Adding SetEnvIfExpr documentation, and more references to expr.html

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1037339 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 43 insertions, 0 deletions

diff --git a/docs/manual/mod/mod_setenvif.xml b/docs/manual/mod/mod_setenvif.xml
index 6c0c92a9d9..ef639a0a2c 100644
--- a/docs/manual/mod/mod_setenvif.xml
+++ b/docs/manual/mod/mod_setenvif.xml
@@ -254,6 +254,49 @@ for additional examples.
 </seealso>
 </directivesynopsis>
 
+
+<directivesynopsis>
+
+<name>SetEnvIfExpr</name>
+<description>Sets environment variables based on an 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 <directive type="section">If</directive>
+    <code>ap_expr</code>. These expressions will be evaluated at runtime,
+    and applied <em>env-variable</em> in the same fashion as <directive
+    >SetEnvIf</directive>.</p>
+
+<example>
+    SetEnvIfExpr "tolower(%req['X-Sendfile']) = 'D:\images\very_big.iso')" iso_delivered
+</example>
+
+    <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>For a more useful example, consider the <code>Referer</code>
+    example from above for a site with more than one domain:</p>
+
+<example>
+    SetEnvIfExpr "${HTTP_REFERER} in www.example.com,example.com,w2.example3.org" intra_site_referral
+</example>
+</usage>
+
+<seealso><a href="../expr.html">Expressions in Apache HTTP Server</a>,
+for a complete reference and more examples.</seealso>
+<seealso><directive type="section">If</directive> can be used to achive similar
+results.</seealso>
+<seealso><module>mod_filter</module></seealso>
+<seealso><module>mod_include></module></seealso>
+</directivesynopsis>
+
 <directivesynopsis>
 <name>SetEnvIfNoCase</name>
 <description>Sets environment variables based on attributes of the request