Allow passing platform context from adapters

.changeset/cyan-numbers-change.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-cloudflare': patch
+---
+
+Pass `env` object to SvelteKit via `platform`

.changeset/many-mayflies-clap.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Allow adapters to pass in `platform` object

documentation/docs/01-routing.md

@@ -51,11 +51,12 @@ Endpoints are modules written in `.js` (or `.ts`) files that export functions co
 // Declaration types for Endpoints
 // * declarations that are not exported are for internal use
 
-export interface RequestEvent<Locals = Record<string, any>> {
+export interface RequestEvent<Locals = Record<string, any>, Platform = Record<string, any>> {
 	request: Request;
 	url: URL;
 	params: Record<string, string>;
 	locals: Locals;
+	platform: Platform;
 }
 
 type Body = JSONString | Uint8Array | ReadableStream | stream.Readable;
@@ -69,8 +70,13 @@ type MaybePromise<T> = T | Promise<T>;
 interface Fallthrough {
 	fallthrough: true;
 }
-export interface RequestHandler<Locals = Record<string, any>, Output extends Body = Body> {
-	(event: RequestEvent<Locals>): MaybePromise<
+
+export interface RequestHandler<
+	Locals = Record<string, any>,
+	Platform = Record<string, any>,
+	Output extends Body = Body
+> {
+	(event: RequestEvent<Locals, Platform>): MaybePromise<
 		Either<Response | EndpointOutput<Output>, Fallthrough>
 	>;
 }

documentation/docs/04-hooks.md

@@ -22,21 +22,22 @@ If unimplemented, defaults to `({ event, resolve }) => resolve(event)`.
 // everything else must be a type of string
 type ResponseHeaders = Record<string, string | string[]>;
 
-export interface RequestEvent<Locals = Record<string, any>> {
+export interface RequestEvent<Locals = Record<string, any>, Platform = Record<string, any>> {
 	request: Request;
 	url: URL;
 	params: Record<string, string>;
 	locals: Locals;
+	platform: Platform;
 }
 
 export interface ResolveOpts {
 	ssr?: boolean;
 }
 
-export interface Handle<Locals = Record<string, any>> {
+export interface Handle<Locals = Record<string, any>, Platform = Record<string, any>> {
 	(input: {
-		event: RequestEvent<Locals>;
-		resolve(event: RequestEvent<Locals>, opts?: ResolveOpts): MaybePromise<Response>;
+		event: RequestEvent<Locals, Platform>;
+		resolve(event: RequestEvent<Locals, Platform>, opts?: ResolveOpts): MaybePromise<Response>;
 	}): MaybePromise<Response>;
 }
 ```
@@ -84,8 +85,8 @@ If unimplemented, SvelteKit will log the error with default formatting.
 
 ```ts
 // Declaration types for handleError hook
-export interface HandleError<Locals = Record<string, any>> {
-	(input: { error: Error & { frame?: string }; event: RequestEvent<Locals> }): void;
+export interface HandleError<Locals = Record<string, any>, Platform = Record<string, any>> {
+	(input: { error: Error & { frame?: string }; event: RequestEvent<Locals, Platform> }): void;
 }
 ```
 
@@ -107,8 +108,12 @@ If unimplemented, session is `{}`.
 
 ```ts
 // Declaration types for getSession hook
-export interface GetSession<Locals = Record<string, any>, Session = any> {
-	(event: RequestEvent<Locals>): Session | Promise<Session>;
+export interface GetSession<
+	Locals = Record<string, any>,
+	Platform = Record<string, any>,
+	Session = any
+> {
+	(event: RequestEvent<Locals, Platform>): MaybePromise<Session>;
 }
 ```
 

documentation/docs/10-adapters.md

@@ -54,6 +54,10 @@ Most adapters will generate static HTML for any [prerenderable](#page-options-pr
 
 You can also use `adapter-static` to generate single-page apps (SPAs) by specifying a [fallback page](https://github.com/sveltejs/kit/tree/master/packages/adapter-static#spa-mode).
 
+#### Platform-specific context
+
+Some adapters may have access to additional information about the request. For example, Cloudflare Workers can access an `env` object containing KV namespaces etc. This can be passed to the `RequestEvent` used in [hooks](#hooks) and [endpoints](#routing-endpoints) as the `platform` property — consult each adapter's documentation to learn more.
+
 ### Community adapters
 
 Additional [community-provided adapters](https://sveltesociety.dev/components#adapters) exist for other platforms. After installing the relevant adapter with your package manager, update your `svelte.config.js`:
@@ -93,6 +97,7 @@ Within the `adapt` method, there are a number of things that an adapter should d
   - Imports `App` from `${builder.getServerDirectory()}/app.js`
   - Instantiates the app with a manifest generated with `builder.generateManifest({ relativePath })`
   - Listens for requests from the platform, converts them to a standard [Request](https://developer.mozilla.org/en-US/docs/Web/API/Request) if necessary, calls the `render` function to generate a [Response](https://developer.mozilla.org/en-US/docs/Web/API/Response) and responds with it
+  - expose any platform-specific information to SvelteKit via the `platform` option passed to `app.render`
   - Globally shims `fetch` to work on the target platform, if necessary. SvelteKit provides a `@sveltejs/kit/install-fetch` helper for platforms that can use `node-fetch`
 - Bundle the output to avoid needing to install dependencies on the target platform, if necessary
 - Put the user's static files and the generated JS/CSS in the correct location for the target platform

packages/adapter-cloudflare/README.md

@@ -50,6 +50,26 @@ When configuring your project settings, you must use the following settings:
 
 > **Important:** You need to add a `NODE_VERSION` environment variable to both the "production" and "preview" environments. You can add this during project setup or later in the Pages project settings. SvelteKit requires Node `14.13` or later, so you should use `14` or `16` as the `NODE_VERSION` value.
 
+## Environment variables
+
+The [`env`](https://developers.cloudflare.com/workers/runtime-apis/fetch-event#parameters) object, containing KV namespaces etc, is passed to SvelteKit via the `platform` property, meaning you can access it in hooks and endpoints:
+
+```ts
+interface Locals {}
+
+interface Platform {
+	env: {
+		COUNTER: DurableObjectNamespace;
+	};
+}
+
+export async function post<Locals, Platform>({ request, platform }) {
+	const counter = platform.env.COUNTER.idFromName('A');
+}
+```
+
+> `platform.env` is only available in the production build. Use [wrangler](https://developers.cloudflare.com/workers/cli-wrangler) to test it locally
+
 ## Changelog
 
 [The Changelog for this package is available on GitHub](https://github.com/sveltejs/kit/blob/master/packages/adapter-cloudflare/CHANGELOG.md).

packages/adapter-cloudflare/files/worker.js

@@ -45,7 +45,7 @@ export default {
 
 		// dynamically-generated pages
 		try {
-			return await app.render(req);
+			return await app.render(req, { platform: { env } });
 		} catch (e) {
 			return new Response('Error rendering route: ' + (e.message || e.toString()), { status: 500 });
 		}

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

@@ -96,14 +96,12 @@ export class App {
 		};
 	}
 
-	render(request, {
-		prerender
-	} = {}) {
+	render(request, options = {}) {
 		if (!(request instanceof Request)) {
 			throw new Error('The first argument to app.render must be a Request object. See https://github.com/sveltejs/kit/pull/3384 for details');
 		}
 
-		return respond(request, this.options, { prerender });
+		return respond(request, this.options, options);
 	}
 }
 `;
@@ -172,7 +170,6 @@ export async function build_server(
 		return relative_file[0] === '.' ? relative_file : `./${relative_file}`;
 	};
 
-	// prettier-ignore
 	fs.writeFileSync(
 		input.app,
 		app_template({

packages/kit/src/runtime/server/index.js

@@ -60,7 +60,8 @@ export async function respond(request, options, state = {}) {
 		request,
 		url,
 		params: {},
-		locals: {}
+		locals: {},
+		platform: state.platform
 	};
 
 	// TODO remove this for 1.0

packages/kit/types/app.d.ts

@@ -1,15 +1,19 @@
 import { PrerenderOptions, SSRNodeLoader, SSRRoute } from './internal';
 
+export interface RequestOptions<Platform = Record<string, any>> {
+	platform?: Platform;
+}
+
 export class App {
 	constructor(manifest: SSRManifest);
-	render(request: Request): Promise<Response>;
+	render(request: Request, options?: RequestOptions): Promise<Response>;
 }
 
 export class InternalApp extends App {
 	render(
 		request: Request,
-		options?: {
-			prerender: PrerenderOptions;
+		options?: RequestOptions & {
+			prerender?: PrerenderOptions;
 		}
 	): Promise<Response>;
 }

packages/kit/types/endpoint.d.ts

@@ -13,8 +13,12 @@ export interface Fallthrough {
 	fallthrough: true;
 }
 
-export interface RequestHandler<Locals = Record<string, any>, Output extends Body = Body> {
-	(event: RequestEvent<Locals>): MaybePromise<
+export interface RequestHandler<
+	Locals = Record<string, any>,
+	Platform = Record<string, any>,
+	Output extends Body = Body
+> {
+	(event: RequestEvent<Locals, Platform>): MaybePromise<
 		Either<Response | EndpointOutput<Output>, Fallthrough>
 	>;
 }

packages/kit/types/hooks.d.ts

@@ -2,25 +2,30 @@ import { MaybePromise } from './helper';
 
 export type StrictBody = string | Uint8Array;
 
-export interface RequestEvent<Locals = Record<string, any>> {
+export interface RequestEvent<Locals = Record<string, any>, Platform = Record<string, any>> {
 	request: Request;
 	url: URL;
 	params: Record<string, string>;
 	locals: Locals;
+	platform: Readonly<Platform>;
 }
 
-export interface GetSession<Locals = Record<string, any>, Session = any> {
-	(event: RequestEvent<Locals>): MaybePromise<Session>;
+export interface GetSession<
+	Locals = Record<string, any>,
+	Platform = Record<string, any>,
+	Session = any
+> {
+	(event: RequestEvent<Locals, Platform>): MaybePromise<Session>;
 }
 
 export interface ResolveOpts {
 	ssr?: boolean;
 }
 
-export interface Handle<Locals = Record<string, any>> {
+export interface Handle<Locals = Record<string, any>, Platform = Record<string, any>> {
 	(input: {
-		event: RequestEvent<Locals>;
-		resolve(event: RequestEvent<Locals>, opts?: ResolveOpts): MaybePromise<Response>;
+		event: RequestEvent<Locals, Platform>;
+		resolve(event: RequestEvent<Locals, Platform>, opts?: ResolveOpts): MaybePromise<Response>;
 	}): MaybePromise<Response>;
 }
 

packages/kit/types/internal.d.ts

@@ -159,6 +159,7 @@ export interface SSRRenderOptions {
 export interface SSRRenderState {
 	fetched?: string;
 	initiator?: SSRPage | null;
+	platform?: any;
 	prerender?: PrerenderOptions;
 	fallback?: string;
 }