| /* |
| * Copyright 2004 Sun Microsystems, Inc. |
| * |
| * Licensed 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. |
| * |
| */ |
| |
| package org.apache.roller.weblogger.util; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.roller.weblogger.util.cache.Cache; |
| import org.apache.roller.weblogger.util.cache.CacheManager; |
| import org.apache.roller.weblogger.util.cache.ExpiringCacheEntry; |
| |
| |
| /** |
| * A tool used to provide throttling support. |
| * |
| * The basic idea is that if the # of hits from a client within a certain |
| * interval of time is greater than the threshold value then the client is |
| * considered to be abusive. |
| */ |
| public class GenericThrottle { |
| |
| private static Log log = LogFactory.getLog(GenericThrottle.class); |
| |
| // threshold and interval to determine who is abusive |
| private int threshold = 1; |
| private int interval = 0; |
| |
| // a cache to maintain the data |
| Cache clientHistoryCache = null; |
| |
| |
| public GenericThrottle(int thresh, int inter, int maxEntries) { |
| |
| // threshold can't be negative, that would mean everyone is abusive |
| if(thresh > -1) { |
| this.threshold = thresh; |
| } |
| |
| // interval must be a positive value |
| if(inter > 0) { |
| this.interval = inter; |
| } |
| |
| // max entries must be a positive value |
| if(maxEntries < 0) { |
| maxEntries = 1; |
| } |
| |
| // cache props |
| Map<String,String> cacheProps = new HashMap<>(); |
| cacheProps.put("id", "throttle"); |
| cacheProps.put("size", ""+maxEntries); |
| cacheProps.put("timeout", ""+this.interval); |
| |
| // get cache instance. handler is null cuz we don't want to register it |
| this.clientHistoryCache = CacheManager.constructCache(null, cacheProps); |
| } |
| |
| |
| /** |
| * Process a new hit from the client. |
| * |
| * Each call to this method increments the hit count for the client and |
| * then returns a boolean value indicating if the hit has pushed the client |
| * over the threshold. |
| * |
| * @return true if client is abusive, false otherwise |
| */ |
| public boolean processHit(String clientId) { |
| |
| if(clientId == null) { |
| return false; |
| } |
| |
| // see if we have any info about this client yet |
| ClientInfo client = null; |
| ExpiringCacheEntry cacheEntry = (ExpiringCacheEntry) this.clientHistoryCache.get(clientId); |
| if(cacheEntry != null) { |
| log.debug("HIT "+clientId); |
| client = (ClientInfo) cacheEntry.getValue(); |
| |
| // this means entry had expired |
| if(client == null) { |
| log.debug("EXPIRED "+clientId); |
| this.clientHistoryCache.remove(clientId); |
| } |
| } |
| |
| // if we already know this client then update their hit count and |
| // see if they have surpassed the threshold |
| if(client != null) { |
| client.hits++; |
| |
| log.debug("STATUS "+clientId+" - "+client.hits+" hits since "+client.start); |
| |
| // abusive client |
| if(client.hits > this.threshold) { |
| return true; |
| } |
| |
| } else { |
| log.debug("NEW "+clientId); |
| |
| // first timer |
| ClientInfo newClient = new ClientInfo(); |
| newClient.hits = 1; |
| |
| ExpiringCacheEntry newEntry = new ExpiringCacheEntry(newClient, this.interval); |
| this.clientHistoryCache.put(clientId, newEntry); |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Check the current status of a client. |
| * |
| * A client is considered abusive if the number of hits from the client |
| * within the configured interval is greater than the set threshold. |
| * |
| * @return true if client is abusive, false otherwise. |
| */ |
| public boolean isAbusive(String clientId) { |
| |
| if(clientId == null) { |
| return false; |
| } |
| |
| // see if we have any info about this client |
| ClientInfo client = null; |
| ExpiringCacheEntry cacheEntry = (ExpiringCacheEntry) this.clientHistoryCache.get(clientId); |
| if(cacheEntry != null) { |
| log.debug("HIT "+clientId); |
| client = (ClientInfo) cacheEntry.getValue(); |
| |
| // this means entry had expired |
| if (client == null) { |
| log.debug("EXPIRED "+clientId); |
| this.clientHistoryCache.remove(clientId); |
| } |
| } |
| |
| return client != null && client.hits > this.threshold; |
| } |
| |
| |
| // just something to keep a few properties in |
| private class ClientInfo { |
| |
| public int hits = 0; |
| public java.util.Date start = new java.util.Date(); |
| |
| } |
| |
| } |