Nix.js Kit Nix.js Kitv2.0.4
Docs/Server/Unified Web Handler
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Unified Web Handler

Since v2.0.2, every runtime path — dev, preview, start, and all four adapters (Node, Bun, Vercel, Netlify) — funnels through a single function: createWebHandler(). This eliminates duplicated request-handling logic and guarantees identical behavior across runtimes.

# createWebHandler()

import { createWebHandler } from "@deijose/nix-js-kit/runtime";

const handler = createWebHandler(routes, actions, {
  staticRoot: "./dist",
  lang: "en",
  clientEntry: "/_nix-js/entry-client.js",
  renderEndpoint: true,
  securityHeaders: true,
  cacheDir: "./.nix-js/cache",
  defaultRevalidate: 60,
});

// handler is a pure Web function: Request → Response
const response = await handler(request);

# Responsibilities (in order)

  1. Server actions — POST /__nix-js/actions (CSRF-verified, body-limited).
  2. SPA render endpoint — GET /__nix-js/render?page=<path> (returns body + head for SPA navigation).
  3. API routes — route.ts files.
  4. Static files — served from staticRoot with ETag, Range, HEAD, and immutable caching for hashed assets.
  5. Dynamic SSR — unmatched paths are rendered on demand.
  6. Error pages — custom 404.page.ts and 500.page.ts.

# WebHandlerOptions

Option Type Default Description
staticRoot string — Absolute path to the build output directory
noCache boolean false Bypass ISR cache (dev mode)
cacheDir string — ISR cache directory
defaultRevalidate number 60 Default ISR TTL in seconds
importer (path) => Promise<unknown> — Module loader for adapter-bundled entries
lang string "es" HTML lang attribute
clientEntry string — Client entry path
renderEndpoint boolean true Whether the render endpoint exists
securityHeaders SecurityHeadersConfig | false true Security headers config; false disables
ℹ Note

The handler is pure — it does not import Node HTTP types. It works in Bun, Deno, Cloudflare Workers, Vercel Edge, and any Web-standard runtime.

# RequestContext

RequestContext carries per-request state across middleware, loaders, and actions. It's the single context type used by the unified handler.

import type { RequestContext } from "@deijose/nix-js-kit/runtime";

# Fields

Field Type Description
params RouteParams Dynamic segment values ({ slug: "hello" })
locals Record<string, unknown> Per-request mutable state, isolated per request
cookies CookieJar Read request cookies (get, getAll, has)
signal AbortSignal Aborts when the client disconnects
requestId string Auto-generated UUID for logging/tracing
platform { runtime, host } Detected runtime (node, bun, edge)
route PageRoute The matched route
response ResponseState Mutable response state (headers + Set-Cookie)

# CookieJar (read)

interface CookieJar {
  get(name: string): string | undefined;
  getAll(): Record<string, string>;
  has(name: string): boolean;
}

# ResponseCookieJar (write)

interface ResponseCookieJar {
  set(name: string, value: string, options?: CookieOptions): void;
  clear(name: string, options?: CookieOptions): void;
  getAll(): string[];
}

# CookieOptions

Option Type Description
httpOnly boolean HttpOnly flag
secure boolean Secure flag
sameSite "strict" | "lax" | "none" SameSite policy
maxAge number Max age in seconds
expires Date Expiration date
path string Cookie path
domain string Cookie domain

# applyToResponse()

Merges accumulated headers, Set-Cookie values, and status into the final Response:

const ctx = new RequestContext(request, { /* options */ });
ctx.response.headers.set("X-Custom", "value");
ctx.response.cookies.set("session", "abc123", { httpOnly: true });

// Later, when building the response:
const response = ctx.applyToResponse(new Response(html, { headers: { "Content-Type": "text/html" } }));
// response now includes X-Custom and Set-Cookie: session=abc123; HttpOnly

# Using the handler in a custom server

import { createServer } from "node:http";
import { scanRoutes, scanActions, createWebHandler, incomingMessageToRequest } from "@deijose/nix-js-kit/runtime";

const routes = await scanRoutes("src/app");
const actions = await scanActions("src/app");
const handler = createWebHandler(routes, actions, {
  staticRoot: "./dist",
  lang: "en",
  clientEntry: "/_nix-js/entry-client.js",
});

createServer(async (req, res) => {
  const request = incomingMessageToRequest(req);
  const response = await handler(request);
  res.writeHead(response.status, Object.fromEntries(response.headers));
  res.end(await response.text());
}).listen(3000);

# Why a unified handler?

Before v2.0.2, the CLI (dev/preview), start, and each adapter had their own request-handling logic. This meant:

  • Bugs fixed in one path weren't fixed in others.
  • Behavior could differ between dev and production.
  • Security headers, error sanitization, and cache policy had to be reimplemented per runtime.

The unified handler solves all three: one function, one behavior, every runtime.

# Subpath export

import {
  createWebHandler,
  RequestContext,
  serveStaticFile,
  resolveStaticFile,
  incomingMessageToRequest,
  guessContentType,
  htmlResponse,
  jsonResponse,
  textResponse,
  notFound,
  methodNotAllowed,
  serverError,
} from "@deijose/nix-js-kit/runtime";
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