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.ajax; import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import org.apache.commons.io.IOUtils; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.params.HttpConnectionParams; 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.util.StringUtil; /** * Provides AJAX-enabled services for changing cover art images. * <p/> * This class is used by the DWR framework (http://getahead.ltd.uk/dwr/). * * @author Sindre Mehus */ public class CoverArtService { private static final Logger LOG = Logger.getLogger(CoverArtService.class); private SecurityService securityService; private MediaFileService mediaFileService; /** * Downloads and saves the cover art at the given URL. * * @param path The directory in which to save the image. * @param url The image URL. * @return The error string if something goes wrong, <code>null</code> otherwise. */ public String setCoverArtImage(String path, String url) { try { saveCoverArt(path, url); return null; } catch (Exception x) { LOG.warn("Failed to save cover art for " + path, x); return x.toString(); } } private void saveCoverArt(String path, String url) throws Exception { InputStream input = null; HttpClient client = new DefaultHttpClient(); try { HttpConnectionParams.setConnectionTimeout(client.getParams(), 20 * 1000); // 20 seconds HttpConnectionParams.setSoTimeout(client.getParams(), 20 * 1000); // 20 seconds HttpGet method = new HttpGet(url); HttpResponse response = client.execute(method); input = response.getEntity().getContent(); // Attempt to resolve proper suffix. String suffix = "jpg"; if (url.toLowerCase().endsWith(".gif")) { suffix = "gif"; } else if (url.toLowerCase().endsWith(".png")) { suffix = "png"; } // Check permissions. File newCoverFile = new File(path, "folder." + suffix); if (!securityService.isWriteAllowed(newCoverFile)) { throw new Exception("Permission denied: " + StringUtil.toHtml(newCoverFile.getPath())); } // If file exists, create a backup. backup(newCoverFile, new File(path, "folder.backup." + suffix)); // Write file. IOUtils.copy(input, new FileOutputStream(newCoverFile)); MediaFile mediaFile = mediaFileService.getMediaFile(path); // Rename existing cover file if new cover file is not the preferred. try { File coverFile = mediaFileService.getCoverArt(mediaFile); if (coverFile != null) { if (!newCoverFile.equals(coverFile)) { coverFile.renameTo(new File(coverFile.getCanonicalPath() + ".old")); LOG.info("Renamed old image file " + coverFile); } } } catch (Exception x) { LOG.warn("Failed to rename existing cover file.", x); } mediaFileService.refreshMediaFile(mediaFile); } finally { IOUtils.closeQuietly(input); client.getConnectionManager().shutdown(); } } private void backup(File newCoverFile, File backup) { if (newCoverFile.exists()) { if (backup.exists()) { backup.delete(); } if (newCoverFile.renameTo(backup)) { LOG.info("Backed up old image file to " + backup); } else { LOG.warn("Failed to create image file backup " + backup); } } } public void setSecurityService(SecurityService securityService) { this.securityService = securityService; } public void setMediaFileService(MediaFileService mediaFileService) { this.mediaFileService = mediaFileService; } }