uk.co.tfd.symplectic.harvester.XmlAide.java Source code

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Here is the source code for uk.co.tfd.symplectic.harvester.XmlAide.java

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/*
 *  Copyright (c) 2011 Ian Boston for Symplectic, relicensed under the AGPL license in repository https://github.com/ieb/symplectic-harvester
 *  Please see the LICENSE file for more details
 */
package uk.co.tfd.symplectic.harvester;

import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.commons.codec.binary.Base64;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.vivoweb.harvester.util.WebAide;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class XmlAide {
    private static final Logger LOGGER = LoggerFactory.getLogger(XmlAide.class);

    public static Document loadXmlDocument(String url)
            throws MalformedURLException, SAXException, IOException, ParserConfigurationException {
        DocumentBuilderFactory docBuildFactory = DocumentBuilderFactory.newInstance();
        docBuildFactory.setIgnoringComments(true);

        String xmlDoc = null;
        if (url.startsWith("http")) {
            xmlDoc = ConcurrentHttpFetch.get(url);
        } else {
            xmlDoc = WebAide.getURLContents(url);
        }
        // doing this fixes makes it work with UTF8 chars
        return docBuildFactory.newDocumentBuilder().parse(new InputSource(new StringReader(xmlDoc)));
    }

    public static String findAttribute(Node n, String elementName, String attrName) {
        NodeList nl = n.getChildNodes();
        for (int i = 0; i < nl.getLength(); i++) {
            Node cn = nl.item(i);
            if (elementName.equals(cn.getNodeName())) {
                Node av = cn.getAttributes().getNamedItem(attrName);
                if (av == null) {
                    return null;
                }
                return av.getNodeValue();
            }
        }
        return null;
    }

    public static String findAttribute(Node n, String attrName) {
        Node av = n.getAttributes().getNamedItem(attrName);
        if (av == null) {
            return null;
        }
        return av.getNodeValue();
    }

    public static Node findNode(Node n, String elementName) {
        NodeList nl = n.getChildNodes();
        for (int i = 0; i < nl.getLength(); i++) {
            Node cn = nl.item(i);
            if (elementName.equals(cn.getNodeName())) {
                return cn;
            }
        }
        return null;
    }

    public static String hash(String userUrl) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        MessageDigest md = MessageDigest.getInstance("SHA1");
        return Base64.encodeBase64URLSafeString(md.digest(userUrl.getBytes("UTF-8")));
    }

    public static String getXmlFromNode(Node node)
            throws TransformerFactoryConfigurationError, TransformerException {
        StringWriter writer = new StringWriter();
        Transformer transformer = TransformerFactory.newInstance().newTransformer();
        transformer.transform(new DOMSource(node), new StreamResult(writer));
        String s = writer.toString().trim();
        if (s.startsWith("<?xml")) {
            int i = s.indexOf(">");
            s = s.substring(i + 1);
        }
        return s;
    }

    public static String getNodeValue(Node n, String elementName) {
        Node element = findNode(n, elementName);
        LOGGER.info("Find Node base:{} elementName:{} found:{} ", new Object[] { n, elementName, element });
        if (element != null) {
            LOGGER.info("Value {} ", element.getTextContent());
            return element.getTextContent();
        }
        return null;
    }
}