| title |
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Hooks |
An optional src/hooks.js (or src/hooks.ts, or src/hooks/index.js) file exports two functions, both optional, that run on the server — handle and getSession.
The location of this file can be configured as
config.kit.files.hooks
This function runs on every request, for both pages and endpoints, and determines the response. It receives the request object and a function called resolve, which invokes SvelteKit's router and generates a response accordingly. This allows you to modify response headers or bodies, or bypass SvelteKit entirely (for implementing endpoints programmatically, for example).
If unimplemented, defaults to ({ request, resolve }) => resolve(request).
To add custom data to the request, which is passed to endpoints, populate the request.locals object, as shown below.
type Headers = Record<string, string>;
type Request<Locals = Record<string, any>> = {
method: string;
host: string;
headers: Headers;
path: string;
params: Record<string, string>;
query: URLSearchParams;
rawBody: string | Uint8Array;
body: ParameterizedBody<Body>;
locals: Locals; // populated by hooks handle
};
type Response = {
status: number;
headers: Headers;
body?: string | Uint8Array;
};
type Handle<Locals = Record<string, any>> = (input: {
request: Request<Locals>;
resolve: (request: Request<Locals>) => Response | Promise<Response>;
}) => Response | Promise<Response>;/** @type {import('@sveltejs/kit').Handle} */
export async function handle({ request, resolve }) {
request.locals.user = await getUserInformation(request.headers.cookie);
const response = await resolve(request);
return {
...response,
headers: {
...response.headers,
'x-custom-header': 'potato'
}
};
}This function takes the request object and returns a session object that is accessible on the client and therefore must be safe to expose to users. It runs whenever SvelteKit server-renders a page.
If unimplemented, session is {}.
type GetSession<Locals = Record<string, any>, Session = any> = {
(request: Request<Locals>): Session | Promise<Session>;
};/** @type {import('@sveltejs/kit').GetSession} */
export function getSession(request) {
return {
user: {
// only include properties needed client-side —
// exclude anything else attached to the user
// like access tokens etc
name: request.locals.user?.name,
email: request.locals.user?.email,
avatar: request.locals.user?.avatar
}
};
}
sessionmust be serializable, which means it must not contain things like functions or custom classes, just built-in JavaScript data types