Home | History | Annotate | Download | only in auth 
      1 /*
      2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/impl/auth/AuthSchemeBase.java $
      3  * $Revision: 653867 $
      4  * $Date: 2008-05-06 11:17:29 -0700 (Tue, 06 May 2008) $
      5  *
      6  * ====================================================================
      7  *
      8  *  Licensed to the Apache Software Foundation (ASF) under one or more
      9  *  contributor license agreements.  See the NOTICE file distributed with
     10  *  this work for additional information regarding copyright ownership.
     11  *  The ASF licenses this file to You under the Apache License, Version 2.0
     12  *  (the "License"); you may not use this file except in compliance with
     13  *  the License.  You may obtain a copy of the License at
     14  *
     15  *      http://www.apache.org/licenses/LICENSE-2.0
     16  *
     17  *  Unless required by applicable law or agreed to in writing, software
     18  *  distributed under the License is distributed on an "AS IS" BASIS,
     19  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     20  *  See the License for the specific language governing permissions and
     21  *  limitations under the License.
     22  * ====================================================================
     23  *
     24  * This software consists of voluntary contributions made by many
     25  * individuals on behalf of the Apache Software Foundation.  For more
     26  * information on the Apache Software Foundation, please see
     27  * <http://www.apache.org/>.
     28  *
     29  */
     30 
     31 package org.apache.http.impl.auth;
     32 
     33 import org.apache.http.FormattedHeader;
     34 import org.apache.http.Header;
     35 import org.apache.http.auth.AUTH;
     36 import org.apache.http.auth.AuthScheme;
     37 import org.apache.http.auth.MalformedChallengeException;
     38 import org.apache.http.protocol.HTTP;
     39 import org.apache.http.util.CharArrayBuffer;
     40 
     41 /**
     42  * Abstract authentication scheme class that serves as a basis
     43  * for all authentication schemes supported by HttpClient. This class
     44  * defines the generic way of parsing an authentication challenge. It
     45  * does not make any assumptions regarding the format of the challenge
     46  * nor does it impose any specific way of responding to that challenge.
     47  *
     48  * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
     49 */
     50 public abstract class AuthSchemeBase implements AuthScheme {
     51 
     52     /**
     53      * Flag whether authenticating against a proxy.
     54      */
     55     private boolean proxy;
     56 
     57     public AuthSchemeBase() {
     58         super();
     59     }
     60 
     61     /**
     62      * Processes the given challenge token. Some authentication schemes
     63      * may involve multiple challenge-response exchanges. Such schemes must be able
     64      * to maintain the state information when dealing with sequential challenges
     65      *
     66      * @param header the challenge header
     67      *
     68      * @throws MalformedChallengeException is thrown if the authentication challenge
     69      * is malformed
     70      */
     71     public void processChallenge(final Header header) throws MalformedChallengeException {
     72         if (header == null) {
     73             throw new IllegalArgumentException("Header may not be null");
     74         }
     75         String authheader = header.getName();
     76         if (authheader.equalsIgnoreCase(AUTH.WWW_AUTH)) {
     77             this.proxy = false;
     78         } else if (authheader.equalsIgnoreCase(AUTH.PROXY_AUTH)) {
     79             this.proxy = true;
     80         } else {
     81             throw new MalformedChallengeException("Unexpected header name: " + authheader);
     82         }
     83 
     84         CharArrayBuffer buffer;
     85         int pos;
     86         if (header instanceof FormattedHeader) {
     87             buffer = ((FormattedHeader) header).getBuffer();
     88             pos = ((FormattedHeader) header).getValuePos();
     89         } else {
     90             String s = header.getValue();
     91             if (s == null) {
     92                 throw new MalformedChallengeException("Header value is null");
     93             }
     94             buffer = new CharArrayBuffer(s.length());
     95             buffer.append(s);
     96             pos = 0;
     97         }
     98         while (pos < buffer.length() && HTTP.isWhitespace(buffer.charAt(pos))) {
     99             pos++;
    100         }
    101         int beginIndex = pos;
    102         while (pos < buffer.length() && !HTTP.isWhitespace(buffer.charAt(pos))) {
    103             pos++;
    104         }
    105         int endIndex = pos;
    106         String s = buffer.substring(beginIndex, endIndex);
    107         if (!s.equalsIgnoreCase(getSchemeName())) {
    108             throw new MalformedChallengeException("Invalid scheme identifier: " + s);
    109         }
    110 
    111         parseChallenge(buffer, pos, buffer.length());
    112     }
    113 
    114     protected abstract void parseChallenge(
    115             CharArrayBuffer buffer, int pos, int len) throws MalformedChallengeException;
    116 
    117     /**
    118      * Returns <code>true</code> if authenticating against a proxy, <code>false</code>
    119      * otherwise.
    120      *
    121      * @return <code>true</code> if authenticating against a proxy, <code>false</code>
    122      * otherwise
    123      */
    124     public boolean isProxy() {
    125         return this.proxy;
    126     }
    127 
    128 }
    129