Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package crawler; import hibernate.HibernateUtil; import java.io.IOException; import java.util.ArrayList; import java.util.StringTokenizer; import java.util.TreeMap; import java.util.TreeSet; import java.util.logging.Level; import java.util.logging.Logger; import model.Platform; import model.Problem; import model.SampleInputOutput; import model.Tutorial; import org.apache.commons.lang3.StringUtils; import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.Transaction; import org.jsoup.Connection.Response; import org.jsoup.Jsoup; import org.jsoup.nodes.Document; import org.jsoup.nodes.Element; import org.jsoup.select.Elements; /** * * @author Dhaval */ public class HackerEarthCrawler implements Crawler { private final static String USER_AGENT = "Mozilla/5.0"; private final static String baseUrl = "https://www.hackerearth.com/"; public HackerEarthCrawler() { } //to check if given url has problem data or not public static boolean isProblemUrl(String str) { //keywords which can't be in problem url String[] discard = { "/#", "/activity/", "@", "/messages/", "/companies/", "/logout/", "/login/", "/jobs/", "/signup/", "/recruit", "/recruiter/", "/leaderboard/", "/ama/", "/notes/", "/tutorial/", "/customers/", "/users/", "privacy/", "/docs/", "/sql/", "/multiplayer", "/machine-learning/", "/mapreduce/", "/frontend/" }; for (int i = 0; i < discard.length; i++) { if (str.contains(discard[i])) { return false; } } //if url don't contain 'practice-problem' or 'problem',it's not a problem url if (!str.contains("/practice-problems/") && !str.contains("/problem/")) { return false; } else if ((str.contains("/practice-problems/") && str.endsWith("/practice-problems/")) || str.contains("p_level=#") || str.contains("p_level=")) { return false; } return true; } //to check if given url has any problem url or not public static boolean isCrawlable(String str) { //if these keywords are present in url it cannot have any new problem urls String[] discard = { "/problem/", "@", "/messages/", "/companies/", "/logout/", "/login/", "/jobs/", "/signup/", "/recruit", "/recruiter/", "/leaderboard/", "/ama/", "/notes/", "/tutorial/", "/customers/", "/users/", "privacy/", "/docs/" }; for (int i = 0; i < discard.length; i++) { if (str.contains(discard[i])) { return false; } } //if this conditions satisfies it is problem url itself,so not need to be further crawl if (str.contains("/practice-problems/") && !str.endsWith("/practice-problems/") && !str.endsWith("p_level=")) { return false; } else if (str.endsWith("/#")) { return false; } return true; } @Override public void crawl() { int flag = 0; //set of urls which should be crawled TreeSet<String> linksset = new TreeSet<String>(); TreeSet<String> tempset = new TreeSet<String>(); TreeSet<String> tutorialset = new TreeSet<String>(); //final set of problem urls TreeSet<String> problemset = new TreeSet<String>(); //visited for maintaing status of if url is already crawled or not TreeMap<String, Integer> visited = new TreeMap<String, Integer>(); //add base url linksset.add(baseUrl); //mark base url as not crawled visited.put(baseUrl, 0); try { while (true) { flag = 0; tempset.clear(); for (String str : linksset) { //check if url is already crawled or not and it has valid domain name if ((visited.get(str) == 0) && (str.startsWith("https://www.hackerearth.com/"))) { System.out.println("crawling " + str); //retriving response of current url as document Document doc = Jsoup.connect(str).timeout(0).userAgent( "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/25.0") .referrer("http://www.google.com").ignoreHttpErrors(true).get(); //retriving all urls from current page Elements links = doc.select("a[href]"); //mark url as crawled visited.put(str, 1); //mark flag as url is crawled flag = 1; //retrive all urls for (Element link : links) { if (link.absUrl("href").endsWith("/tutorial/")) { tutorialset.add(link.absUrl("href")); } //check if url is problem url then add it in problemurlset if (link.absUrl("href").startsWith("https://www.hackerearth.com/") && isProblemUrl(link.absUrl("href"))) { problemset.add(link.absUrl("href")); } //check if url has valid domain and it has problem urls or not if (link.absUrl("href").contains(("https://www.hackerearth.com/")) && isCrawlable(link.absUrl("href"))) { //if link is not visited then mark it as uncrawled if (!visited.containsKey(link.absUrl("href"))) { visited.put(link.absUrl("href"), 0); } //add it in tempsetorary set tempset.add(link.absUrl("href")); //System.out.println("\n base: "+str+" ::: link : " + link.absUrl("href")); } } } } //if nothing is left to crawl break the loop if (flag == 0) { break; } //add all retrieved links to linksset linksset.addAll(tempset); } System.out.println("\n\ntotal problem urls " + problemset.size()); int i = 0; for (String str : problemset) { System.out.println("link " + i + " : " + str); i++; } } catch (IOException ex) { Logger.getLogger(HackerEarthCrawler.class.getName()).log(Level.SEVERE, null, ex); } //scrap and store into database //for every problem url scrap problem page for (String problemUrl : problemset) { System.out.println("problemUrl :" + problemUrl); try { //create problem class to store in database Problem problem = new Problem(); String problemSIOC = "", problemIOC = ""; String problemTitle = "", problemStatement = "", problemInput = "", problemOutput = "", problemConstraints = ""; String sampleInput = "", sampleOutput = ""; String problemExplanation = ""; //set default timelimit to 1 second double problemTimeLimit = 1.0; ArrayList<String> tags = new ArrayList<String>(); //get response for given problem url Response response = Jsoup.connect(problemUrl).execute(); Document doc = response.parse(); //retrieve problem title from page Element elementTitle = doc.getElementsByTag("title").first(); StringTokenizer stTitle = new StringTokenizer(elementTitle.text(), "|"); problemTitle = stTitle.nextToken().trim(); Element content = doc.getElementsByClass("starwars-lab").first(); problemSIOC = content.text(); Elements e = content.children(); //to find problem statement String breakloop[] = { "input", "input:", "input :", "input format:", "input format :", "input format", "Input and output", "constraints :", "constraints:", "constraints", "$$Input :$$" }; flag = 0; for (Element p : e) { String tempStatement = ""; for (Element pp : p.getAllElements()) { for (String strbreak : breakloop) { if (StringUtils.equalsIgnoreCase(pp.ownText(), strbreak)) { //System.out.println("strbreak :"+strbreak); tempStatement = p.text().substring(0, p.text().toLowerCase().indexOf(strbreak.toLowerCase())); // System.out.println("temp "+tempStatement); flag = 1; break; } } } if (flag == 1) { problemStatement += tempStatement; //remove extra space at end if (tempStatement.length() == 0) { problemStatement = problemStatement.substring(0, problemStatement.length() - 1); } break; } problemStatement += p.text() + " "; } System.out.println("problemSIOC :" + problemSIOC); System.out.println("problemStatement :" + problemStatement); if (problemStatement.length() <= problemSIOC.length()) { //remove problem statement from whole text and remove extra spaces at the beginning and the end problemIOC = problemSIOC.substring(problemStatement.length()).trim(); } else { problemIOC = ""; } System.out.println("problemIOC :" + problemIOC); //keywords for identifying input String decideInput[] = { "Input format :", "Input format:", "Input format", "inputformat:", "inputformat :", "inputformat", "input and output", "input :", "input:", "input" }; //keywords for identifying output String decideOutput[] = { "output format :", "output format:", "Output format", "outputformat:", "outputformat :", "outputformat", "output :", "output:", "output" }; //keywords for identifying constraint String decideConstraint[] = { "constraints:", "constraints :", "constraints", "Constraints :", "constraint:", "constraint :", "constraint", "Contraints :" }; int posin = 0, posoutput = 0, poscon = 0, idxin, idxout, idxcon, flaginput = 0, flagoutput = 0, flagcon = 0, inlen = 0, outlen = 0, conlen = 0; //find inputformat position,length of keyword for (idxin = 0; idxin < decideInput.length; idxin++) { if (StringUtils.containsIgnoreCase(problemIOC, decideInput[idxin])) { posin = problemIOC.toLowerCase().indexOf(decideInput[idxin].toLowerCase()); flaginput = 1; inlen = decideInput[idxin].length(); //decide it is keyowrd for actucal input or it is "sample input" if (StringUtils.containsIgnoreCase(problemIOC, "sample input")) { if (posin > problemIOC.toLowerCase().indexOf("sample input")) { flaginput = 0; inlen = 0; } else { break; } } else { break; } } } //find outputformat position,length of keyword for (idxout = 0; idxout < decideOutput.length; idxout++) { if (StringUtils.containsIgnoreCase(problemIOC, decideOutput[idxout])) { posoutput = problemIOC.toLowerCase().indexOf(decideOutput[idxout].toLowerCase()); flagoutput = 1; outlen = decideOutput[idxout].length(); break; } } //find constraint position,length of keyword for (idxcon = 0; idxcon < decideConstraint.length; idxcon++) { if (StringUtils.containsIgnoreCase(problemIOC, decideConstraint[idxcon])) { poscon = problemIOC.toLowerCase().indexOf(decideConstraint[idxcon].toLowerCase()); flagcon = 1; conlen = decideConstraint[idxcon].length(); break; } } System.out.println("input " + flaginput + " " + inlen + " " + posin); System.out.println("output " + flagoutput + " " + outlen + " " + posoutput); System.out.println("constraint " + flagcon + " " + conlen + " " + poscon); //retrieve problem input and output if present in problem page //if input format is present if (flaginput == 1) { //if input keyword is "input and output" and contraint is present in problem page if (idxin == 6 && flagcon == 1) { problemInput = problemIOC.substring(inlen, poscon); } //if input keyword is "input and output" and contraint is not present in problem page else if (idxin == 6 && flagcon == 0) { problemInput = problemIOC.substring(inlen); } //if output format and constraint is present else if (flagoutput == 1 && flagcon == 1) { //if constraint is present before input format if (poscon < posin) { problemInput = problemIOC.substring(posin + inlen, posoutput); problemOutput = problemIOC.substring(posoutput + outlen); } //if constraint is present before sample else if (poscon < posoutput) { problemInput = problemIOC.substring(inlen, poscon); problemOutput = problemIOC.substring(posoutput + outlen); } else { problemInput = problemIOC.substring(inlen, posoutput); problemOutput = problemIOC.substring(posoutput + outlen, poscon); } } //if constraint is not present else if (flagoutput == 1 && flagcon == 0) { problemInput = problemIOC.substring(inlen, posoutput); problemOutput = problemIOC.substring(posoutput + outlen); } else if (flagoutput == 0 && flagcon == 1) { if (poscon < posin) { problemInput = problemIOC.substring(posin + inlen); } else { problemInput = problemIOC.substring(poscon + conlen, posin); } problemOutput = ""; } else { problemInput = problemIOC.substring(inlen); problemOutput = ""; } } //if input format and output format is not present else { problemInput = ""; problemOutput = ""; } //if constraint is present if (flagcon == 1) { //if constraint is present before input format if (poscon < posin) { problemConstraints = problemIOC.substring(0, posin); } //if constraint is present before output format else if (poscon < posoutput) { problemConstraints = problemIOC.substring(poscon + conlen, posoutput); } else { problemConstraints = problemIOC.substring(poscon + conlen); } } System.out.println("problemInput :" + problemInput); System.out.println("problemOutput :" + problemOutput); System.out.println("problemConstraints :" + problemConstraints); //retrieve problem tags from problem page Element elementtag = doc.getElementsByClass("problem-tags").first().child(1); StringTokenizer st = new StringTokenizer(elementtag.text(), ","); while (st.hasMoreTokens()) { tags.add(st.nextToken().trim()); } //retrieve sample input sample output if present Element elementSIO = doc.getElementsByClass("input-output-container").first(); //if sample input output is present if (elementSIO != null) { //find position of sample output int soutpos = elementSIO.text().indexOf("SAMPLE OUTPUT"); sampleInput = elementSIO.text().substring(12, soutpos); sampleOutput = elementSIO.text().substring(soutpos + 13); System.out.println("Sample input :\n" + sampleInput + "\n\n\n"); System.out.println("Sample Output :\n" + sampleOutput); } else { sampleInput = ""; sampleOutput = ""; } //retrieve problem explanation from problem page if present Element elementExplanation = doc.getElementsByClass("standard-margin").first().child(0); if (elementExplanation.text().toLowerCase().contains("explanation")) { problemExplanation = elementExplanation.nextElementSibling().text(); } System.out.println("Explanation :" + problemExplanation); //retrieve timelimit Element elementTL = doc.getElementsByClass("problem-guidelines").first().child(0).child(1); StringTokenizer stTL = new StringTokenizer(elementTL.ownText(), " "); problemTimeLimit = Double.parseDouble(stTL.nextToken()); //System.out.println("problemTimeLimit :"+problemTimeLimit); //set all retrieved information to problem class problem.setProblemUrl(problemUrl); if (problemTitle.length() == 0) { problemTitle = null; } if (problemStatement.length() == 0) { problemStatement = null; } if (problemInput.length() == 0) { problemInput = null; } if (problemOutput.length() == 0) { problemOutput = null; } if (problemExplanation.length() == 0) { problemExplanation = null; } if (problemConstraints.length() == 0) { problemConstraints = null; } problem.setTitle(problemTitle); problem.setProblemUrl(problemUrl); problem.setProblemStatement(problemStatement); problem.setInputFormat(problemInput); problem.setOutputFormat(problemOutput); problem.setTimeLimit(problemTimeLimit); problem.setExplanation(problemExplanation); problem.setConstraints(problemConstraints); //set sample input output to problem class SampleInputOutput sampleInputOutput = new SampleInputOutput(problem, sampleInput, sampleOutput); problem.getSampleInputOutputs().add(sampleInputOutput); //set platform as hackerearth problem.setPlatform(Platform.HackerEarth); for (String strtag : tags) { problem.getTags().add(strtag); } //store in database Session session = null; Transaction transaction = null; try { //start session session = HibernateUtil.getSessionFactory().openSession(); transaction = session.beginTransaction(); //check if problem is already stored in database String hql = "FROM Problem p where p.problemUrl = :problem_url"; Problem oldProblem = (Problem) session.createQuery(hql).setString("problem_url", problemUrl) .uniqueResult(); String task; //if problem is present in database if (oldProblem != null) { //update the old problem task = "updated"; //retrieve id of old problem problem.setId(oldProblem.getId()); session.delete(oldProblem); session.flush(); session.save(problem); } else { task = "saved"; session.save(problem); } transaction.commit(); //log the info to console Logger.getLogger(CodeForcesCrawler.class.getName()).log(Level.INFO, "{0} {1}", new Object[] { task, problem.getProblemUrl() }); } catch (HibernateException ee) { if (transaction != null) { transaction.rollback(); } Logger.getLogger(CodeForcesCrawler.class.getName()).log(Level.SEVERE, "Cannot Insert/Update problem into databse: " + problemUrl, e); } finally { //close the session if (session != null) { session.close(); } } } catch (Exception ee) { System.out.println(ee.toString()); } } System.out.println("\n\n\n\ntutorial urls\n\n"); try { for (String tutorialurl : tutorialset) { //System.out.println(tutorialurl+"\n\n"); Response tutorialres = Jsoup.connect(tutorialurl).execute(); Document doc = tutorialres.parse(); Tutorial tutorial = new Tutorial(); tutorial.setContent(doc.getElementsByClass("tutorial").first().text()); tutorial.setName(baseUrl); tutorialurl = tutorialurl.substring(0, tutorialurl.length() - 10); StringTokenizer tutorialtok = new StringTokenizer(tutorialurl, "/"); String tempstr = ""; while (tutorialtok.hasMoreTokens()) { tempstr = tutorialtok.nextToken(); } Session session = null; Transaction transaction = null; try { //start session session = HibernateUtil.getSessionFactory().openSession(); transaction = session.beginTransaction(); //check if problem is already stored in database String hql = "FROM Tutorial p where p.name = :name"; Tutorial oldProblem = (Tutorial) session.createQuery(hql).setString("name", tempstr) .uniqueResult(); String task; //if problem is present in database if (oldProblem != null) { //update the old problem task = "updated"; //retrieve id of old problem tutorial.setName(oldProblem.getName()); session.delete(oldProblem); session.flush(); session.save(tutorial); } else { task = "saved"; tutorial.setName(tempstr); session.save(tutorial); } transaction.commit(); //log the info to console Logger.getLogger(CodeForcesCrawler.class.getName()).log(Level.INFO, "{0} {1}", new Object[] { task, tutorial.getName() }); } catch (HibernateException ee) { if (transaction != null) { transaction.rollback(); } Logger.getLogger(CodeForcesCrawler.class.getName()).log(Level.SEVERE, "Cannot Insert/Update problem into databse: " + tempstr, ee); } finally { //close the session if (session != null) { session.close(); } } } } catch (Exception e) { System.out.println(e.getMessage()); } } }