/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. The ASF licenses this file to You
* under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License. For additional information regarding
* copyright in this work, please see the NOTICE file in the top level
* directory of this distribution.
*/
package org.apache.roller.ui.rendering.util;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.roller.config.RollerConfig;
import org.apache.roller.util.Utilities;
import org.apache.roller.util.cache.Cache;
import org.apache.roller.util.cache.CacheManager;
import org.apache.roller.util.cache.LazyExpiringCacheEntry;
/**
* Cache for weblog page content.
*/
public class WeblogPageCache {
private static Log log = LogFactory.getLog(WeblogPageCache.class);
// a unique identifier for this cache, this is used as the prefix for
// roller config properties that apply to this cache
public static final String CACHE_ID = "cache.weblogpage";
// keep cached content
private boolean cacheEnabled = true;
private Cache contentCache = null;
// reference to our singleton instance
private static WeblogPageCache singletonInstance = new WeblogPageCache();
private WeblogPageCache() {
cacheEnabled = RollerConfig.getBooleanProperty(CACHE_ID+".enabled");
Map cacheProps = new HashMap();
cacheProps.put("id", CACHE_ID);
Enumeration allProps = RollerConfig.keys();
String prop = null;
while(allProps.hasMoreElements()) {
prop = (String) allProps.nextElement();
// we are only interested in props for this cache
if(prop.startsWith(CACHE_ID+".")) {
cacheProps.put(prop.substring(CACHE_ID.length()+1),
RollerConfig.getProperty(prop));
}
}
log.info(cacheProps);
if(cacheEnabled) {
contentCache = CacheManager.constructCache(null, cacheProps);
} else {
log.warn("Caching has been DISABLED");
}
}
public static WeblogPageCache getInstance() {
return singletonInstance;
}
public Object get(String key, long lastModified) {
if(!cacheEnabled)
return null;
Object entry = null;
LazyExpiringCacheEntry lazyEntry =
(LazyExpiringCacheEntry) this.contentCache.get(key);
if(lazyEntry != null) {
entry = lazyEntry.getValue(lastModified);
if(entry != null) {
log.debug("HIT "+key);
} else {
log.debug("HIT-EXPIRED "+key);
}
} else {
log.debug("MISS "+key);
}
return entry;
}
public void put(String key, Object value) {
if(!cacheEnabled)
return;
contentCache.put(key, new LazyExpiringCacheEntry(value));
log.debug("PUT "+key);
}
public void remove(String key) {
if(!cacheEnabled)
return;
contentCache.remove(key);
log.debug("REMOVE "+key);
}
public void clear() {
if(!cacheEnabled)
return;
contentCache.clear();
log.debug("CLEAR");
}
/**
* Generate a cache key from a parsed weblog page request.
* This generates a key of the form ...
*
* <handle>/<ctx>[/anchor][/language][/user]
* or
* <handle>/<ctx>[/weblogPage][/date][/category][/language][/user]
*
*
* examples ...
*
* foo/en
* foo/entry_anchor
* foo/20051110/en
* foo/MyCategory/en/user=myname
*
*/
public String generateKey(WeblogPageRequest pageRequest) {
StringBuffer key = new StringBuffer();
key.append(this.CACHE_ID).append(":");
key.append(pageRequest.getWeblogHandle());
if(pageRequest.getWeblogAnchor() != null) {
String anchor = null;
try {
// may contain spaces or other bad chars
anchor = URLEncoder.encode(pageRequest.getWeblogAnchor(), "UTF-8");
} catch(UnsupportedEncodingException ex) {
// ignored
}
key.append("/entry/").append(anchor);
} else {
if(pageRequest.getWeblogPageName() != null) {
key.append("/page/").append(pageRequest.getWeblogPageName());
}
if(pageRequest.getWeblogDate() != null) {
key.append("/").append(pageRequest.getWeblogDate());
}
if(pageRequest.getWeblogCategoryName() != null) {
String cat = null;
try {
// may contain spaces or other bad chars
cat = URLEncoder.encode(pageRequest.getWeblogCategoryName(), "UTF-8");
} catch(UnsupportedEncodingException ex) {
// ignored
}
key.append("/").append(cat);
}
}
if(pageRequest.getLocale() != null) {
key.append("/").append(pageRequest.getLocale());
}
// add page number when applicable
if(pageRequest.getWeblogAnchor() == null) {
key.append("/page=").append(pageRequest.getPageNum());
}
// add login state
if(pageRequest.getAuthenticUser() != null) {
key.append("/user=").append(pageRequest.getAuthenticUser());
}
// we allow for arbitrary query params for custom pages
if(pageRequest.getWeblogPageName() != null &&
pageRequest.getCustomParams().size() > 0) {
String queryString = paramsToString(pageRequest.getCustomParams());
key.append("/qp=").append(queryString);
}
return key.toString();
}
private String paramsToString(Map map) {
if(map == null) {
return null;
}
StringBuffer string = new StringBuffer();
String key = null;
String[] value = null;
Iterator keys = map.keySet().iterator();
while(keys.hasNext()) {
key = (String) keys.next();
value = (String[]) map.get(key);
if(value != null) {
string.append(",").append(key).append("=").append(value[0]);
}
}
return Utilities.toBase64(string.toString().substring(1).getBytes());
}
}