1. 16BIT IITR Data Collection Module A web crawler (also known as a web spider or web robot) is a program or automated script which browses the World Wide Web in a methodical, automated manner. Search engines such as Google, Bing etc. uses web crawlers to index the newly created data on Internet. Web Crawler

2. 16BIT IITR Data Collection Module News Crawlers are focused on retrieving newly published News Data. News Crawlers monitors a set of defined News sources and captures the news as soon as it publishes. News Crawler News URL Downloader Predefined Set of News Sources News Database New URLs Crawl every 30 Min News Article Downloader News Articles New URLs Architecture of News Crawler at IITR Web Crawler

3. 16BIT IITR Data Collection Module A Simple Java Program for Downloading a Web Page Web Crawler

4. 16BIT IITR Data Collection Module Given a Web Page, we can retrieve different components by Parsing it. Many HTML Parsers are available such as Jsoup, Xerces, NekoHTML Following Java program uses Jsoup parser to extract Hyperlinks from a web page. Parsing a Web Page import org.jsoup.Jsoup; import org.jsoup.nodes.Document; import org.jsoup.nodes.Element; import org.jsoup.select.Elements; import java.io.IOException; import java.io.File; public class ExtractLinks { public static void main(String[] args) throws IOException { File input = new File("data.html"); Document doc = Jsoup.parse(input, "UTF-8", “ "); Elements links = doc.select("a[href]"); System.out.println("Total Number of Links:"+links.size()); for (Element link : links) { System.out.println(link.attr("abs:href")); } Web Crawler

5. 16BIT IITR Data Collection Module There are many API available for extracting the main content from web pages, such as Boilerplate API Following Java program demonstrates the use of Boilerplate API to extract the article text from a news article Retrieving Article Text import java.io.PrintWriter; import java.net.URL; import de.l3s.boilerpipe.BoilerpipeExtractor; import de.l3s.boilerpipe.extractors.CommonExtractors; import de.l3s.boilerpipe.sax.HTMLHighlighter; public class BoilerplateDemo { public static void main(String[] args) throws Exception { URL url = new URL("http://www.thehindu.com/news/national/land-acquisition-ordinance-bill-gets-a-burial/article7597517.ece"); final BoilerpipeExtractor extractor = CommonExtractors.ARTICLE_EXTRACTOR; // choose the operation mode (i.e., highlighting or extraction) //final HTMLHighlighter hh = HTMLHighlighter.newHighlightingInstance(); final HTMLHighlighter hh = HTMLHighlighter.newExtractingInstance(); PrintWriter out = new PrintWriter("highlighted.html", "UTF-8"); out.println(hh.process(url, extractor)); out.close(); System.out.println("Now open file highlighted.html in your web browser"); } Web Crawler

6. 16BIT IITR Data Collection Module Objective: To extract Article Content from Given News URL News URL: http://www.hindustantimes.com/world-t20/amitabh-bachchan-to-sing-national-anthem-before-india- pakistan-match/story-QXxnQAvmJsisvIYtSFv33L.htmlhttp://www.hindustantimes.com/world-t20/amitabh-bachchan-to-sing-national-anthem-before-india- pakistan-match/story-QXxnQAvmJsisvIYtSFv33L.html Article Extraction Article Extractor Bollywood superstar Amitabh Bachchan will sing the National Anthem before the start of the marquee India-Pakistan World Twenty20 cricket match at the Eden Gardens on March 19. Bachchan has confirmed the development by retweeting a post in his official Twitter handle while sources in the Cricket Association of Bengal today said this was an effort by its president Sourav Ganguly. “The president was involved and the plan was on for a long time,” CAB sources said. While the ‘Big B’ will sing the National Anthem in his signature baritone, Pakistan will also make their presence felt with classical singer Shafaqat Amanat Ali who is slated to sing the Pakistani National Anthem.

7. 16BIT IITR Data Collection Module Add-ons: Noise Article Extractor http://timesofindia.indiatimes.com/india/India-became-3rd-largest-economy-in-2011-from-10th-in-2005/articleshow/34416429.cms

8. 16BIT IITR Data Collection Module Article Extraction Article Extractor

9. 16BIT IITR Data Collection Module Article Extraction Article Extractor String url = “input_url.html”; String name = “CLASS or ID name”; Document doc = Jsoup.connect(url).timeout(100*1000).userAgent("Mozilla").get(); article = doc.getElementsByClass(name).text(); Or article = doc.getElementById(name).text(); String url = “http://www.dnaindia.com/world/report-pakistan-blast-in-peshawar-bus- kills-at-least-15-govt-employees-over-25-injured-2189902”; String name = “body-text”; Document doc = Jsoup.connect(url).timeout(100*1000).userAgent("Mozilla").get(); article = doc.getElementsByClass(name).text(); Example

10. 16BIT IITR Data Collection Module Metadata refers to data about data. It is always in the form of key-value pairs. Key : name = “author” Value : content = “TCA Sharad Raghavan” Metadata of News Webpages Extract Meta-Key Phrase

11. 16BIT IITR Data Collection Module Metadata content of a typical news webpage: Title, Description, News keywords, Author name, Last modified date, Publishing date, etc. News websites use various types of protocols to insert metadata. OGP (Open Graph Protocol) is one of them. Some of the well know OGP tags are : og:title - The title of your object as it should appear within the graph, e.g., "The Rock". og:type - The type of your object, e.g., "video.movie". Depending on the type you specify, other properties may also be required. og:image - An image URL which should represent your object within the graph. og:url - The canonical URL of your object that will be used as its permanent ID in the graph, e.g., "http://www.imdb.com/title/tt0117500/". Metadata of News Webpages Extract Meta-Key Phrase

12. 16BIT IITR Data Collection Module Open Graph Protocol (OGP) provided by Facebook, allows the embedding of web content as Facebook social graph objects. It defines tags which can be used by web content generators for converting web objects into corresponding graph object. Open Graph Protocol Facebook Graph Object Extract Meta-Key Phrase

13. 16BIT IITR Data Collection Module Keywords which are most relevant to the article. “news_keyword” Tag Extract Meta-Key Phrase

14. 16BIT IITR Data Collection Module Online social networking and microblogging service. Enables its registered user to read and send messages of 140 characters known as tweets. Twitter contains data in following forms: Tweet: Message to send with 140 characters or less. Follower: A person who has chosen to read your tweets on an ongoing basis. Reply or @ : The @ symbol means you are talking to or about the person. Retweet or RT: The act of repeating what some one else has tweeted so that your followers can see it. HashTag or # : HashTag provide a theme for the tweet that allow all similar tweets to be searched. Twitter Twitter Crawler

15. 16BIT IITR Data Collection Module Twitter Twitter Crawler To Follow Tweet Reply Persons Retweeted Retweets HashTag

16. 16BIT IITR Data Collection Module Data from twitter can be extracted using either Twitter APIs or R packages. 1.Twitter APIs: REST API Streaming API 2.R packages: twitteR RTwitterAPI Data Extraction from Twitter Twitter Crawler

17. 16BIT IITR Data Collection Module 1.Login Twitter account. 2.Open link https://apps.twitter.com/app/new and create an application. 3.Generate Access token. 4.Create a New Java Project and include the Twitter4j Library from https://dl.dropboxusercontent.com/u/1737239/twitter4j-core-2.2.5.jar https://dl.dropboxusercontent.com/u/1737239/twitter4j-core-2.2.5.jar Data Extraction from Twitter using a REST API: Twitter4J Twitter Crawler

18. 16BIT IITR Data Collection Module Java Code to Extract Tweets related to Query “World Cup” Twitter Crawler

19. 16BIT IITR Data Collection Module Java Code to Extract Trends from Twitter Twitter Crawler