github.srlee309.lessWrongBookCreator.scraper.PostSectionExtractor.java Source code

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Here is the source code for github.srlee309.lessWrongBookCreator.scraper.PostSectionExtractor.java

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/* 
 * Copyright (C) 2015 Scott Lee
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package github.srlee309.lessWrongBookCreator.scraper;

import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PushbackInputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import javax.imageio.ImageIO;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Abstract class to define common code for extracting post sections from websites
 */
public abstract class PostSectionExtractor {
    protected static final Logger logger = LoggerFactory.getLogger(PostSectionExtractor.class);
    protected final String newLine = System.getProperty("line.separator");

    public abstract String getPostSectionString(PostExtractionDetails postExtractionDetails, Document doc);

    /**
     * Saves all images in the given Element to a local newUrl and converts the src for all img tags to the local file
     * @param postContent - from which to extract the images
    */
    protected final void convertImagesToLocal(Element postContent) {
        Elements imgs = postContent.getElementsByTag("img");
        for (Element img : imgs) {
            String src = img.absUrl("src");
            String folder = "htmlOutput";

            int indexName = src.lastIndexOf("/");
            String name = src;
            if (indexName != -1) {
                indexName = src.lastIndexOf("/") + 1;
                name = src.substring(indexName, src.length());
            }
            img.attr("src", name);
            saveImage(src, folder, name);
        }
    }

    /**
     * @param src of image to download and save
     * @param folder to which to save the image
     * @param fileName to use for the saved image
     */
    protected final void saveImage(String src, String folder, String fileName) {
        if (fileName.contains("?")) {
            fileName = fileName.substring(0, fileName.lastIndexOf("?"));
        }

        fileName = fileName.replaceAll("[^a-zA-Z0-9.-]", "_"); // replace non valid file fileName characters
        File outputFile = new File(folder + "\\" + fileName);
        try {
            URL url = new URL(src);

            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestProperty("User-Agent",
                    "Mozilla/5.0 (Windows NT 6.3; rv:36.0) Gecko/20100101 Firefox/36.0");
            connection.setRequestMethod("HEAD");
            connection.setInstanceFollowRedirects(false);
            int rspCode = connection.getResponseCode();
            if (rspCode == 301) { // redirected, so get new url
                String newUrl = connection.getHeaderField("Location");
                url = new URL(newUrl);
            }
            connection.disconnect();
            FileUtils.copyURLToFile(url, outputFile);
        } catch (MalformedURLException e) {
            logger.error("Malformed url exception for image src:  " + src, e);
        } catch (IOException e) {
            logger.error("IO exception for saving image src locally:  " + src, e);
        }
    }

    public boolean downloadFileFromURL(String fetchUrl, File outputFile)
            throws IOException, FileNotFoundException, IOException {

        HttpURLConnection c;

        //save file       
        URL url = new URL(fetchUrl);
        c = (HttpURLConnection) url.openConnection();

        //set cache and request method settings  
        c.setUseCaches(false);
        c.setDoOutput(false);

        //set other headers  
        c.setRequestProperty("Content-Type", "image/jpeg");
        System.out.println(c.getContentType());
        //connect  
        c.connect();

        BufferedInputStream in = new BufferedInputStream(c.getInputStream());

        OutputStream out = new BufferedOutputStream(new FileOutputStream(outputFile));
        byte[] buf = new byte[256];
        int n = 0;
        while ((n = in.read(buf)) >= 0) {
            out.write(buf, 0, n);
        }
        out.flush();
        out.close();

        return true;
    }

}