001/*
002 * Copyright 2002-2019 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.servlet.resource;
018
019import javax.servlet.http.HttpServletRequest;
020import javax.servlet.http.HttpServletResponse;
021
022import org.springframework.util.Assert;
023import org.springframework.web.bind.ServletRequestBindingException;
024import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
025
026/**
027 * An interceptor that exposes the {@link ResourceUrlProvider} instance it
028 * is configured with as a request attribute.
029 *
030 * @author Rossen Stoyanchev
031 * @since 4.1
032 */
033public class ResourceUrlProviderExposingInterceptor extends HandlerInterceptorAdapter {
034
035        /**
036         * Name of the request attribute that holds the {@link ResourceUrlProvider}.
037         */
038        public static final String RESOURCE_URL_PROVIDER_ATTR = ResourceUrlProvider.class.getName();
039
040        private final ResourceUrlProvider resourceUrlProvider;
041
042
043        public ResourceUrlProviderExposingInterceptor(ResourceUrlProvider resourceUrlProvider) {
044                Assert.notNull(resourceUrlProvider, "ResourceUrlProvider is required");
045                this.resourceUrlProvider = resourceUrlProvider;
046        }
047
048        @Override
049        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
050                        throws Exception {
051
052                try {
053                        request.setAttribute(RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
054                }
055                catch (ResourceUrlEncodingFilter.LookupPathIndexException ex) {
056                        throw new ServletRequestBindingException(ex.getMessage(), ex);
057                }
058                return true;
059        }
060
061}