oc-fastify-server-adapter

Fastify HTTP server adapter for the OC registry. The adapter is opt-in and implements OC's neutral HttpServerAdapter interface.

Installation

npm install oc-fastify-server-adapter fastify

oc is a peer dependency. Use this adapter with an OC version that exports the HTTP server adapter types (>=0.50.56).

Usage

const oc = require('oc');
const createFastifyAdapter = require('oc-fastify-server-adapter').default;

const registry = oc.Registry({
  // regular OC registry options...
  server: {
    adapter: createFastifyAdapter,
    options: {
      host: '0.0.0.0',
      port: 3030,
      trustProxy: true
    }
  }
});

options.host defaults to 0.0.0.0, matching Node/Express server.listen(port) behavior. Set it to 127.0.0.1 or another interface to bind more narrowly.

Opt-in contract and differences from Express

• registry.start() returns a Fastify instance as app, not an Express application. Code that reaches into app must use Fastify APIs.
• server.httpServer() and the { server } value returned by registry.start() are the underlying Node http.Server.
• User routes are registered through Fastify's router. OC route patterns such as :param and *splat are normalized, but advanced Express-only route syntax is not supported.
• fromConnect() supports common Connect middleware, including middleware that ends the response without calling next(). Middleware that depends on Express-specific request/response APIs may still need changes.
• JSON and urlencoded body limits follow the OC/Express configuration. Gzip, deflate, and brotli encoded request bodies are inflated before Fastify parses them.
• Urlencoded bodies use qs parsing to match Express extended: true semantics. Query strings use Node's querystring parser to match Express 5's simple parser.
• Cookies use OC/Express-style options. maxAge is accepted in milliseconds and translated to Fastify's seconds-based serializer, with Path=/ as the default. Signed cookies are not supported unless the adapter grows a Fastify cookie secret option.
• Multipart uploads are normalized to OC's uploaded file shape. Oversized fields return a LIMIT_FIELD_VALUE-style 413 instead of silently truncating.
• Strong ETags and 304 conditional responses are enabled to match the Express registry.
• OPTIONS requests are handled by the adapter so OC CORS middleware can answer preflight requests. The Allow header is scoped to matching routes when possible; unmatched OPTIONS paths still receive the global adapter method set for preflight compatibility.
• Handler errors are rendered by OC's configured error handler. The Fastify adapter returns text/html error bodies when OC enables the error handler, but default Fastify 404/error body shapes can differ from Express for requests outside OC routes.
• Non-empty OC route handler chains must eventually send a response. This matches existing OC callback-style handlers; empty handler arrays return 404 defensively.
• Logging uses Fastify response timing, so formatting is not byte-for-byte identical to Morgan's Express output.