webcrawler.js

//PhantomJS http://phantomjs.org/ based web crawler Anton Ivanov anton.al.ivanov@gmail.com 2012

var fs = require('fs');
var system = require('system');
var arg_url = system.args[1] || '';
var snapshot = system.args[2] || '';

fs.exists('sitemap.xml', function(exists) {
  if (exists) {
    fs.unlink('sitemap.xml');
  }
});

var url_info = new Array();
var all_urls = new Array();
var sitemap_header = '<?xml version="1.0" encoding="UTF-8"?>' + "\n";
sitemap_header += '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' + "\n";
var sitemap_footer = "\n</urlset>";

(function(host) {

    function Crawler() {
        this.visitedURLs = {};
    };

    Crawler.webpage = require('webpage');
    Crawler.fs = require('fs');
    Crawler.baseUrl = arg_url;

    Crawler.prototype.crawl = function (url, depth, takeSnapshot, onSuccess, onFailure) {
        if (0 == depth || this.visitedURLs[url]) {
            return;
        };
        var self = this;
        var page = Crawler.webpage.create();

        page.viewportSize = {
          width: 1280,
          height: 1024
        };

        page.onResourceError = function(resourceError) {
          page.reason = resourceError.errorString;
          page.reason_url = resourceError.url;
        }

        page.open(url, function (status) {
            if ('fail' === status) {
                onFailure({
                    url: url,
                    status: status
                });
            } else {
                var delay, checker = (function() {
                    console.log('Waiting for page load... ' + url);
                    var documentHTML = page.evaluate(function () {
                        var body = document.querySelector('.main-wrapper');
                        if (body.getAttribute('data-status') == 'ready') {
                            return document.body && document.body.innerHTML ? document.body : "";
                        }
                    });

                    if (documentHTML) {
                        clearTimeout(delay);

                        // Save content into directory.
                        if (page.url.substring(0, Crawler.baseUrl.length) == Crawler.baseUrl) {
                            var resource = page.url.substring(Crawler.baseUrl.length);
                            resource = resource.replace(/^#[!]?/, '');
                            if (resource.length == 0) {
                                resource = resource + "/index.html";
                            } else if (resource.match(/\.html$/) === null) {
                                resource = resource + ".html";
                            } else {
                                resource = resource + ".html";
                            }
                            fs.write('content/static/' + resource, page.content, 'w');

                            if (takeSnapshot) {
                                page.render('tmp/' + resource + '.png');
                            }

                            if (all_urls.indexOf(page.url) == -1) {
                                url_info.push("\t<url><loc>" + page.url + "</loc><changefreq>monthly</changefreq></url>");
                                all_urls.push(page.url);
                            }

                            // I am going to write this file every single time because I do not understand Javascript.
                            fs.write("sitemap.xml", sitemap_header + url_info.join("\n") + sitemap_footer, 'w');
                        }

                        // Add URL to JSON

                        self.getAllURLs(page, depth -1, onSuccess, onFailure);
//                        self.crawlURLs(urls, depth - 1, onSuccess, onFailure);
                        self.visitedURLs[url] = true;
                        onSuccess({
                            url: url,
                            status: status,
                            content: documentHTML
                        });
                    }
                });
                delay = setInterval(checker, 100);
            };
        });
    };

    Crawler.prototype.getAllURLs = function(page, depth, onSuccess, onFailure) {
        var self = this;

        var delay, checker = (function() {
          console.log('Waiting for navigation links to load...');
            var links = page.evaluate(function () {
              // Try to find some links in a couple of different menus on the site.
              var nav = document.querySelector('a.ng-binding, a.nav-link');
//                var body = document.getElementsByTagName('body')[0];
                if (typeof nav !== 'undefined' || nav !== null) {
                    return [].map.call(document.querySelectorAll('a.ng-binding, a.nav-link'), function(link) {
                        return link.getAttribute('href');
                    });
                }
            });

            if (links) {
                clearTimeout(delay);
                console.log('Found ' + links.length + ' links');
                self.crawlURLs(links, depth, onSuccess, onFailure);
            }
        });

        delay = setInterval(checker, 100);
    };

    Crawler.prototype.crawlURLs = function(urls, depth, onSuccess, onFailure) {
        var self = this;
        var baseUrl = arg_url;
        urls.filter(function (url) {
            if (url.match(/^#[!]?\/[a-zA-Z0-9\-]+/) !== null && url !== '#[!]?/') {
                return Crawler.isTopLevelURL(baseUrl + url);
            } else if (url.length !== '#[!]?/') {
                return Crawler.isTopLevelURL(url);
            } else {
                return false;
            }
        }).forEach(function (url) {
            console.log('Found: ' + url);
            self.crawl(baseUrl + url, depth, onSuccess, onFailure);
        });
    };

    Crawler.isTopLevelURL = function(url) {
       // return true;
        return 0 == url.indexOf("http");
    };

    host.Crawler = Crawler;
})(phantom);

new phantom.Crawler().crawl(arg_url, 4, snapshot,
    function onSuccess(page) {
        console.log("Loaded page. URL = " + page.url + " content length = " + page.content.length + " status = " + page.status);
    },
    function onFailure(page) {
        console.log("Could not load page. URL = " +  page.url + " status = " + page.status);
    }
);