= Using Node.js =

Hello world (text mode):
<code javascript>
const http     = require('http');
const hostname = '127.0.0.1';
const port     = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  
  // Text mode:
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World\n');
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});  
</code>

Hello World (HTML mode):
<code javascript>
const http     = require('http');
const hostname = '127.0.0.1';
const port     = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  
  // HTML mode:
  res.setHeader('Content-Type', 'text/html');
  res.write("Requested URL: " + req.url);
  res.write("<h3>Phone Logs</h3>");
  res.write("<a href='/data/report_01-02-2017.htm'>report_01-02-2017</a>");  // url of file, relative to root of http server
  res.end();
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});  
</code>


Read requested files:
<code javascript>
const http = require('http');
const fs   = require('fs');
const path = require('path');
const url  = require('url');

const hostname = '127.0.0.1';
const port     = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  // Read requested file
  fs.readFile('./data/report_01-02-2017.htm', function(err, data) {  // relative path of file
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.write(data);
    res.end();
  });
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});
</code>

Serve Homepage and subpages:
<code javascript>
const http = require('http');
const fs   = require('fs');
const path = require('path');
const url  = require('url');

const hostname = '127.0.0.1';
const port = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  
  
  
  var q = url.parse(req.url, true);
  var filename = "." + q.pathname;
  
  switch(q.pathname) {
      case '/':
        // Serve Homepage
        res.setHeader('Content-Type', 'text/html');
        res.write("Requested URL: " + req.url);
        res.write("<h3>Phone Logs</h3>");
        //res.write("<a href='/data/report_01-02-2017.htm'>report_01-02-2017</a>");  // url of file, relative to root of http server
        
        // Read file listing
        var pth = "./data";
        fs.readdir(pth, function (err, files) {
            if (err) {
                throw err;
            }

            files.map(function (file) {
                return path.join(pth, file);
            }).filter(function (file) {
                //return fs.statSync(file).isFile();
                return fs.stat(file).isFile();
            }).forEach(function (file) {
                console.log("%s (%s)", file, path.extname(file));
                res.write("<pre>%s (%s)</pre>\n", file, path.extname(file));
            });
        });
        
        res.end();
        break;
          
      default:
        // Read and serve requested file, eg. '/data/report_01-02-2017.htm'
        fs.readFile(filename, function(err, data) {
            if (err) {
              res.writeHead(404, {'Content-Type': 'text/html'});
              return res.end("404 Not Found");
            }  
            res.writeHead(200, {'Content-Type': 'text/html'});
            res.write(data);
            return res.end();
        });
        break;
  }
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});
</code>

== Running App Forever ==
Install ''forever'' module:
  $ npm install -g forever

Start your application:
  $ forever server.js

Alternatively, start your application as a service:
  $ forever start server.js

''forever'' restarts your app when it crashes or stops for some reason. To restrict restarts to 5 times, use:
  $ forever -m5 server.js

List all running processes, note the integer in the brackets, and use it to stop a process:
  $ forever list
  $ forever stop 0

List all running processes, and restart a running process goes:
  $ forever list
  $ forever restart 0

When working on your application file, you can use the -w parameter to restart automatically whenever your server.js file changes:
  $ forever -w server.js

== Running App as Cronjob ==
<code javascript>
// Run main loop as a cronjob.
// Alternative to: $ forever start app.js (requires: $ npm install forever)
var CronJob = require('cron').CronJob;
var job = new CronJob({
  cronTime: '00 30 11 * * 1-5',
  onTick: function() {
    /*
     * Runs every weekday (Monday through Friday)
     * at 11:30:00 AM. It does not run on Saturday
     * or Sunday.
     */
  },
  start: false,
  timeZone: 'America/New_York'
});
job.start();
</code>

<code javascript>
// Run main loop, executing doSomeWork() on timer
// Alternative to: $ forever start app.js (requires: $ npm install forever)
function run() {
    setInterval(doSomeWork, refreshInterval);
};

run();
</code>
== References ==
  * [[https://www.w3schools.com/nodejs/default.asp|W3 Schools Tutorial: Node.js]]
  * [[https://nodejs.org/dist/latest-v6.x/docs/api/synopsis.html|Node.js API Synopsis]]
  * [[http://nodeexamples.com|Node Examples]]
  * [[https://github.com/mapbox/node-sqlite3/wiki/API|SQLite3 API for Node JS]]