merged 1.1 branch into head

[mir.git] / source / mircoders / abuse / ThrottleFilter.java

diff --git a/source/mircoders/abuse/ThrottleFilter.java b/source/mircoders/abuse/ThrottleFilter.java
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+/*
+ * Copyright (C) 2001, 2002 The Mir-coders group
+ *
+ * This file is part of Mir.
+ *
+ * Mir 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Mir 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 Mir; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * In addition, as a special exception, The Mir-coders gives permission to link
+ * the code of this program with  any library licensed under the Apache Software License,
+ * The Sun (tm) Java Advanced Imaging library (JAI), The Sun JIMI library
+ * (or with modified versions of the above that use the same license as the above),
+ * and distribute linked combinations including the two.  You must obey the
+ * GNU General Public License in all respects for all of the code used other than
+ * the above mentioned libraries.  If you modify this file, you may extend this
+ * exception to your version of the file, but you are not obligated to do so.
+ * If you do not wish to do so, delete this exception statement from your version.
+ */
+package mircoders.abuse;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import mir.entity.Entity;
+import mir.session.Request;
+import mir.util.StringRoutines;
+
+/**
+ * A ip-based throttling filter.
+ *
+ * <p>
+ * Expressions have the form <time in minutes>:<posting limit>
+ */
+public class ThrottleFilter extends AbstractFilterType {
+
+  public ThrottleFilter(String aName) {
+    super(aName);
+  }
+
+  public FilterInstance constructFilterInstance(String anExpression) throws AbuseExc {
+    List parts = StringRoutines.splitString(anExpression.trim(), ":");
+
+    if (parts.size()==2) {
+      try {
+        final int interval = Integer.parseInt((String) parts.get(0));
+        final int limit = Integer.parseInt((String) parts.get(1));
+
+        if (interval<1) {
+          throw new AbuseExc("Interval should be larger than 0");
+        }
+        if (limit<1) {
+          throw new AbuseExc("Limit should be larger than 0");
+        }
+        final ThrottleManager manager = new ThrottleManager(interval*1000*60);
+
+        return new FilterInstance() {
+          public boolean test(Entity anEntity, Request aRequest) {
+            manager.addMessage(aRequest.getHeader("ip"));
+            if (manager.count(aRequest.getHeader("ip")) > limit) {
+              return true;
+            }
+
+            return false;
+          }
+
+          public String status() {
+            return Integer.toString(manager.messages.size()) + " messages";
+          }
+        };
+      }
+      catch (AbuseExc e) {
+        throw e;
+      }
+      catch (Throwable t) {
+        throw new AbuseExc("Invalid expression: <interval>:<limit> expected");
+      }
+    }
+               throw new AbuseExc("Invalid expression: <interval>:<limit> expected");
+  }
+
+  private class ThrottleManager {
+    private long horizon;
+    private List messages;
+
+    public ThrottleManager(long aHorizon) {
+      horizon = aHorizon;
+
+      messages = new ArrayList();
+    }
+
+    public void flush() {
+      long limit = System.currentTimeMillis() - horizon;
+
+      while (messages.size()>0 && ((Message) messages.get(0)).getTime()<=limit) {
+        messages.remove(0);
+      }
+    }
+
+    public void addMessage(String anIp) {
+      Message newMessage = new Message(anIp, System.currentTimeMillis());
+      messages.add(newMessage);
+    }
+
+    public int count(String anIp) {
+      flush();
+
+      int result = 0;
+      Iterator i = messages.iterator();
+      while (i.hasNext()) {
+        Message message = (Message) i.next();
+        if (message.getIp().equals(anIp)) {
+          result = result + 1;
+        }
+      }
+
+      return result;
+    }
+
+    private class Message {
+      private String ip;
+      private long time;
+
+      public Message(String anIp, long aTime) {
+        ip = anIp;
+        time = aTime;
+      }
+
+      public String getIp() {
+        return ip;
+      }
+
+      public long getTime() {
+        return time;
+      }
+    }
+  }
+}