From 7528b97154f0402aa5ff008ceff7a96c927c493a Mon Sep 17 00:00:00 2001 From: Stefan Fritsch Date: Mon, 29 Oct 2012 20:39:05 +0000 Subject: [PATCH] Backport r1403476: Mention string-valued expression in the BNF. Clarify when header names are added to the Vary header. git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1403486 13f79535-47bb-0310-9956-ffa450edef68 --- docs/manual/expr.xml | 17 +++++++++++++++-- docs/manual/mod/mod_log_config.xml | 3 ++- docs/manual/mod/mod_log_debug.xml | 8 +++++--- docs/manual/mod/mod_rewrite.xml | 8 +++++--- 4 files changed, 27 insertions(+), 9 deletions(-) diff --git a/docs/manual/expr.xml b/docs/manual/expr.xml index 10f0d749e8..7b1f6d6626 100644 --- a/docs/manual/expr.xml +++ b/docs/manual/expr.xml @@ -55,6 +55,10 @@ Grammar in Backus-Naur Form notation

Backus-Naur Form (BNF) is a notation technique for context-free grammars, often used to describe the syntax of languages used in computing. + In most cases, expressions are used to express boolean values. + For these, the starting boint in the BNF is expr. However, a few directives + like LogMessage accept expressions + that evaluate to a string value. For those, the starting boint in the BNF is code. 

@@ -135,7 +139,10 @@ listfunction ::= listfuncname "(" word ")"
 
     
The following variables provide the values of the named HTTP request
     headers. The values of other headers can be obtained with the
-    req function.

+    req function. Using these
+    variables may cause the header name to be added to the Vary
+    header of the HTTP response, except where otherwise noted for the
+    directive accepting the expression.

 
     
@@ -425,7 +432,8 @@ listfunction ::= listfuncname "(" word ")"
 
     
-        
+        
@@ -457,6 +465,11 @@ listfunction ::= listfuncname "(" word ")"
     
The functions marked as "restricted" are not available in some modules
     like mod_include.

 
+    
When the functions req or http are used,
+    the header name will automatically be added to the Vary header of the
+    HTTP response, except where otherwise noted for the directive accepting
+    the expression.

+
     
In addition to string-valued functions, there are also list-valued functions which
     take one string as argument and return a wordlist, i.e. a list of strings. The wordlist
     can be used with the special -in operator.
diff --git a/docs/manual/mod/mod_log_config.xml b/docs/manual/mod/mod_log_config.xml
index d2f1fc71dc..feda90c371 100644
--- a/docs/manual/mod/mod_log_config.xml
+++ b/docs/manual/mod/mod_log_config.xml
@@ -461,7 +461,8 @@ CustomLog logs/access_log "%h %l %u %t \"%r\" %>s %b"
     environment. Alternatively, the condition
     can be expressed as arbitrary boolean expression. If the condition is not satisfied, the request
-    will not be logged.

+    will not be logged. References to HTTP headers  in the expression
+    will not cause the header names to be added to the Vary header.
Environment variables can be set on a per-request
     basis using the mod_setenvif
diff --git a/docs/manual/mod/mod_log_debug.xml b/docs/manual/mod/mod_log_debug.xml
index 1556b664ed..f1517449a2 100644
--- a/docs/manual/mod/mod_log_debug.xml
+++ b/docs/manual/mod/mod_log_debug.xml
@@ -93,8 +93,9 @@
 
     
This directive causes a user defined message to be logged to the
     error log. The message can use variables and functions from the
-    ap_expr syntax. The messages are logged at
-    loglevel info.

+    ap_expr syntax. References to HTTP headers
+    will not cause header names to be added to the Vary header. The
+    messages are logged at loglevel info.
The hook specifies before which phase of request procesing the message
     will be logged. The following hooks are supported:

@@ -122,7 +123,8 @@
 
     
The optional expression allows to restrict the message if a
     condition is met. The details of the expression syntax are described in
-    the ap_expr documentation.

+    the ap_expr documentation. References to HTTP
+    headers will not cause the header names to be added to the Vary header.

 
diff --git a/docs/manual/mod/mod_rewrite.xml b/docs/manual/mod/mod_rewrite.xml
index edfdd2e9c5..0479e5e721 100644
--- a/docs/manual/mod/mod_rewrite.xml
+++ b/docs/manual/mod/mod_rewrite.xml
@@ -567,9 +567,11 @@ Alias /myapp /opt/myapp-1.2.3
         
 
-      
If the TestString has the special value expr, the
-      CondPattern will be treated as an
-      ap_expr.

+      
If the TestString has the special value expr,
+      the CondPattern will be treated as an
+      ap_expr. HTTP headers referenced in the
+      expression will be added to the Vary header if the novary
+      flag is not given.
Other things you should be aware of:

 
-- 
2.40.0



     
NameDescriptionRestricted

     
req, httpGet HTTP request header
Get HTTP request header; header names may be added to the Vary
+            header, see below

     
resp
         Get HTTP response header

     
reqenv