michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with 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,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * 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.client;
michael@0: 
michael@0: import java.util.Arrays;
michael@0: import java.util.Collection;
michael@0: import java.util.Collections;
michael@0: import java.util.HashMap;
michael@0: import java.util.List;
michael@0: import java.util.Locale;
michael@0: import java.util.Map;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.androidextra.HttpClientAndroidLog;
michael@0: /* LogFactory removed by HttpClient for Android script. */
michael@0: import ch.boye.httpclientandroidlib.FormattedHeader;
michael@0: import ch.boye.httpclientandroidlib.Header;
michael@0: import ch.boye.httpclientandroidlib.HttpResponse;
michael@0: import ch.boye.httpclientandroidlib.annotation.Immutable;
michael@0: import ch.boye.httpclientandroidlib.auth.AuthScheme;
michael@0: import ch.boye.httpclientandroidlib.auth.AuthSchemeRegistry;
michael@0: import ch.boye.httpclientandroidlib.auth.AuthenticationException;
michael@0: import ch.boye.httpclientandroidlib.auth.MalformedChallengeException;
michael@0: import ch.boye.httpclientandroidlib.client.AuthenticationHandler;
michael@0: import ch.boye.httpclientandroidlib.client.params.AuthPolicy;
michael@0: import ch.boye.httpclientandroidlib.client.protocol.ClientContext;
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:  * Base class for {@link AuthenticationHandler} implementations.
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: @Immutable
michael@0: public abstract class AbstractAuthenticationHandler implements AuthenticationHandler {
michael@0: 
michael@0:     public HttpClientAndroidLog log = new HttpClientAndroidLog(getClass());
michael@0: 
michael@0:     private static final List<String> DEFAULT_SCHEME_PRIORITY =
michael@0:         Collections.unmodifiableList(Arrays.asList(new String[] {
michael@0:                 AuthPolicy.SPNEGO,
michael@0:                 AuthPolicy.NTLM,
michael@0:                 AuthPolicy.DIGEST,
michael@0:                 AuthPolicy.BASIC
michael@0:     }));
michael@0: 
michael@0:     public AbstractAuthenticationHandler() {
michael@0:         super();
michael@0:     }
michael@0: 
michael@0:     protected Map<String, Header> parseChallenges(
michael@0:             final Header[] headers) throws MalformedChallengeException {
michael@0: 
michael@0:         Map<String, Header> map = new HashMap<String, Header>(headers.length);
michael@0:         for (Header header : headers) {
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:             map.put(s.toLowerCase(Locale.ENGLISH), header);
michael@0:         }
michael@0:         return map;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns default list of auth scheme names in their order of preference.
michael@0:      *
michael@0:      * @return list of auth scheme names
michael@0:      */
michael@0:     protected List<String> getAuthPreferences() {
michael@0:         return DEFAULT_SCHEME_PRIORITY;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns default list of auth scheme names in their order of preference
michael@0:      * based on the HTTP response and the current execution context.
michael@0:      *
michael@0:      * @param response HTTP response.
michael@0:      * @param context HTTP execution context.
michael@0:      *
michael@0:      * @since 4.1
michael@0:      */
michael@0:     protected List<String> getAuthPreferences(
michael@0:             final HttpResponse response,
michael@0:             final HttpContext context) {
michael@0:         return getAuthPreferences();
michael@0:     }
michael@0: 
michael@0:     public AuthScheme selectScheme(
michael@0:             final Map<String, Header> challenges,
michael@0:             final HttpResponse response,
michael@0:             final HttpContext context) throws AuthenticationException {
michael@0: 
michael@0:         AuthSchemeRegistry registry = (AuthSchemeRegistry) context.getAttribute(
michael@0:                 ClientContext.AUTHSCHEME_REGISTRY);
michael@0:         if (registry == null) {
michael@0:             throw new IllegalStateException("AuthScheme registry not set in HTTP context");
michael@0:         }
michael@0: 
michael@0:         Collection<String> authPrefs = getAuthPreferences(response, context);
michael@0:         if (authPrefs == null) {
michael@0:             authPrefs = DEFAULT_SCHEME_PRIORITY;
michael@0:         }
michael@0: 
michael@0:         if (this.log.isDebugEnabled()) {
michael@0:             this.log.debug("Authentication schemes in the order of preference: "
michael@0:                 + authPrefs);
michael@0:         }
michael@0: 
michael@0:         AuthScheme authScheme = null;
michael@0:         for (String id: authPrefs) {
michael@0:             Header challenge = challenges.get(id.toLowerCase(Locale.ENGLISH));
michael@0: 
michael@0:             if (challenge != null) {
michael@0:                 if (this.log.isDebugEnabled()) {
michael@0:                     this.log.debug(id + " authentication scheme selected");
michael@0:                 }
michael@0:                 try {
michael@0:                     authScheme = registry.getAuthScheme(id, response.getParams());
michael@0:                     break;
michael@0:                 } catch (IllegalStateException e) {
michael@0:                     if (this.log.isWarnEnabled()) {
michael@0:                         this.log.warn("Authentication scheme " + id + " not supported");
michael@0:                         // Try again
michael@0:                     }
michael@0:                 }
michael@0:             } else {
michael@0:                 if (this.log.isDebugEnabled()) {
michael@0:                     this.log.debug("Challenge for " + id + " authentication scheme not available");
michael@0:                     // Try again
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0:         if (authScheme == null) {
michael@0:             // If none selected, something is wrong
michael@0:             throw new AuthenticationException(
michael@0:                 "Unable to respond to any of these challenges: "
michael@0:                     + challenges);
michael@0:         }
michael@0:         return authScheme;
michael@0:     }
michael@0: 
michael@0: }