src/org/jsecurity/web/filter/authc/PassThruAuthenticationFilter.java

/*
 * 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.
 */
package org.jsecurity.web.filter.authc;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * An authentication filter that redirects the user to the login page when they are trying to access
 * a protected resource.  However, if the user is trying to access the login page, the filter lets
 * the request pass through to the application code.
 * <p/>
 * The difference between this filter and the {@link FormAuthenticationFilter FormAuthenticationFilter} is that
 * on a login submission (by default an HTTP POST to the login URL), the <code>FormAuthenticationFilter</code> filter
 * attempts to automatically authenticate the user by passing the <code>username</code> and <code>password</code>
 * request parameter values to
 * {@link org.jsecurity.subject.Subject#login(org.jsecurity.authc.AuthenticationToken) Subject.login(usernamePasswordToken)}
 * directly.
 * <p/>
 * Conversely, this controller always passes all requests to the {@link #setLoginUrl loginUrl} through, both GETs and
 * POSTs.  This is useful in cases where the developer wants to write their own login behavior, which should include a
 * call to {@link org.jsecurity.subject.Subject#login(org.jsecurity.authc.AuthenticationToken) Subject.login(AuthenticationToken)}
 * at some point.  For example,  if the developer has their own custom MVC login controller or validator,
 * this <code>PassThruAuthenticationFilter</code> may be appropriate.
 *
 * @author Jeremy Haile
 * @see FormAuthenticationFilter
 * @since 0.9
 */
public class PassThruAuthenticationFilter extends AuthenticationFilter {

    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        if (isLoginRequest(request, response)) {
            return true;
        } else {
            saveRequestAndRedirectToLogin(request, response);
            return false;
        }
    }

}