1 package org.apache.turbine.util; 2 3 /* 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 */ 21 22 import java.util.Date; 23 import java.util.Locale; 24 import java.util.TimeZone; 25 26 import javax.servlet.http.HttpServletResponse; 27 28 import org.apache.commons.lang3.time.FastDateFormat; 29 import org.apache.turbine.Turbine; 30 import org.apache.turbine.pipeline.PipelineData; 31 32 /** 33 * This class provides utilities for handling some semi-trivial HTTP stuff that 34 * would otherwise be handled elsewhere. 35 * 36 * @author <a href="mailto:magnus@handpoint.com">Magnús Þór Torfason</a> 37 * @version $Id$ 38 */ 39 public class HttpUtils 40 { 41 /** 42 * The date format to use for HTTP Dates. 43 */ 44 private static FastDateFormat httpDateFormat = FastDateFormat.getInstance( 45 "EEE, dd MMM yyyy HH:mm:ss z", 46 TimeZone.getTimeZone("GMT"), 47 Locale.US); 48 49 /** 50 * Formats a java Date according to rfc 1123, the rfc standard for dates in 51 * http. 52 * 53 * @param date The Date to format 54 * @return A String representation of the date 55 */ 56 public static String formatHttpDate(Date date) 57 { 58 return httpDateFormat.format(date); 59 } 60 61 /** 62 * This method sets the required expiration headers in the response for a 63 * given {@link PipelineData} object. This method attempts to set all relevant headers, 64 * both for HTTP 1.0 and HTTP 1.1. 65 * 66 * @param pipelineData The {@link PipelineData} object we are setting cache information for. 67 * @param expiry The number of milliseconds until the document should expire, 68 * <code>0</code> indicating immediate expiration (i.e. no caching). 69 */ 70 public static void setCacheHeaders(PipelineData pipelineData, int expiry) 71 { 72 HttpServletResponse response = pipelineData.get(Turbine.class, HttpServletResponse.class); 73 74 if (0 == expiry) 75 { 76 response.setHeader("Pragma", "no-cache"); 77 response.setHeader("Cache-Control", "no-cache"); 78 response.setDateHeader("Expires", System.currentTimeMillis()); 79 } 80 else 81 { 82 response.setDateHeader("Expires", System.currentTimeMillis() + expiry); 83 } 84 } 85 }