Fetch handlers and Workers context

@effront/core/workers provides a Web Fetch handler and typed access to host-supplied request values.

createFetchHandler

createFetchHandler(application) accepts an application whose Layer requirements are satisfied by HttpRouter.HttpRouter and HttpServerRequest.HttpServerRequest. It returns a FetchHandler:

import { createFetchHandler } from "@effront/core/workers";
import application from "./entry.effront";

export default { fetch: createFetchHandler(application) };

The exported handler type is:

export type FetchHandler<Env = unknown, ExecutionContext = unknown> = (
  request: Request,
  env: Env,
  executionContext: ExecutionContext,
) => Promise<Response>;

createFetchHandler returns the default type with unknown host values. Reader type arguments describe those values inside application Effects. For arbitrary external service requirements, use native HTTP capture or Alchemy.

The application Layer is acquired for each invocation. Its Scope stays open until the response body completes, fails, or is cancelled. A bodyless response releases it immediately. Buffered responses can release request services after response construction; a streaming body must retain them through consumption.

Invalid Content-Length values and values above 10 MiB produce 413. Server Function POST requests also enforce a 10 MiB limit on received bytes without that header. Custom HTTP route bodies without Content-Length are not universally measured.

Core context readers

Import these functions from @effront/core/workers.

import { createWorkersContextAccessors } from "@effront/core/workers";

type Env = { readonly APP_LABEL: string };
type HostContext = { waitUntil(promise: Promise<unknown>): void };
export const { getWorkersEnv, getWorkersRequestContext } = createWorkersContextAccessors<
  Env,
  HostContext
>();

The factory creates readers, not a service or Layer. Its readers share the same request Context as the direct accessors and preserve the identity of the host-provided objects. Each reader returns an Effect that reads the current request when executed, including when the Effect was created earlier. It has no typed failure or service requirement. A missing request Context causes a TypeError defect. Type arguments do not validate host values at runtime.

Cloudflare context readers

@effront/cloudflare/workers reads the same Context and fixes the execution-context type to CloudflareExecutionContext.

These readers have the same execution, missing-context, and runtime-validation rules as the core readers.

WorkersRequestContext

WorkersRequestContext from @effront/core/workers exports both a type and an Effect Context.Reference value. The reference holds WorkersRequestContext<unknown, unknown> and throws TypeError by default when no value is provided.

createFetchHandler supplies these exact host values separately for each request.