expressServer.js

const http = require('http');
const fs = require('fs');
const path = require('path');
const swaggerUI = require('swagger-ui-express');
const jsYaml = require('js-yaml');
const express = require('express');
const cors = require('cors');
const cookieParser = require('cookie-parser');
const bodyParser = require('body-parser');
const OpenApiValidator = require('express-openapi-validator');
const logger = require('./logger');
const config = require('./config');


class ExpressServer {
  constructor(port, openApiYaml) {
    this.port = port;
    this.app = express();
    this.openApiPath = openApiYaml;
    try {
      this.schema = jsYaml.safeLoad(fs.readFileSync(openApiYaml));
    } catch (e) {
      logger.error('failed to start Express Server', e.message);
    }
    this.setupMiddleware();
  }

  setupMiddleware() {
    this.app.use(cors());
    this.app.use(bodyParser.json({ limit: '14MB' }));
    this.app.use(express.json());
    this.app.use(express.urlencoded({ extended: false }));
    this.app.use(cookieParser());
    // Leaving these here as they are useful for testing
    //Simple test to see that the server is up and responding
    //this.app.get('/hello', (req, res) => res.send(`Hello World. path: ${this.openApiPath}`));
    //Send the openapi document *AS GENERATED BY THE GENERATOR*
    //this.app.get('/openapi', (req, res) => res.sendFile((path.join(__dirname, 'api', 'openapi.yaml'))));
    //View the openapi document in a visual interface. Should be able to test from this page
    //this.app.use('/api-docs', swaggerUI.serve, swaggerUI.setup(this.schema));
 
    // Install OpenAPIValidator middleware
    //   NOTES version 5.0.4:
    //      There is a bug in this version that causes the validation error:
    //         "reference \"id\" resolves to more than one schema"
    //      This is caused by the "example" definitions where the id field
    //      is only populated with example values e.g 'id1' and *should not*
    //      be expecte to be unique in the file.  Whereas, the current version
    //      of the OpenApiValidator sends the entire dataset to AJV to validate
    //      and it returns the above error.  To get around this I strip out all
    //      the example data from the YAML file in index.js and generate a 
    //      "openapi.yaml.sans_example" file to use here.
    this.app.use(
      OpenApiValidator.middleware({
        apiSpec: this.openApiPath + ".sans_example",
        operationHandlers: path.join(__dirname),
        validateResponses: false, // this causes "reference \"id1a\" resolves to more than one schema"
        validateApiSpec: true,
        validateRequests: true, // this causes "reference \"id1a\" resolves to more than one schema"
        validateSecurity: true,
        validateFormats: true,
        fileUploader: { dest: config.FILE_UPLOAD_PATH },
      }),
    );

    this.app.get('/login-redirect', (req, res) => {
      res.status(200);
      res.json(req.query);
    });
    this.app.get('/oauth2-redirect.html', (req, res) => {
      res.status(200);
      res.json(req.query);
    });

    // Setup error handler
    this.app.use((err, req, res, next) => {
      //console.error(err); // dump error to console for debug
      res.status(err.status || 500).json({
        message: err.message,
        errors: err.errors,
      });
    });
  }

  launch() {
    http.createServer(this.app).listen(this.port);
    logger.info(`Listening on port ${this.port}`);
  }


  async close() {
    if (this.server !== undefined) {
      await this.server.close();
      logger.info(`Server on port ${this.port} shut down`);
    }
  }
}

module.exports = ExpressServer;