diff -r 6ae5e4f8329b -r c404a87db5b7 src/org/sonews/daemon/command/XPatCommand.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/sonews/daemon/command/XPatCommand.java	Sun Aug 29 17:43:58 2010 +0200
@@ -0,0 +1,170 @@
+/*
+ *   SONEWS News Server
+ *   see AUTHORS for the list of contributors
+ *
+ *   This program 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.
+ *
+ *   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sonews.daemon.command;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Locale;
+import java.util.regex.PatternSyntaxException;
+import org.sonews.daemon.NNTPConnection;
+import org.sonews.storage.StorageBackendException;
+import org.sonews.storage.StorageManager;
+import org.sonews.util.Pair;
+
+/**
+ * <pre>
+ *   XPAT header range|<message-id> pat [pat...]
+ *
+ *   The XPAT command is used to retrieve specific headers from
+ *   specific articles, based on pattern matching on the contents of
+ *   the header. This command was first available in INN.
+ *
+ *   The required header parameter is the name of a header line (e.g.
+ *   "subject") in a news group article. See RFC-1036 for a list
+ *   of valid header lines. The required range argument may be
+ *   any of the following:
+ *               an article number
+ *               an article number followed by a dash to indicate
+ *                  all following
+ *               an article number followed by a dash followed by
+ *                  another article number
+ *
+ *   The required message-id argument indicates a specific
+ *   article. The range and message-id arguments are mutually
+ *   exclusive. At least one pattern in wildmat must be specified
+ *   as well. If there are additional arguments the are joined
+ *   together separated by a single space to form one complete
+ *   pattern. Successful responses start with a 221 response
+ *   followed by a the headers from all messages in which the
+ *   pattern matched the contents of the specified header line. This
+ *   includes an empty list. Once the output is complete, a period
+ *   is sent on a line by itself. If the optional argument is a
+ *   message-id and no such article exists, the 430 error response
+ *   is returned. A 502 response will be returned if the client only
+ *   has permission to transfer articles.
+ *
+ *   Responses
+ *
+ *       221 Header follows
+ *       430 no such article
+ *       502 no permission
+ *
+ *   Response Data:
+ *
+ *       art_nr fitting_header_value
+ * 
+ * </pre>
+ * [Source:"draft-ietf-nntp-imp-02.txt"] [Copyright: 1998 S. Barber]
+ * 
+ * @author Christian Lins
+ * @since sonews/0.5.0
+ */
+public class XPatCommand implements Command
+{
+
+  @Override
+  public String[] getSupportedCommandStrings()
+  {
+    return new String[]{"XPAT"};
+  }
+  
+  @Override
+  public boolean hasFinished()
+  {
+    return true;
+  }
+
+  @Override
+  public String impliedCapability()
+  {
+    return null;
+  }
+
+  @Override
+  public boolean isStateful()
+  {
+    return false;
+  }
+
+  @Override
+  public void processLine(NNTPConnection conn, final String line, byte[] raw)
+    throws IOException, StorageBackendException
+  {
+    if(conn.getCurrentChannel() == null)
+    {
+      conn.println("430 no group selected");
+      return;
+    }
+
+    String[] command = line.split("\\p{Space}+");
+
+    // There may be multiple patterns and Thunderbird produces
+    // additional spaces between range and pattern
+    if(command.length >= 4)
+    {
+      String header  = command[1].toLowerCase(Locale.US);
+      String range   = command[2];
+      String pattern = command[3];
+
+      long start = -1;
+      long end   = -1;
+      if(range.contains("-"))
+      {
+        String[] rsplit = range.split("-", 2);
+        start = Long.parseLong(rsplit[0]);
+        if(rsplit[1].length() > 0)
+        {
+          end = Long.parseLong(rsplit[1]);
+        }
+      }
+      else // TODO: Handle Message-IDs
+      {
+        start = Long.parseLong(range);
+      }
+
+      try
+      {
+        List<Pair<Long, String>> heads = StorageManager.current().
+          getArticleHeaders(conn.getCurrentChannel(), start, end, header, pattern);
+        
+        conn.println("221 header follows");
+        for(Pair<Long, String> head : heads)
+        {
+          conn.println(head.getA() + " " + head.getB());
+        }
+        conn.println(".");
+      }
+      catch(PatternSyntaxException ex)
+      {
+        ex.printStackTrace();
+        conn.println("500 invalid pattern syntax");
+      }
+      catch(StorageBackendException ex)
+      {
+        ex.printStackTrace();
+        conn.println("500 internal server error");
+      }
+    }
+    else
+    {
+      conn.println("430 invalid command usage");
+    }
+  }
+
+}