This module provides directives to control and modify HTTP request and response headers. Headers can be merged, replaced or removed.
The directives provided by .htaccess
files.
The directives are processed in the following order:
.htaccess
Order is important. These two headers have a different effect if reversed:
This way round, the MirrorID
header is not set. If
reversed, the MirrorID header is set to "mirror 12".
MyHeader
, to the response including a
timestamp for when the request was received and how long it
took to begin serving the request. This header can be used by
the client to intuit load on the server or in isolating
bottlenecks between the client and the server.
results in this header being added to the response:
results in this header being added to the response:
MyHeader
on the response if and
only if header "MyRequestHeader" is present on the request. This
is useful for constructing headers in response to some client
stimulus. Note that this example requires the services of the
If the header MyRequestHeader: value
is present on
the HTTP request, the response will contain the following header:
This directive can replace, merge or remove HTTP request headers. The header is modified just before the content handler is run, allowing incoming headers to be modified. The action it performs is determined by the first argument. This can be one of the following values:
set
append
add
append
should be
used instead.unset
This argument is followed by a header name, which can
include the final colon, but it is not required. Case is
ignored. For add
, append
and
set
a value is given as the third argument. If
value contains spaces, it should be surrounded by double
quotes. For unset, no value should be given.
The
This directive can replace, merge or remove HTTP response headers. The header is modified just after the content handler and output filters are run, allowing outgoing headers to be modified. The action it performs is determined by the first argument. This can be one of the following values:
set
append
add
unset
echo
This argument is followed by a header name, which
can include the final colon, but it is not required. Case is
ignored for set
, append
, add
and unset
. The header name for echo
is case sensitive and may be a regular expression.
For add
, append
and set
a
value is specified as the third argument. If value
contains spaces, it should be surrounded by doublequotes.
value may be a character string, a string containing format
specifiers or a combination of both. The following format specifiers
are supported in value:
%t |
The time the request was received in Universal Coordinated Time
since the epoch (Jan. 1, 1970) measured in microseconds. The value
is preceded by t= . |
%D |
The time from when the request was received to the time the
headers are sent on the wire. This is a measure of the duration
of the request. The value is preceded by D= . |
%{FOOBAR}e |
The contents of the environment
variable FOOBAR . |
When the add
, append
, or set
argument, a fourth argument may be used to specify conditions
under which the action will be taken. If the environment variable specified in the
env=...
argument exists (or if the environment
variable does not exist and env=!...
is specified)
then the action specified by the
The