org.paxle.gui.impl.servlets.MetaDataIconServlet.java Source code

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Here is the source code for org.paxle.gui.impl.servlets.MetaDataIconServlet.java

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/**
 * This file is part of the Paxle project.
 * Visit http://www.paxle.net for more information.
 * Copyright 2007-2010 the original author or authors.
 *
 * Licensed under the terms of the Common Public License 1.0 ("CPL 1.0").
 * Any use, reproduction or distribution of this program constitutes the recipient's acceptance of this agreement.
 * The full license text is available under http://www.opensource.org/licenses/cpl1.0.txt
 * or in the file LICENSE.txt in the root directory of the Paxle distribution.
 *
 * Unless required by applicable law or agreed to in writing, this software is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 */

package org.paxle.gui.impl.servlets;

import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.URLConnection;
import java.util.Iterator;

import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.servlet.Servlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Properties;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Service;
import org.apache.velocity.context.Context;
import org.apache.velocity.tools.view.VelocityLayoutServlet;
import org.paxle.core.metadata.IMetaData;
import org.paxle.gui.impl.tools.MetaDataTool;

@Component(metatype = false, immediate = true)
@Service(Servlet.class)
@Properties({ @Property(name = "org.paxle.servlet.path", value = "/metaDataIcon"),
        @Property(name = "org.paxle.servlet.doUserAuth", boolValue = false) })
public class MetaDataIconServlet extends VelocityLayoutServlet {
    private static final long serialVersionUID = 1L;
    private static final String REQ_PARAM_SERVICEPID = "servicePID";

    @Override
    protected void doRequest(HttpServletRequest request, HttpServletResponse response) {
        try {
            final Context context = this.getVelocityView().createContext(request, response);
            final String servicePID = request.getParameter(REQ_PARAM_SERVICEPID);

            if (servicePID != null) {
                // getting the metaDataTool
                final MetaDataTool tool = (MetaDataTool) context.get(MetaDataTool.TOOL_NAME);
                if (tool == null) {
                    this.log("No MetaDataTool found");
                    return;
                }

                final IMetaData metaData = tool.getMetaData(servicePID);
                if (metaData == null) {
                    this.log(String.format("No metadata found for service with PID '%s'.", servicePID));
                    return;
                }

                // getting the icon
                InputStream in = metaData.getIcon(16);
                if (in == null)
                    in = this.getClass().getResourceAsStream("/resources/images/cog.png");

                // loading date
                final ByteArrayOutputStream bout = new ByteArrayOutputStream();
                IOUtils.copy(in, bout);
                bout.close();
                in.close();

                // trying to detect the mimetype of the image
                final ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
                String contentType = URLConnection.guessContentTypeFromStream(bin);
                bin.close();

                // reading the image
                BufferedImage img = null;
                Iterator<ImageReader> readers = null;
                if (contentType != null) {
                    readers = ImageIO.getImageReadersByMIMEType(contentType);
                    while (readers != null && readers.hasNext() && img == null) {
                        // trying the next reader
                        ImageReader reader = readers.next();

                        InputStream input = null;
                        try {
                            input = new ByteArrayInputStream(bout.toByteArray());
                            reader.setInput(ImageIO.createImageInputStream(input));
                            img = reader.read(0);
                        } catch (Exception e) {
                            this.log(String.format("Unable to read metadata icon for service with PID '%s'.",
                                    servicePID), e);
                        } finally {
                            if (input != null)
                                input.close();
                        }
                    }
                }

                if (img != null) {
                    response.setHeader("Content-Type", "image/png");
                    ImageIO.write(img, "png", response.getOutputStream());
                    return;
                } else {
                    response.sendError(404);
                    return;
                }
            } else {
                response.sendError(500, "Invalid usage");
            }
        } catch (Throwable e) {
            this.log(String.format("Unexpected '%s'.", e.getClass().getName()), e);
        }
    }
}