1<html> 2<head> 3<!-- 4/* 5 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/protocol/package.html $ 6 * $Revision: 496070 $ 7 * $Date: 2007-01-14 04:18:34 -0800 (Sun, 14 Jan 2007) $ 8 * 9 * ==================================================================== 10 * Licensed to the Apache Software Foundation (ASF) under one 11 * or more contributor license agreements. See the NOTICE file 12 * distributed with this work for additional information 13 * regarding copyright ownership. The ASF licenses this file 14 * to you under the Apache License, Version 2.0 (the 15 * "License"); you may not use this file except in compliance 16 * with the License. You may obtain a copy of the License at 17 * 18 * http://www.apache.org/licenses/LICENSE-2.0 19 * 20 * Unless required by applicable law or agreed to in writing, 21 * software distributed under the License is distributed on an 22 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 23 * KIND, either express or implied. See the License for the 24 * specific language governing permissions and limitations 25 * under the License. 26 * ==================================================================== 27 * 28 * This software consists of voluntary contributions made by many 29 * individuals on behalf of the Apache Software Foundation. For more 30 * information on the Apache Software Foundation, please see 31 * <http://www.apache.org/>. 32 * 33 */ 34--> 35</head> 36<body> 37HTTP protocol execution framework. 38 39Apart from simply sending and receiving messages, there are a lot 40of things to consider when communicating with HTTP. Many details 41such as transport encodings or connection management are handled 42by setting up or interpreting 43{@link org.apache.http.Header headers} in the messages. 44In order to relieve applications from the responsibility of 45implementing these nitty-gritty details of the protocol, 46HTTP components provides an execution framework that sets up 47some of the headers before sending a message, and interprets 48headers when a message has been received. 49<br/> 50An HTTP {@link org.apache.http.protocol.HttpProcessor processor} 51typically keeps lists of so-called interceptors that will be executed 52before a message is sent and after it has been received. 53An application should initialize a processor, set up the lists 54with the required and desired processors, and then communicate 55through that processor. There are four kinds of interceptors, 56depending on whether they act on 57{@link org.apache.http.HttpRequestInterceptor requests} or 58{@link org.apache.http.HttpResponseInterceptor responses}, 59on the client or server side: 60 61<table border="1" cellpadding="5"> 62<tr><th></th> 63 <th>Client</th> 64 <th>Server</th> 65</tr> 66<tr><th>Request</th> 67 <td>prepares headers before a request is sent</td> 68 <td>interprets headers when a request is received</td> 69</tr> 70<tr><th>Response</th> 71 <td>interprets headers when a response is received</td> 72 <td>prepares headers before a response is sent</td> 73</tr> 74</table> 75 76<p> 77{@link org.apache.http.protocol.HttpRequestExecutor HttpRequestExecutor} 78is a processor for the client side, 79{@link org.apache.http.protocol.HttpService HttpService} 80for the server side. 81On the client side, a {@link org.apache.http.protocol.HttpContext context} 82is used to tie together a request, the response to it, and other data 83that might be associated with the request execution. It is passed to 84the request executor whenever needed. 85</p> 86 87<p> 88<font size="+1"> 89<i> 90Information about required and recommended interceptors for the 91client side will be provided elsewhere. For the time being, please 92refer to the comments in the example applications or ask on 93one of the mailing lists. 94</i> 95</font> 96</p> 97 98<p> 99<b>Note:</b> 100If you want to develop a server-side application, we recommend that 101you implement your application as a servlet running in a servlet engine 102like <a href="http://tomcat.apache.org/">Tomcat</a> or full-blown 103JSEE container like <a href="http://geronimo.apache.org/">Geronimo</a>. 104If you prefer to implement a server-side application based on our 105{@link org.apache.http.protocol.HttpService HttpService}, we'll 106assume that you know what you're doing and that you don't need 107help in figuring out which interceptors need to be configured. 108</p> 109 110 111</body> 112</html> 113