nginx / current / reference / http-ngx_http_charset_module.html

Module ngx_http_charset_module

The ngx_http_charset_module module adds the specified charset to the “Content-Type” response header field. In addition, the module can convert data from one charset to another, with some limitations:

  • conversion is performed one way — from server to client,
  • only single-byte charsets can be converted
  • or single-byte charsets to/from UTF-8.

Example Configuration

include        conf/koi-win;

charset        windows-1251;
source_charset koi8-r;


Syntax: charset charset | off;
charset off;
Context: http, server, location, if in location

Adds the specified charset to the “Content-Type” response header field. If this charset is different from the charset specified in the source_charset directive, a conversion is performed.

The parameter off cancels the addition of charset to the “Content-Type” response header field.

A charset can be defined with a variable:

charset $charset;

In such a case, all possible values of a variable need to be present in the configuration at least once in the form of the charset_map, charset, or source_charset directives. For utf-8, windows-1251, and koi8-r charsets, it is sufficient to include the files conf/koi-win, conf/koi-utf, and conf/win-utf into configuration. For other charsets, simply making a fictitious conversion table works, for example:

charset_map iso-8859-5 _ { }

In addition, a charset can be set in the “X-Accel-Charset” response header field. This capability can be disabled using the proxy_ignore_headers, fastcgi_ignore_headers, uwsgi_ignore_headers, scgi_ignore_headers, and grpc_ignore_headers directives.

Syntax: charset_map charset1 charset2 { ... }
Context: http

Describes the conversion table from one charset to another. A reverse conversion table is built using the same data. Character codes are given in hexadecimal. Missing characters in the range 80-FF are replaced with “?”. When converting from UTF-8, characters missing in a one-byte charset are replaced with “&#XXXX;”.


charset_map koi8-r windows-1251 {
    C0 FE ; # small yu
    C1 E0 ; # small a
    C2 E1 ; # small b
    C3 F6 ; # small ts

When describing a conversion table to UTF-8, codes for the UTF-8 charset should be given in the second column, for example:

charset_map koi8-r utf-8 {
    C0 D18E ; # small yu
    C1 D0B0 ; # small a
    C2 D0B1 ; # small b
    C3 D186 ; # small ts

Full conversion tables from koi8-r to windows-1251, and from koi8-r and windows-1251 to utf-8 are provided in the distribution files conf/koi-win, conf/koi-utf, and conf/win-utf.

Syntax: charset_types mime-type ...;
charset_types text/html text/xml text/plain text/vnd.wap.wml
application/javascript application/rss+xml;
Context: http, server, location

This directive appeared in version 0.7.9.

Enables module processing in responses with the specified MIME types in addition to “text/html”. The special value “*” matches any MIME type (0.8.29).

Until version 1.5.4, “ application/x-javascript” was used as the default MIME type instead of “ application/javascript”.

Syntax: override_charset on | off;
override_charset off;
Context: http, server, location, if in location

Determines whether a conversion should be performed for answers received from a proxied or a FastCGI/uwsgi/SCGI/gRPC server when the answers already carry a charset in the “Content-Type” response header field. If conversion is enabled, a charset specified in the received response is used as a source charset.

It should be noted that if a response is received in a subrequest then the conversion from the response charset to the main request charset is always performed, regardless of the override_charset directive setting.

Syntax: source_charset charset;
Context: http, server, location, if in location

Defines the source charset of a response. If this charset is different from the charset specified in the charset directive, a conversion is performed.