Count all photos that are available on Flickr and Panoramio for a specific geo fence

countPhotosForGeoLocation

/*
	
    This script counts all photos that are available on Flickr and Panoramio for a specific geo fence and returns a JSON object with the data.
    For convenience it's embedded in a little node.js server so that you can upload it to your server and use it as an API.
    
    Here's an example url with all query attributes prefilled. Please use your own Flickr API key!
    The location is the Berlin TV Tower (http://en.wikipedia.org/wiki/Fernsehturm_Berlin)
    
    Example URL: http://piccounter-philippschmitt.rhcloud.com/?lat=52.520732&lon=13.409537&latRes=0.00015&lonRes=0.0003&flickrKey=60d03369d3e92b4578c8f2df2de5af66
    
    Created 2014-10-26
    by Philipp Schmitt

    http://philippschmitt.com

*/


// load modules
var http = require('http'),
    qs = require('qs'),		
    url = require('url'),
	request = require('request');

// create the http server
http.createServer(function (req, res) {
    
    // parse URL and create object containing GET vars
	var url_parts = url.parse(req.url, true);
	var query = url_parts.query;

	// check if query string is ok
	if( query.lat && query.latRes && query.lon && query.lonRes && query.flickrKey ) {

		// load photos
		countPhotosForCurrentPosition( parseFloat(query.lat), parseFloat(query.latRes), parseFloat(query.lon), parseFloat(query.lonRes), query.flickrKey, function( result ) {
		// callback: 
		// serve query results as JSON
		res.writeHead(200, {'Content-Type': 'application/json'});
		res.end( JSON.stringify(result) );
		});
	
	// nope. bad request
	} else {
		res.writeHead(400, {'Content-Type': 'application/json'});
		res.end( JSON.stringify({}) );
	}

// listen to port: 8124
}).listen(8124);


// function to load photos asynchronously
var countPhotosForCurrentPosition = function(lat, latRes, lon, lonRes, flickrKey, callback) {
	
	// define helper vars
	var total = 0,
		flickr = 0,
		pnrmio = 0,
		flickrDone = false,
		pnrmioDone = false;

	// FLickr Query URL
	var flickrURL = 'https://api.flickr.com/services/rest/?api_key='+ flickrKey +'&method=flickr.photos.search&bbox='+ (lon-lonRes) +'%2C'+ (lat-latRes) +'%2C+'+ (lon+lonRes) +'%2C+'+ (lat+latRes) +'&min_upload_date=820483200&accuracy=16&format=json&nojsoncallback=1&content_type=1&has_geo=1';
	// Panoramio Query URL array
	var pnrmioURL = [];


	// FLICKR Query
	request(flickrURL, function (error, response, body) {
		if (!error && response.statusCode == 200) {
			var data = JSON.parse(body);

			// Add all photos to our counter
			flickr += parseInt( data.photos.total );

			// confirm that flickr is done counting photos
			flickrDone = true; 
		} else {
			// an error occured
			console.log('Flickr error');
		}
	});	
	

	// PANORAMIO Query

	/* Helper function:
	 * The Panoramio photos.count attribute is inaccurate. 
	 * We have to go through all available photos and count.
	 * But Panoramio queries are limited to 100 photos. 
	 * That's why we query over and over again
	 */
	var queryPanoramio = function (from, to) {

		var options = {
		    url: 'http://www.panoramio.com/map/get_panoramas.php?set=full&from='+ from +'&to='+ to +'&minx='+ (lon-lonRes) +'&miny='+ (lat-latRes) +'&maxx='+ (lon+lonRes) +'&maxy='+ (lat+latRes) +'&size=small&mapfilter=false',
		    json: true,
		    method: 'GET'
		};

		// add current query URL to list
		pnrmioURL.push( options.url );

		// do the actual request
		request(options, function (error, response, body) {
			// success: work with the data
			if (!error && response.statusCode == 200) {
				
				// add length of photo array (i.e. number of photos) to our counter		    
		   		pnrmio += body.photos.length;
		   		
		   		// Are there more photos?
		   		if( to+99 <= body.count && body.has_more==true ) {
		   			// yep: query the next 100 pics
		   			queryPanoramio(to+1, to+100);
		   		} else {
		   			// we're done.
		   			pnrmioDone = true;
		   		}

			} else {	
				// an error occured
				console.log('Panoramio error');
			}
		});
	};
	
	// do the initial query
	queryPanoramio(0,100);
	
	
	// check every 10ms, if both Flickr and Panoramio are done counting
	var waiter = setInterval(function() {
		// it's time!
		if( flickrDone == true && pnrmioDone==true ) {
			
			// stop waiter
			clearInterval(waiter);
			
			// invoke callback function and return results object
			callback({
				// total amount of photos
				total: flickr + pnrmio,
				// flickr subsection
				flickr: {
					// all photos fetched from flickr
					total: flickr,
					// the Flickr query URL
					flickrURL: flickrURL
				},
				// Panoramio subsection
				pnrmio: {
					// number of photos fetched from Panoramio
					total: pnrmio,
					// query URLs for Panoramio API
					pnrmioURL: pnrmioURL
				}				
			});
		}
		
	}, 10);	
};