Apache HTTP Server
Apache HTTP Server is a
free software/
open source web server for
Unix-like 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,
[http://news.netcraft.com/archives/web_server_survey.html] serving as the
de facto reference platform against which other web servers are designed and judged.
Apache features 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.
Apache is developed and maintained by an open community of developers under the auspices of the
Apache Software Foundation.
The first version of the Apache web server was 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.
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 FAQ on the project's official site states: "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." However, the most widespread interpretation is that the name comes from the fact that when it was developed in early 1995, the web server consisted a set of
patches to the codebase of NCSA HTTPd 1.3 and was therefore "a patchy" server. This was the explanation initially given on the project's website.
[Wayback Machine link to the Apache website, 1997]When first released, 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 web servers in terms of functionality and performance. Since April 1996 Apache has been the most popular HTTP server on the
Internet. By May 1999 Apache installations served 57% of all
websites. Its popularity continued to rise, and in February 2006 Apache served 68% of all websites.
[Netcraft Web Server Survey, February 2006] Microsoft's
Internet Information Services (IIS) is the main competitor to Apache, trailed by
Sun Microsystems' Sun Java System Web Server and a host of other applications such as
Zeus.
The
License under which software from the Apache Foundation is distributed is a distinctive part of the Apache HTTP Server's history and presence in the open source software environment. The Apache License 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 version 2.0 of the
GNU General Public License (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:
The current draft of Version 3 of the GPL includes a provision (Section 7e) which allows it to be compatible with licenses that have patent retaliation clauses, including the Apache License.
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
LAMP web server application stack, alongside
Linux,
MySQL, and the
PHP/
Perl/
Python programming languages.
Apache is redistributed as part of various
proprietary packages, such as 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 from a personal computer over the Internet. A user who has Apache installed on their desktop can put arbitrary files in the Apache's document root which can then be shared.
Programmers developing web applications often use a locally installed version of Apache in order to preview and test code as it is being developed.
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 analyzed through a web browser using free scripts such as
AWStats or
Visitors.
Version 2 of the Apache server was a substantial re-write of much of the code, with a strong focus on further modularisation and the development of a portability layer; the
APR. 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. The first
alpha release of Apache 2 was in March 2000 with the first
general availability release in May 2002.
Version 2.2 introduced a new auth API that allows for more flexibility. It also features improved cache modules and proxy modules.
*
Comparison of web servers*
Stronghold, commercial version formerly distributed by
Red Hat*
ApacheBench*
POSSE project*
.htaccess
*
Apache HTTP Server official website*
ONLamp.com Apache DevCenter*
Apache Week*
Apache News Online
