Error Handling

Throwing HTTP Errors

Any resource method can throw an HttpError subclass. The decision machine catches it and writes the appropriate HTTP response:

import { BadRequestError, NotFoundError } from "resource-machine";

override async processPost() {
  const raw = await this.req.getBody();
  let body: unknown;
  try {
    body = JSON.parse(raw.toString());
  } catch {
    throw new BadRequestError("Invalid JSON");
  }

  if (!isValid(body)) {
    throw new BadRequestError("Schema validation failed");
  }

  await db.save(body);
  return true;
}

The response body is a JSON object:

{
	"code": "BadRequest",
	"message": "Invalid JSON"
}

Logging

ResourceMachine uses pino for logging. Every request gets a scoped logger at this.req.log (attached by pino-http). Unhandled errors are logged at error level with full stack traces.

Customize the logger by passing your own pino instance to createServer:

import pino from "pino";
import { createServer } from "resource-machine";

const logger = pino({
	level: "debug",
	transport: {
		target: "pino-pretty",
		options: { colorize: true },
	},
});

const server = createServer({ logger });

Unhandled Errors

If a resource method throws something that is not an HttpError, ResourceMachine logs it and responds with 500 Internal Server Error.