001/*
002 * Copyright 2002-2015 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.filter;
018
019import java.io.IOException;
020
021import javax.servlet.FilterChain;
022import javax.servlet.ServletException;
023import javax.servlet.http.HttpServletRequest;
024import javax.servlet.http.HttpServletResponse;
025
026import org.springframework.context.i18n.LocaleContextHolder;
027import org.springframework.web.context.request.RequestContextHolder;
028import org.springframework.web.context.request.ServletRequestAttributes;
029
030/**
031 * Servlet Filter that exposes the request to the current thread,
032 * through both {@link org.springframework.context.i18n.LocaleContextHolder} and
033 * {@link RequestContextHolder}. To be registered as filter in {@code web.xml}.
034 *
035 * <p>Alternatively, Spring's {@link org.springframework.web.context.request.RequestContextListener}
036 * and Spring's {@link org.springframework.web.servlet.DispatcherServlet} also expose
037 * the same request context to the current thread.
038 *
039 * <p>This filter is mainly for use with third-party servlets, e.g. the JSF FacesServlet.
040 * Within Spring's own web support, DispatcherServlet's processing is perfectly sufficient.
041 *
042 * @author Juergen Hoeller
043 * @author Rod Johnson
044 * @author Rossen Stoyanchev
045 * @since 2.0
046 * @see org.springframework.context.i18n.LocaleContextHolder
047 * @see org.springframework.web.context.request.RequestContextHolder
048 * @see org.springframework.web.context.request.RequestContextListener
049 * @see org.springframework.web.servlet.DispatcherServlet
050 */
051public class RequestContextFilter extends OncePerRequestFilter {
052
053        private boolean threadContextInheritable = false;
054
055
056        /**
057         * Set whether to expose the LocaleContext and RequestAttributes as inheritable
058         * for child threads (using an {@link java.lang.InheritableThreadLocal}).
059         * <p>Default is "false", to avoid side effects on spawned background threads.
060         * Switch this to "true" to enable inheritance for custom child threads which
061         * are spawned during request processing and only used for this request
062         * (that is, ending after their initial task, without reuse of the thread).
063         * <p><b>WARNING:</b> Do not use inheritance for child threads if you are
064         * accessing a thread pool which is configured to potentially add new threads
065         * on demand (e.g. a JDK {@link java.util.concurrent.ThreadPoolExecutor}),
066         * since this will expose the inherited context to such a pooled thread.
067         */
068        public void setThreadContextInheritable(boolean threadContextInheritable) {
069                this.threadContextInheritable = threadContextInheritable;
070        }
071
072
073        /**
074         * Returns "false" so that the filter may set up the request context in each
075         * asynchronously dispatched thread.
076         */
077        @Override
078        protected boolean shouldNotFilterAsyncDispatch() {
079                return false;
080        }
081
082        /**
083         * Returns "false" so that the filter may set up the request context in an
084         * error dispatch.
085         */
086        @Override
087        protected boolean shouldNotFilterErrorDispatch() {
088                return false;
089        }
090
091        @Override
092        protected void doFilterInternal(
093                        HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
094                        throws ServletException, IOException {
095
096                ServletRequestAttributes attributes = new ServletRequestAttributes(request, response);
097                initContextHolders(request, attributes);
098
099                try {
100                        filterChain.doFilter(request, response);
101                }
102                finally {
103                        resetContextHolders();
104                        if (logger.isTraceEnabled()) {
105                                logger.trace("Cleared thread-bound request context: " + request);
106                        }
107                        attributes.requestCompleted();
108                }
109        }
110
111        private void initContextHolders(HttpServletRequest request, ServletRequestAttributes requestAttributes) {
112                LocaleContextHolder.setLocale(request.getLocale(), this.threadContextInheritable);
113                RequestContextHolder.setRequestAttributes(requestAttributes, this.threadContextInheritable);
114                if (logger.isTraceEnabled()) {
115                        logger.trace("Bound request context to thread: " + request);
116                }
117        }
118
119        private void resetContextHolders() {
120                LocaleContextHolder.resetLocaleContext();
121                RequestContextHolder.resetRequestAttributes();
122        }
123
124}