Java tutorial
/* (c) 2017 Open Source Geospatial Foundation - all rights reserved * This code is licensed under the GPL 2.0 license, available at the root * application directory. */ package org.geoserver.gwc.config; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.geoserver.platform.GeoServerExtensions; import org.geoserver.platform.resource.Resource; import org.geoserver.platform.resource.ResourceStore; import org.geoserver.platform.resource.Resources; import org.geoserver.util.Filter; import org.geoserver.util.IOUtils; import org.geowebcache.config.ConfigurationException; import org.geowebcache.config.ConfigurationResourceProvider; import org.geowebcache.config.XMLFileResourceProvider; import org.geowebcache.storage.DefaultStorageFinder; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.text.SimpleDateFormat; import java.util.Arrays; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.List; import java.util.Optional; public class GeoserverXMLResourceProvider implements ConfigurationResourceProvider { private static Log LOGGER = LogFactory.getLog(GeoserverXMLResourceProvider.class); static final String GEOWEBCACHE_CONFIG_DIR_PROPERTY = XMLFileResourceProvider.GWC_CONFIG_DIR_VAR; static final String GEOWEBCACHE_CACHE_DIR_PROPERTY = DefaultStorageFinder.GWC_CACHE_DIR; public static final String DEFAULT_CONFIGURATION_DIR_NAME = "gwc"; /** * Location of the configuration file */ private final Resource configDirectory; /** * Name of the configuration file */ private final String configFileName; private String templateLocation; public GeoserverXMLResourceProvider(String providedConfigDirectory, String configFileName, ResourceStore resourceStore) throws ConfigurationException { this.configFileName = configFileName; this.configDirectory = inferConfigDirectory(resourceStore, providedConfigDirectory); LOGGER.info(String.format("Will look for '%s' in directory '%s'.", configFileName, configDirectory.dir().getAbsolutePath())); } public GeoserverXMLResourceProvider(final String configFileName, final ResourceStore resourceStore) throws ConfigurationException { this(null, configFileName, resourceStore); } /** * Helper method that infers the directory that contains or will contain GWC configuration. First we will * check if a specific location was set using properties GEOWEBCACHE_CONFIG_DIR and GEOWEBCACHE_CACHE_DIR, * then we will check if a location was provided and then fallback on the default location. */ private static Resource inferConfigDirectory(ResourceStore resourceStore, String providedConfigDirectory) { // check if a specific location was provided using a context property otherwise use the provided directory String configDirectoryPath = findFirstDefined(GEOWEBCACHE_CONFIG_DIR_PROPERTY, GEOWEBCACHE_CACHE_DIR_PROPERTY).orElse(providedConfigDirectory); // if the configuration directory stills not defined we use the default location if (configDirectoryPath == null) { configDirectoryPath = DEFAULT_CONFIGURATION_DIR_NAME; } // instantiate a resource for the configuration directory File configurationDirectory = new File(configDirectoryPath); if (configurationDirectory.isAbsolute()) { return Resources.fromPath(configurationDirectory.getAbsolutePath()); } // configuration directory path is relative to geoserver data directory return resourceStore.get(configDirectoryPath); } /** * Returns an {@link Optional} containing the value of the first defined property, * or an empty {@code Optional} if no property is defined in the current context. */ private static Optional<String> findFirstDefined(String... propertiesNames) { for (String propertyName : propertiesNames) { // looks the property using GeoServer extensions mechanism String propertyValue = GeoServerExtensions.getProperty(propertyName); if (propertyValue != null) { // this property is defined so let's use is value LOGGER.debug(String.format("Property '%s' is set with value '%s'.", propertyName, propertyValue)); return Optional.of(propertyValue); } } // no property is defined return Optional.empty(); } public Resource getConfigDirectory() { return configDirectory; } public String getConfigFileName() { return configFileName; } @Override public InputStream in() throws IOException { return findOrCreateConfFile().in(); } @Override public OutputStream out() throws IOException { return findOrCreateConfFile().out(); } @Override public void backup() throws IOException { backUpConfig(findOrCreateConfFile()); } @Override public String getId() { return configDirectory.path(); } @Override public void setTemplate(final String templateLocation) { this.templateLocation = templateLocation; } private Resource findConfigFile() throws IOException { return configDirectory.get(configFileName); } public String getLocation() throws IOException { return findConfigFile().path(); } private Resource findOrCreateConfFile() throws IOException { Resource xmlFile = findConfigFile(); if (Resources.exists(xmlFile)) { LOGGER.info("Found configuration file in " + configDirectory.path()); } else if (templateLocation != null) { LOGGER.warn("Found no configuration file in config directory, will create one at '" + xmlFile.path() + "' from template " + getClass().getResource(templateLocation).toExternalForm()); // grab template from classpath try { IOUtils.copy(getClass().getResourceAsStream(templateLocation), xmlFile.out()); } catch (IOException e) { throw new IOException("Error copying template config to " + xmlFile.path(), e); } } return xmlFile; } private void backUpConfig(final Resource xmlFile) throws IOException { String timeStamp = new SimpleDateFormat("yyyy-MM-dd'T'HHmmss").format(new Date()); String backUpFileName = "geowebcache_" + timeStamp + ".bak"; Resource parentFile = xmlFile.parent(); LOGGER.debug("Backing up config file " + xmlFile.name() + " to " + backUpFileName); List<Resource> previousBackUps = Resources.list(parentFile, new Filter<Resource>() { public boolean accept(Resource res) { if (configFileName.equals(res.name())) { return false; } if (res.name().startsWith(configFileName) && res.name().endsWith(".bak")) { return true; } return false; } }); final int maxBackups = 10; if (previousBackUps.size() > maxBackups) { Collections.sort(previousBackUps, new Comparator<Resource>() { @Override public int compare(Resource o1, Resource o2) { return (int) (o1.lastmodified() - o2.lastmodified()); } }); Resource oldest = previousBackUps.get(0); LOGGER.debug("Deleting oldest config backup " + oldest + " to keep a maximum of " + maxBackups + " backups."); oldest.delete(); } Resource backUpFile = parentFile.get(backUpFileName); IOUtils.copy(xmlFile.in(), backUpFile.out()); LOGGER.debug("Config backup done"); } @Override public boolean hasInput() { try { return Resources.exists(findOrCreateConfFile()); } catch (IOException e) { return false; } } @Override public boolean hasOutput() { return true; } }