001package org.apache.turbine.util; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import java.util.Date; 023import java.util.Locale; 024import java.util.TimeZone; 025 026import javax.servlet.http.HttpServletResponse; 027 028import org.apache.commons.lang3.time.FastDateFormat; 029import org.apache.turbine.Turbine; 030import org.apache.turbine.pipeline.PipelineData; 031 032/** 033 * This class provides utilities for handling some semi-trivial HTTP stuff that 034 * would otherwise be handled elsewhere. 035 * 036 * @author <a href="mailto:magnus@handpoint.com">Magnús Þór Torfason</a> 037 * @version $Id$ 038 */ 039public class HttpUtils 040{ 041 /** 042 * The date format to use for HTTP Dates. 043 */ 044 private static FastDateFormat httpDateFormat = FastDateFormat.getInstance( 045 "EEE, dd MMM yyyy HH:mm:ss z", 046 TimeZone.getTimeZone("GMT"), 047 Locale.US); 048 049 /** 050 * Formats a java Date according to rfc 1123, the rfc standard for dates in 051 * http. 052 * 053 * @param date The Date to format 054 * @return A String representation of the date 055 */ 056 public static String formatHttpDate(Date date) 057 { 058 return httpDateFormat.format(date); 059 } 060 061 /** 062 * This method sets the required expiration headers in the response for a 063 * given {@link PipelineData} object. This method attempts to set all relevant headers, 064 * both for HTTP 1.0 and HTTP 1.1. 065 * 066 * @param pipelineData The {@link PipelineData} object we are setting cache information for. 067 * @param expiry The number of milliseconds until the document should expire, 068 * <code>0</code> indicating immediate expiration (i.e. no caching). 069 */ 070 public static void setCacheHeaders(PipelineData pipelineData, int expiry) 071 { 072 HttpServletResponse response = pipelineData.get(Turbine.class, HttpServletResponse.class); 073 074 if (0 == expiry) 075 { 076 response.setHeader("Pragma", "no-cache"); 077 response.setHeader("Cache-Control", "no-cache"); 078 response.setDateHeader("Expires", System.currentTimeMillis()); 079 } 080 else 081 { 082 response.setDateHeader("Expires", System.currentTimeMillis() + expiry); 083 } 084 } 085}