Java tutorial
/* This file is part of Subsonic. Subsonic 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. Subsonic 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 Subsonic. If not, see <http://www.gnu.org/licenses/>. Copyright 2009 (C) Sindre Mehus */ package net.sourceforge.subsonic.controller; import net.sourceforge.subsonic.Logger; import net.sourceforge.subsonic.domain.MediaFile; import net.sourceforge.subsonic.service.MediaFileService; import net.sourceforge.subsonic.service.SecurityService; import net.sourceforge.subsonic.service.SettingsService; import net.sourceforge.subsonic.service.metadata.JaudiotaggerParser; import net.sourceforge.subsonic.util.FileUtil; import org.apache.commons.codec.digest.DigestUtils; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.StringUtils; import org.springframework.web.bind.ServletRequestBindingException; import org.springframework.web.bind.ServletRequestUtils; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.Controller; import org.springframework.web.servlet.mvc.LastModified; import javax.imageio.ImageIO; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.awt.*; import java.awt.image.BufferedImage; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; /** * Controller which produces cover art images. * * @author Sindre Mehus */ public class CoverArtController implements Controller, LastModified { private static final Logger LOG = Logger.getLogger(CoverArtController.class); private SecurityService securityService; private MediaFileService mediaFileService; public long getLastModified(HttpServletRequest request) { String path = request.getParameter("path"); if (StringUtils.trimToNull(path) == null) { return 0; } File file = new File(path); if (!FileUtil.exists(file)) { return -1; } return FileUtil.lastModified(file); } public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { File file = getImageFile(request); Integer size = ServletRequestUtils.getIntParameter(request, "size"); // Check access. if (file != null && !securityService.isReadAllowed(file)) { response.sendError(HttpServletResponse.SC_FORBIDDEN); return null; } // Optimize if no scaling is required. if (size == null) { sendUnscaled(file, response); return null; } // Send default image if no path is given. (No need to cache it, since it will be cached in browser.) if (file == null) { sendDefault(size, response); return null; } // Send cached image, creating it if necessary. try { File cachedImage = getCachedImage(file, size); sendImage(cachedImage, response); } catch (IOException e) { sendDefault(size, response); } return null; } private File getImageFile(HttpServletRequest request) throws ServletRequestBindingException { Integer id = ServletRequestUtils.getIntParameter(request, "id"); if (id != null) { MediaFile mediaFile = mediaFileService.getMediaFile(id); if (mediaFile != null) { return mediaFileService.getCoverArt(mediaFile); } } String path = StringUtils.trimToNull(request.getParameter("path")); return path != null ? new File(path) : null; } private void sendImage(File file, HttpServletResponse response) throws IOException { InputStream in = new FileInputStream(file); try { IOUtils.copy(in, response.getOutputStream()); } finally { IOUtils.closeQuietly(in); } } private void sendDefault(Integer size, HttpServletResponse response) throws IOException { InputStream in = null; try { in = getClass().getResourceAsStream("default_cover.jpg"); BufferedImage image = ImageIO.read(in); image = scale(image, size, size); ImageIO.write(image, "jpeg", response.getOutputStream()); } finally { IOUtils.closeQuietly(in); } } private void sendUnscaled(File file, HttpServletResponse response) throws IOException { InputStream in = null; try { in = getImageInputStream(file); IOUtils.copy(in, response.getOutputStream()); } finally { IOUtils.closeQuietly(in); } } private File getCachedImage(File file, int size) throws IOException { String md5 = DigestUtils.md5Hex(file.getPath()); File cachedImage = new File(getImageCacheDirectory(size), md5 + ".jpeg"); // Is cache missing or obsolete? if (!cachedImage.exists() || FileUtil.lastModified(file) > cachedImage.lastModified()) { InputStream in = null; OutputStream out = null; try { in = getImageInputStream(file); out = new FileOutputStream(cachedImage); BufferedImage image = ImageIO.read(in); if (image == null) { throw new Exception("Unable to decode image."); } image = scale(image, size, size); ImageIO.write(image, "jpeg", out); } catch (Throwable x) { // Delete corrupt (probably empty) thumbnail cache. LOG.warn("Failed to create thumbnail for " + file, x); IOUtils.closeQuietly(out); cachedImage.delete(); throw new IOException("Failed to create thumbnail for " + file + ". " + x.getMessage()); } finally { IOUtils.closeQuietly(in); IOUtils.closeQuietly(out); } } return cachedImage; } /** * Returns an input stream to the image in the given file. If the file is an audio file, * the embedded album art is returned. */ private InputStream getImageInputStream(File file) throws IOException { JaudiotaggerParser parser = new JaudiotaggerParser(); if (parser.isApplicable(file)) { MediaFile mediaFile = mediaFileService.getMediaFile(file); return new ByteArrayInputStream(parser.getImageData(mediaFile)); } else { return new FileInputStream(file); } } private synchronized File getImageCacheDirectory(int size) { File dir = new File(SettingsService.getSubsonicHome(), "thumbs"); dir = new File(dir, String.valueOf(size)); if (!dir.exists()) { if (dir.mkdirs()) { LOG.info("Created thumbnail cache " + dir); } else { LOG.error("Failed to create thumbnail cache " + dir); } } return dir; } public static BufferedImage scale(BufferedImage image, int width, int height) { int w = image.getWidth(); int h = image.getHeight(); BufferedImage thumb = image; // For optimal results, use step by step bilinear resampling - halfing the size at each step. do { w /= 2; h /= 2; if (w < width) { w = width; } if (h < height) { h = height; } BufferedImage temp = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = temp.createGraphics(); g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); g2.drawImage(thumb, 0, 0, temp.getWidth(), temp.getHeight(), null); g2.dispose(); thumb = temp; } while (w != width); return thumb; } public void setSecurityService(SecurityService securityService) { this.securityService = securityService; } public void setMediaFileService(MediaFileService mediaFileService) { this.mediaFileService = mediaFileService; } }