tds.itemrenderer.processing.ITSUrlGridTask.java Source code

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Here is the source code for tds.itemrenderer.processing.ITSUrlGridTask.java

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/*******************************************************************************
 * Educational Online Test Delivery System 
 * Copyright (c) 2014 American Institutes for Research
 *   
 * Distributed under the AIR Open Source License, Version 1.0 
 * See accompanying file AIR-License-1_0.txt or at
 * http://www.smarterapp.org/documents/American_Institutes_for_Research_Open_Source_Software_License.pdf
 ******************************************************************************/
package tds.itemrenderer.processing;

import java.io.File;
import java.io.IOException;

import org.apache.commons.io.FileUtils;
import org.apache.commons.net.util.Base64;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import tds.itemrenderer.data.IITSDocument;
import tds.itemrenderer.data.ITSTypes.ITSContentType;
import tds.itemrenderer.data.ITSTypes.ITSContextType;
import AIR.Common.Utilities.Path;

/**
 * @author jmambo
 *
 */
public class ITSUrlGridTask extends TaskExecutor<String> {

    private final String _xmlRootPath;

    public ITSUrlGridTask(String xmlFilePath) {
        _xmlRootPath = xmlFilePath.replace(Path.getFileName(xmlFilePath), "");
    }

    public ITSContentType getContentSupported() {
        return ITSContentType.Xml;
    }

    /**
     * Process element content
     * 
     * @param itsDocument
     * @param contentType
     * @param contextType
     * @param language
     * @param xml
     * @return
     */
    public String process(IITSDocument itsDocument, ITSContentType contentType, ITSContextType contextType,
            String language, String xml) {
        NodeList imageElements = getImageElements(xml);

        if (imageElements != null) {
            for (int i = 0; i < imageElements.getLength(); i++) {
                Element imageElement = (Element) imageElements.item(i);
                if (imageElement.getNodeName().equalsIgnoreCase("FileSpec")) {
                    processFileSpec(imageElement);
                }
                if (imageElement.getNodeName().equalsIgnoreCase("Image")) {
                    processImage(imageElement);
                }
            }
        }

        return xml;
    }

    /**
     * Process FileSpec element
     * 
     * @param fileSpecElement
     */
    private void processFileSpec(Element fileSpecElement) {
        String imageFilePath = Path.combine(_xmlRootPath, fileSpecElement.getTextContent());
        fileSpecElement.setTextContent(getBase64(imageFilePath));
    }

    /**
     * Process image element
     * 
     * @param imageElement
     */
    private void processImage(Element imageElement) {
        String imgSrcAttrib = imageElement.getAttribute("src");
        String imageFilePath = Path.combine(_xmlRootPath, imgSrcAttrib);
        imageElement.setAttribute("src", getBase64(imageFilePath));
    }

    /**
     * Convert to base 64
     * 
     * @param imageFilePath
     * @return
     */
    private String getBase64(String imageFilePath) {
        // create data uri format
        String dataUriFormat = "data:image/%s;base64,";
        String imageExt = Path.getExtension(imageFilePath).replace(".", "");
        String dataUri = String.format(dataUriFormat, imageExt);

        // get base64 data
        byte[] imageBytes = null;
        try {
            imageBytes = FileUtils.readFileToByteArray(new File(imageFilePath));
        } catch (IOException e) {
            throw new ITSDocumentProcessingException(e);
        }
        String imageBase64 = Base64.encodeBase64String(imageBytes);

        // return data uri
        return dataUri + imageBase64;
    }

    /**
     * Get a list of all the image elements.
     * 
     * @param xml
     * @return
     */
    private NodeList getImageElements(String xml) {
        Document document = XmlUtils.createDocument(xml);
        return XmlUtils.getNodeListByPath(document, "//FileSpec|//Image");
    }

}