Apache Module mod_setenvif

Available Languages: en | + ja | + ko

+ + + +

Description:	Allows the setting of environment variables based +on characteristics of the request
Status:	Base
Module Identifier:	setenvif_module
Source File:	mod_setenvif.c

Summary

+ + +

The mod_setenvif module allows you to set + environment variables according to whether different aspects of + the request match regular expressions you specify. These + environment variables can be used by other parts of the server + to make decisions about actions to be taken.

+ +

The directives are considered in the order they appear in + the configuration files. So more complex sequences can be used, + such as this example, which sets netscape if the + browser is mozilla but not MSIE.

+ +

+ BrowserMatch ^Mozilla netscape + BrowserMatch MSIE !netscape +

BrowserMatch Directive

+ + + + + + + +

Description:	Sets environment variables conditional on HTTP User-Agent +
Syntax:	`BrowserMatch regex [!]env-variable[=value] +[[!]env-variable[=value]] ...`
Context:	server config, virtual host, directory, .htaccess
Override:	FileInfo
Status:	Base
Module:	mod_setenvif

The BrowserMatch is a special cases of the + SetEnvIf directive that + sets environment variables conditional on the + User-Agent HTTP request header. The following two + lines have the same effect:

+ BrowserMatchNoCase Robot is_a_robot + SetEnvIfNoCase User-Agent Robot is_a_robot +

+ +

Some additional examples:

+ BrowserMatch ^Mozilla forms jpeg=yes browser=netscape + BrowserMatch "^Mozilla/[2-3]" tables agif frames javascript + BrowserMatch MSIE !javascript +

+ +

BrowserMatchNoCase Directive

+ + + + + + + + +

Description:	Sets environment variables conditional on User-Agent without +respect to case
Syntax:	`BrowserMatchNoCase regex [!]env-variable[=value] + [[!]env-variable[=value]] ...`
Context:	server config, virtual host, directory, .htaccess
Override:	FileInfo
Status:	Base
Module:	mod_setenvif
Compatibility:	Apache 1.2 and + above (in Apache 1.2 this directive was found in the + now-obsolete mod_browser module)

+ +

The BrowserMatchNoCase directive is + semantically identical to the BrowserMatch directive. + However, it provides for case-insensitive matching. For + example:

+ BrowserMatchNoCase mac platform=macintosh + BrowserMatchNoCase win platform=windows +

+ +

The BrowserMatch and + BrowserMatchNoCase directives are special cases of + the SetEnvIf and SetEnvIfNoCase + directives. The following two lines have the same effect:

+ BrowserMatchNoCase Robot is_a_robot + SetEnvIfNoCase User-Agent Robot is_a_robot +

+ +

SetEnvIf Directive

+ + + + + + + +

Description:	Sets environment variables based on attributes of the request +
Syntax:	`SetEnvIf attribute + regex [!]env-variable[=value] + [[!]env-variable[=value]] ...`
Context:	server config, virtual host, directory, .htaccess
Override:	FileInfo
Status:	Base
Module:	mod_setenvif

The SetEnvIf directive defines + environment variables based on attributes of the request. The + attribute specified in the first argument can be one of three + things:

+ +

An HTTP request header field (see RFC2616 + for more information about these); for example: Host, + User-Agent, Referer, and + Accept-Language. A regular expression may be + used to specify a set of request headers.
One of the following aspects of the request: +
- Remote_Host - the hostname (if available) of + the client making the request
- Remote_Addr - the IP address of the client + making the request
- Server_Addr - the IP address of the server + on which the request was received (only with versions later + than 2.0.43)
- Request_Method - the name of the method + being used (GET, POST, et + cetera)
- Request_Protocol - the name and version of + the protocol with which the request was made (e.g., + "HTTP/0.9", "HTTP/1.1", etc.)
- Request_URI - the resource requested on the HTTP + request line -- generally the portion of the URL + following the scheme and host portion without the query string
+
The name of an environment variable in the list of those +associated with the request. This allows +SetEnvIf directives to test against the result +of prior matches. Only those environment variables defined by earlier +SetEnvIf[NoCase] directives are available for testing in +this manner. 'Earlier' means that they were defined at a broader scope +(such as server-wide) or previously in the current directive's scope. +Environment variables will be considered only if there was no match +among request characteristics and a regular expression was not +used for the attribute.

+ +

The second argument (regex) is a regular expression. If the regex +matches against the attribute, then the remainder of the +arguments are evaluated.

+ +

The rest of the arguments give the names of variables to set, and +optionally values to which they should be set. These take the form +of

+ +

varname, or
!varname, or
varname=value

+ +

In the first form, the value will be set to "1". The second + will remove the given variable if already defined, and the + third will set the variable to the literal value given by + value. Since version 2.0.51 Apache will + recognize occurrences of $1..$9 within + value and replace them by parenthesized subexpressions + of regex.

+ +

Example:

+ + SetEnvIf Request_URI "\.gif$" object_is_image=gif + SetEnvIf Request_URI "\.jpg$" object_is_image=jpg + SetEnvIf Request_URI "\.xbm$" object_is_image=xbm + : + SetEnvIf Referer www\.mydomain\.com intra_site_referral + : + SetEnvIf object_is_image xbm XBIT_PROCESSING=1 + : + SetEnvIf ^TS* ^[a-z].* HAVE_TS +

+ +

The first three will set the environment variable + object_is_image if the request was for an image + file, and the fourth sets intra_site_referral if + the referring page was somewhere on the + www.mydomain.com Web site.

+ +

The last example will set environment variable + HAVE_TS if the request contains any headers that + begin with "TS" whose values begins with any character in the + set [a-z].

+ +

SetEnvIfNoCase Directive