~~ $HeadURL$ ~~ $Revision$ ~~ $Date$ ~~ ~~ ==================================================================== ~~ Licensed to the Apache Software Foundation (ASF) under one ~~ or more contributor license agreements. See the NOTICE file ~~ distributed with this work for additional information ~~ regarding copyright ownership. The ASF licenses this file ~~ to you under the Apache License, Version 2.0 (the ~~ "License"); you may not use this file except in compliance ~~ with the License. You may obtain a copy of the License at ~~ ~~ http://www.apache.org/licenses/LICENSE-2.0 ~~ ~~ Unless required by applicable law or agreed to in writing, ~~ software distributed under the License is distributed on an ~~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY ~~ KIND, either express or implied. See the License for the ~~ specific language governing permissions and limitations ~~ under the License. ~~ ==================================================================== ~~ ~~ This software consists of voluntary contributions made by many ~~ individuals on behalf of the Apache Software Foundation. For more ~~ information on the Apache Software Foundation, please see ~~ . ---------- HttpComponents HttpClient Overview ---------- ---------- ---------- HttpClient Overview The Hyper-Text Transfer Protocol (HTTP) is perhaps the most significant protocol used on the Internet today. Web services, network-enabled appliances and the growth of network computing continue to expand the role of the HTTP protocol beyond user-driven web browsers, while increasing the number of applications that require HTTP support. Although the java.net package provides basic functionality for accessing resources via HTTP, it doesn't provide the full flexibility or functionality needed by many applications. HttpClient seeks to fill this void by providing an efficient, up-to-date, and feature-rich package implementing the client side of the most recent HTTP standards and recommendations. Designed for extension while providing robust support for the base HTTP protocol, HttpClient may be of interest to anyone building HTTP-aware client applications such as web browsers, web service clients, or systems that leverage or extend the HTTP protocol for distributed communication. Features * Standards based, pure Java, implementation of HTTP versions 1.0 and 1.1 * Full implementation of all HTTP methods (GET, POST, PUT, DELETE, HEAD, OPTIONS, and TRACE) in an extensible OO framework. * Supports encryption with HTTPS (HTTP over SSL) protocol. * Transparent connections through HTTP proxies. * Tunneled HTTPS connections through HTTP proxies, via the CONNECT method. * Basic, Digest authentication schemes. Please note NTLM is currently not supported. * Plug-in mechanism for custom authentication schemes. * Pluggable secure socket factories, making it easier to use third party solutions * Connection management support for use in multi-threaded applications. Supports setting the maximum total connections as well as the maximum connections per host. Detects and closes stale connections. * Automatic Cookie handling for reading Set-Cookie: headers from the server and sending them back out in a Cookie: header when appropriate. * Plug-in mechanism for custom cookie policies. * Request output streams to avoid buffering any content body by streaming directly to the socket to the server. * Response input streams to efficiently read the response body by streaming directly from the socket to the server. * Persistent connections using KeepAlive in HTTP/1.0 and persistance in HTTP/1.1 * Direct access to the response code and headers sent by the server. * The ability to set connection timeouts. * Source code is freely available under the Apache License. Modules HttpClient currently is a single module that comprises code for authentication, cookies, connection management, and the client itself. It may be changed to a more modular structure in the future. * HttpClient module The {{{httpclient/index.html}HttpClient}} module is a full-featured, standards compliant HTTP client built on top of {{{/httpcomponents-core/index.html}HttpCore}}. * HttpMime module The {{{httpmime/index.html}HttpMime}} module extends {{{http://james.apache.org/mime4j/index.html}mime4j}} library with some HTTP specific functionality and integrates it with the HttpComponents framework. Standards Compliance HttpClient strives to conform to the following specifications endorsed by the Internet Engineering Task Force (IETF) and the internet at large: * {{{http://www.ietf.org/rfc/rfc1945.txt}RFC 1945}} - Hypertext Transfer Protocol -- HTTP/1.0 * {{{http://www.ietf.org/rfc/rfc2616.txt}RFC 2116}} - Hypertext Transfer Protocol -- HTTP/1.1 * {{{http://www.ietf.org/rfc/rfc2617.txt}RFC2617}} HTTP Authentication: Basic and Digest Access Authentication * {{{http://www.ietf.org/rfc/rfc2109.txt}RFC2109}} HTTP State Management Mechanism (Cookies) * {{{http://www.ietf.org/rfc/rfc2965.txt}RFC2965}} HTTP State Management Mechanism (Cookies v2) Examples Some examples of HttpClient components in action can be found {{{examples.html}here}}.