View Javadoc
1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.directory.api.ldap.codec.api;
21  
22  
23  import java.io.InputStream;
24  import java.nio.ByteBuffer;
25  
26  import org.apache.directory.api.asn1.DecoderException;
27  import org.apache.directory.api.asn1.ber.Asn1Decoder;
28  import org.apache.directory.api.asn1.ber.tlv.TLVStateEnum;
29  import org.apache.directory.api.i18n.I18n;
30  import org.apache.directory.api.ldap.model.message.Message;
31  import org.slf4j.Logger;
32  import org.slf4j.LoggerFactory;
33  
34  
35  /**
36   * The LdapDecoder decodes ASN.1 BER encoded PDUs into LDAP messages
37   *
38   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
39   */
40  public class LdapDecoder
41  {
42      /** The logger */
43      private static final Logger LOG = LoggerFactory.getLogger( LdapDecoder.class );
44  
45      /** A speedup for logger */
46      private static final boolean IS_DEBUG = LOG.isDebugEnabled();
47  
48      /** The ASN 1 decoder instance */
49      private Asn1Decoder asn1Decoder;
50  
51      /** The name of the LdapSession's attribute for the LDAP container used during the decoding */
52      public static final String MESSAGE_CONTAINER_ATTR = "LDAP-container";
53  
54      /** The maximum PDU size, stored into the LDAPSession's attribute */
55      public static final String MAX_PDU_SIZE_ATTR = "LDAP-maxPduSize";
56  
57  
58      /**
59       * Creates an instance of a Ldap Decoder implementation.
60       */
61      public LdapDecoder()
62      {
63          asn1Decoder = new Asn1Decoder();
64      }
65  
66  
67      /**
68       * Decodes a PDU from an input stream into a Ldap message container. We can only
69       * decode one complete message.
70       *
71       * @param in The input stream to read and decode PDU bytes from
72       * @param container The LdapMessageContainer containing the message to decode
73       * @return return The decoded message
74       * @throws DecoderException If the decoding failed
75       */
76      public Message decode( InputStream in, LdapMessageContainer<MessageDecorator<? extends Message>> container )
77          throws DecoderException
78      {
79          try
80          {
81              int amount;
82  
83              while ( in.available() > 0 )
84              {
85                  byte[] buf = new byte[in.available()];
86  
87                  amount = in.read( buf );
88                  if ( amount == -1 )
89                  {
90                      break;
91                  }
92  
93                  asn1Decoder.decode( ByteBuffer.wrap( buf, 0, amount ), container );
94              }
95          }
96          catch ( Exception e )
97          {
98              String message = I18n.err( I18n.ERR_04060, e.getLocalizedMessage() );
99              LOG.error( message );
100             throw new DecoderException( message, e );
101         }
102 
103         if ( container.getState() == TLVStateEnum.PDU_DECODED )
104         {
105             if ( IS_DEBUG )
106             {
107                 LOG.debug( "Decoded LdapMessage : " + container );
108             }
109 
110             return container.getMessage();
111         }
112         else
113         {
114             LOG.error( I18n.err( I18n.ERR_04062 ) );
115             throw new DecoderException( I18n.err( I18n.ERR_04063 ) );
116         }
117     }
118 }