Hono

@cratis/arc.hono adds middleware to a Hono 4 application. Hono speaks the Fetch API, so the adapter copies the request onto a fixed internal origin, hands it to Arc, and returns Arc’s response.

Mount the application

server.ts

import { Hono } from 'hono';
import { cratisArc, serveCratisArc } from '@cratis/arc.hono';
import { arc } from './arc.js';

const app = new Hono<{ Variables: { startedAt: number } }>();
app.use('*', async (context, next) => { context.set('startedAt', Date.now()); await next(); });
app.use(cratisArc(arc));
app.get('/health', context => context.text(`ok since ${context.get('startedAt')}`));
const hosted = await serveCratisArc(app, arc, { port: 3000, hostname: '127.0.0.1' });
process.once('SIGTERM', () => { void hosted.dispose().then(() => arc.dispose()); });

arc is the built application from Host adapters. cratisArc(arc) returns HTTP/SSE middleware that continues to your routes for foreign paths; mount it before adding your routes. Use app.use('/v1/*', cratisArc(arc)) to expose Arc under a prefix. serveCratisArc starts a Node listener with WebSocket upgrades and returns its listener and async disposer; it does not dispose arc. If you own the Node listener, call const disposeSockets = cratisArc(arc).injectWebSocket(listener) instead, then dispose the sockets before closing the listener.

Run on Node

To run on Node.js, add @hono/node-server, an optional peer dependency. On that server, the adapter also checks the raw request-target before dispatch, so URL normalization and absolute-form paths cannot promote a foreign path into an Arc endpoint.

Other Hono runtimes

Runtimes other than @hono/node-server do not expose the raw request-target spelling, so they cannot attest the same raw-path defense without host-specific validation. context.signal follows the signal of the request Hono received, which depends on that runtime.

Pass a verified principal

cratisArc(arc, native) accepts a callback returning trusted native context. On Node, secure comes from the TLS socket; a proxy’s secure and authority, and a host-verified principal, still require a trusted callback. See Native principal.

Observable queries over WebSockets

serveCratisArc(app, arc, { port, native? }) installs observable WebSockets on the Node listener. Arc core imports Node modules: Hono runtimes other than Node have not been verified, even for HTTP/SSE, and need their own validated host and WebSocket bridge. The pinned @hono/node-server 1.x does not export the Hono WebSocket upgrade helper, so this Node adapter still uses @hono/node-ws internally. See WebSockets.

Related

• Host adapters
• Express and Fastify