gather-public-proxy/lib/location-checker.js

Find free anonymous proxy

/*!
 * Gather Public Proxy
 * Copyright(c) 2014 Gautier Fauchart <gautier.fauchart@gmail.com>
 * MIT Licensed
 */

/**
 *  Module dependencies.
 */

var request = require("request");
var _ = require("lodash");
var Q = require("q");

/**
 * expose locationChecker
 */

module.exports = locationChecker;

/**
 * setup locationChecker
 * @param {Object} options
 * @api private
 */

function locationChecker(_option){
    this.option = _option;
    this.queue = [];
    this.inProgress = 0;
    this.online = true;
}

/**
 * start engine
 * @return promise
 * @api public
 */

locationChecker.prototype.start = function(){
    this.deferred = Q.defer();
    return this.deferred.promise;
}

/**
 * Stop locationChecker, prevent request and resolve promise
 * @api public
 */

locationChecker.prototype.end = function(){
    this.online = false;
    this.queue = null;
    this.deferred.resolve();
}

/**
 * set stopInput = true, for stopping engine when queue is empty
 * @api public
 */

locationChecker.prototype.endInput = function(){
    this.stopInput = true;
    if (this.inProgress == 0 && this.queue.length == 0)
	this.end();
}

/**
 * add proxy to queue
 * @param {Proxy} proxy
 * @api public
 */

locationChecker.prototype.add = function(proxy){
    var that = this;

    that.queue.push(proxy);
    that.execute();
}

/**
 * execute request
 * @api private
 */

locationChecker.prototype.execute = function(){

    var that = this;

    if (!this.online)
	return;
    
    if (this.inProgress >=  this.option.thead)
	return;

    var proxy = this.queue.shift();
    if (!proxy){
	if (this.stopInput && this.inProgress == 0)
	    this.end();
	return
    }

    this.inProgress++; 
    options = {
        url: "http://www.freegeoip.net/json/" + proxy.ip,
        timeout: 4000
    };

    request(options, function(error, response, body) {
	that.inProgress--; 

        if (!error && response.statusCode == 200) {
	    _.extend(proxy, JSON.parse(body))
	    that.deferred.notify(proxy);
	}
	_.defer(function(){
	    that.execute();
	});	
    });
}