mod_gzip is an external extension module for the Apache HTTP Server v1 and v2.
It allows using the Gzip compression method for a significant reduction of the volume of web page content served over the HTTP protocol.
mod_gzip can be compiled into Apache as either a static or dynamic module.
It is possible to check a server to see if it is sending out compressed data, and compression compatibility of a browser for example here.
When textual content is compressed using mod_gzip, it should maintain its MIME-type, according to their recommended media type:
One of the earliest Apache 1.3 versions introduced some internal function for regular expression evaluation. This function is used by mod_gzip (for evaluating the filter rules), therefore mod_gzip would not work together with Apache 1.2.x or earlier versions. [1]
Compatibility between Apache 1.3.x and mod_gzip 1.3.y is granted in general: the Apache 1.3 API doesn't change any more, mod_gzip would even work together with very old Apache 1.3 versions.
The mod_deflate module is similar to mod_gzip, but usable only with Apache v2. Early versions of mod_deflate provided lesser amount of compression than mod_gzip. [2] Starting with Apache 2.0.45, the compression level of mod_deflate is configurable using the DeflateCompressionLevel directive, so this difference disappeared.
A mod_gz module was independently developed by Ian Holsman. This module implements a gzip compression filter for Apache 2.0, providing similar functionality to mod_gzip. One important difference between the two modules is that mod_gzip includes its own gzip implementation, whereas mod_gz relies on an external zlib library.
In PHP similar effect achievable for the output of PHP scripts with:
CherryPy offers the Gzip filter, [3] which uses the zlib module of Python standard library.
The mod_gzip module licensed with Apache License.
Module level content compression for Apache started with mod_gzip, written by Kevin Kiley and Konstantin Balashow [4] in autumn 2000, documented by Michael Schröpl, [5] [6] published by Remote Communications Inc. (RCI). [7] RCI was purchased by HyperSpace Communications, RCI released the code into the public domain. [8]
The developers of the Apache 2.0.x servers have included the mod_deflate module in the codebase for the server to perform a similar GZIP-encoding function. mod_gzip remained external extension module.
The Apache HTTP Server is a free and open-source cross-platform web server software, released under the terms of Apache License 2.0. It is developed and maintained by a community of developers under the auspices of the Apache Software Foundation.
gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and intended for use by GNU. Version 0.1 was first publicly released on 31 October 1992, and version 1.0 followed in February 1993.
zlib is a software library used for data compression as well as a data format. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. zlib is also a crucial component of many software platforms, including Linux, macOS, and iOS. It has also been used in gaming consoles such as the PlayStation 4, PlayStation 3, Wii U, Wii, Xbox One and Xbox 360.
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7z is a compressed archive file format that supports several different data compression, encryption and pre-processing algorithms. The 7z format initially appeared as implemented by the 7-Zip archiver. The 7-Zip program is publicly available under the terms of the GNU Lesser General Public License. The LZMA SDK 4.62 was placed in the public domain in December 2008. The latest stable version of 7-Zip and LZMA SDK is version 22.01.
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Mark Adler is an American software engineer. He is best known for his work in the field of data compression as the author of the Adler-32 checksum function, and a co-author together with Jean-loup Gailly of the zlib compression library and gzip. He has contributed to Info-ZIP, and has participated in developing the Portable Network Graphics (PNG) image format. Adler was also the Spirit Cruise Mission Manager for the Mars Exploration Rover mission.
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Slowloris is a type of denial of service attack tool which allows a single machine to take down another machine's web server with minimal bandwidth and side effects on unrelated services and ports.
Google Chrome Frame was a plug-in designed for Internet Explorer based on the open-source Chromium project, first announced on September 22, 2009. It went stable in September 2010, on the first birthday of the project. It was discontinued on February 25, 2014 and is no longer supported.
mod_deflate is an optional module for the Apache HTTP Server, Apache v2.0 and later. It is based on Deflate lossless data compression algorithm that uses a combination of the LZ77 algorithm and Huffman coding. This module provides the DEFLATE output filter that allows output from Apache HTTP server to be compressed before being sent to the client over the network. It also provides a filter for decompressing a gzip compressed response body.
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Brotli is a lossless data compression algorithm developed by Google. It uses a combination of the general-purpose LZ77 lossless compression algorithm, Huffman coding and 2nd-order context modelling. Brotli is primarily used by web servers and content delivery networks to compress HTTP content, making internet websites load faster. A successor to gzip, it is supported by all major web browsers and has become increasingly popular, as it provides better compression than gzip.
