import OpenAPIBackend from 'openapi-backend';

// create api with your definition file or object
const api = new OpenAPIBackend({ definition: './petstore.yml' });

// register your framework specific request handlers here
api.register({
  getPets: (c, req, res) => res.status(200).json({ result: 'ok' }),
  getPetById: (c, req, res) => res.status(200).json({ result: 'ok' }),
  validationFail: (c, req, res) => res.status(400).json({ err: c.validation.errors }),
  notFound: (c, req, res) => res.status(404).json({ err: 'not found' }),
});

// initalize the backend
api.init();

import express from 'express';

const app = express();
app.use(express.json());
app.use((req, res) => api.handleRequest(req, req, res));
app.listen(9000);

// API Gateway Proxy handler
module.exports.handler = (event, context) =>
  api.handleRequest(
    {
      method: event.httpMethod,
      path: event.path,
      query: event.queryStringParameters,
      body: event.body,
      headers: event.headers,
    },
    event,
    context,
  );

module.exports = (context, req) =>
  api.handleRequest(
    {
      method: req.method,
      path: req.params.path,
      query: req.query,
      body: req.body,
      headers: req.headers,
    },
    context,
    req,
  );

import Hapi from '@hapi/hapi';

const server = new Hapi.Server({ host: '0.0.0.0', port: 9000 });
server.route({
  method: ['GET', 'POST', 'PUT', 'PATCH', 'DELETE'],
  path: '/{path*}',
  handler: (req, h) =>
    api.handleRequest(
      {
        method: req.method,
        path: req.path,
        body: req.payload,
        query: req.query,
        headers: req.headers,
      },
      req,
      h,
    ),
});
server.start();

import Koa from 'koa';
import bodyparser from 'koa-bodyparser';

const app = new Koa();

app.use(bodyparser());
app.use((ctx) =>
  api.handleRequest(
    ctx.request,
    ctx,
  ),
);
app.listen(9000);

async function getPetByIdHandler(c, req, res) {
  const id = c.request.params.id;
  const pet = await pets.getPetById(id);
  return res.status(200).json({ result: pet });
}
api.register('getPetById', getPetByIdHandler);
// or
api.register({
  getPetById: getPetByIdHandler,
});

function validationFailHandler(c, req, res) {
  return res.status(400).json({ status: 400, err: c.validation.errors });
}
api.register('validationFail', validationFailHandler);

api.register({
  getPets: (c) => {
    // when a postResponseHandler is registered, your operation handlers' return value gets passed to context.response
    return [{ id: 1, name: 'Garfield' }];
  },
  postResponseHandler: (c, req, res) => {
    const valid = c.api.validateResponse(c.response, c.operation);
    if (valid.errors) {
      // response validation failed
      return res.status(502).json({ status: 502, err: valid.errors });
    }
    return res.status(200).json(c.response);
  },
});

api.register({
  getPets: (c) => {
    // when a postResponseHandler is registered, your operation handlers' return value gets passed to context.response
    return [{ id: 1, name: 'Garfield' }];
  },
  postResponseHandler: (c, req, res) => {
    const valid = c.api.validateResponseHeaders(res.headers, c.operation, {
      statusCode: res.statusCode,
      setMatchType: 'exact',
    });
    if (valid.errors) {
      // response validation failed
      return res.status(502).json({ status: 502, err: valid.errors });
    }
    return res.status(200).json(c.response);
  },
});

api.registerSecurityHandler('ApiKey', (c) => {
  const authorized = c.request.headers['x-api-key'] === 'SuperSecretPassword123';
  // truthy return values are interpreted as auth success
  // you can also add any auth information to the return value
  return authorized;
});

api.register('unauthorizedHandler', (c, req, res) => {
  return res.status(401).json({ err: 'unauthorized' })
});

api.register('notImplemented', (c, req, res) => {
  const { status, mock } = c.api.mockResponseForOperation(c.operation.operationId);
  return res.status(status).json(mock);
});

api.mockResponseForOperation('getPets'); // => { status: 200, mock: [{ id: 1, name: 'Garfield' }, { id: 2, name: 'Odie' }]}
api.mockResponseForOperation('getPetById'); // => { status: 200, mock: { id: 1, name: 'Garfield' }}