Chicago Node.js: Intro to Node.js Workshop

0.README

Slides: https://docs.google.com/presentation/d/17qCqjo9MgNKdH3i0pVgqkbXyVPYS-7_COCi-etR9new/pub?start=false&loop=false&delayms=3000#slide=id.gab72b792_05

Event: http://www.meetup.com/Chicago-Nodejs/events/98566142/

To select the code in the slides, go to the gear menu in the bottom-left and select Speaker Notes.

Answers are below.

1.Read a File.js

//index.js

var fs = require('fs');

var fileName = process.argv[2];

fs.readFile(fileName, function(err, contents){
  if(err)
    return console.log(err.message);

  // may vary depending on line endings of your OS
  var lines = contents.toString().split('\n').length - 1
  console.log(lines);
});

2.Create a Module.js

// logger.js

module.exports = function Logger(logMethod){
  this.log = logMethod || console.log;
};

3.Emit some Events.js

// radioactive_element.js:

var EventEmitter = require('events').EventEmitter;
var inherits = require('util').inherits;
function Element(symbol, startingSize, decayMs){
  this.symbol = symbol;
  this.size = startingSize;

  // preserve the scope so that we can use it inside a nested function, like checkDecay
  var self = this;

  var intervalHandle = setInterval(checkDecay, decayMs);

  function checkDecay(){
    var chance = Math.random();
    if (chance > 0.5) {
      self.size--;
      self.emit('decay', self);

      if(self.size == 0){
        self.emit('dead', self);
        //stop checking
        clearInterval(intervalHandle);
      }
    }
  }
};

//inherit the EventEmitter goodness
inherits(Element, EventEmitter);
module.exports = Element;

4.Make an HTTP Server.js

//index.js

var http = require('http');
var viewCount = 0;

var server = http.createServer(function (request, response) {
  response.writeHead(200, {"Content-Type": "text/plain"});

  if(request.url === '/'){
    response.write('I just counted your view!');
    viewCount++;
  }

  if(request.url === '/viewcount'){
    response.write(viewCount.toString());
  }

  response.end();
});

server.listen(8000);
console.log("Server running at http://localhost:8000/");

5.Do Some Routing.js

//index.js

var http = require('http');

var viewCount = 0;

var server = http.createServer(function (request, response) {
  console.log('Handling: '+request.method+' : '+request.url);
  response.writeHead(200, {"Content-Type": "text/plain"});

  if(request.url === '/count' && request.method === 'POST'){
    viewCount++;
  }

  if(request.url === '/count' && request.method === 'DELETE'){
    viewCount--;
  }

  if(request.url === '/count' && request.method === 'GET'){
    response.write(viewCount.toString());
  }

  // use a regular expression to match a variable route
  var countRegex = new RegExp('/count/(\\d+)');
  var countMatch = request.url.match(countRegex)
  if(request.method === 'PUT' && countMatch){
    viewCount = parseInt(countMatch[1], 10);
  }

  // use a regular expression to match a variable route
  var yeahRegex = new RegExp('/y(e+)ah');
  var yeahMatch = request.url.match(yeahRegex);
  if(request.method === 'GET' && yeahMatch){
    var message = 'y' + yeahMatch[1] + 'ah!';
    response.write(message.toUpperCase());
  }

  response.end();
});

server.listen(8000);
console.log("Server running at http://localhost:8000/");


// We can test the routes with curl, like so:

/*
$ curl -X POST http://localhost:8000/count
$ curl -X POST http://localhost:8000/count
$ curl -X GET http://localhost:8000/count
2
$ curl -X DELETE http://localhost:8000/count
$ curl -X GET http://localhost:8000/count
1
$ curl -X PUT http://localhost:8000/count/10
$ curl -X GET http://localhost:8000/count
10
$ curl -X GET http://localhost:8000/yeeeeeeeeeeeeeeah
YEEEEEEEEEEEEEEAH!
$ curl -X GET http://localhost:8000/yeah
YEAH!
*/