Apache Module mod_charset_lite
Summary
This is an experimental module and should
be used with care. Experiment with your
mod_charset_lite configuration to ensure that it
performs the desired function.
mod_charset_lite allows the administrator to
specify the source character set of objects as well as the
character set they should be translated into before sending to the
client. mod_charset_lite does not translate the
data itself but instead tells Apache what translation to
perform. mod_charset_lite is applicable to EBCDIC
and ASCII host environments. In an EBCDIC environment, Apache
normally translates text content from the code page of the Apache
process locale to ISO-8859-1. mod_charset_lite
can be used to specify that a different translation is to be
performed. In an ASCII environment, Apache normally performs no
translation, so mod_charset_lite is needed in
order for any translation to take place.
This module provides a small subset of configuration
mechanisms implemented by Russian Apache and its associated
mod_charset.
Invalid character set names
The character set name parameters of CharsetSourceEnc and
CharsetDefault
must be acceptable to the translation mechanism used by APR on the
system where mod_charset_lite is deployed. These
character set names are not standardized and are usually not the
same as the corresponding values used in http headers. Currently,
APR can only use iconv(3), so you can easily test your character
set names using the iconv(1) program, as follows:
iconv -f charsetsourceenc-value -t charsetdefault-value
Mismatch between character set of content and translation
rules
If the translation rules don't make sense for the content,
translation can fail in various ways, including:
- The translation mechanism may return a bad return code,
and the connection will be aborted.
- The translation mechanism may silently place special
characters (e.g., question marks) in the output buffer when
it cannot translate the input buffer.
The CharsetDefault directive specifies the
charset that content in the associated container should be
translated to.
The value of the charset argument must be accepted
as a valid character set name by the character set support in
APR. Generally, this means that it must be supported by
iconv.
Example
<Directory /export/home/trawick/apacheinst/htdocs/convert>
CharsetSourceEnc UTF-16BE
CharsetDefault ISO-8859-1
</Directory>
The CharsetOptions directive configures certain
behaviors of mod_charset_lite. Option can
be one of
DebugLevel=n- The
DebugLevel keyword allows you to specify
the level of debug messages generated by
mod_charset_lite. By default, no messages are
generated. This is equivalent to DebugLevel=0.
With higher numbers, more debug messages are generated, and
server performance will be degraded. The actual meanings of
the numeric values are described with the definitions of the
DBGLVL_ constants near the beginning of
mod_charset_lite.c.
ImplicitAdd | NoImplicitAdd- The
ImplicitAdd keyword specifies that
mod_charset_lite should implicitly insert its
filter when the configuration specifies that the character
set of content should be translated. If the filter chain is
explicitly configured using the AddOutputFilter directive, NoImplicitAdd
should be specified so that mod_charset_lite
doesn't add its filter.
The CharsetSourceEnc directive specifies the
source charset of files in the associated container.
The value of the charset argument must be accepted
as a valid character set name by the character set support in
APR. Generally, this means that it must be supported by
iconv.
Example
<Directory /export/home/trawick/apacheinst/htdocs/convert>
CharsetSourceEnc UTF-16BE
CharsetDefault ISO-8859-1
</Directory>
The character set names in this example work with the iconv
translation support in Solaris 8.
