Multiple API Specs

Multiple Validators and API specs

It may be useful to serve multiple APIs with separate specs via single service. An example might be an API that serves both v1 and v2 from the same service. The sample code below shows how one might accomplish this.

See complete example

const express = require('express');
const path = require('path');
const bodyParser = require('body-parser');
const http = require('http');
const OpenApiValidator = require('express-openapi-validator');

app = express();
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.text());
app.use(bodyParser.json());

const versions = [1, 2];

for (const v of versions) {
  const apiSpec = path.join(__dirname, `api.v${v}.yaml`);
  app.use(
    OpenApiValidator.middleware({
      apiSpec,
    }),
  );

  routes(app, v);
}

http.createServer(app).listen(3000);
console.log('Listening on port 3000');

function routes(app, v) {
  if (v === 1) routesV1(app);
  if (v === 2) routesV2(app);
}

function routesV1(app) {
  const v = '/v1';
  app.post(`${v}/pets`, (req, res, next) => {
    res.json({ ...req.body });
  });
  app.get(`${v}/pets`, (req, res, next) => {
    res.json([
      {
        id: 1,
        name: 'happy',
        type: 'cat',
      },
    ]);
  });

  app.use((err, req, res, next) => {
    // format error
    res.status(err.status || 500).json({
      message: err.message,
      errors: err.errors,
    });
  });
}

function routesV2(app) {
  const v = '/v2';
  app.get(`${v}/pets`, (req, res, next) => {
    res.json([
      {
        pet_id: 1,
        pet_name: 'happy',
        pet_type: 'kitty',
      },
    ]);
  });
  app.post(`${v}/pets`, (req, res, next) => {
    res.json({ ...req.body });
  });

  app.use((err, req, res, next) => {
    // format error
    res.status(err.status || 500).json({
      message: err.message,
      errors: err.errors,
    });
  });
}

module.exports = app;