/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * Licensed 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.
 */

package org.springframework.security.context.httpinvoker;

import org.springframework.security.Authentication;
import org.springframework.security.AuthenticationCredentialsNotFoundException;

import org.springframework.security.context.SecurityContextHolder;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.remoting.httpinvoker.SimpleHttpInvokerRequestExecutor;

import java.io.IOException;

import java.net.HttpURLConnection;


/**
 * Adds BASIC authentication support to <code>SimpleHttpInvokerRequestExecutor</code>.
 *
 * @author Ben Alex
 * @version $Id$
 */
public class AuthenticationSimpleHttpInvokerRequestExecutor extends SimpleHttpInvokerRequestExecutor {
    //~ Static fields/initializers =====================================================================================

    private static final Log logger = LogFactory.getLog(AuthenticationSimpleHttpInvokerRequestExecutor.class);

    //~ Methods ========================================================================================================

    /**
     * Provided so subclasses can perform additional configuration if required (eg set additional request
     * headers for non-security related information etc).
     *
     * @param con the HTTP connection to prepare
     * @param contentLength the length of the content to send
     *
     * @throws IOException if thrown by HttpURLConnection methods
     */
    protected void doPrepareConnection(HttpURLConnection con, int contentLength)
        throws IOException {}

    /**
     * Called every time a HTTP invocation is made.<p>Simply allows the parent to setup the connection, and
     * then adds an <code>Authorization</code> HTTP header property that will be used for BASIC authentication.</p>
     *  <p>The <code>SecurityContextHolder</code> is used to obtain the relevant principal and credentials.</p>
     *
     * @param con the HTTP connection to prepare
     * @param contentLength the length of the content to send
     *
     * @throws IOException if thrown by HttpURLConnection methods
     * @throws AuthenticationCredentialsNotFoundException if the <code>SecurityContextHolder</code> does not contain a
     *         valid <code>Authentication</code> with both its <code>principal</code> and <code>credentials</code> not
     *         <code>null</code>
     */
    protected void prepareConnection(HttpURLConnection con, int contentLength)
        throws IOException, AuthenticationCredentialsNotFoundException {
        super.prepareConnection(con, contentLength);

        Authentication auth = SecurityContextHolder.getContext().getAuthentication();

        if ((auth != null) && (auth.getName() != null) && (auth.getCredentials() != null)) {
            String base64 = auth.getName() + ":" + auth.getCredentials().toString();
            con.setRequestProperty("Authorization", "Basic " + new String(Base64.encodeBase64(base64.getBytes())));

            if (logger.isDebugEnabled()) {
                logger.debug("HttpInvocation now presenting via BASIC authentication SecurityContextHolder-derived: "
                    + auth.toString());
            }
        } else {
            if (logger.isDebugEnabled()) {
                logger.debug("Unable to set BASIC authentication header as SecurityContext did not provide "
                        + "valid Authentication: " + auth);
            }
        }

        doPrepareConnection(con, contentLength);
    }
}
