init backend

backend/.gitignore

+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# Typescript v1 declaration files
+typings/
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env
+
+# next.js build output
+.next

backend/app.js

+const express = require('express');
+const path = require('path');
+const cookieParser = require('cookie-parser');
+const logger = require('morgan');
+const admin = require('firebase-admin');
+const serviceAccount = require('./chatman-a99e6-firebase-adminsdk-e2t5v-36aaaada49.json');
+
+const indexRouter = require('./routes/index');
+const usersRouter = require('./routes/users');
+
+const app = express();
+
+admin.initializeApp({
+  credential: admin.credential.cert(serviceAccount),
+  databaseURL: 'https://chatman-a99e6.firebaseio.com/'
+});
+
+let registrationToken = "dhoxHmhVQzo:APA91bGt3zNCA0OdxZ4PV2HCiWqFRSaPftZr6-rKB53O_ZSnTiBDB_YV8vSbaCjXLYzy_pkhd2VBppm6ohXcePhhPC-h4jXA2IwPADqmauhpN4_6eWEAmiBiPPw2WOjsP3CSIW6i569w";
+let message = {
+  notification: {
+    title: 'Hi :*',
+    body: 'Pakabar ?'
+  },
+  token: registrationToken
+}
+
+
+
+app.get('/send', function(req, res) {
+  admin.messaging().send(message)
+  .then(response => {
+    console.log('Success : ' + response)
+    res.send('success');
+  })
+  .catch(err => {
+    console.log('Error : ' + err)
+    res.send('error');
+  });
+});
+
+app.use(logger('dev'));
+app.use(express.json());
+app.use(express.urlencoded({ extended: false }));
+app.use(cookieParser());
+app.use(express.static(path.join(__dirname, 'public')));
+
+app.use('/', indexRouter);
+app.use('/users', usersRouter);
+
+app.listen(3000, function() {
+  console.log('chatman running at port 3000');
+});
+
+module.exports = app;

backend/bin/www

+#!/usr/bin/env node
+
+/**
+ * Module dependencies.
+ */
+
+var app = require('../app');
+var debug = require('debug')('backend:server');
+var http = require('http');
+
+/**
+ * Get port from environment and store in Express.
+ */
+
+var port = normalizePort(process.env.PORT || '3000');
+app.set('port', port);
+
+/**
+ * Create HTTP server.
+ */
+
+var server = http.createServer(app);
+
+/**
+ * Listen on provided port, on all network interfaces.
+ */
+
+server.listen(port);
+server.on('error', onError);
+server.on('listening', onListening);
+
+/**
+ * Normalize a port into a number, string, or false.
+ */
+
+function normalizePort(val) {
+  var port = parseInt(val, 10);
+
+  if (isNaN(port)) {
+    // named pipe
+    return val;
+  }
+
+  if (port >= 0) {
+    // port number
+    return port;
+  }
+
+  return false;
+}
+
+/**
+ * Event listener for HTTP server "error" event.
+ */
+
+function onError(error) {
+  if (error.syscall !== 'listen') {
+    throw error;
+  }
+
+  var bind = typeof port === 'string'
+    ? 'Pipe ' + port
+    : 'Port ' + port;
+
+  // handle specific listen errors with friendly messages
+  switch (error.code) {
+    case 'EACCES':
+      console.error(bind + ' requires elevated privileges');
+      process.exit(1);
+      break;
+    case 'EADDRINUSE':
+      console.error(bind + ' is already in use');
+      process.exit(1);
+      break;
+    default:
+      throw error;
+  }
+}
+
+/**
+ * Event listener for HTTP server "listening" event.
+ */
+
+function onListening() {
+  var addr = server.address();
+  var bind = typeof addr === 'string'
+    ? 'pipe ' + addr
+    : 'port ' + addr.port;
+  debug('Listening on ' + bind);
+}

backend/chatman-a99e6-firebase-adminsdk-e2t5v-36aaaada49.json

+{
+  "type": "service_account",
+  "project_id": "chatman-a99e6",
+  "private_key_id": "36aaaada49b1771324c071d95a3908da21aac7c2",
+  "private_key": "-----BEGIN PRIVATE KEY-----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\npypz9utdRmkQWnQAivenfR4=\n-----END PRIVATE KEY-----\n",
+  "client_email": "firebase-adminsdk-e2t5v@chatman-a99e6.iam.gserviceaccount.com",
+  "client_id": "111555813811256028469",
+  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
+  "token_uri": "https://oauth2.googleapis.com/token",
+  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
+  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/firebase-adminsdk-e2t5v%40chatman-a99e6.iam.gserviceaccount.com"
+}

backend/package.json

+{
+  "name": "backend",
+  "version": "0.0.0",
+  "private": true,
+  "scripts": {
+    "start": "node ./bin/www"
+  },
+  "dependencies": {
+    "cookie-parser": "~1.4.3",
+    "debug": "~2.6.9",
+    "express": "~4.16.0",
+    "firebase-admin": "^7.0.0",
+    "morgan": "~1.9.0"
+  }
+}

backend/public/index.html

+<html>
+
+<head>
+  <title>Express</title>
+  <link rel="stylesheet" href="/stylesheets/style.css">
+</head>
+
+<body>
+  <h1>Express</h1>
+  <p>Welcome to Express</p>
+</body>
+
+</html>

backend/public/stylesheets/style.css

+body {
+  padding: 50px;
+  font: 14px "Lucida Grande", Helvetica, Arial, sans-serif;
+}
+
+a {
+  color: #00B7FF;
+}

backend/routes/index.js

+var express = require('express');
+var router = express.Router();
+
+/* GET home page. */
+router.get('/', function(req, res, next) {
+  res.render('index', { title: 'Express' });
+});
+
+module.exports = router;

backend/routes/users.js

+var express = require('express');
+var router = express.Router();
+
+/* GET users listing. */
+router.get('/', function(req, res, next) {
+  res.send('respond with a resource');
+});
+
+module.exports = router;