index.js

var webshot = require('webshot'),
fs      = require('fs'),
loki = require('lokijs'),
db = new loki('db.json');


// Creates webshot and stores it.








// grab the packages we need
var express = require('express');
var app = express();
var port = process.env.PORT || 8080;

// routes will go here

// start the server
app.listen(port);
console.log('Server started!');

app.get('/api/:url', function(req, res) {

		var requestURL = req.params.url;

		console.log(requestURL);

		var timestamp = new Date().getTime()/1000;
		openFolder(timestamp, function(folderPath){
			db.loadDatabase({}, function () {
			var cachedImages = db.getCollection('cachedImages');
			if(cachedImages === null){
				db.addCollection('cachedImages');
				var cachedImages = db.getCollection('cachedImages');
			}


			var view = cachedImages.addDynamicView('usableCachedPictures'); 
			view.applyWhere(function (obj) {
			 return obj.url == requestURL;
			});
			view.applyWhere(function (obj) {
			 return obj.time > (timestamp-3600); 
			});
			var cachedImages = view.data();
			if(cachedImages.length){
				var filename = hash(cachedImages[0].time+cachedImages[0].url)+'.png';

				//final return
				returnFile(res, folderPath+filename);
			}else{
				var filename = hash(timestamp+requestURL)+'.png';


				var options = {
				  shotSize: {
				    width: 1024
				  , height: 'all'
				  }
				}


				webshot(requestURL, folderPath+filename, options, function(err) {
				  var cachedImages = db.getCollection('cachedImages');
				  //var removalView = cachedImages.addDynamicView('unsableCachedPictures'); 
					cachedImages.removeWhere(function (obj) {
					 return obj.url == requestURL;
					});

					cachedImages.insert({
					  url: requestURL,
					  time: timestamp
					});
					db.saveDatabase();

					//final return
					returnFile(res, folderPath+filename);
				});
			}
			});

		});


});


//opens or creates folder for new timestamp, deletes old ones
//current timestamp
//callback(folderTitle)
function openFolder(timestamp, callback){
	var timestamp = Math.round(timestamp/1000);
	var path = './cached_images/'+timestamp;

	//check if path exists
	try {
	    // Query the entry
	    stats = fs.lstatSync(path);

	    // Is it a directory?
	    if (stats.isDirectory()) {
	        // Yes it is
	        callback(path+'/');
	    }
	}
	catch (e) {
		//delete dbFile
		var del = require('del');
		del(['db.json']).then(function (paths) {
			//delete complete dir
			rmdir = require('rimraf');
			rmdir('./cached_images', function(error){
				var mkdirp = require('mkdirp');

				//create new dirs
				mkdirp('cached_images',function(err){

					mkdirp(path, function(err) {

						callback(path+'/');
					});
				})
			});
		});

		
	}
}


function returnFile(result, path){
	fs.readFile(path, function(err, data) {
	  if (err) throw err; // Fail if the file can't be read.
	    result.writeHead(200, {'Content-Type': 'image/png'});
	    result.end(data); // Send the file data to the browser.
	});
}

function hash(string){
	  var hash = 0, i, chr, len;
  if (string.length == 0) return hash;
  for (i = 0, len = string.length; i < len; i++) {
    chr   = string.charCodeAt(i);
    hash  = ((hash << 5) - hash) + chr;
    hash |= 0; // Convert to 32bit integer
  }
  return hash;
}