= Nginx Compression =

'''`nginx(8)`''' is able to seamlessly compress data before sending over the wire. This reduces the amount of traffic, at the cost of computation time.

<<TableOfContents>>

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== Unit Measurements ==

In `nginx(8)` configuration files, size and offset are measured in...

 * bytes (no suffix)
 * kilobytes (`k` or `K` suffix)
 * megabytes (`m` or `M` suffix)
 * gigabytes (`g` or `G` suffix)

To be clear, a size or offset without any suffix will be treated as a measurement in bytes.

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== Usage ==



=== Gzip ===

The `gzip` directive belongs in the [[Nginx/Http|http block]] and takes either `on` or `off`.

For many deployments, this is all the configuration needed to get 'good enough' results.

{{{
http {
  gzip on;
}
}}}

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=== Gzip_Buffers ===

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=== Gzip_Comp_Level ===

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=== Gzip_Disable ===

The `gzip_disable` directive disables compression based on the user agent. It takes a regex that should match user agents for which compression is disabled.

{{{
http {
  # Disable compression for Internet Explorer up to version 6
  gzip_disable "MSIE [1-6]\.";

  # A special value that is equivalent to the regex "MSIE [4-6]\." but faster
  gzip_disable "msie6";
}
}}}

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=== Gzip_Http_Version ===

The `gzip_http_version` directive disables compression based on the version of [[Protocols/HTTP|HTTP]] used.

The default is:

{{{
http {
  gzip_http_version 1.1
}
}}}

This is because HTTP 1.0 does not allow for simulatenously keepalive and compression.

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=== Gzip_Min_Length ===

The `gzip_min_length` directive sets a threshold based on a response's `"Content-Length"` header. Below this threshold, data is sent uncompressed.

{{{
http {
  gzip_min_length 1024;
}
}}}

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=== Gzip_Proxied ===

The `gzip_proxied` directive causes data to be compressed for proxied connections.

By default this is not done because the proxy should cache that data itself. That proxy already is a solution for reducing traffic. The computation time of (1) `nginx(8)` compressing the data and (2) the proxy decompressing the data scales poorly.

The directive takes one or more of the following values:

||'''Setting'''     ||'''Meaning'''                                                                             ||
||`expired`         ||compress even if a response has an `"Expires"` header set to a value that disables caching||
||`no-cache`        ||compress even if a response has a `"Cache-Control"` header set to `"no-cache"`            ||
||`no-store`        ||compress even if a response has a `"Cache-Control"` header set to `"no-store"`            ||
||`private`         ||compress even if a response has a `"Cache-Control"` header set to `"private"`             ||
||`no_last_modified`||compress even if a response does not have a `"Last-Modified"` header                      ||
||`no_etag`         ||compress even if a response does not have an `"ETag"` header                              ||
||`auth`            ||compress even if a response has an `"Authorizationn"` header                              ||

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=== Gzip_Type ===

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=== Gzip_Vary ===

The `gzip_vary` directive causes both compressed and uncompressed data to be cached. This is only useful if some data won't be compressed.

{{{
http {
  gzip_vary on;
}
}}}

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== See also ==

[[https://nginx.org/en/docs/http/ngx_http_gzip_module.html|Module ngx_http_gzip_module documentation]]



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