handle({
 			event,
 			resolve: (event, opts) =>

From 6972d8fa12062c54a86959e93c4a7dd5da418dd9 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 18:52:40 +0000
Subject: [PATCH 04/14] swapped test app to basics

---
 packages/kit/test/apps/basics/package.json    |  4 +-
 .../src/routes/socketIO}/+server.ts           |  0
 .../test/apps/basics/src/routes/ws/+server.ts | 26 ++++++
 packages/kit/test/apps/ws/README.md           |  1 -
 packages/kit/test/apps/ws/package.json        | 27 ------
 .../kit/test/apps/ws/playwright.config.js     |  1 -
 packages/kit/test/apps/ws/src/app.html        | 11 ---
 .../kit/test/apps/ws/src/routes/+page.svelte  | 29 ------
 packages/kit/test/apps/ws/svelte.config.js    |  6 --
 packages/kit/test/apps/ws/test/test.js        | 89 -------------------
 packages/kit/test/apps/ws/tsconfig.json       |  8 --
 packages/kit/test/apps/ws/vite.config.js      | 14 ---
 pnpm-lock.yaml                                | 51 ++---------
 13 files changed, 35 insertions(+), 232 deletions(-)
 rename packages/kit/test/apps/{ws/src/routes/ws => basics/src/routes/socketIO}/+server.ts (100%)
 create mode 100644 packages/kit/test/apps/basics/src/routes/ws/+server.ts
 delete mode 100644 packages/kit/test/apps/ws/README.md
 delete mode 100644 packages/kit/test/apps/ws/package.json
 delete mode 100644 packages/kit/test/apps/ws/playwright.config.js
 delete mode 100644 packages/kit/test/apps/ws/src/app.html
 delete mode 100644 packages/kit/test/apps/ws/src/routes/+page.svelte
 delete mode 100644 packages/kit/test/apps/ws/svelte.config.js
 delete mode 100644 packages/kit/test/apps/ws/test/test.js
 delete mode 100644 packages/kit/test/apps/ws/tsconfig.json
 delete mode 100644 packages/kit/test/apps/ws/vite.config.js

diff --git a/packages/kit/test/apps/basics/package.json b/packages/kit/test/apps/basics/package.json
index eadca24b6a31..fdf201943958 100644
--- a/packages/kit/test/apps/basics/package.json
+++ b/packages/kit/test/apps/basics/package.json
@@ -18,10 +18,12 @@
 		"@sveltejs/vite-plugin-svelte": "^3.0.1",
 		"cross-env": "^7.0.3",
 		"marked": "^14.0.0",
+		"socket.io": "^4.8.1",
 		"svelte": "^4.2.10",
 		"svelte-check": "^4.0.1",
 		"typescript": "^5.3.3",
-		"vite": "^5.3.2"
+		"vite": "^5.3.2",
+		"ws": "^8.18.0"
 	},
 	"type": "module"
 }
diff --git a/packages/kit/test/apps/ws/src/routes/ws/+server.ts b/packages/kit/test/apps/basics/src/routes/socketIO/+server.ts
similarity index 100%
rename from packages/kit/test/apps/ws/src/routes/ws/+server.ts
rename to packages/kit/test/apps/basics/src/routes/socketIO/+server.ts
diff --git a/packages/kit/test/apps/basics/src/routes/ws/+server.ts b/packages/kit/test/apps/basics/src/routes/ws/+server.ts
new file mode 100644
index 000000000000..9003acc299f3
--- /dev/null
+++ b/packages/kit/test/apps/basics/src/routes/ws/+server.ts
@@ -0,0 +1,26 @@
+import { WebSocketServer } from 'ws';
+// import { Server } from "socket.io";
+
+const wss = new WebSocketServer({ noServer: true });
+// const io = new Server();
+
+wss.on('connection', (ws) => {
+	ws.on('error', console.error);
+
+	ws.on('message', (message) => {
+		console.log('received: %s', message);
+	});
+});
+
+export function UPGRADE({ upgrade }) {
+	wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
+		console.log('UPGRADED');
+		wss.emit('connection', ws, upgrade.request);
+	});
+}
+
+export function GET({ request }) {
+	console.log(request);
+
+	return new Response('ok');
+}
diff --git a/packages/kit/test/apps/ws/README.md b/packages/kit/test/apps/ws/README.md
deleted file mode 100644
index dddfaa2ca89c..000000000000
--- a/packages/kit/test/apps/ws/README.md
+++ /dev/null
@@ -1 +0,0 @@
-This app exists to test websocket implementations.
diff --git a/packages/kit/test/apps/ws/package.json b/packages/kit/test/apps/ws/package.json
deleted file mode 100644
index 20d0a22b928b..000000000000
--- a/packages/kit/test/apps/ws/package.json
+++ /dev/null
@@ -1,27 +0,0 @@
-{
-	"name": "test-ws",
-	"private": true,
-	"version": "0.0.1",
-	"scripts": {
-		"dev": "vite dev",
-		"build": "vite build",
-		"preview": "vite preview",
-		"check": "svelte-kit sync && tsc && svelte-check",
-		"test": "pnpm test:dev && pnpm test:build",
-		"test:dev": "cross-env DEV=true playwright test",
-		"test:build": "playwright test"
-	},
-	"devDependencies": {
-		"@sveltejs/adapter-node": "workspace:^",
-		"@sveltejs/kit": "workspace:^",
-		"@sveltejs/vite-plugin-svelte": "^3.0.1",
-		"cross-env": "^7.0.3",
-		"socket.io": "^4.8.1",
-		"svelte": "^4.2.10",
-		"svelte-check": "^4.0.1",
-		"typescript": "^5.3.3",
-		"vite": "^5.3.2",
-		"ws": "^8.18.0"
-	},
-	"type": "module"
-}
diff --git a/packages/kit/test/apps/ws/playwright.config.js b/packages/kit/test/apps/ws/playwright.config.js
deleted file mode 100644
index 33d36b651014..000000000000
--- a/packages/kit/test/apps/ws/playwright.config.js
+++ /dev/null
@@ -1 +0,0 @@
-export { config as default } from '../../utils.js';
diff --git a/packages/kit/test/apps/ws/src/app.html b/packages/kit/test/apps/ws/src/app.html
deleted file mode 100644
index b8ba4699b2ba..000000000000
--- a/packages/kit/test/apps/ws/src/app.html
+++ /dev/null
@@ -1,11 +0,0 @@
-<!doctype html>
-<html lang="en">
-	<head>
-		<meta charset="utf-8" />
-		<meta name="viewport" content="width=device-width, initial-scale=1" />
-		%sveltekit.head%
-	</head>
-	<body>
-		<div style="display: contents">%sveltekit.body%</div>
-	</body>
-</html>
diff --git a/packages/kit/test/apps/ws/src/routes/+page.svelte b/packages/kit/test/apps/ws/src/routes/+page.svelte
deleted file mode 100644
index e83274902d05..000000000000
--- a/packages/kit/test/apps/ws/src/routes/+page.svelte
+++ /dev/null
@@ -1,29 +0,0 @@
-<script>
-	import { browser } from '$app/environment';
-
-	const events = [];
-	if (browser) {
-		console.log('connecting');
-		const websocket = new WebSocket('/ws');
-
-		console.log(websocket);
-
-		websocket.onopen = () => {
-			console.log('connected');
-			websocket.send('hello');
-		};
-
-		websocket.onmessage = (event) => {
-			events.push(event.data);
-			console.log(event.data);
-		};
-	}
-</script>
-
-<h1>Hello</h1>
-
-<div>
-	{#each events as event}
-		<p>{event}</p>
-	{/each}
-</div>
diff --git a/packages/kit/test/apps/ws/svelte.config.js b/packages/kit/test/apps/ws/svelte.config.js
deleted file mode 100644
index 821c14379ec8..000000000000
--- a/packages/kit/test/apps/ws/svelte.config.js
+++ /dev/null
@@ -1,6 +0,0 @@
-/** @type {import('@sveltejs/kit').Config} */
-const config = {
-	kit: {}
-};
-
-export default config;
diff --git a/packages/kit/test/apps/ws/test/test.js b/packages/kit/test/apps/ws/test/test.js
deleted file mode 100644
index 1633e55d28b4..000000000000
--- a/packages/kit/test/apps/ws/test/test.js
+++ /dev/null
@@ -1,89 +0,0 @@
-import process from 'node:process';
-import { expect } from '@playwright/test';
-import { test } from '../../../utils.js';
-
-/** @typedef {import('@playwright/test').Response} Response */
-
-test.describe.configure({ mode: 'parallel' });
-
-test.describe('env', () => {
-	test('resolves upwards', async ({ page }) => {
-		await page.goto('/basepath/env');
-		expect(await page.textContent('[data-testid="static"]')).toBe('static: resolves upwards!');
-		expect(await page.textContent('[data-testid="dynamic"]')).toBe('dynamic: resolves upwards!');
-	});
-});
-
-test.describe('paths', () => {
-	test('serves /basepath', async ({ page }) => {
-		await page.goto('/basepath');
-		expect(await page.textContent('h1')).toBe('Hello');
-	});
-
-	test('serves assets from /basepath', async ({ request }) => {
-		const response = await request.get('/basepath/answer.txt');
-		expect(await response.text()).toBe('42');
-	});
-
-	test('uses relative paths during SSR', async ({ page, javaScriptEnabled }) => {
-		await page.goto('/basepath');
-
-		let base = javaScriptEnabled ? '/basepath' : '.';
-		expect(await page.textContent('[data-testid="base"]')).toBe(`base: ${base}`);
-		expect(await page.textContent('[data-testid="assets"]')).toBe(`assets: ${base}`);
-
-		await page.goto('/basepath/deeply/nested/page');
-
-		base = javaScriptEnabled ? '/basepath' : '../..';
-		expect(await page.textContent('[data-testid="base"]')).toBe(`base: ${base}`);
-		expect(await page.textContent('[data-testid="assets"]')).toBe(`assets: ${base}`);
-	});
-
-	test('serves /basepath with trailing slash always', async ({ page }) => {
-		await page.goto('/basepath');
-		expect(new URL(page.url()).pathname).toBe('/basepath/');
-	});
-
-	test('respects trailing slash option when navigating from /basepath', async ({
-		page,
-		clicknav
-	}) => {
-		await page.goto('/basepath');
-		expect(new URL(page.url()).pathname).toBe('/basepath/');
-		await clicknav('[data-testid="link"]');
-		expect(new URL(page.url()).pathname).toBe('/basepath/hello');
-	});
-});
-
-test.describe('Service worker', () => {
-	if (process.env.DEV) return;
-
-	test('build /basepath/service-worker.js', async ({ baseURL, request }) => {
-		const response = await request.get('/basepath/service-worker.js');
-		const content = await response.text();
-
-		const fn = new Function('self', 'location', content);
-
-		const self = {
-			addEventListener: () => {},
-			base: null,
-			build: null
-		};
-
-		const pathname = '/basepath/service-worker.js';
-
-		fn(self, {
-			href: baseURL + pathname,
-			pathname
-		});
-
-		expect(self.base).toBe('/basepath');
-		expect(self.build[0]).toMatch(/\/basepath\/_app\/immutable\/entry\/start\.[\w-]+\.js/);
-		expect(self.image_src).toMatch(/\/basepath\/_app\/immutable\/assets\/image\.[\w-]+\.jpg/);
-	});
-
-	test('does not register /basepath/service-worker.js', async ({ page }) => {
-		await page.goto('/basepath');
-		expect(await page.content()).not.toMatch(/navigator\.serviceWorker/);
-	});
-});
diff --git a/packages/kit/test/apps/ws/tsconfig.json b/packages/kit/test/apps/ws/tsconfig.json
deleted file mode 100644
index b1096bf168cd..000000000000
--- a/packages/kit/test/apps/ws/tsconfig.json
+++ /dev/null
@@ -1,8 +0,0 @@
-{
-	"compilerOptions": {
-		"allowJs": true,
-		"checkJs": true,
-		"noEmit": true
-	},
-	"extends": "./.svelte-kit/tsconfig.json"
-}
diff --git a/packages/kit/test/apps/ws/vite.config.js b/packages/kit/test/apps/ws/vite.config.js
deleted file mode 100644
index 8e2cdfd37133..000000000000
--- a/packages/kit/test/apps/ws/vite.config.js
+++ /dev/null
@@ -1,14 +0,0 @@
-import { sveltekit } from '@sveltejs/kit/vite';
-import path from 'path';
-
-/** @type {import('vite').UserConfig} */
-const config = {
-	plugins: [sveltekit()],
-	server: {
-		fs: {
-			allow: [path.resolve('../../../src')]
-		}
-	},
-};
-
-export default config;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0496bf454bfc..9df4c6213689 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -454,6 +454,9 @@ importers:
       marked:
         specifier: ^14.0.0
         version: 14.1.1
+      socket.io:
+        specifier: ^4.8.1
+        version: 4.8.1
       svelte:
         specifier: ^4.2.10
         version: 4.2.19
@@ -466,6 +469,9 @@ importers:
       vite:
         specifier: ^5.3.2
         version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
+      ws:
+        specifier: ^8.18.0
+        version: 8.18.0
 
   packages/kit/test/apps/dev-only:
     devDependencies:
@@ -644,39 +650,6 @@ importers:
         specifier: ^5.3.2
         version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
 
-  packages/kit/test/apps/ws:
-    devDependencies:
-      '@sveltejs/adapter-node':
-        specifier: workspace:^
-        version: link:../../../../adapter-node
-      '@sveltejs/kit':
-        specifier: workspace:^
-        version: link:../../..
-      '@sveltejs/vite-plugin-svelte':
-        specifier: ^3.0.1
-        version: 3.1.0(svelte@4.2.19)(vite@5.3.6(@types/node@18.19.50)(lightningcss@1.24.1))
-      cross-env:
-        specifier: ^7.0.3
-        version: 7.0.3
-      socket.io:
-        specifier: ^4.8.1
-        version: 4.8.1
-      svelte:
-        specifier: ^4.2.10
-        version: 4.2.19
-      svelte-check:
-        specifier: ^4.0.1
-        version: 4.0.1(picomatch@4.0.2)(svelte@4.2.19)(typescript@5.6.3)
-      typescript:
-        specifier: ^5.3.3
-        version: 5.6.3
-      vite:
-        specifier: ^5.3.2
-        version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
-      ws:
-        specifier: ^8.18.0
-        version: 8.18.0
-
   packages/kit/test/build-errors:
     devDependencies:
       vitest:
@@ -6339,18 +6312,6 @@ snapshots:
     transitivePeerDependencies:
       - picomatch
 
-  svelte-check@4.0.1(picomatch@4.0.2)(svelte@4.2.19)(typescript@5.6.3):
-    dependencies:
-      '@jridgewell/trace-mapping': 0.3.25
-      chokidar: 3.6.0
-      fdir: 6.3.0(picomatch@4.0.2)
-      picocolors: 1.1.0
-      sade: 1.8.1
-      svelte: 4.2.19
-      typescript: 5.6.3
-    transitivePeerDependencies:
-      - picomatch
-
   svelte-eslint-parser@0.39.2(svelte@5.1.9):
     dependencies:
       eslint-scope: 7.2.2

From ff4097e3576e2613b6bd6d96674ea5ed468f455e Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 20:17:57 +0000
Subject: [PATCH 05/14] Fixed formatting overreach

---
 packages/kit/src/exports/public.d.ts | 38 ++++++++++++++--------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/packages/kit/src/exports/public.d.ts b/packages/kit/src/exports/public.d.ts
index a8357260f964..c8db2c0f8832 100644
--- a/packages/kit/src/exports/public.d.ts
+++ b/packages/kit/src/exports/public.d.ts
@@ -317,7 +317,7 @@ export interface KitConfig {
 	/**
 	 * The directory where SvelteKit keeps its stuff, including static assets (such as JS and CSS) and internally-used routes.
 	 *
-	 * If `paths.assets` is specified, there will be two app directories - `${paths.assets}/${appDir}` and `${paths.base}/${appDir}`.
+	 * If `paths.assets` is specified, there will be two app directories — `${paths.assets}/${appDir}` and `${paths.base}/${appDir}`.
 	 * @default "_app"
 	 */
 	appDir?: string;
@@ -550,10 +550,10 @@ export interface KitConfig {
 		/**
 		 * How to respond to HTTP errors encountered while prerendering the app.
 		 *
-		 * - `'fail'` - fail the build
-		 * - `'ignore'` - silently ignore the failure and continue
-		 * - `'warn'` - continue, but print a warning
-		 * - `(details) => void` - a custom error handler that takes a `details` object with `status`, `path`, `referrer`, `referenceType` and `message` properties. If you `throw` from this function, the build will fail
+		 * - `'fail'` — fail the build
+		 * - `'ignore'` — silently ignore the failure and continue
+		 * - `'warn'` — continue, but print a warning
+		 * - `(details) => void` — a custom error handler that takes a `details` object with `status`, `path`, `referrer`, `referenceType` and `message` properties. If you `throw` from this function, the build will fail
 		 *
 		 * ```js
 		 * /// file: svelte.config.js
@@ -582,10 +582,10 @@ export interface KitConfig {
 		/**
 		 * How to respond when hash links from one prerendered page to another don't correspond to an `id` on the destination page.
 		 *
-		 * - `'fail'` - fail the build
-		 * - `'ignore'` - silently ignore the failure and continue
-		 * - `'warn'` - continue, but print a warning
-		 * - `(details) => void` - a custom error handler that takes a `details` object with `path`, `id`, `referrers` and `message` properties. If you `throw` from this function, the build will fail
+		 * - `'fail'` — fail the build
+		 * - `'ignore'` — silently ignore the failure and continue
+		 * - `'warn'` — continue, but print a warning
+		 * - `(details) => void` — a custom error handler that takes a `details` object with `path`, `id`, `referrers` and `message` properties. If you `throw` from this function, the build will fail
 		 *
 		 * @default "fail"
 		 * @since 1.15.7
@@ -594,10 +594,10 @@ export interface KitConfig {
 		/**
 		 * How to respond when an entry generated by the `entries` export doesn't match the route it was generated from.
 		 *
-		 * - `'fail'` - fail the build
-		 * - `'ignore'` - silently ignore the failure and continue
-		 * - `'warn'` - continue, but print a warning
-		 * - `(details) => void` - a custom error handler that takes a `details` object with `generatedFromId`, `entry`, `matchedId` and `message` properties. If you `throw` from this function, the build will fail
+		 * - `'fail'` — fail the build
+		 * - `'ignore'` — silently ignore the failure and continue
+		 * - `'warn'` — continue, but print a warning
+		 * - `(details) => void` — a custom error handler that takes a `details` object with `generatedFromId`, `entry`, `matchedId` and `message` properties. If you `throw` from this function, the build will fail
 		 *
 		 * @default "fail"
 		 * @since 1.16.0
@@ -787,9 +787,9 @@ export interface LoadEvent<
 	 *	}
 	 *	```
 	 *
-	 * Setting the same header multiple times (even in separate `load` functions) is an error - you can only set a given header once.
+	 * Setting the same header multiple times (even in separate `load` functions) is an error — you can only set a given header once.
 	 *
-	 * You cannot add a `set-cookie` header with `setHeaders` - use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API in a server-only `load` function instead.
+	 * You cannot add a `set-cookie` header with `setHeaders` — use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API in a server-only `load` function instead.
 	 *
 	 * `setHeaders` has no effect when a `load` function runs in the browser.
 	 */
@@ -804,7 +804,7 @@ export interface LoadEvent<
 	/**
 	 * This function declares that the `load` function has a _dependency_ on one or more URLs or custom identifiers, which can subsequently be used with [`invalidate()`](https://svelte.dev/docs/kit/$app-navigation#invalidate) to cause `load` to rerun.
 	 *
-	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf - it's only necessary if you're using a custom API client that bypasses `fetch`.
+	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf — it's only necessary if you're using a custom API client that bypasses `fetch`.
 	 *
 	 * URLs can be absolute or relative to the page being loaded, and must be [encoded](https://developer.mozilla.org/en-US/docs/Glossary/percent-encoding).
 	 *
@@ -1109,9 +1109,9 @@ export interface RequestEvent<
 	 *	}
 	 *	```
 	 *
-	 * Setting the same header multiple times (even in separate `load` functions) is an error - you can only set a given header once.
+	 * Setting the same header multiple times (even in separate `load` functions) is an error — you can only set a given header once.
 	 *
-	 * You cannot add a `set-cookie` header with `setHeaders` - use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API instead.
+	 * You cannot add a `set-cookie` header with `setHeaders` — use the [`cookies`](https://svelte.dev/docs/kit/@sveltejs-kit#Cookies) API instead.
 	 */
 	setHeaders(headers: Record<string, string>): void;
 	/**
@@ -1242,7 +1242,7 @@ export interface ServerLoadEvent<
 	/**
 	 * This function declares that the `load` function has a _dependency_ on one or more URLs or custom identifiers, which can subsequently be used with [`invalidate()`](https://svelte.dev/docs/kit/$app-navigation#invalidate) to cause `load` to rerun.
 	 *
-	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf - it's only necessary if you're using a custom API client that bypasses `fetch`.
+	 * Most of the time you won't need this, as `fetch` calls `depends` on your behalf — it's only necessary if you're using a custom API client that bypasses `fetch`.
 	 *
 	 * URLs can be absolute or relative to the page being loaded, and must be [encoded](https://developer.mozilla.org/en-US/docs/Glossary/percent-encoding).
 	 *

From 6d5fb17265b110c30998091368324bda04a409c2 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 20:19:28 +0000
Subject: [PATCH 06/14] swapped to options-2 due to strange handle collision,
 implemented suggestions, adjusted handling

---
 packages/kit/src/exports/vite/dev/index.js    |  3 +-
 packages/kit/src/runtime/server/endpoint.js   | 57 ++++++++++++-------
 .../test/apps/basics/src/routes/ws/+server.ts | 26 ---------
 packages/kit/test/apps/options-2/package.json |  5 +-
 .../apps/options-2/src/routes/+page.svelte    |  4 ++
 .../src/routes/socket.io/+page.svelte         | 33 +++++++++++
 .../options-2/src/routes/socket.io/+server.js | 18 ++++++
 .../apps/options-2/src/routes/ws/+page.svelte | 35 ++++++++++++
 .../src/routes/ws/+server.js}                 |  9 +--
 pnpm-lock.yaml                                | 48 ++++++++++++++++
 10 files changed, 179 insertions(+), 59 deletions(-)
 delete mode 100644 packages/kit/test/apps/basics/src/routes/ws/+server.ts
 create mode 100644 packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte
 create mode 100644 packages/kit/test/apps/options-2/src/routes/socket.io/+server.js
 create mode 100644 packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
 rename packages/kit/test/apps/{basics/src/routes/socketIO/+server.ts => options-2/src/routes/ws/+server.js} (73%)

diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index 6f92ae590ada..ef968967964e 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -586,8 +586,7 @@ export async function dev(vite, vite_config, svelte_config) {
 							async_local_storage.enterWith({ event, config, prerender });
 						},
 						emulator
-					},
-					undefined
+					}
 				);
 
 				if (rendered.status === 404) {
diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index ba0f10c9e10c..b968c780b1c2 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -12,12 +12,20 @@ import { method_not_allowed } from './utils.js';
 export async function render_endpoint(event, mod, state) {
 	const method = /** @type {import('types').HttpMethod} */ (event.request.method);
 
+	/**
+ * The handler function to use for the request
+ * @type {import('@sveltejs/kit').RequestHandler | import('@sveltejs/kit').UpgradeHandler | undefined}
+ */
 	let handler = mod[method] || mod.fallback;
 
-	if (method === 'HEAD' && mod.GET && !mod.HEAD) {
+	if (method === 'HEAD' && (mod.GET && !mod.HEAD)) {
 		handler = mod.GET;
 	}
 
+	if (method === 'GET' && !mod.GET && mod.UPGRADE) {
+		handler = mod.UPGRADE;
+	}
+
 	if (!handler) {
 		return method_not_allowed(mod, method);
 	}
@@ -40,32 +48,37 @@ export async function render_endpoint(event, mod, state) {
 	}
 
 	try {
+
 		if (method === 'GET' && event.request.headers.has('upgrade') && event.upgrade && mod.UPGRADE) {
-			await mod.UPGRADE(/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event));
-		} else {
-			let response = await handler(
+			console.log('upgrade')
+			await handler(
 				/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
 			);
+			return;
+		}
+
+		let response = await handler(
+			/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
+		);
+
+		if (!(response instanceof Response)) {
+			throw new Error(
+				`Invalid response from route ${event.url.pathname}: handler should return a Response object`
+			);
+		}
 
-			if (!(response instanceof Response)) {
-				throw new Error(
-					`Invalid response from route ${event.url.pathname}: handler should return a Response object`
-				);
-			}
-
-			if (state.prerendering) {
-				// the returned Response might have immutable Headers
-				// so we should clone them before trying to mutate them
-				response = new Response(response.body, {
-					status: response.status,
-					statusText: response.statusText,
-					headers: new Headers(response.headers)
-				});
-				response.headers.set('x-sveltekit-prerender', String(prerender));
-			}
-
-			return response;
+		if (state.prerendering) {
+			// the returned Response might have immutable Headers
+			// so we should clone them before trying to mutate them
+			response = new Response(response.body, {
+				status: response.status,
+				statusText: response.statusText,
+				headers: new Headers(response.headers)
+			});
+			response.headers.set('x-sveltekit-prerender', String(prerender));
 		}
+
+		return response;
 	} catch (e) {
 		if (e instanceof Redirect) {
 			return new Response(undefined, {
diff --git a/packages/kit/test/apps/basics/src/routes/ws/+server.ts b/packages/kit/test/apps/basics/src/routes/ws/+server.ts
deleted file mode 100644
index 9003acc299f3..000000000000
--- a/packages/kit/test/apps/basics/src/routes/ws/+server.ts
+++ /dev/null
@@ -1,26 +0,0 @@
-import { WebSocketServer } from 'ws';
-// import { Server } from "socket.io";
-
-const wss = new WebSocketServer({ noServer: true });
-// const io = new Server();
-
-wss.on('connection', (ws) => {
-	ws.on('error', console.error);
-
-	ws.on('message', (message) => {
-		console.log('received: %s', message);
-	});
-});
-
-export function UPGRADE({ upgrade }) {
-	wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
-		console.log('UPGRADED');
-		wss.emit('connection', ws, upgrade.request);
-	});
-}
-
-export function GET({ request }) {
-	console.log(request);
-
-	return new Response('ok');
-}
diff --git a/packages/kit/test/apps/options-2/package.json b/packages/kit/test/apps/options-2/package.json
index 963d87a3c03e..79d850f540da 100644
--- a/packages/kit/test/apps/options-2/package.json
+++ b/packages/kit/test/apps/options-2/package.json
@@ -16,10 +16,13 @@
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.1",
 		"cross-env": "^7.0.3",
+		"socket.io": "^4.8.1",
+		"socket.io-client": "^4.8.1",
 		"svelte": "^4.2.10",
 		"svelte-check": "^4.0.1",
 		"typescript": "^5.3.3",
-		"vite": "^5.3.2"
+		"vite": "^5.3.2",
+		"ws": "^8.18.0"
 	},
 	"type": "module"
 }
diff --git a/packages/kit/test/apps/options-2/src/routes/+page.svelte b/packages/kit/test/apps/options-2/src/routes/+page.svelte
index badacc8173d8..b869628a945d 100644
--- a/packages/kit/test/apps/options-2/src/routes/+page.svelte
+++ b/packages/kit/test/apps/options-2/src/routes/+page.svelte
@@ -8,3 +8,7 @@
 <p data-testid="assets">assets: {assets}</p>
 
 <a href="{base}/hello" data-testid="link">Go to /hello</a>
+<br>
+<a href="{base}/ws" data-testid="link">Go to /ws</a>
+<br>
+<a href="{base}/socket.io" data-testid="link">Go to /socket.io</a>
diff --git a/packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte b/packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte
new file mode 100644
index 000000000000..4e85476b189e
--- /dev/null
+++ b/packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte
@@ -0,0 +1,33 @@
+<script>
+	import { browser } from "$app/environment";
+	import { io  } from "socket.io-client"
+	import { base } from '$app/paths';
+
+	const messages = []
+
+	if(browser) {
+		const socket = io(undefined, {path: `${base}/socket.io`})
+
+		socket.on("connect", () => {
+			console.log("connected")
+			socket.emit("chat message", "hello world")
+		})
+
+		socket.on("disconnect", () => {
+			console.log("disconnected")
+		})
+
+		socket.on("message", (data) => {
+			messages.push(data)
+			console.log(data)
+		})
+	}
+</script>
+
+<h1>Messages:</h1>
+
+<div>
+	{#each messages as message}
+		<p>{message}</p>
+	{/each}
+</div>
diff --git a/packages/kit/test/apps/options-2/src/routes/socket.io/+server.js b/packages/kit/test/apps/options-2/src/routes/socket.io/+server.js
new file mode 100644
index 000000000000..97fae0007788
--- /dev/null
+++ b/packages/kit/test/apps/options-2/src/routes/socket.io/+server.js
@@ -0,0 +1,18 @@
+import { createServer } from 'node:http';
+import { Server }from 'socket.io';
+
+const httpServer  = createServer();
+const io = new Server(httpServer);
+
+io.on('connection', (socket) => {
+	socket.on('error', console.error);
+
+	socket.on('chat message', (data) => {
+		console.log('received message: %s', data);
+		socket.emit('chat message', data);
+	});
+});
+
+export function UPGRADE({ upgrade }) {
+	io.engine.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head)
+}
diff --git a/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte b/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
new file mode 100644
index 000000000000..fd6ee5196764
--- /dev/null
+++ b/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
@@ -0,0 +1,35 @@
+<script>
+	import { browser } from "$app/environment";
+	import { base } from '$app/paths';
+
+	let messages = []
+
+	if(browser) {
+		const socket = new WebSocket(`${base}/ws`)
+
+		console.log(socket)
+
+		socket.onopen = () => {
+			console.log("websocket connected")
+			socket.send("hello world")
+		}
+
+		socket.onclose = () => {
+			console.log("disconnected")
+		}
+
+		socket.onmessage = (event) => {
+			console.log(event.data)
+			messages.push(event.data)
+			console.log(messages)
+		}
+	}
+</script>
+
+<h1>Messages:</h1>
+
+<div>
+	{#each messages as message}
+		<p>{message}</p>
+	{/each}
+</div>
diff --git a/packages/kit/test/apps/basics/src/routes/socketIO/+server.ts b/packages/kit/test/apps/options-2/src/routes/ws/+server.js
similarity index 73%
rename from packages/kit/test/apps/basics/src/routes/socketIO/+server.ts
rename to packages/kit/test/apps/options-2/src/routes/ws/+server.js
index 9003acc299f3..c839e67c0fb1 100644
--- a/packages/kit/test/apps/basics/src/routes/socketIO/+server.ts
+++ b/packages/kit/test/apps/options-2/src/routes/ws/+server.js
@@ -1,14 +1,13 @@
 import { WebSocketServer } from 'ws';
-// import { Server } from "socket.io";
 
 const wss = new WebSocketServer({ noServer: true });
-// const io = new Server();
 
 wss.on('connection', (ws) => {
 	ws.on('error', console.error);
 
 	ws.on('message', (message) => {
 		console.log('received: %s', message);
+		ws.send(String(message));
 	});
 });
 
@@ -18,9 +17,3 @@ export function UPGRADE({ upgrade }) {
 		wss.emit('connection', ws, upgrade.request);
 	});
 }
-
-export function GET({ request }) {
-	console.log(request);
-
-	return new Response('ok');
-}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9df4c6213689..9aff84134510 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -457,6 +457,9 @@ importers:
       socket.io:
         specifier: ^4.8.1
         version: 4.8.1
+      socket.io-client:
+        specifier: ^4.8.1
+        version: 4.8.1
       svelte:
         specifier: ^4.2.10
         version: 4.2.19
@@ -613,6 +616,12 @@ importers:
       cross-env:
         specifier: ^7.0.3
         version: 7.0.3
+      socket.io:
+        specifier: ^4.8.1
+        version: 4.8.1
+      socket.io-client:
+        specifier: ^4.8.1
+        version: 4.8.1
       svelte:
         specifier: ^4.2.10
         version: 4.2.19
@@ -625,6 +634,9 @@ importers:
       vite:
         specifier: ^5.3.2
         version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
+      ws:
+        specifier: ^8.18.0
+        version: 8.18.0
 
   packages/kit/test/apps/writes:
     devDependencies:
@@ -2424,6 +2436,9 @@ packages:
   emoji-regex@8.0.0:
     resolution: {integrity: sha512-MSjYzcWNOA0ewAHpz0MxpYFvwg6yjy1NG3xteoqz644VCo/RPgnr1/GGt+ic3iJTzQ8Eu3TdM14SawnVUmGE6A==}
 
+  engine.io-client@6.6.2:
+    resolution: {integrity: sha512-TAr+NKeoVTjEVW8P3iHguO1LO6RlUz9O5Y8o7EY0fU+gY1NYqas7NN3slpFtbXEsLMHk0h90fJMfKjRkQ0qUIw==}
+
   engine.io-parser@5.2.3:
     resolution: {integrity: sha512-HqD3yTBfnBxIrbnM1DoD6Pcq8NECnh8d4As1Qgh0z5Gg3jRRIqijury0CL3ghu/edArpUYiYqQiDUQBIs4np3Q==}
     engines: {node: '>=10.0.0'}
@@ -3490,6 +3505,10 @@ packages:
   socket.io-adapter@2.5.5:
     resolution: {integrity: sha512-eLDQas5dzPgOWCk9GuuJC2lBqItuhKI4uxGgo9aIV7MYbk2h9Q6uULEh8WBzThoI7l+qU9Ast9fVUmkqPP9wYg==}
 
+  socket.io-client@4.8.1:
+    resolution: {integrity: sha512-hJVXfu3E28NmzGk8o1sHhN3om52tRvwYeidbj7xKy2eIIse5IoKX3USlS6Tqt3BHAtflLIkCQBkzVrEEfWUyYQ==}
+    engines: {node: '>=10.0.0'}
+
   socket.io-parser@4.2.4:
     resolution: {integrity: sha512-/GbIKmo8ioc+NIWIhwdecY0ge+qVBSMdgxGygevmdHj24bsfgtCmcUUcQ5ZzcylGFHsN3k4HB4Cgkl96KVnuew==}
     engines: {node: '>=10.0.0'}
@@ -3908,6 +3927,10 @@ packages:
       utf-8-validate:
         optional: true
 
+  xmlhttprequest-ssl@2.1.2:
+    resolution: {integrity: sha512-TEU+nJVUUnA4CYJFLvK5X9AOeH4KvDvhIfm0vV1GaQRtchnG0hgK5p8hw/xjv8cunWYCsiPCSDzObPyhEwq3KQ==}
+    engines: {node: '>=0.4.0'}
+
   xxhash-wasm@1.0.2:
     resolution: {integrity: sha512-ibF0Or+FivM9lNrg+HGJfVX8WJqgo+kCLDc4vx6xMeTce7Aj+DLttKbxxRR/gNLSAelRc1omAPlJ77N/Jem07A==}
 
@@ -5133,6 +5156,18 @@ snapshots:
 
   emoji-regex@8.0.0: {}
 
+  engine.io-client@6.6.2:
+    dependencies:
+      '@socket.io/component-emitter': 3.1.2
+      debug: 4.3.5
+      engine.io-parser: 5.2.3
+      ws: 8.17.1
+      xmlhttprequest-ssl: 2.1.2
+    transitivePeerDependencies:
+      - bufferutil
+      - supports-color
+      - utf-8-validate
+
   engine.io-parser@5.2.3: {}
 
   engine.io@6.6.2:
@@ -6225,6 +6260,17 @@ snapshots:
       - supports-color
       - utf-8-validate
 
+  socket.io-client@4.8.1:
+    dependencies:
+      '@socket.io/component-emitter': 3.1.2
+      debug: 4.3.5
+      engine.io-client: 6.6.2
+      socket.io-parser: 4.2.4
+    transitivePeerDependencies:
+      - bufferutil
+      - supports-color
+      - utf-8-validate
+
   socket.io-parser@4.2.4:
     dependencies:
       '@socket.io/component-emitter': 3.1.2
@@ -6641,6 +6687,8 @@ snapshots:
 
   ws@8.18.0: {}
 
+  xmlhttprequest-ssl@2.1.2: {}
+
   xxhash-wasm@1.0.2: {}
 
   yallist@2.1.2: {}

From cf06d39c3b96f977a37e68911b9eef6d6dbbd218 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:16:04 +0000
Subject: [PATCH 07/14] simplified example

---
 packages/kit/src/exports/public.d.ts          |  2 +-
 packages/kit/src/runtime/server/endpoint.js   |  1 -
 packages/kit/src/runtime/server/respond.js    |  5 +--
 .../src/routes/socket.io/+page.svelte         | 33 -----------------
 .../options-2/src/routes/socket.io/+server.js | 18 ----------
 .../options-2/src/routes/uws/+page.svelte     | 35 +++++++++++++++++++
 .../apps/options-2/src/routes/uws/+server.js  | 19 ++++++++++
 .../apps/options-2/src/routes/ws/+page.svelte |  3 +-
 pnpm-lock.yaml                                |  3 --
 9 files changed, 58 insertions(+), 61 deletions(-)
 delete mode 100644 packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte
 delete mode 100644 packages/kit/test/apps/options-2/src/routes/socket.io/+server.js
 create mode 100644 packages/kit/test/apps/options-2/src/routes/uws/+page.svelte
 create mode 100644 packages/kit/test/apps/options-2/src/routes/uws/+server.js

diff --git a/packages/kit/src/exports/public.d.ts b/packages/kit/src/exports/public.d.ts
index c8db2c0f8832..f0b5edc35aac 100644
--- a/packages/kit/src/exports/public.d.ts
+++ b/packages/kit/src/exports/public.d.ts
@@ -1081,7 +1081,7 @@ export interface RequestEvent<
 		/**
 	 * The upgrade request object
 	 */
-	upgrade?: {request: IncomingMessage, socket: Duplex, head: Buffer}
+	upgrade: {request: IncomingMessage, socket: Duplex, head: Buffer} | null
 	/**
 	 * Info about the current route
 	 */
diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index b968c780b1c2..00cb5ed36c98 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -50,7 +50,6 @@ export async function render_endpoint(event, mod, state) {
 	try {
 
 		if (method === 'GET' && event.request.headers.has('upgrade') && event.upgrade && mod.UPGRADE) {
-			console.log('upgrade')
 			await handler(
 				/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
 			);
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
index 3b013d32ac8a..91c8e130fabd 100644
--- a/packages/kit/src/runtime/server/respond.js
+++ b/packages/kit/src/runtime/server/respond.js
@@ -182,6 +182,7 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 		params,
 		platform: state.platform,
 		request,
+		upgrade: upgradeRequest || null,
 		route: { id: route?.id ?? null },
 		setHeaders: (new_headers) => {
 			for (const key in new_headers) {
@@ -208,10 +209,6 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 		isSubRequest: state.depth > 0
 	};
 
-	if(upgradeRequest) {
-		event.upgrade = upgradeRequest;
-	}
-
 	/** @type {import('types').RequiredResolveOptions} */
 	let resolve_opts = {
 		transformPageChunk: default_transform,
diff --git a/packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte b/packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte
deleted file mode 100644
index 4e85476b189e..000000000000
--- a/packages/kit/test/apps/options-2/src/routes/socket.io/+page.svelte
+++ /dev/null
@@ -1,33 +0,0 @@
-<script>
-	import { browser } from "$app/environment";
-	import { io  } from "socket.io-client"
-	import { base } from '$app/paths';
-
-	const messages = []
-
-	if(browser) {
-		const socket = io(undefined, {path: `${base}/socket.io`})
-
-		socket.on("connect", () => {
-			console.log("connected")
-			socket.emit("chat message", "hello world")
-		})
-
-		socket.on("disconnect", () => {
-			console.log("disconnected")
-		})
-
-		socket.on("message", (data) => {
-			messages.push(data)
-			console.log(data)
-		})
-	}
-</script>
-
-<h1>Messages:</h1>
-
-<div>
-	{#each messages as message}
-		<p>{message}</p>
-	{/each}
-</div>
diff --git a/packages/kit/test/apps/options-2/src/routes/socket.io/+server.js b/packages/kit/test/apps/options-2/src/routes/socket.io/+server.js
deleted file mode 100644
index 97fae0007788..000000000000
--- a/packages/kit/test/apps/options-2/src/routes/socket.io/+server.js
+++ /dev/null
@@ -1,18 +0,0 @@
-import { createServer } from 'node:http';
-import { Server }from 'socket.io';
-
-const httpServer  = createServer();
-const io = new Server(httpServer);
-
-io.on('connection', (socket) => {
-	socket.on('error', console.error);
-
-	socket.on('chat message', (data) => {
-		console.log('received message: %s', data);
-		socket.emit('chat message', data);
-	});
-});
-
-export function UPGRADE({ upgrade }) {
-	io.engine.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head)
-}
diff --git a/packages/kit/test/apps/options-2/src/routes/uws/+page.svelte b/packages/kit/test/apps/options-2/src/routes/uws/+page.svelte
new file mode 100644
index 000000000000..fd6ee5196764
--- /dev/null
+++ b/packages/kit/test/apps/options-2/src/routes/uws/+page.svelte
@@ -0,0 +1,35 @@
+<script>
+	import { browser } from "$app/environment";
+	import { base } from '$app/paths';
+
+	let messages = []
+
+	if(browser) {
+		const socket = new WebSocket(`${base}/ws`)
+
+		console.log(socket)
+
+		socket.onopen = () => {
+			console.log("websocket connected")
+			socket.send("hello world")
+		}
+
+		socket.onclose = () => {
+			console.log("disconnected")
+		}
+
+		socket.onmessage = (event) => {
+			console.log(event.data)
+			messages.push(event.data)
+			console.log(messages)
+		}
+	}
+</script>
+
+<h1>Messages:</h1>
+
+<div>
+	{#each messages as message}
+		<p>{message}</p>
+	{/each}
+</div>
diff --git a/packages/kit/test/apps/options-2/src/routes/uws/+server.js b/packages/kit/test/apps/options-2/src/routes/uws/+server.js
new file mode 100644
index 000000000000..c839e67c0fb1
--- /dev/null
+++ b/packages/kit/test/apps/options-2/src/routes/uws/+server.js
@@ -0,0 +1,19 @@
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ noServer: true });
+
+wss.on('connection', (ws) => {
+	ws.on('error', console.error);
+
+	ws.on('message', (message) => {
+		console.log('received: %s', message);
+		ws.send(String(message));
+	});
+});
+
+export function UPGRADE({ upgrade }) {
+	wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
+		console.log('UPGRADED');
+		wss.emit('connection', ws, upgrade.request);
+	});
+}
diff --git a/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte b/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
index fd6ee5196764..5a2b6e9be63c 100644
--- a/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
+++ b/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
@@ -20,8 +20,9 @@
 
 		socket.onmessage = (event) => {
 			console.log(event.data)
-			messages.push(event.data)
+			messages = [...messages, event.data];
 			console.log(messages)
+
 		}
 	}
 </script>
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9aff84134510..7797ae2858b2 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -457,9 +457,6 @@ importers:
       socket.io:
         specifier: ^4.8.1
         version: 4.8.1
-      socket.io-client:
-        specifier: ^4.8.1
-        version: 4.8.1
       svelte:
         specifier: ^4.2.10
         version: 4.2.19

From f28ff1c70535c7c656097d4e3c9315e22bd58f1f Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:18:16 +0000
Subject: [PATCH 08/14] restore previous formatting

---
 packages/kit/src/exports/public.d.ts       | 6 +++---
 packages/kit/src/exports/vite/dev/index.js | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/kit/src/exports/public.d.ts b/packages/kit/src/exports/public.d.ts
index f0b5edc35aac..57948a354329 100644
--- a/packages/kit/src/exports/public.d.ts
+++ b/packages/kit/src/exports/public.d.ts
@@ -551,7 +551,7 @@ export interface KitConfig {
 		 * How to respond to HTTP errors encountered while prerendering the app.
 		 *
 		 * - `'fail'` — fail the build
-		 * - `'ignore'` — silently ignore the failure and continue
+		 * - `'ignore'` - silently ignore the failure and continue
 		 * - `'warn'` — continue, but print a warning
 		 * - `(details) => void` — a custom error handler that takes a `details` object with `status`, `path`, `referrer`, `referenceType` and `message` properties. If you `throw` from this function, the build will fail
 		 *
@@ -583,7 +583,7 @@ export interface KitConfig {
 		 * How to respond when hash links from one prerendered page to another don't correspond to an `id` on the destination page.
 		 *
 		 * - `'fail'` — fail the build
-		 * - `'ignore'` — silently ignore the failure and continue
+		 * - `'ignore'` - silently ignore the failure and continue
 		 * - `'warn'` — continue, but print a warning
 		 * - `(details) => void` — a custom error handler that takes a `details` object with `path`, `id`, `referrers` and `message` properties. If you `throw` from this function, the build will fail
 		 *
@@ -595,7 +595,7 @@ export interface KitConfig {
 		 * How to respond when an entry generated by the `entries` export doesn't match the route it was generated from.
 		 *
 		 * - `'fail'` — fail the build
-		 * - `'ignore'` — silently ignore the failure and continue
+		 * - `'ignore'` - silently ignore the failure and continue
 		 * - `'warn'` — continue, but print a warning
 		 * - `(details) => void` — a custom error handler that takes a `details` object with `generatedFromId`, `entry`, `matchedId` and `message` properties. If you `throw` from this function, the build will fail
 		 *
diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index ef968967964e..f4daa46fe98d 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -43,7 +43,7 @@ export async function dev(vite, vite_config, svelte_config) {
 	globalThis.fetch = (info, init) => {
 		if (typeof info === 'string' && !SCHEME.test(info)) {
 			throw new Error(
-				`Cannot use relative URL (${info}) with global fetch - use \`event.fetch\` instead: https://svelte.dev/docs/kit/web-standards#fetch-apis`
+				`Cannot use relative URL (${info}) with global fetch — use \`event.fetch\` instead: https://svelte.dev/docs/kit/web-standards#fetch-apis`
 			);
 		}
 

From cb2458e1b3df1c064d0de919f833caa29e5fb625 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:21:26 +0000
Subject: [PATCH 09/14] fixed basics deps

---
 packages/kit/test/apps/basics/package.json | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/packages/kit/test/apps/basics/package.json b/packages/kit/test/apps/basics/package.json
index fdf201943958..eadca24b6a31 100644
--- a/packages/kit/test/apps/basics/package.json
+++ b/packages/kit/test/apps/basics/package.json
@@ -18,12 +18,10 @@
 		"@sveltejs/vite-plugin-svelte": "^3.0.1",
 		"cross-env": "^7.0.3",
 		"marked": "^14.0.0",
-		"socket.io": "^4.8.1",
 		"svelte": "^4.2.10",
 		"svelte-check": "^4.0.1",
 		"typescript": "^5.3.3",
-		"vite": "^5.3.2",
-		"ws": "^8.18.0"
+		"vite": "^5.3.2"
 	},
 	"type": "module"
 }

From f9806b7325259d211af5a03bb2a3ea71b0b2be92 Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:22:18 +0000
Subject: [PATCH 10/14] removed un-needed parenthesis

---
 packages/kit/src/runtime/server/endpoint.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index 00cb5ed36c98..218b5a3ca7db 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -18,7 +18,7 @@ export async function render_endpoint(event, mod, state) {
  */
 	let handler = mod[method] || mod.fallback;
 
-	if (method === 'HEAD' && (mod.GET && !mod.HEAD)) {
+	if (method === 'HEAD' && mod.GET && !mod.HEAD) {
 		handler = mod.GET;
 	}
 

From 1bdcc5fc0a3229f505b28b9707b0eb66467df38a Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:46:46 +0000
Subject: [PATCH 11/14] updated lockfile

---
 pnpm-lock.yaml | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 7797ae2858b2..d0b1290e9165 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -454,9 +454,6 @@ importers:
       marked:
         specifier: ^14.0.0
         version: 14.1.1
-      socket.io:
-        specifier: ^4.8.1
-        version: 4.8.1
       svelte:
         specifier: ^4.2.10
         version: 4.2.19
@@ -469,9 +466,6 @@ importers:
       vite:
         specifier: ^5.3.2
         version: 5.3.6(@types/node@18.19.50)(lightningcss@1.24.1)
-      ws:
-        specifier: ^8.18.0
-        version: 8.18.0
 
   packages/kit/test/apps/dev-only:
     devDependencies:

From 8832329d8e11a2b82412e982c5dadacf7f9af7dc Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:50:17 +0000
Subject: [PATCH 12/14] cleaning and formatting

---
 packages/kit/src/exports/public.d.ts          |  4 +-
 packages/kit/src/exports/vite/dev/index.js    | 37 +++++++++----------
 packages/kit/src/runtime/app/server/index.js  |  1 -
 packages/kit/src/runtime/server/endpoint.js   |  7 ++--
 packages/kit/src/runtime/server/index.js      | 16 +++++---
 packages/kit/src/runtime/server/respond.js    |  2 +-
 packages/kit/src/types/internal.d.ts          | 14 +++----
 .../apps/options-2/src/routes/+page.svelte    |  4 +-
 .../options-2/src/routes/uws/+page.svelte     | 35 ------------------
 .../apps/options-2/src/routes/uws/+server.js  | 19 ----------
 .../apps/options-2/src/routes/ws/+page.svelte | 27 +++++++-------
 11 files changed, 56 insertions(+), 110 deletions(-)
 delete mode 100644 packages/kit/test/apps/options-2/src/routes/uws/+page.svelte
 delete mode 100644 packages/kit/test/apps/options-2/src/routes/uws/+server.js

diff --git a/packages/kit/src/exports/public.d.ts b/packages/kit/src/exports/public.d.ts
index 57948a354329..0e101ba1e744 100644
--- a/packages/kit/src/exports/public.d.ts
+++ b/packages/kit/src/exports/public.d.ts
@@ -1078,10 +1078,10 @@ export interface RequestEvent<
 	 * The original request object
 	 */
 	request: Request;
-		/**
+	/**
 	 * The upgrade request object
 	 */
-	upgrade: {request: IncomingMessage, socket: Duplex, head: Buffer} | null
+	upgrade: { request: IncomingMessage; socket: Duplex; head: Buffer } | null;
 	/**
 	 * Info about the current route
 	 */
diff --git a/packages/kit/src/exports/vite/dev/index.js b/packages/kit/src/exports/vite/dev/index.js
index f4daa46fe98d..eda1f1298f9a 100644
--- a/packages/kit/src/exports/vite/dev/index.js
+++ b/packages/kit/src/exports/vite/dev/index.js
@@ -567,27 +567,24 @@ export async function dev(vite, vite_config, svelte_config) {
 					return;
 				}
 
-				const rendered = await server.respond(
-					request,
-					{
-						getClientAddress: () => {
-							const { remoteAddress } = req.socket;
-							if (remoteAddress) return remoteAddress;
-							throw new Error('Could not determine clientAddress');
-						},
-						read: (file) => {
-							if (file in manifest._.server_assets) {
-								return fs.readFileSync(from_fs(file));
-							}
+				const rendered = await server.respond(request, {
+					getClientAddress: () => {
+						const { remoteAddress } = req.socket;
+						if (remoteAddress) return remoteAddress;
+						throw new Error('Could not determine clientAddress');
+					},
+					read: (file) => {
+						if (file in manifest._.server_assets) {
+							return fs.readFileSync(from_fs(file));
+						}
 
-							return fs.readFileSync(path.join(svelte_config.kit.files.assets, file));
-						},
-						before_handle: (event, config, prerender) => {
-							async_local_storage.enterWith({ event, config, prerender });
-						},
-						emulator
-					}
-				);
+						return fs.readFileSync(path.join(svelte_config.kit.files.assets, file));
+					},
+					before_handle: (event, config, prerender) => {
+						async_local_storage.enterWith({ event, config, prerender });
+					},
+					emulator
+				});
 
 				if (rendered.status === 404) {
 					// @ts-expect-error
diff --git a/packages/kit/src/runtime/app/server/index.js b/packages/kit/src/runtime/app/server/index.js
index 8a3c7283d6a8..33c9b0a0d1ba 100644
--- a/packages/kit/src/runtime/app/server/index.js
+++ b/packages/kit/src/runtime/app/server/index.js
@@ -71,4 +71,3 @@ export function read(asset) {
 
 	throw new Error(`Asset does not exist: ${file}`);
 }
-
diff --git a/packages/kit/src/runtime/server/endpoint.js b/packages/kit/src/runtime/server/endpoint.js
index 218b5a3ca7db..c3614e6da46d 100644
--- a/packages/kit/src/runtime/server/endpoint.js
+++ b/packages/kit/src/runtime/server/endpoint.js
@@ -13,9 +13,9 @@ export async function render_endpoint(event, mod, state) {
 	const method = /** @type {import('types').HttpMethod} */ (event.request.method);
 
 	/**
- * The handler function to use for the request
- * @type {import('@sveltejs/kit').RequestHandler | import('@sveltejs/kit').UpgradeHandler | undefined}
- */
+	 * The handler function to use for the request
+	 * @type {import('@sveltejs/kit').RequestHandler | import('@sveltejs/kit').UpgradeHandler | undefined}
+	 */
 	let handler = mod[method] || mod.fallback;
 
 	if (method === 'HEAD' && mod.GET && !mod.HEAD) {
@@ -48,7 +48,6 @@ export async function render_endpoint(event, mod, state) {
 	}
 
 	try {
-
 		if (method === 'GET' && event.request.headers.has('upgrade') && event.upgrade && mod.UPGRADE) {
 			await handler(
 				/** @type {import('@sveltejs/kit').RequestEvent<Record<string, any>>} */ (event)
diff --git a/packages/kit/src/runtime/server/index.js b/packages/kit/src/runtime/server/index.js
index 655159a2e567..c95d68370cf7 100644
--- a/packages/kit/src/runtime/server/index.js
+++ b/packages/kit/src/runtime/server/index.js
@@ -96,10 +96,16 @@ export class Server {
 	 * @param {{request: import('http').IncomingMessage, socket: import('stream').Duplex , head: Buffer}?} webhookRequest
 	 */
 	async respond(request, options, webhookRequest) {
-		return respond(request, this.#options, this.#manifest, {
-			...options,
-			error: false,
-			depth: 0
-		}, webhookRequest);
+		return respond(
+			request,
+			this.#options,
+			this.#manifest,
+			{
+				...options,
+				error: false,
+				depth: 0
+			},
+			webhookRequest
+		);
 	}
 }
diff --git a/packages/kit/src/runtime/server/respond.js b/packages/kit/src/runtime/server/respond.js
index 91c8e130fabd..852aee368d1d 100644
--- a/packages/kit/src/runtime/server/respond.js
+++ b/packages/kit/src/runtime/server/respond.js
@@ -330,7 +330,7 @@ export async function respond(request, options, manifest, state, upgradeRequest)
 			event,
 			resolve: (event, opts) =>
 				resolve(event, opts).then((response) => {
-					if(!response) return;
+					if (!response) return;
 					// add headers/cookies here, rather than inside `resolve`, so that we
 					// can do it once for all responses instead of once per `return`
 					for (const key in headers) {
diff --git a/packages/kit/src/types/internal.d.ts b/packages/kit/src/types/internal.d.ts
index d60972a97447..7b0ef17cec3e 100644
--- a/packages/kit/src/types/internal.d.ts
+++ b/packages/kit/src/types/internal.d.ts
@@ -135,7 +135,7 @@ export class InternalServer extends Server {
 			before_handle?: (event: RequestEvent, config: any, prerender: PrerenderOption) => void;
 			emulator?: Emulator;
 		},
-		webhookRequest?: {request: IncomingMessage, socket: Duplex, head: Buffer},
+		webhookRequest?: { request: IncomingMessage; socket: Duplex; head: Buffer }
 	): Promise<Response>;
 }
 
@@ -390,12 +390,12 @@ export interface PageNodeIndexes {
 export type PrerenderEntryGenerator = () => MaybePromise<Array<Record<string, string>>>;
 
 export type SSREndpoint = Partial<Record<HttpMethod, RequestHandler>> & {
-  UPGRADE?: UpgradeHandler;
-  prerender?: PrerenderOption;
-  trailingSlash?: TrailingSlash;
-  config?: any;
-  entries?: PrerenderEntryGenerator;
-  fallback?: RequestHandler;
+	UPGRADE?: UpgradeHandler;
+	prerender?: PrerenderOption;
+	trailingSlash?: TrailingSlash;
+	config?: any;
+	entries?: PrerenderEntryGenerator;
+	fallback?: RequestHandler;
 };
 
 export interface SSRRoute {
diff --git a/packages/kit/test/apps/options-2/src/routes/+page.svelte b/packages/kit/test/apps/options-2/src/routes/+page.svelte
index b869628a945d..a8faccaba6e3 100644
--- a/packages/kit/test/apps/options-2/src/routes/+page.svelte
+++ b/packages/kit/test/apps/options-2/src/routes/+page.svelte
@@ -8,7 +8,7 @@
 <p data-testid="assets">assets: {assets}</p>
 
 <a href="{base}/hello" data-testid="link">Go to /hello</a>
-<br>
+<br />
 <a href="{base}/ws" data-testid="link">Go to /ws</a>
-<br>
+<br />
 <a href="{base}/socket.io" data-testid="link">Go to /socket.io</a>
diff --git a/packages/kit/test/apps/options-2/src/routes/uws/+page.svelte b/packages/kit/test/apps/options-2/src/routes/uws/+page.svelte
deleted file mode 100644
index fd6ee5196764..000000000000
--- a/packages/kit/test/apps/options-2/src/routes/uws/+page.svelte
+++ /dev/null
@@ -1,35 +0,0 @@
-<script>
-	import { browser } from "$app/environment";
-	import { base } from '$app/paths';
-
-	let messages = []
-
-	if(browser) {
-		const socket = new WebSocket(`${base}/ws`)
-
-		console.log(socket)
-
-		socket.onopen = () => {
-			console.log("websocket connected")
-			socket.send("hello world")
-		}
-
-		socket.onclose = () => {
-			console.log("disconnected")
-		}
-
-		socket.onmessage = (event) => {
-			console.log(event.data)
-			messages.push(event.data)
-			console.log(messages)
-		}
-	}
-</script>
-
-<h1>Messages:</h1>
-
-<div>
-	{#each messages as message}
-		<p>{message}</p>
-	{/each}
-</div>
diff --git a/packages/kit/test/apps/options-2/src/routes/uws/+server.js b/packages/kit/test/apps/options-2/src/routes/uws/+server.js
deleted file mode 100644
index c839e67c0fb1..000000000000
--- a/packages/kit/test/apps/options-2/src/routes/uws/+server.js
+++ /dev/null
@@ -1,19 +0,0 @@
-import { WebSocketServer } from 'ws';
-
-const wss = new WebSocketServer({ noServer: true });
-
-wss.on('connection', (ws) => {
-	ws.on('error', console.error);
-
-	ws.on('message', (message) => {
-		console.log('received: %s', message);
-		ws.send(String(message));
-	});
-});
-
-export function UPGRADE({ upgrade }) {
-	wss.handleUpgrade(upgrade.request, upgrade.socket, upgrade.head, (ws) => {
-		console.log('UPGRADED');
-		wss.emit('connection', ws, upgrade.request);
-	});
-}
diff --git a/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte b/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
index 5a2b6e9be63c..d68ebdcc35c3 100644
--- a/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
+++ b/packages/kit/test/apps/options-2/src/routes/ws/+page.svelte
@@ -1,29 +1,28 @@
 <script>
-	import { browser } from "$app/environment";
+	import { browser } from '$app/environment';
 	import { base } from '$app/paths';
 
-	let messages = []
+	let messages = [];
 
-	if(browser) {
-		const socket = new WebSocket(`${base}/ws`)
+	if (browser) {
+		const socket = new WebSocket(`${base}/ws`);
 
-		console.log(socket)
+		console.log(socket);
 
 		socket.onopen = () => {
-			console.log("websocket connected")
-			socket.send("hello world")
-		}
+			console.log('websocket connected');
+			socket.send('hello world');
+		};
 
 		socket.onclose = () => {
-			console.log("disconnected")
-		}
+			console.log('disconnected');
+		};
 
 		socket.onmessage = (event) => {
-			console.log(event.data)
+			console.log(event.data);
 			messages = [...messages, event.data];
-			console.log(messages)
-
-		}
+			console.log(messages);
+		};
 	}
 </script>
 

From b3ce4267585b19a4001b6c45b117b0632f948cab Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 21:56:26 +0000
Subject: [PATCH 13/14] fixed exports test

---
 packages/kit/src/utils/exports.spec.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/kit/src/utils/exports.spec.js b/packages/kit/src/utils/exports.spec.js
index e27817c17b5c..4f0e52781d40 100644
--- a/packages/kit/src/utils/exports.spec.js
+++ b/packages/kit/src/utils/exports.spec.js
@@ -174,7 +174,7 @@ test('validates +server.js', () => {
 		validate_server_exports({
 			answer: 42
 		});
-	}, "Invalid export 'answer' (valid exports are GET, POST, PATCH, PUT, DELETE, OPTIONS, HEAD, fallback, prerender, trailingSlash, config, entries, or anything with a '_' prefix)");
+	}, "Invalid export 'answer' (valid exports are UPGRADE, GET, POST, PATCH, PUT, DELETE, OPTIONS, HEAD, fallback, prerender, trailingSlash, config, entries, or anything with a '_' prefix)");
 
 	check_error(() => {
 		validate_server_exports({

From 44e84aedb8c851cd97bbf292d17bbabc48a7025c Mon Sep 17 00:00:00 2001
From: Luke Hagar <lukeslakemail@gmail.com>
Date: Tue, 5 Nov 2024 22:00:07 +0000
Subject: [PATCH 14/14] regenerated types

---
 packages/kit/types/index.d.ts | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/packages/kit/types/index.d.ts b/packages/kit/types/index.d.ts
index 491de54d9698..d352912d5d9c 100644
--- a/packages/kit/types/index.d.ts
+++ b/packages/kit/types/index.d.ts
@@ -4,6 +4,8 @@
 declare module '@sveltejs/kit' {
 	import type { CompileOptions } from 'svelte/compiler';
 	import type { PluginOptions } from '@sveltejs/vite-plugin-svelte';
+	import type { IncomingMessage } from 'node:http';
+	import type { Duplex } from 'node:stream';
 	/**
 	 * [Adapters](https://svelte.dev/docs/kit/adapters) are responsible for taking the production build and turning it into something that can be deployed to a platform of your choosing.
 	 */
@@ -667,8 +669,8 @@ declare module '@sveltejs/kit' {
 	 */
 	export type Handle = (input: {
 		event: RequestEvent;
-		resolve(event: RequestEvent, opts?: ResolveOptions): MaybePromise<Response>;
-	}) => MaybePromise<Response>;
+		resolve(event: RequestEvent, opts?: ResolveOptions): MaybePromise<void | Response>;
+	}) => MaybePromise<void | Response>;
 
 	/**
 	 * The server-side [`handleError`](https://svelte.dev/docs/kit/hooks#shared-hooks-handleError) hook runs when an unexpected error is thrown while responding to a request.
@@ -1058,6 +1060,10 @@ declare module '@sveltejs/kit' {
 		 * The original request object
 		 */
 		request: Request;
+		/**
+		 * The upgrade request object
+		 */
+		upgrade: { request: IncomingMessage; socket: Duplex; head: Buffer } | null;
 		/**
 		 * Info about the current route
 		 */
@@ -1115,6 +1121,16 @@ declare module '@sveltejs/kit' {
 		RouteId extends string | null = string | null
 	> = (event: RequestEvent<Params, RouteId>) => MaybePromise<Response>;
 
+	/**
+	 * A `(event: UpgradeEvent) => void` function exported from a `+server.js` file with the name UPGRADE and handles server upgrade requests.
+	 *
+	 * It receives `Params` as the first generic argument, which you can skip by using [generated types](https://svelte.dev/docs/kit/types#Generated-types) instead.
+	 */
+	export type UpgradeHandler<
+		Params extends Partial<Record<string, string>> = Partial<Record<string, string>>,
+		RouteId extends string | null = string | null
+	> = (event: RequestEvent<Params, RouteId>) => MaybePromise<void>;
+
 	export interface ResolveOptions {
 		/**
 		 * Applies custom transforms to HTML. If `done` is true, it's the final chunk. Chunks are not guaranteed to be well-formed HTML
@@ -1734,6 +1750,7 @@ declare module '@sveltejs/kit' {
 	type PrerenderEntryGenerator = () => MaybePromise<Array<Record<string, string>>>;
 
 	type SSREndpoint = Partial<Record<HttpMethod, RequestHandler>> & {
+		UPGRADE?: UpgradeHandler;
 		prerender?: PrerenderOption;
 		trailingSlash?: TrailingSlash;
 		config?: any;