edu.indiana.lib.twinpeaks.net.HttpAuthenticator.java Source code

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Here is the source code for edu.indiana.lib.twinpeaks.net.HttpAuthenticator.java

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/**********************************************************************************
*
 * Copyright (c) 2003, 2004, 2007, 2008 The Sakai Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ECL-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 edu.indiana.lib.twinpeaks.net;

import edu.indiana.lib.twinpeaks.util.*;

import java.io.*;
import java.net.*;
import java.util.*;

/**
 * Handle network authentication.
 *<p>
 * When we try to access a protected site,
 * <code>getPasswordAuthentication()</code> is called by the network
 * connection code (<code>HttpURLConnection</code> in our case) to obtain
 * any credentials (username and password) required to access the site.
 *<p>
 * Note:
 * This only occurs until we successfully "log in" - after that, we are
 * not invoked again for the site in question.
 */
public class HttpAuthenticator extends java.net.Authenticator {

    private static org.apache.commons.logging.Log _log = LogUtils.getLog(HttpAuthenticator.class);

    private HashMap credentialMap = new HashMap();

    /**
     * Establish realm login credentials
     * @param realm Realm for authentication (<code>ADS</code>)
     * @param username User for login
     * @param password Password
     */
    public synchronized void setCredentials(String realm, String username, String password) {
        credentialMap.put(realm, new Credentials(username, password));
    }

    /**
     * Override the default implementation to provide the credentials required
     * for our network authentication
     */
    protected synchronized PasswordAuthentication getPasswordAuthentication() {
        Credentials credential;
        int attempts;

        _log.debug("Authorization requested for \"" + getRequestingPrompt() + "\", scheme: \""
                + getRequestingScheme() + "\", site: \"" + getRequestingSite() + "\"");

        credential = (Credentials) credentialMap.get(getRequestingPrompt());
        if (credential == null) {
            _log.warn("No credentials configured");
            return null;
        }

        /*
         * If the login has been rejected once, quit now.  This avoids a
         * "redirect loop" with the server.  Reset the counter every few
         * attempts to allow an an occasional authorization "retry".
         */
        attempts = credential.getAuthorizationAttempts() + 1;
        credential.setAuthorizationAttempts(attempts);

        if (attempts > 1) {
            if ((attempts % 3) == 0) {
                credential.setAuthorizationAttempts(0);
            }
            _log.warn("Authorization refused");
            return null;
        }
        _log.warn("Returning credentials for authorization");
        return new PasswordAuthentication(credential.getUsername(), credential.getPassword());
    }

    /**
     * Store authentication information
     */
    private static class Credentials {
        private String username;
        private char[] password;
        private int attempts;

        private Credentials() {
        }

        /**
         * Constructor
         * @param username This user
         * @param password And password
         */
        public Credentials(String username, String password) {
            this.username = username;
            this.password = password.toCharArray();
            this.attempts = 0;
        }

        /**
         * Get this username
         * @return The username
         */
        public String getUsername() {
            return username;
        }

        /**
         * Get the password for this user
         * @return The password
         */
        public char[] getPassword() {
            return password;
        }

        /**
         * Set the number of attempted logins for this user
         * @param value The number of attempted logins
         */
        public synchronized void setAuthorizationAttempts(int value) {
            attempts = value;
        }

        /**
         * Get the number of attempted logins for this user
         * @return The number of attempted logins
         */
        public synchronized int getAuthorizationAttempts() {
            return attempts;
        }
    }
}