User:WikipediaAdventures/Apache HTTP Server

Apache HTTP Server is a free software/open source HTTP web server for Unix-like systems (BSD, Linux, and UNIX systems), Microsoft Windows, Novell NetWare and other platforms. Apache is notable for playing a key role in the initial growth of the World Wide Web, and continues to be the most popular web server in use, serving as the reference platform against which other web servers are designed and judged.

Apache features highly configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported by several graphical user interfaces (GUIs) which permit easier, more intuitive configuration of the server.

The Apache HTTP Server is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

History
Apache web server was originally created by Rob McCool, who was heavily involved with the National Center for Supercomputing Applications web server, known simply as NCSA httpd. When Rob left NCSA in mid-1994, the development of httpd stalled, leaving a variety of patches for improvements circulating through e-mails. These patches were put together by a small group of developers, who eventually released "A patchy server", which later became known as Apache Web Server.

Rob McCool was not alone in his efforts. Several other developers helped form the original "Apache Group": Brian Behlendorf, Roy T. Fielding, Rob Hartill, David Robinson, Cliff Skolnick, Randy Terbush, Robert S. Thau, Andrew Wilson, Eric Hagberg, Frank Peters, and Nicolas Pioch.

The author claims the name was initially chosen as a catchy name in order to be original, but the most widespread interpretation (which almost immediately surfaced) is that the name comes from the fact that when it was developed in early 1995, it consisted of changes in the code to the most popular HTTP server of the time, NCSA HTTPd 1.3 and was therefore "a patchy" server. However, in the FAQ on the server's official site, it is stated: "The name 'Apache' was chosen from respect for the Native American Indian tribe of Apache (Indé), well-known for their superior skills in warfare strategy and their inexhaustible endurance".

At the time, Apache was the only viable open source alternative to the Netscape web server (currently known as Sun Java System Web Server). It has since evolved to rival other Unix-based HTTP servers in terms of functionality and performance. Since April 1996 Apache has been the most popular HTTP server on the Internet: in May 1999 it was running on 57% of all web servers; by January 2006 the usage had increased to 67% (Netcraft Web Server Survey, January 2006). Microsoft's Internet Information Services (IIS) is the main competitor to Apache, trailed by Sun Microsystem's Sun Java Web Server and a host of other applications such as Zeus.

License
The License under which software from the Apache Foundation is distributed is a distinctive part of the Apache HTTP Server's history and presense in the open source software environment. The Apache License is atypical in that it allows for the distribution of both open- and closed-source derivations of the source code.

Furthermore, it is perhaps surprising that the Free Software Foundation does not consider the Apache License to be "compatible" with the GPL, meaning that software licensed under the Apache License cannot be integrated with software that is distributed under the GPL. Here is what the FSF says about the Apache License:


 * This is a free software license but it is incompatible with the GPL. The Apache Software License is incompatible with the GPL because it has a specific requirement that is not in the GPL: it has certain patent termination cases that the GPL does not require. (We don't think those patent termination cases are inherently a bad idea, but nonetheless they are incompatible with the GNU GPL.)

Usage
Apache is primarily used to serve static, and dynamic content on the World Wide Web. Many web applications are designed expecting the environment and features that Apache provides.

Apache is the web server component of the popular web server application stack called LAMP (Linux, Apache, MySQL, PHP/Perl/Python).

Apache is redistributed as part of various proprietary packages,for example: the Oracle database or the IBM WebSphere application server. Mac OS X integrates Apache as its built-in web server. It is also supported in some way by Borland in the Kylix and Delphi development tools. Apache is included with Novell NetWare 6.5, where it is the default web server.

Apache is used for many other tasks where content needs to be made available in a secure and reliable way. One example is sharing files off of a personal computer over the Internet. A user who has Apache installed on their desktop can can put arbitrary files in the Apache's document root which can then be shared.

Programmers developping web applications often use a locally installed version of Apache in order to preview and test code as it is being developed.

Features
Apache supports a variety of features, many implemented as compiled modules which extend the core functionality. These can range from server-side programming language support to authentication schemes. Some common language interfaces support Perl, Python, Tcl, and PHP. Popular authentication modules include mod_access, mod_auth, and mod_digest. A sample of other features include SSL and TLS support (mod_ssl), a proxy module, a useful URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), custom log files (mod_log_config), and filtering support (mod_include and mod_ext_filter). Apache logs can be analysed through a web browser using free scripts such as AWStats or Visitors.

Apache 2
Version 2 of the Apache server was written from scratch and contains no code from NCSA. The Apache 2.x core has several major enhancements over Apache 1.x. These include UNIX threading, better support for non-Unix platforms (such as Windows), a new Apache API, and IPv6 support.

Version 2.2 introduced a new auth API that allows for more flexibility, it also features improved cache modules and proxy modules.