createMiddleware

createMiddleware wraps request and response middleware functions with fetch events.

Import

import { createMiddleware } from "@solidjs/start/middleware";

Type

type RequestMiddleware = (
  event: FetchEvent
) => Response | Promise<Response> | void | Promise<void | Response>;

type ResponseMiddleware = (
  event: FetchEvent,
  response: { body?: unknown }
) => Response | Promise<Response> | void | Promise<void>;

function createMiddleware(args: {
  onRequest?: RequestMiddleware | RequestMiddleware[];
  onBeforeResponse?: ResponseMiddleware | ResponseMiddleware[];
}): {
  onRequest?: _RequestMiddleware | _RequestMiddleware[];
  onBeforeResponse?: _ResponseMiddleware | _ResponseMiddleware[];
};

Parameters

`args`

Type: { onRequest?: RequestMiddleware | RequestMiddleware[]; onBeforeResponse?: ResponseMiddleware | ResponseMiddleware[] }
Required: Yes

Middleware functions grouped by request phase.

Return value

Type: { onRequest?: _RequestMiddleware | _RequestMiddleware[]; onBeforeResponse?: _ResponseMiddleware | _ResponseMiddleware[] }

Returns the value from Vinxi defineMiddleware.

Behavior

onRequest functions are wrapped so that a returned response ends the middleware.
onBeforeResponse functions are wrapped with the current fetch event and response object.
Single middleware inputs produce single wrapped functions.
Array inputs are mapped to arrays of wrapped functions.

Examples

Basic usage

import { createMiddleware } from "@solidjs/start/middleware";

export default createMiddleware({
  onRequest: async (event) => {
    event.response.headers.set(
      "x-request-path",
      new URL(event.request.url).pathname
    );
  },
});

Last updated: 5/6/26, 4:10 AMEdit this pageReport an issue with this page