coar 97/08/26 09:43:13
Added: htdocs/manual/mod mod_setenvif.html Log: Ta-daah! The documentation for mod_setenvif, which defines the SetEnvIf* and BrowserMatch* directives. (And in time for 1.3b1, too) Revision Changes Path 1.1 apachen/htdocs/manual/mod/mod_setenvif.html Index: mod_setenvif.html =================================================================== <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML> <HEAD> <TITLE>Apache module mod_setenvif</TITLE> </HEAD> <!-- Background white, links blue (unvisited), navy (visited), red (active) --> <BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#000080" ALINK="#FF0000" > <!--#include virtual="header.html" --> <H1 ALIGN="CENTER">Module mod_setenvif</H1> <P> This module is contained in the <SAMP>mod_setenvif.c</SAMP> file, and <STRONG>is</STRONG> compiled in by default. It provides for the ability to set environment variables based upon attributes of the request. </P> <H2>Summary</H2> <P> The <SAMP>mod_setenvif</SAMP> module allows you to set environment variables according to whether different aspects of the request match regular expressions you specify. These envariables can be used by other parts of the server to make decisions about actions to be taken. </P> <H2>Directives</H2> <UL> <LI><A HREF="#BrowserMatch">BrowserMatch</A> </LI> <LI><A HREF="#BrowserMatchNoCase">BrowserMatchNoCase</A> </LI> <LI><A HREF="#SetEnvIf">SetEnvIf</A> </LI> <LI><A HREF="#SetEnvIfNoCase">SetEnvIfNoCase</A> </LI> </UL> <HR> <!-- the HR is part of the directive description --> <H2><A NAME="BrowserMatch">The <SAMP>BrowserMatch</SAMP> Directive</A></H2> <P> <STRONG>Syntax:</STRONG> BrowserMatch <EM>regex envar[=value] [...]</EM> <BR> <STRONG>Default:</STRONG> <EM>none</EM> <BR> <STRONG>Context:</STRONG> server config <BR> <STRONG>Override:</STRONG> <EM>none</EM> <BR> <STRONG>Status:</STRONG> Base <BR> <STRONG>Module:</STRONG> mod_setenvif <BR> <STRONG>Compatibility:</STRONG> Apache 1.2 and above </P> <P> The BrowserMatch directive defines environment variables based on the <SAMP>User-Agent</SAMP> HTTP request header field. The first argument should be a POSIX.2 extended regular expression (similar to an <SAMP>egrep</SAMP>-style regex). 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 </P> <OL> <LI><SAMP><EM>varname</EM></SAMP>, or </LI> <LI><SAMP>!<EM>varname</EM></SAMP>, or </LI> <LI><SAMP><EM>varname</EM>=<EM>value</EM></SAMP> </LI> </OL> <P> 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 value given by <SAMP><EM>value</EM></SAMP>. If a <SAMP>User-Agent</SAMP> string matches more than one entry, they will be merged. Entries are processed in the order in which they appear, and later entries can override earlier ones. </P> <P> For example: </P> <PRE> BrowserMatch ^Mozilla forms jpeg=yes browser=netscape BrowserMatch "^Mozilla/[2-3]" tables agif frames javascript BrowserMatch MSIE !javascript </PRE> <P> Note that the regular expression string is <STRONG>case-sensitive</STRONG>. For cane-INsensitive matching, see the <A HREF="#BrowserMatchNoCase" ><SAMP>BrowserMatchNoCase</SAMP></A> directive. </P> <P> The <SAMP>BrowserMatch</SAMP> and <SAMP>BrowserMatchNoCase</SAMP> directives are special cases of the <A HREF="#SetEnvIf" ><SAMP>SetEnvIf</SAMP></A> and <A HREF="#SetEnvIfNoCase" ><SAMP>SetEnvIfNoCase</SAMP></A> directives. The following two lines have the same effect: </P> <PRE> BrowserMatchNoCase Robot is_a_robot SetEnvIfNoCase User-Agent Robot is_a_robot </PRE> <HR> <!-- the HR is part of the directive description --> <H2> <A NAME="BrowserMatchNoCase"> The <SAMP>BrowserMatchNoCase</SAMP> Directive </A> </H2> <P> <STRONG>Syntax:</STRONG> BrowserMatchNoCase <EM>regex envar[=value] [...]</EM> <BR> <STRONG>Default:</STRONG> <EM>none</EM> <BR> <STRONG>Context:</STRONG> server config <BR> <STRONG>Override:</STRONG> <EM>none</EM> <BR> <STRONG>Status:</STRONG> Base <BR> <STRONG>Module:</STRONG> mod_setenvif <BR> <STRONG>Compatibility:</STRONG> Apache 1.2 and above </P> <P> The <SAMP>BrowserMatchNoCase</SAMP> directive is semantically identical to the <A HREF="#BrowserMatch" ><SAMP>BrowserMatch</SAMP></A> directive. However, it provides for case-insensitive matching. For example: </P> <PRE> BrowserMatchNoCase mac platform=macintosh BrowserMatchNoCase win platform=windows </PRE> <P> The <SAMP>BrowserMatch</SAMP> and <SAMP>BrowserMatchNoCase</SAMP> directives are special cases of the <A HREF="#SetEnvIf" ><SAMP>SetEnvIf</SAMP></A> and <A HREF="#SetEnvIfNoCase" ><SAMP>SetEnvIfNoCase</SAMP></A> directives. The following two lines have the same effect: </P> <PRE> BrowserMatchNoCase Robot is_a_robot SetEnvIfNoCase User-Agent Robot is_a_robot </PRE> <HR> <!-- the HR is part of the directive description --> <H2> <A NAME="SetEnvIf"> The <SAMP>SetEnvIf</SAMP> Directive </A> </H2> <P> <STRONG>Syntax:</STRONG> SetEnvIf <EM> attribute regex envar[=value] [...]</EM> <BR> <STRONG>Default:</STRONG> <EM>none</EM> <BR> <STRONG>Context:</STRONG> server config <BR> <STRONG>Override:</STRONG> <EM>none</EM> <BR> <STRONG>Status:</STRONG> Base <BR> <STRONG>Module:</STRONG> mod_setenvif <BR> <STRONG>Compatibility:</STRONG> Apache 1.3 and above </P> <P> The <SAMP>SetEnvIf</SAMP> directive defines environment variables based on attributes of the request. These attributes can be the values of various HTTP request header fields (see <A HREF="http://ds.internic.net/rfc/rfc2068.txt" >RFC2068</A> for more information about these), or of other aspects of the request, including the following: </P> <UL> <LI><SAMP>Remote_Host</SAMP> - the hostname (if available) of the client making the request </LI> <LI><SAMP>Remote_Addr</SAMP> - the IP address of the client making the request </LI> <LI><SAMP>Remote_User</SAMP> - the authenticated username (if available) </LI> <LI><SAMP>Request_Method</SAMP> - the name of the method being used (<SAMP>GET</SAMP>, <SAMP>POST</SAMP>, <EM>et cetera</EM>) </LI> <LI><SAMP>Request_URI</SAMP> - the portion of the URL following the scheme and host portion </LI> </UL> <P> Some of the more commonly used request header field names include <SAMP>Host</SAMP>, <SAMP>User-Agent</SAMP>, and <SAMP>Referer</SAMP>. </P> <P> Example: </P> <PRE> SetEnvIf Request_URI "\.(gif)|(jpg)|(xbm)$" object_is_image SetEnvIf Referer www\.mydomain\.com intra_site_referral </PRE> <P> The first will set the envariable <SAMP>object_is_image</SAMP> if the request was for an image file, and the second sets <SAMP>intra_site_referral</SAMP> if the referring page was somewhere on the <SAMP>www.mydomain.com</SAMP> Web site. </P> <HR> <!-- the HR is part of the directive description --> <H2> <A NAME="SetEnvIfNoCase"> The <SAMP>SetEnvIfNoCase</SAMP> Directive </A> </H2> <P> <STRONG>Syntax:</STRONG> SetEnvIfNoCase <EM> attribute regex envar[=value] [...]</EM> <BR> <STRONG>Default:</STRONG> <EM>none</EM> <BR> <STRONG>Context:</STRONG> server config <BR> <STRONG>Override:</STRONG> <EM>none</EM> <BR> <STRONG>Status:</STRONG> Base <BR> <STRONG>Module:</STRONG> mod_setenvif <BR> <STRONG>Compatibility:</STRONG> Apache 1.3 and above </P> <P> The <SAMP>SetEnvIfNoCase</SAMP> is semantically identical to the <A HREF="#SetEnvIf" ><SAMP>SetEnvIf</SAMP></A> directive, and differs only in that the regular expression matching is performed in a case-insensitive manner. For example: </P> <PRE> SetEnvIfNoCase Host Apache\.Org site=apache </PRE> <P> This will cause the <SAMP>site</SAMP> envariable to be set to "<SAMP>apache</SAMP>" if the HTTP request header field <SAMP>Host:</SAMP> was included and contained <SAMP>Apache.Org</SAMP>, <SAMP>apache.org</SAMP>, or any other combination. </P> <!--#include virtual="footer.html" --> </BODY> </HTML>