ex10.js

var net = require('net');

var server = net.createServer(function(socket) {
    var date = printTime();
    socket.end(date);
  });

function zeroFill(i) {
  return (i < 10 ? '0' : '') + i;
}

function printTime() {
  var date = new Date();
  return date.getFullYear() + 
        '-' + zeroFill(date.getMonth() + 1) +
        '-' + date.getDate() +
        ' ' + date.getHours() +
        ':' + date.getMinutes() + '\n';
}

server.listen(Number(process.argv[2]));

ex11.js

var http = require('http');
var fs = require('fs');

var server = http.createServer(function(req, res) {
  var stream = fs.createReadStream(process.argv[3]);
  stream.on('open', function() {
    stream.pipe(res);
  });
});

server.listen(process.argv[2]);

ex12.js

var http = require('http');
var fs = require('fs');
var map = require('through2-map');

var server = http.createServer(function(req, res) {
    req.pipe(map(function (chunk) {
      return chunk.toString().toUpperCase();
    })).pipe(res);
});

server.listen(process.argv[2]);

ex13.js

var http = require('http');
var fs = require('fs');
var url = require('url');

var server = http.createServer(function(req, res) {
    reqUrl = url.parse(req.url, true);
    var date = new Date(reqUrl.query.iso);
    res.writeHead(200, { 'Content-Type': 'application/json' });
    if (reqUrl.pathname === '/api/parsetime') {
      var time = {
        hour: date.getHours(),
        minute: date.getMinutes(),
        second: date.getSeconds()
      };
      res.end(JSON.stringify(time));
    } else {
      var time = {
        unixtime: date.getTime()
      };
      res.end(JSON.stringify(time));
    }
});

server.listen(process.argv[2]);

ex8.js

var http = require('http');

http.get(process.argv[2], function(res) {
  var data = '';
  res.setEncoding('utf8');
  res.on('data', function(new_data) {
    data += new_data;
  });
  res.on('end', function() {
    console.log(data.length);
    console.log(data);
  });
});

ex9.js

var http = require('http');

var data = [];

function getData(urlNumber) {
  if (urlNumber < (process.argv.length)) {
    http.get(process.argv[urlNumber], function(res) {
      var dataString = ''; 
      res.setEncoding('utf8');
      res.on('data', function(new_data) {
        dataString += new_data;
      });
      res.on('end', function() {
        data.push(dataString);
        getData(urlNumber + 1);
      });
    });
  } else {
    for (var i = 0; i < data.length; i++) {
      console.log(data[i]);
    }
  }
}

getData(2);

learnmenode.js

var module = require('./module');
var http = require('http');

function sumNumbers(argv) {
  var sum = 0;
  for (var i = 2; i < argv.length; i++) {
    sum += +argv[i];
  }
  console.log(sum);
}

function countNewlines(filepath) {
  fs.readFile(filepath, function(err, data) {
    if (!err) {
      console.log(data.toString().split('\n').length - 1);
    }
  });
}

function readDirectories(filepath, ext) {
  fs.readdir(filepath, function(err, list) {
    for (var i = 0; i < list.length; i++) {
      if (list[i].match('.' + ext + '$')) {
        console.log(list[i]);
      }
    }
  });
}

function listFiles(err, list) {
  if (err) {
    console.log(err);
  } else {
    for (var i = 0; i < list.length; i++) {
        console.log(list[i]);
    }
  }
}

// module(process.argv[2], process.argv[3], listFiles);

http.get(process.argv[2], function(res) {
  res.setEncoding('utf8');
  res.on('data', console.log);
});

module.js

var fs = require('fs');

module.exports = function readDirectories(filepath, ext, callback) {
  fs.readdir(filepath, function(err, list) {
    if (err) {
      return callback(err);
    }
    files = list.filter(function(file) {
      if (file.match('.' + ext + '$')){
        return file;
      }
    });
    callback(null, files);
  });
};