/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.localserver;

import org.apache.commons.codec.BinaryDecoder;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Base64;
import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.ProtocolException;
import org.apache.http.auth.AUTH;
import org.apache.http.util.EncodingUtils;

public class BasicAuthTokenExtractor
{

	public String extract( final HttpRequest request ) throws HttpException
	{
		String auth = null;

		Header h = request.getFirstHeader( AUTH.WWW_AUTH_RESP );
		if( h != null )
		{
			String s = h.getValue();
			if( s != null )
			{
				auth = s.trim();
			}
		}

		if( auth != null )
		{
			int i = auth.indexOf( ' ' );
			if( i == -1 )
			{
				throw new ProtocolException( "Invalid Authorization header: " + auth );
			}
			String authscheme = auth.substring( 0, i );
			if( authscheme.equalsIgnoreCase( "basic" ) )
			{
				String s = auth.substring( i + 1 ).trim();
				try
				{
					byte[] credsRaw = EncodingUtils.getAsciiBytes( s );
					BinaryDecoder codec = new Base64();
					auth = EncodingUtils.getAsciiString( codec.decode( credsRaw ) );
				}
				catch( DecoderException ex )
				{
					throw new ProtocolException( "Malformed BASIC credentials" );
				}
			}
		}
		return auth;
	}

}
