From: Eric Covener <covener@apache.org>
Date: Sat, 17 Sep 2016 20:41:07 +0000 (+0000)
Subject: Merge r1761272 from trunk:
X-Git-Tag: 2.4.24~241
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0657543f73f8307fc2e31b6151492ad10fecfe69;p=thirdparty%2Fapache%2Fhttpd.git

Merge r1761272 from trunk:

expand third common in the expression functions doc

Explain some risks at looking at per-request environment variables
set by other modules within <If>.

http://stackoverflow.com/questions/39462011/htaccess-if-else-always-selects-else





git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1761274 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/docs/manual/expr.xml b/docs/manual/expr.xml
index 525843bdfce..6226f213fb4 100644
--- a/docs/manual/expr.xml
+++ b/docs/manual/expr.xml
@@ -464,7 +464,7 @@ listfunction ::= listfuncname "<strong>(</strong>" word "<strong>)</strong>"
     <table border="1" style="zebra">
     <columnspec><column width=".2"/><column width=".4"/><column width=".4"/></columnspec>
 
-    <tr><th>Name</th><th>Description</th><th>Restricted</th></tr>
+    <tr><th>Name</th><th>Description</th><th>Special notes</th></tr>
     <tr><td><code>req</code>, <code>http</code></td>
         <td>Get HTTP request header; header names may be added to the Vary
             header, see below</td><td></td></tr>
@@ -475,15 +475,15 @@ listfunction ::= listfuncname "<strong>(</strong>" word "<strong>)</strong>"
         <td>Get HTTP response header</td><td></td></tr>
     <tr><td><code>reqenv</code></td>
         <td>Lookup request environment variable (as a shortcut,
-        <code>v</code> can be used too to access
-        variables).</td><td></td></tr>
+        <code>v</code> can also be used to access variables). 
+        <td>ordering</td></tr>
     <tr><td><code>osenv</code></td>
         <td>Lookup operating system environment variable</td><td></td></tr>
     <tr><td><code>note</code></td>
-        <td>Lookup request note</td><td></td></tr>
+        <td>Lookup request note</td><td>ordering</td></tr>
     <tr><td><code>env</code></td>
         <td>Return first match of <code>note</code>, <code>reqenv</code>,
-            <code>osenv</code></td><td></td></tr>
+            <code>osenv</code></td><td>ordering</td></tr>
     <tr><td><code>tolower</code></td>
         <td>Convert string to lower case</td><td></td></tr>
     <tr><td><code>toupper</code></td>
@@ -506,15 +506,39 @@ listfunction ::= listfuncname "<strong>(</strong>" word "<strong>)</strong>"
             encoding</td><td></td></tr>
     <tr><td><code>file</code></td>
         <td>Read contents from a file (including line endings, when present)
-        </td><td>yes</td></tr>
+        </td><td>restricted</td></tr>
+    <tr><td><code>filemod</code></td>
+        <td>Return last modification time of a file (or 0 if file does not exist
+            or is not regular file)</td><td>restricted</td></tr>
     <tr><td><code>filesize</code></td>
         <td>Return size of a file (or 0 if file does not exist or is not
-            regular file)</td><td>yes</td></tr>
+            regular file)</td><td>restricted</td></tr>
 
     </table>
 
-    <p>The functions marked as "restricted" are not available in some modules
-    like <module>mod_include</module>.</p>
+    <p>The functions marked as "restricted" in the final column are not 
+    available in some modules like <module>mod_include</module>.</p>
+
+    <p>The functions marked as "ordering" in the final column require some
+    consideration for the ordering of different components of the server,
+    especially when the function is used within the 
+    &lt;<directive module="core">If</directive>&gt; directive which is
+    evaluated relatively early.</p>
+    <note>
+    <title>Environment variable ordering</title>
+    When environment variables are looked up within an 
+    &lt;<directive module="core">If</directive>&gt; condition, it's important 
+    to consider how extremely early in request processing that this 
+    resolution occurs. As a guideline, any directive defined outside of virtual host 
+    context (directory, location, htaccess) is not likely to have yet had a 
+    chance to execute. <directive module="mod_setenvif">SetEnvIf</directive>
+    in virtual host scope is one directive that runs prior to this resolution
+    <br/>
+    <br/>
+    When <code>reqenv</code> is used outside of &lt;<directive module="core"
+    >If</directive>&gt;, the resolution will generally occur later, but the 
+    exact timing depends on the directive the expression has been used within.
+    </note>
 
     <p>When the functions <code>req</code> or <code>http</code> are used,
     the header name will automatically be added to the Vary header of the