michael@0: /*
michael@0:  * ====================================================================
michael@0:  *
michael@0:  *  Licensed to the Apache Software Foundation (ASF) under one or more
michael@0:  *  contributor license agreements.  See the NOTICE file distributed with
michael@0:  *  this work for additional information regarding copyright ownership.
michael@0:  *  The ASF licenses this file to You under the Apache License, Version 2.0
michael@0:  *  (the "License"); you may not use this file except in compliance with
michael@0:  *  the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *      http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  *  Unless required by applicable law or agreed to in writing, software
michael@0:  *  distributed under the License is distributed on an "AS IS" BASIS,
michael@0:  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
michael@0:  *  See the License for the specific language governing permissions and
michael@0:  *  limitations under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib.impl.auth;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.annotation.NotThreadSafe;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.FormattedHeader;
michael@0: import ch.boye.httpclientandroidlib.Header;
michael@0: import ch.boye.httpclientandroidlib.HttpRequest;
michael@0: import ch.boye.httpclientandroidlib.auth.AUTH;
michael@0: import ch.boye.httpclientandroidlib.auth.AuthenticationException;
michael@0: import ch.boye.httpclientandroidlib.auth.ContextAwareAuthScheme;
michael@0: import ch.boye.httpclientandroidlib.auth.Credentials;
michael@0: import ch.boye.httpclientandroidlib.auth.MalformedChallengeException;
michael@0: import ch.boye.httpclientandroidlib.protocol.HTTP;
michael@0: import ch.boye.httpclientandroidlib.protocol.HttpContext;
michael@0: import ch.boye.httpclientandroidlib.util.CharArrayBuffer;
michael@0: 
michael@0: /**
michael@0:  * Abstract authentication scheme class that serves as a basis
michael@0:  * for all authentication schemes supported by HttpClient. This class
michael@0:  * defines the generic way of parsing an authentication challenge. It
michael@0:  * does not make any assumptions regarding the format of the challenge
michael@0:  * nor does it impose any specific way of responding to that challenge.
michael@0:  *
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: @NotThreadSafe // proxy
michael@0: public abstract class AuthSchemeBase implements ContextAwareAuthScheme {
michael@0: 
michael@0:     /**
michael@0:      * Flag whether authenticating against a proxy.
michael@0:      */
michael@0:     private boolean proxy;
michael@0: 
michael@0:     public AuthSchemeBase() {
michael@0:         super();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Processes the given challenge token. Some authentication schemes
michael@0:      * may involve multiple challenge-response exchanges. Such schemes must be able
michael@0:      * to maintain the state information when dealing with sequential challenges
michael@0:      *
michael@0:      * @param header the challenge header
michael@0:      *
michael@0:      * @throws MalformedChallengeException is thrown if the authentication challenge
michael@0:      * is malformed
michael@0:      */
michael@0:     public void processChallenge(final Header header) throws MalformedChallengeException {
michael@0:         if (header == null) {
michael@0:             throw new IllegalArgumentException("Header may not be null");
michael@0:         }
michael@0:         String authheader = header.getName();
michael@0:         if (authheader.equalsIgnoreCase(AUTH.WWW_AUTH)) {
michael@0:             this.proxy = false;
michael@0:         } else if (authheader.equalsIgnoreCase(AUTH.PROXY_AUTH)) {
michael@0:             this.proxy = true;
michael@0:         } else {
michael@0:             throw new MalformedChallengeException("Unexpected header name: " + authheader);
michael@0:         }
michael@0: 
michael@0:         CharArrayBuffer buffer;
michael@0:         int pos;
michael@0:         if (header instanceof FormattedHeader) {
michael@0:             buffer = ((FormattedHeader) header).getBuffer();
michael@0:             pos = ((FormattedHeader) header).getValuePos();
michael@0:         } else {
michael@0:             String s = header.getValue();
michael@0:             if (s == null) {
michael@0:                 throw new MalformedChallengeException("Header value is null");
michael@0:             }
michael@0:             buffer = new CharArrayBuffer(s.length());
michael@0:             buffer.append(s);
michael@0:             pos = 0;
michael@0:         }
michael@0:         while (pos < buffer.length() && HTTP.isWhitespace(buffer.charAt(pos))) {
michael@0:             pos++;
michael@0:         }
michael@0:         int beginIndex = pos;
michael@0:         while (pos < buffer.length() && !HTTP.isWhitespace(buffer.charAt(pos))) {
michael@0:             pos++;
michael@0:         }
michael@0:         int endIndex = pos;
michael@0:         String s = buffer.substring(beginIndex, endIndex);
michael@0:         if (!s.equalsIgnoreCase(getSchemeName())) {
michael@0:             throw new MalformedChallengeException("Invalid scheme identifier: " + s);
michael@0:         }
michael@0: 
michael@0:         parseChallenge(buffer, pos, buffer.length());
michael@0:     }
michael@0: 
michael@0: 
michael@0:     @SuppressWarnings("deprecation")
michael@0:     public Header authenticate(
michael@0:             final Credentials credentials,
michael@0:             final HttpRequest request,
michael@0:             final HttpContext context) throws AuthenticationException {
michael@0:         return authenticate(credentials, request);
michael@0:     }
michael@0: 
michael@0:     protected abstract void parseChallenge(
michael@0:             CharArrayBuffer buffer, int beginIndex, int endIndex) throws MalformedChallengeException;
michael@0: 
michael@0:     /**
michael@0:      * Returns <code>true</code> if authenticating against a proxy, <code>false</code>
michael@0:      * otherwise.
michael@0:      *
michael@0:      * @return <code>true</code> if authenticating against a proxy, <code>false</code>
michael@0:      * otherwise
michael@0:      */
michael@0:     public boolean isProxy() {
michael@0:         return this.proxy;
michael@0:     }
michael@0: 
michael@0:     @Override
michael@0:     public String toString() {
michael@0:         return getSchemeName();
michael@0:     }
michael@0: 
michael@0: }