server.js

/*

    Instagram real-time updates demo app.

*/


var url = require('url'),
	settings = require('./settings'),
	helpers = require('./helpers'),
	crypto = require('crypto'),
	subscriptions = require('./subscriptions');

var app = settings.app;


app.get('/callbacks/geo/:geoName', function(request, response){
    // The GET callback for each subscription verification.
	var params = url.parse(request.url, true).query;
	response.send(params['hub.challenge'] || 'No hub.challenge present');
});


app.post('/callbacks/geo/:geoName', function(request, response){
    // The POST callback for Instagram to call every time there's an update
    // to one of our subscriptions.
    
    // First, let's verify the payload's integrity by making sure it's
    // coming from a trusted source. We use the client secret as the key
    // to the HMAC.
    var hmac = crypto.createHmac('sha1', settings.CLIENT_SECRET);
    hmac.update(request.rawBody);
    var providedSignature = request.headers['x-hub-signature'];
    var calculatedSignature = hmac.digest(encoding='hex');
    
    // If they don't match up or we don't have any data coming over the
    // wire, then bail out early.
    if((providedSignature != calculatedSignature) || !request.body)
        response.send('FAIL');
    
    // Go through and process each update. Note that every update doesn't
    // include the updated data - we use the data in the update to query
    // the Instagram API to get the data we want.
	var updates = request.body;
	var geoName = request.params.geoName;
	for(index in updates){
		var update = updates[index];
		if(update['object'] == "geography")
			helpers.processGeography(geoName, update);
	}
	response.send('OK');
});


// Render the home page
app.get('/', function(request, response){
    helpers.getMedia(function(error, media){
		response.render('geo.jade', {
		    locals: { images: media }
		});
	});
});

app.listen(settings.appPort);