001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.shiro.web.filter.authc;
020
021import org.apache.shiro.web.filter.PathMatchingFilter;
022
023import javax.servlet.ServletRequest;
024import javax.servlet.ServletResponse;
025
026/**
027 * Filter that allows access to a path immeidately without performing security checks of any kind.
028 * <p/>
029 * This filter is useful primarily in exclusionary policies, where you have defined a url pattern
030 * to require a certain security level, but maybe only subset of urls in that pattern should allow any access.
031 * <p/>
032 * For example, if you had a user-only section of a website, you might want to require that access to
033 * any url in that section must be from an authenticated user.
034 * <p/>
035 * Here is how that would look in the IniShiroFilter configuration:
036 * <p/>
037 * <code>[urls]<br/>
038 * /user/** = authc</code>
039 * <p/>
040 * But if you wanted <code>/user/signup/**</code> to be available to anyone, you have to exclude that path since
041 * it is a subset of the first.  This is where the AnonymousFilter ('anon') is useful:
042 * <p/>
043 * <code>[urls]<br/>
044 * /user/signup/** = anon<br/>
045 * /user/** = authc</code>>
046 * <p/>
047 * Since the url pattern definitions follow a 'first match wins' paradigm, the <code>anon</code> filter will
048 * match the <code>/user/signup/**</code> paths and the <code>/user/**</code> path chain will not be evaluated.
049 *
050 * @since 0.9
051 */
052public class AnonymousFilter extends PathMatchingFilter {
053
054    /**
055     * Always returns <code>true</code> allowing unchecked access to the underlying path or resource.
056     *
057     * @return <code>true</code> always, allowing unchecked access to the underlying path or resource.
058     */
059    @Override
060    protected boolean onPreHandle(ServletRequest request, ServletResponse response, Object mappedValue) {
061        // Always return true since we allow access to anyone
062        return true;
063    }
064
065}