app.js

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Setup Application Insights if applicable, this must be done before loading any other depdendencies
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const config = require('./config');
if (config.APPLICATIONINSIGHTS_CONNECTION_STRING) {
  const appInsights = require('applicationinsights')
  console.log('Setting up application insights')
  try {
    appInsights.setup().setSendLiveMetrics(true).setAutoCollectConsole(true).start();
    console.log('✅ ApplicationInsights ready')
  } catch (err) {
    console.error('❌ ApplicationInsights failed\n', err)
  }
}


if (['true', true].includes(config.DEBUG)) {
  console.log('====================\n ENVIRONMENT\n====================');
  console.log('Environment variables', process.env);
  console.log('Starting app with this config', config);
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Import dependencies
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const http = require('http');                                         // For hosting the web server
const fs = require('fs');                                             // For working with the file system
const path = require('path');                                         // For combining paths
const yamljs = require('yamljs');                                     // For converting YAML to JSON
const express = require('express');                                   // Main system for running the API
const morgan = require('morgan');                                     // For outputing information about the requests
const cors = require('cors');                                         // For handeling CORS
const swaggerUi = require('swagger-ui-express');                      // For hosting and displaying the APIs documentation
const OpenApiValidator = require('express-openapi-validator');        // Validates all routes based on the requested resource
require('dotenv').config({ path: `.env.${process.env.NODE_ENV}` })    // Load different .env files based on NODE_ENV

const WSDLClient = require('./lib/WSDLClient/WSDLClient');            // WSDLClient is initialized here for pre-loading all WSDL-files into memory
WSDLClient.loadAllFiles();                                            // Load all files into memory

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Determine variables and constants
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const host = config.hostname;                                         // Get the hosting address
const port = config.port;                                             // Get the hosting port

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Create App
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const app = express();

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Register middleware
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
app.use(express.json());                                                // Automatically parse JSON body
app.use(morgan('dev'));                                                 // Output request information to stdout

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Handle CORS
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const corsOptions = {
  origin: true,
  credentials: true
}
app.use(cors(corsOptions));

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Documentation & Validation
// Host SwaggerUI and validate incoming requests based on OpenAPI 3.0 spesification files
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
app.use('/assets/', express.static(path.join(__dirname, '/assets')))
const swaggerUIOptions = {
  deepLinking: false,
  displayOperationId: true,
  customCss: '.topbar { background-color: #B2DCDA!important; } .topbar-wrapper img { content:url(\'/assets/images/vtfk-logo.svg\'); height: 100px; }',
  customfavIcon: '/assets/images/favicon.ico',
  customSiteTitle: 'Matrikkel API Dokumentasjon'
}

const oasDocumentationEndpoints = [];
const routeChildren = fs.readdirSync(path.join(__dirname, 'routes'));
if (routeChildren && Array.isArray(routeChildren)) {
  for (let i = 0; i < routeChildren.length; i++) {
    const oasSpecPath = path.join(__dirname, 'routes', routeChildren[i], 'openapispec.yaml');
    if (fs.existsSync(oasSpecPath)) {
      // Load the file as JSON and determine what the endpoint will be
      const oasJSON = yamljs.load(oasSpecPath)
      const oasDocEndpoint = '/api/' + routeChildren[i] + '/docs';
      oasDocumentationEndpoints.push(oasDocEndpoint);

      // Host the documentation
      app.use(oasDocEndpoint, swaggerUi.serve, swaggerUi.setup(oasJSON, swaggerUIOptions));

      // Register the API validator
      app.use(
        OpenApiValidator.middleware({
          apiSpec: oasSpecPath,
          validateRequests: true
        })
      )
    }
  }
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Authentication
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Import dependencies
const passport = require('passport');                                 // Engine for authenticating using different strategies
const headerAPIKeyStrategy = require('./auth/authentication/apikey'); // Passport strategy for authenticating with APIKey
// Register strategies
passport.use(headerAPIKeyStrategy);
// Use strategies
app.all('*',
  passport.authenticate(['headerapikey'], { session: false }),
  (req, res, next) => {
    // Setup some custom properties that should be usable in the routes and middleware
    req.custom = {};
    req.__metadata = {};
    // This function triggers when a request has been successfully authenticated
    req.custom.timestamp = new Date();
    next();
  }
);

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Routes
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// v1 routes
app.use('/api/v1/*', require('./routes/v1/beforeRouteMiddleware'));
app.use('/api/v1/matrikkelenheter', require('./routes/v1/matrikkelenheter'));
app.use('/api/v1/store', require('./routes/v1/store'));
app.use('/api/v1/raw', require('./routes/v1/raw'));

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Common functions
// Commin functionality for the send response and send error middleware
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function determineDocumentationLinks (req) {
  const requestedHost = req.protocol + '://' + req.get('host');

  let documentation;

  // Attempt to determine what documentation is correct for the failed request
  if (req.openapi && req.openapi.expressRoute) {
    // Attempt to match the express route with the API version
    let route = req.openapi.expressRoute;
    if (req.openapi.expressRoute.startsWith('/')) {
      route = route.substring(1);
    }
    const split = route.split('/');
    if (split.length >= 2) {
      const reconstructedRoute = '/' + split[0] + '/' + split[1] + '/docs';
      if (oasDocumentationEndpoints.includes(reconstructedRoute)) {
        documentation = {
          full: encodeURI(requestedHost + reconstructedRoute)
        }

        if (req.openapi.schema && req.openapi.schema.operationId && req.openapi.schema.tags) {
          documentation.method = encodeURI(requestedHost + reconstructedRoute + '/#/' + req.openapi.schema.tags[0] + '/' + req.openapi.schema.operationId)
        }
      }
    }
  }

  return documentation
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Send response
// All routes sets the req.response object so that it can be sent to the requestor by a common function
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
app.use('/*', (req, res, next) => {
  let response;
  if (req.query.metadata) {
    let itemCount = 0;
    if (req.response && Array.isArray(req.response)) {
      itemCount = req.response.length;
    }
    response = {
      __metadata: {
        uri: req.protocol + '://' + req.get('host') + req.baseUrl,
        operationId: req.openapi ? req.openapi.schema.operationId : '',
        durationMS: (new Date().getMilliseconds()) - req.custom.timestamp.getMilliseconds(),
        items: itemCount,
        ...req.__metadata
      },
      data: req.response
    }
    const documentation = determineDocumentationLinks(req);
    if (documentation) { response.__metadata.documentation = documentation; }
  } else {
    response = req.response;
  }

  res.type('json').send(JSON.stringify(response, null, 2));
})

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Error handling
// This will catch any errors that occured anywhere in the routes and handle them
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
app.use((err, req, res, next) => {
  console.log('❌ Error occured ❌');
  // Construct an error object
  let error = {}
  // Setup the error object based on type
  if (typeof err === 'object') {
    // Get all enumurable and non-enumurable property from the error object
    Object.getOwnPropertyNames(err).forEach((key) => {
      error[key] = err[key];
    })
  } else if (typeof err === 'string') {
    error.message = err;
  } else {
    error = err;
  }
  // Attempt to link to documentation
  const documentation = determineDocumentationLinks(req);
  if (documentation) { error.documentation = documentation; }

  // Output the error
  console.error(error);

  // Send the error
  res.status(err.status || 500).json(error);
  next();
})

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Host the server
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const server = http.createServer(app);
server.listen(port, host, () => {
  let hostname = host;
  if (host === '0.0.0.0') { hostname = 'localhost' }

  // Output the root adress the server is listening on
  console.log('Root endpoint:')
  console.log('Your server is listening on port %d (http://%s:%d)', port, hostname, port);

  // Output API endpoint documentation URLs
  console.log('\nDocumentation endpoints:')
  oasDocumentationEndpoints.forEach((endpoint) => {
    console.log('http://%s:%d' + endpoint, hostname, port);
  })
})