ImageRetriever.java

package org.wikipedia.miner.web.util;

import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;

import javax.xml.parsers.ParserConfigurationException;

import org.wikipedia.miner.model.Article;
import org.xml.sax.SAXException;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonParser;

public class ImageRetriever {

	private static String baseUrl = "http://en.wikipedia.org/w/api.php" ;
	
	private WebContentRetriever retriever ;
	private Gson gson = new Gson(); 
	
	
	private Set<String> bannedImages = new HashSet<String>() ;
	
	public ImageRetriever(WebContentRetriever retriever) {
		
		this.retriever = retriever ;
		
		bannedImages.add("File:Commons-logo.svg") ;
	}
	
	
	public  List<String> getImageTitles(Integer articleId) throws UnsupportedEncodingException, IOException {
		
		List<String> imageTitles = new ArrayList<String>() ;
		
		URL url = new URL(baseUrl + "?action=query&pageids=" + articleId + "&prop=images&format=json") ;
		
		String json = retriever.getWebContent(url) ;
		
		Response response = gson.fromJson(json, Response.class) ;
		
		if (response == null)
			return imageTitles ;
		
		if (response.query == null)
			return imageTitles ;
		
		if (response.query.pages == null)
			return imageTitles ;
		
		for (Page page:response.query.pages.values()) {
			
			if (page.images == null)
				continue ;
			
			for (Image image:page.images) {
				if (bannedImages.contains(image.title))
					continue ;
				
				imageTitles.add(image.title) ;
			}
		}
		
		return imageTitles ;
	}
	
	public String getImageUrl(String imageTitle, Integer width, Integer height) throws UnsupportedEncodingException, MalformedURLException, IOException {
		
		String url = baseUrl + "?action=query&titles=" + URLEncoder.encode(imageTitle, "UTF-8") + "&prop=imageinfo&iiprop=url&format=json" ;
		
		if (width != null)
			url = url + "&iiurlwidth=" + width ;
		
		if (height != null)
			url = url + "&iiurlheight=" + height ;
		
		//System.out.println(url) ;
		
		String json = retriever.getWebContent(new URL(url)) ;
		
		//System.out.println(json);
		
		Response response = gson.fromJson(json, Response.class) ;
		
		if (response == null)
			return null ;
		
		if (response.query == null)
			return null ;
		
		if (response.query.pages == null)
			return null ;
		
		for (Page page:response.query.pages.values()) {
			
			if (page.imageinfo == null)
				continue ;
			
			for (ImageInfo imageinfo:page.imageinfo) {
				if (imageinfo.thumburl != null)
					return imageinfo.thumburl ;
				
				if (imageinfo.url != null)
					return imageinfo.url ;
			}
		}
		
		return null ;
	}
	
	public static void main(String args[]) throws ParserConfigurationException, IOException, ClassNotFoundException, InstantiationException, IllegalAccessException, SAXException {
		
		File conf = new File("../configs/hub.xml") ;
		
		WebContentRetriever wcr = new WebContentRetriever(new HubConfiguration(conf)) ;
		ImageRetriever ir = new ImageRetriever(wcr) ;
		
				
		for(String img:ir.getImageTitles(852)) {
			System.out.println(img + ": " + ir.getImageUrl(img, 100, null));
		}
	}
	
	
	
	private static class Response {
		public Query query ;
	}
	
	private static class Query {
		public Map<Integer,Page> pages ;
	}
	
	private static class Page {
		public int pageid ;
		public int ns ;
		public String title ;
		
		public List<Image> images ;
		public List<ImageInfo> imageinfo ;
	}
	
	private static class Image {
		public int ns ;
		public String title ;
	}
	
	private static class ImageInfo {
		public String thumburl ;
		public int thumbwidth ;
		public int thumbheight ;
		public String url ;
	}
	
}