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| <modulesynopsis metafile="mod_setenvif.xml.meta"> |
| |
| <name>mod_setenvif</name> |
| <description>Allows the setting of environment variables based |
| on characteristics of the request</description> |
| <status>Base</status> |
| <sourcefile>mod_setenvif.c</sourcefile> |
| <identifier>setenvif_module</identifier> |
| |
| |
| <summary> |
| |
| <p>The <module>mod_setenvif</module> module allows you to set |
| internal 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, as well as becoming |
| available to CGI scripts and SSI pages.</p> |
| |
| <p>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 <code>netscape</code> if the |
| browser is mozilla but not MSIE.</p> |
| |
| <highlight language="config"> |
| BrowserMatch ^Mozilla netscape |
| BrowserMatch MSIE !netscape |
| </highlight> |
| |
| <p>When the server looks up a path via an internal |
| <glossary ref="subrequest">subrequest</glossary> such as looking |
| for a <directive module="mod_dir" >DirectoryIndex</directive> |
| or generating a directory listing with <module>mod_autoindex</module>, |
| per-request environment variables are <em>not</em> inherited in the |
| subrequest. Additionally, |
| <directive module="mod_setenvif">SetEnvIf</directive> directives |
| are not separately evaluated in the subrequest due to the API phases |
| <module>mod_setenvif</module> takes action in.</p> |
| |
| <p>A regular expression only needs quoting when it contains space, |
| in which case single and double quotes are equivalent. Unlike |
| <module>mod_rewrite</module>, <module>mod_setenvif</module> strips every |
| other backslash when parsing the expression; thus <code>\\</code> |
| requires <code>\\\</code>, and <code>\\\</code> requires |
| <code>\\\\\</code>.</p> |
| |
| </summary> |
| |
| <seealso><a href="../env.html">Environment Variables in Apache HTTP Server</a></seealso> |
| |
| <directivesynopsis> |
| <name>BrowserMatch</name> |
| <description>Sets environment variables conditional on HTTP User-Agent |
| </description> |
| <syntax>BrowserMatch <em>regex [!]env-variable</em>[=<em>value</em>] |
| [[!]<em>env-variable</em>[=<em>value</em>]] ...</syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>FileInfo</override> |
| |
| <usage> |
| <p>The <directive>BrowserMatch</directive> is a special cases of the |
| <directive module="mod_setenvif">SetEnvIf</directive> directive that |
| sets environment variables conditional on the |
| <code>User-Agent</code> HTTP request header. The following two |
| lines have the same effect:</p> |
| <highlight language="config"> |
| BrowserMatch Robot is_a_robot |
| SetEnvIf User-Agent Robot is_a_robot |
| </highlight> |
| |
| <p>Some additional examples:</p> |
| <highlight language="config"> |
| BrowserMatch ^Mozilla forms jpeg=yes browser=netscape |
| BrowserMatch "^Mozilla/[2-3]" tables agif frames javascript |
| BrowserMatch MSIE !javascript |
| </highlight> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>BrowserMatchNoCase</name> |
| <description>Sets environment variables conditional on User-Agent without |
| respect to case</description> |
| <syntax>BrowserMatchNoCase <em>regex [!]env-variable</em>[=<em>value</em>] |
| [[!]<em>env-variable</em>[=<em>value</em>]] ...</syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>FileInfo</override> |
| |
| <usage> |
| |
| <p>The <directive>BrowserMatchNoCase</directive> directive is |
| semantically identical to the <directive |
| module="mod_setenvif">BrowserMatch</directive> directive. |
| However, it provides for case-insensitive matching. For |
| example:</p> |
| <highlight language="config"> |
| BrowserMatchNoCase mac platform=macintosh |
| BrowserMatchNoCase win platform=windows |
| </highlight> |
| |
| <p>The <directive>BrowserMatch</directive> and |
| <directive>BrowserMatchNoCase</directive> directives are special cases of |
| the <directive module="mod_setenvif">SetEnvIf</directive> and <directive |
| module="mod_setenvif">SetEnvIfNoCase</directive> |
| directives. The following two lines have the same effect:</p> |
| <highlight language="config"> |
| BrowserMatchNoCase Robot is_a_robot |
| SetEnvIfNoCase User-Agent Robot is_a_robot |
| </highlight> |
| </usage> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SetEnvIf</name> |
| <description>Sets environment variables based on attributes of the request |
| </description> |
| <syntax>SetEnvIf <em>attribute |
| regex [!]env-variable</em>[=<em>value</em>] |
| [[!]<em>env-variable</em>[=<em>value</em>]] ...</syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>FileInfo</override> |
| |
| <usage> |
| <p>The <directive>SetEnvIf</directive> directive defines |
| environment variables based on attributes of the request. The |
| <em>attribute</em> specified in the first argument can be one of the |
| following things:</p> |
| |
| <ol> |
| <li>An HTTP request header field (see <a |
| href="http://www.rfc-editor.org/rfc/rfc2616.txt">RFC2616</a> |
| for more information about these); for example: <code>Host</code>, |
| <code>User-Agent</code>, <code>Referer</code>, and |
| <code>Accept-Language</code>. A regular expression may be |
| used to specify a set of request headers.</li> |
| |
| <li>One of the following aspects of the request: |
| <ul> |
| <li><code>Remote_Host</code> - the hostname (if available) of |
| the client making the request</li> |
| |
| <li><code>Remote_Addr</code> - the IP address of the client |
| making the request</li> |
| |
| <li><code>Server_Addr</code> - the IP address of the server |
| on which the request was received (only with versions later |
| than 2.0.43)</li> |
| |
| <li><code>Request_Method</code> - the name of the method |
| being used (<code>GET</code>, <code>POST</code>, <em>et |
| cetera</em>)</li> |
| |
| <li><code>Request_Protocol</code> - the name and version of |
| the protocol with which the request was made (<em>e.g.</em>, |
| "HTTP/0.9", "HTTP/1.1", <em>etc.</em>)</li> |
| |
| <li><code>Request_URI</code> - the resource requested on the HTTP |
| request line -- generally the portion of the URL |
| following the scheme and host portion without the query string. See |
| the <directive module="mod_rewrite">RewriteCond</directive> |
| directive of <module>mod_rewrite</module> for extra information on |
| how to match your query string.</li> |
| </ul> |
| </li> |
| |
| <li>The name of an environment variable in the list of those |
| associated with the request. This allows |
| <directive>SetEnvIf</directive> directives to test against the result |
| of prior matches. Only those environment variables defined by earlier |
| <code>SetEnvIf[NoCase]</code> 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 <em>attribute</em>.</li> |
| |
| </ol> |
| |
| <p>The second argument (<em>regex</em>) is a <glossary |
| ref="regex">regular expression</glossary>. If the <em>regex</em> |
| matches against the <em>attribute</em>, then the remainder of the |
| arguments are evaluated.</p> |
| |
| <p>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><code><em>varname</em></code>, or</li> |
| |
| <li><code>!<em>varname</em></code>, or</li> |
| |
| <li><code><em>varname</em>=<em>value</em></code></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 literal value given by |
| <code><em>value</em></code>. Since version 2.0.51, Apache httpd will |
| recognize occurrences of <code>$1</code>..<code>$9</code> within |
| <var>value</var> and replace them by parenthesized subexpressions |
| of <var>regex</var>. <code>$0</code> provides access to the whole |
| string matched by that pattern.</p> |
| |
| <p>If the special value <code>--early</code> is specified, and this |
| directive is not in directory context, the directive will be evaluated |
| earlier during request processing. This allows the output variables |
| set by this directive to be used as input to the "early mode" option of |
| the <directive module="mod_headers">RequestHeader</directive> directive. |
| Available in 2.5.1 and later.</p> |
| |
| <highlight language="config"> |
| SetEnvIf Request_URI "\.gif$" object_is_image=gif |
| SetEnvIf Request_URI "\.jpg$" object_is_image=jpg |
| SetEnvIf Request_URI "\.xbm$" object_is_image=xbm |
| |
| SetEnvIf Referer www\.mydomain\.example\.com intra_site_referral |
| |
| SetEnvIf object_is_image xbm XBIT_PROCESSING=1 |
| |
| SetEnvIf Request_URI "\.(.*)$" EXTENSION=$1 |
| |
| SetEnvIf ^TS ^[a-z] HAVE_TS |
| </highlight> |
| |
| <p>The first three will set the environment variable |
| <code>object_is_image</code> if the request was for an image |
| file, and the fourth sets <code>intra_site_referral</code> if |
| the referring page was somewhere on the |
| <code>www.mydomain.example.com</code> Web site.</p> |
| |
| <p>The last example will set environment variable |
| <code>HAVE_TS</code> if the request contains any headers that |
| begin with "TS" whose values begins with any character in the |
| set [a-z].</p> |
| </usage> |
| |
| <seealso><a href="../env.html">Environment Variables in Apache HTTP Server</a>, |
| for additional examples. |
| </seealso> |
| </directivesynopsis> |
| |
| |
| <directivesynopsis> |
| |
| <name>SetEnvIfExpr</name> |
| <description>Sets environment variables based on an ap_expr expression</description> |
| <syntax>SetEnvIfExpr <em>expr |
| [!]env-variable</em>[=<em>value</em>] |
| [[!]<em>env-variable</em>[=<em>value</em>]] ...</syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>FileInfo</override> |
| |
| <usage> |
| <p>The <directive>SetEnvIfExpr</directive> directive defines |
| environment variables based on an <a href="../expr.html">expression</a>. |
| These expressions will be evaluated at runtime, |
| and applied <em>env-variable</em> in the same fashion as <directive |
| >SetEnvIf</directive>, including backreferences.</p> |
| |
| <highlight language="config"> |
| SetEnvIfExpr "tolower(req('X-Sendfile')) == 'd:\images\very_big.iso')" iso_delivered |
| SetEnvIfExpr "tolower(req('X-Sendfile')) =~ /(.*\.iso$)/" iso-path=$1 |
| </highlight> |
| |
| <p>This would set the environment variable <code>iso_delivered</code> |
| every time our application attempts to send it via <code>X-Sendfile</code></p> |
| |
| <p>A more useful example would be to set the variable rfc1918 if the |
| remote IP address is a private address according to RFC 1918:</p> |
| |
| <highlight language="config"> |
| SetEnvIfExpr "-R '10.0.0.0/8' || -R '172.16.0.0/12' || -R '192.168.0.0/16'" rfc1918 |
| </highlight> |
| </usage> |
| |
| <seealso><a href="../expr.html">Expressions in Apache HTTP Server</a>, |
| for a complete reference and more examples.</seealso> |
| <seealso><directive module="core" type="section">If</directive> can be used to achieve similar |
| results.</seealso> |
| <seealso><module>mod_filter</module></seealso> |
| </directivesynopsis> |
| |
| <directivesynopsis> |
| <name>SetEnvIfNoCase</name> |
| <description>Sets environment variables based on attributes of the request |
| without respect to case</description> |
| <syntax>SetEnvIfNoCase <em>attribute regex |
| [!]env-variable</em>[=<em>value</em>] |
| [[!]<em>env-variable</em>[=<em>value</em>]] ...</syntax> |
| <contextlist><context>server config</context> |
| <context>virtual host</context><context>directory</context> |
| <context>.htaccess</context></contextlist> |
| <override>FileInfo</override> |
| |
| <usage> |
| |
| <p>The <directive>SetEnvIfNoCase</directive> is semantically identical to |
| the <directive module="mod_setenvif">SetEnvIf</directive> directive, |
| and differs only in that the regular expression matching is |
| performed in a case-insensitive manner. For example:</p> |
| <highlight language="config"> |
| SetEnvIfNoCase Host Example\.Org site=example |
| </highlight> |
| |
| <p>This will cause the <code>site</code> environment variable |
| to be set to "<code>example</code>" if the HTTP request header |
| field <code>Host:</code> was included and contained |
| <code>Example.Org</code>, <code>example.org</code>, or any other |
| combination.</p> |
| </usage> |
| </directivesynopsis> |
| </modulesynopsis> |