Apache Module mod_headers

Description: -	Customization of HTTP request - and response headers
Status: +	Customization of HTTP request and response +headers
Status:	Extension
Module Identifier:	headers_module
Source File:	mod_headers.c
Compatibility: -	RequestHeader is available only in Apache 2.0

Summary

+ RequestHeader +is available only in Apache 2.0

Summary

This module provides directives to control and modify HTTP request and response headers. Headers can be merged, replaced or removed.

Topics

Order of Processing
Example

Order of Processing

Topics

Order of Processing
Examples

Order of Processing

The directives provided by mod_header can occur almost - anywhere within the server configuration. They are valid in the +

The directives provided by mod_headers can occur + almost anywhere within the server configuration. They are valid in the main server config and virtual host sections, inside - <Directory>, <Location> and <Files> sections, - and within .htaccess files.

+ <Directory>, + <Location> and + <Files> sections, + and within .htaccess files.

The directives are processed in the following order:

main server
virtual host
<Directory> sections and .htaccess
<Location>
<Files>
<Directory> sections and + .htaccess
<Files>
<Location>

Order is important. These two headers have a different effect if reversed:

-RequestHeader append MirrorID "mirror 12" - RequestHeader unset MirrorID -

+ RequestHeader append MirrorID "mirror 12" + RequestHeader unset MirrorID +

This way round, the MirrorID header is not set. If reversed, - the MirrorID header is set to "mirror 12".

Example

This way round, the MirrorID header is not set. If + reversed, the MirrorID header is set to "mirror 12".

Examples

Copy all request headers that begin with "TS" to the - response headers: - -
- Header echo ^TS* -
Add a header, 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. - -
- Header add MyHeader "%D %t" -
- results in this header being added to the response: -
- MyHeader: D=3775428 t=991424704447256 -
+
+ Copy all request headers that begin with "TS" to the + response headers: + +
+ Header echo ^TS +
Say hello to Joe +
+ Add a header, 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. + +
+ Header add MyHeader "%D %t" +
-
- Header add MyHeader "Hello Joe. It took %D microseconds for Apache to serve this request." -
- results in this header being added to the response: -
- MyHeader: Hello Joe. It took D=3775428 microseconds for Apache to serve this request. -
+
results in this header being added to the response:
+ +
+ MyHeader: D=3775428 t=991424704447256 +
Conditionally send 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 - mod_setenvif module. - -
- SetEnvIf MyRequestHeader value HAVE_MyRequestHeader - Header add MyHeader "%D %t mytext" env=HAVE_MyRequestHeader -
- If the header "MyRequestHeader: value" is present on the - HTTP request, the response will contain the following - header: -
- MyHeader: D=3775428 t=991424704447256 mytext -
+
+ Say hello to Joe + +
+ Header add MyHeader "Hello Joe. It took %D microseconds \ + for Apache to serve this request." +
+ +
results in this header being added to the response:
+ +
+ MyHeader: Hello Joe. It took D=3775428 microseconds for Apache + to serve this request. +
+
+ Conditionally send 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 + mod_setenvif module. + +
+ SetEnvIf MyRequestHeader value HAVE_MyRequestHeader + Header add MyHeader "%D %t mytext" env=HAVE_MyRequestHeader +
+ +
If the header MyRequestHeader: value is present on + the HTTP request, the response will contain the following header:
+ +
+ MyHeader: D=3775428 t=991424704447256 mytext +

Header Directive

will take effect. Otherwise, the directive will have no effect on the request.

The Header directives are processed just before the response - is sent to the network. These means that it is possible to set - and/or override most headers, except for those headers added by - the header filter.

The Header directives are processed just + before the response is sent to the network. These means that it is + possible to set and/or override most headers, except for those headers + added by the header filter.

RequestHeader Directive

Description: Configure HTTP response headers

Syntax: - Header set|append|add|unset|echo header -[value]

Context: + Header set|append|add|unset|echo header +[value [env=[!]variable]]

Context: server config, virtual host, directory, .htaccess

Override: FileInfo

Status: Extension

Module: @@ -116,62 +128,62 @@ RequestHeader append MirrorID "mirror 12"
modified. The action it performs is determined by the first argument. This can be one of the following values:

set
- The response header is set, replacing any previous header - with this name. The value may be a format - string.
append
- The response header is appended to any existing header of - the same name. When a new value is merged onto an existing - header it is separated from the existing header with a comma. - This is the HTTP standard way of giving a header multiple - values.
add
- The response header is added to the existing set of headers, - even if this header already exists. This can result in two - (or more) headers having the same name. This can lead to - unforeseen consequences, and in general "append" should be - used instead.
unset
- The response header of this name is removed, if it exists. - If there are multiple headers of the same name, all will be - removed.
echo
- Request headers with this name are echoed back in the - response headers. header may be a regular - expression.

- -

This argument is followed by a header name, which +

set: The response header is set, replacing any previous header + with this name. The value may be a format string.
append: The response header is appended to any existing header of + the same name. When a new value is merged onto an existing + header it is separated from the existing header with a comma. + This is the HTTP standard way of giving a header multiple values.
add: The response header is added to the existing set of headers, + even if this header already exists. This can result in two + (or more) headers having the same name. This can lead to + unforeseen consequences, and in general "append" should be + used instead.
unset: The response header of this name is removed, if it exists. + If there are multiple headers of the same name, all will be + removed.
echo: Request headers with this name are echoed back in the + response headers. header may be a regular expression.

+ +

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.

+ 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 Header directive is used with the add, append, or set @@ -183,14 +195,14 @@ variable FOOBAR.

performs is determined by the first argument. This can be one of the following values:

set
- The request header is set, replacing any previous header - with this name
append
- The request header is appended to any existing header of the - same name. When a new value is merged onto an existing header - it is separated from the existing header with a comma. This - is the HTTP standard way of giving a header multiple - values.
add
- The request header is added to the existing set of headers, - even if this header already exists. This can result in two - (or more) headers having the same name. This can lead to - unforeseen consequences, and in general "append" should be - used instead.
unset
- The request header of this name is removed, if it exists. If - there are multiple headers of the same name, all will be - removed.

set: The request header is set, replacing any previous header + with this name
append: The request header is appended to any existing header of the + same name. When a new value is merged onto an existing header + it is separated from the existing header with a comma. This + is the HTTP standard way of giving a header multiple + values.
add: The request header is added to the existing set of headers, + even if this header already exists. This can result in two + (or more) headers having the same name. This can lead to + unforeseen consequences, and in general append should be + used instead.
unset: The request header of this name is removed, if it exists. If + there are multiple headers of the same name, all will be removed.

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.

+ 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 RequestHeader directive is processed just before the request is run by its handler in the fixup phase. diff --git a/docs/manual/mod/mod_headers.xml b/docs/manual/mod/mod_headers.xml index 71ab5ab4f0..1144446cff 100644 --- a/docs/manual/mod/mod_headers.xml +++ b/docs/manual/mod/mod_headers.xml @@ -59,7 +59,7 @@ is available only in Apache 2.0 response headers: - Header echo ^TS* + Header echo ^TS diff --git a/docs/manual/mod/quickreference.html.en b/docs/manual/mod/quickreference.html.en index 8761d613be..ef7edc412a 100644 --- a/docs/manual/mod/quickreference.html.en +++ b/docs/manual/mod/quickreference.html.en @@ -290,8 +290,8 @@ found MIME content-type

- + @@ -484,8 +484,8 @@ extensions - + -- 2.50.1

Module: @@ -201,37 +213,36 @@ variable FOOBAR.
Description:	Configure HTTP request headers
Syntax: -	`RequestHeader set\|append\|add\|unset header -[value]`
Context: +	`RequestHeader set\|append\|add\|unset header +[value]`
Context:	server config, virtual host, directory, .htaccess
Override:	FileInfo
Status:	Extension
Group `unix-group`	#-1	sv	M
Group under which the server will answer requests
Header set\|append\|add\|unset\|echo header -[value]		svdh	E
Configure HTTP response headers
Header set\|append\|add\|unset\|echo `header` +[`value` [env=[!]`variable`]]		svdh	E
Configure HTTP response headers
HeaderName `filename`		svdh	B
Name of the file that will be inserted at the top of the index listing
HostnameLookups on\|off\|double	off	svd	C
Enables DNS lookups on client IP addresses
RemoveType extension [extension] ...		vdh	B
Removes any content type associations for a set of file extensions
RequestHeader set\|append\|add\|unset header -[value]		svdh	E
Configure HTTP request headers
RequestHeader set\|append\|add\|unset `header` +[`value`]		svdh	E
Configure HTTP request headers
Require `entity-name` [`entity-name`] ...		dh	C
Selects which authenticated users can access a resource
RewriteBase URL-path		dh	E
Sets the base URL for per-directory rewrites