app.js

/* global require:true, console:true, process:true, __dirname:true */
'use strict'

// Example run command: `node app.js 9000 6380 true`; listen on port 9000, connect to redis on 6380, debug printing on.

var express = require('express'),
    http = require('http'),
    redis = require('redis'),
    redisClient,
    port = process.argv[2] || 80,
    rport = process.argv[3] || 6379,
    debug = process.argv[4] || null

// Database setup
redisClient = redis.createClient(rport)

redisClient.on('connect', function() {
    console.log('Connected to redis.')
})

// Data handling
var save = function save(d) {
    redisClient.hmset(d.postId, d)
    if (debug)
        console.log('saved to redis: ' + d.postId + ', at: ' + (new Date()).toString())
}

// Server setup
var app = express()
app.use(express.bodyParser())
app.use(express.static(__dirname + '/public'))

// Handle POSTs from frontend
app.post('/', function handlePost(req, res) {
    // Get experiment data from request body
    var d = req.body
        // If a postId doesn't exist, add one (it's random, based on date)
    if (!d.postId) d.postId = (+new Date()).toString(36)
        // Add a timestamp
    d.timestamp = (new Date()).getTime()
    // Save the data to our database
    save(d)
    // Send a 'success' response to the frontend
    res.send(200)
})

// On access to /participantCount, return current number of keys
app.get('/participantCount', function handleGet(req, res) {
    var finish = function(d) {
            res.json(d)
        }
        // get all keys from redis
    redisClient.keys("*", function(err, res) {
        finish({
            participantCount: res.length
        })
    });
})

// Create the server and tell which port to listen to
http.createServer(app).listen(port, function(err) {
    if (!err) console.log('Listening on port ' + port)
})