htaccess re-applies a matched rule constantly and ends up in a loop - apache

Question

According to http://htaccess.madewithlove.be/ the following ruleset works perfectly:
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^images/([^\?]+)$ /_lib/mask_images.php [L]
RewriteRule ^search/([^\?]+)/merchant/([^\?]+)/brand/([^\?]+)/page/([^\?]+)$ /search.php?keyword=$1&merchant=$2&brand=$3&page=$4 [L]
RewriteRule ^search/([^\?]+)/brand/([^\?]+)/page/([^\?]+)$ /search.php?keyword=$1&brand=$2&page=$3 [L]
RewriteRule ^search/([^\?]+)/merchant/([^\?]+)/page/([^\?]+)$ /search.php?keyword=$1&merchant=$2&page=$3 [L]
RewriteRule ^search/([^\?]+)/page/([^\?]+)$ /search.php?keyword=$1&page=$2 [L]
RewriteRule ^search/([^\?]+)/brand/([^\?]+)$ /search.php?keyword=$1&brand=$2 [L]
RewriteRule ^search/([^\?]+)/merchant/([^\?]+)$ /search.php?keyword=$1&merchant=$2 [L]
RewriteRule ^search/([^\?]+)/merchant/([^\?]+)/brand/([^\?]+)$ /search.php?keyword=$1&merchant=$2&brand=$3 [L]
RewriteRule ^search/([^\?]+)$ /search.php?keyword=$1 [L]
RewriteRule ([^\?]+)/productID/([^\?]+)$ /detail.php?keyword=$1&productID=$2 [L]
RewriteRule ([^\?]+)$ /detail.php?keyword=$1 [L]
The issue is that when the last 2 rules are applied and matched, Apache re-applies the matched rules (and correctly assigned arguments) and goes into an infinite loop.
I added:
RewriteCond %{REQUEST_URI} !search.php$
RewriteCond %{REQUEST_URI} !detail.php$
RewriteCond %{REQUEST_URI} !index.php$
to the above ruleset. Again, verified and working by the htaccess tester website, it now stops processing and outputs "detail.php" as the argument.
Here is what the Rewrite Log says:
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^images/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)/brand/(.*)/page/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/brand/(.*)/page/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)/page/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/page/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/brand/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)/brand/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '^search/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '(.*)/productID/(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/hello -> hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) [perdir /var/www/html/] applying pattern '(.*)$' to uri 'hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (2) [perdir /var/www/html/] rewrite 'hello' -> '/detail.php?keyword=hello'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (3) split uri=/detail.php?keyword=hello -> uri=/detail.php, args=keyword=hello
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (2) [perdir /var/www/html/] trying to replace prefix /var/www/html/ with /
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaabfcc50/initial] (1) [perdir /var/www/html/] internal redirect with /detail.php [INTERNAL REDIRECT]
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^images/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)/brand/(.*)/page/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/brand/(.*)/page/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)/page/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/page/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/brand/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)/merchant/(.*)/brand/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '^search/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '(.*)/productID/(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] strip per-dir prefix: /var/www/html/detail.php -> detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) [perdir /var/www/html/] applying pattern '(.*)$' to uri 'detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (2) [perdir /var/www/html/] rewrite 'detail.php' -> '/detail.php?keyword=detail.php'
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (3) split uri=/detail.php?keyword=detail.php -> uri=/detail.php, args=keyword=detail.php
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (2) [perdir /var/www/html/] trying to replace prefix /var/www/html/ with /
192.168.0.2 - - [11/Nov/2011:08:54:27 +0200] [website1.co.za/sid#2afe7a520d70][rid#2aaaaac0e0c0/initial/redir#1] (1) [perdir /var/www/html/] internal redirect with /detail.php [INTERNAL REDIRECT]
As you can see, it matches the correct rule and the arguments are setup correctly, but for some reason it then RE-APPLIES that internal redirect again and the argument going through changes from what it should be (which, in this example is "hello") to the file name, detail.php
NO idea how to go about this since everything I know of currently, this should be working because /search works brilliantly.
EDIT
This is what detail.php contains:
<?
echo $_GET["keyword"]."<br>";
echo $_GET["merchant"]."<br>";
echo $_GET["brand"]."<br>";
echo $_GET["page"]."<br>";
echo $_GET["productID"]."<br>";
exit();
?>

Answer 1

The final [L] to /detail.php does an (internal) redirect. And hence Apache sees a totally new request coming in - re-applying the rules ones more.
So options may be to make sure that the rule does not apply to the /detail.php (i.e. by ensuring the argument name is a bit different) or pre-cathcing an ^/detail.php early and negating out.
http://www.sitepoint.com/mod_rewrite-no-endless-loops/ tries to explain this with different words. Another common approach is using things like:
# Loop stopping snippets.
# Uncomment if there are specific pages to exempt.
# RewriteCond %{REQUEST_URI} ^/(stats/|missing\.html|failed_auth\.html|error/).* [NC]
# RewriteRule .* - [L]
RewriteCond %{ENV:REDIRECT_STATUS} 200
RewriteRule .* - [L]
where you detect this on the second pass (after the internal redirect) and have it bail in a generic way early.
Dw.

Answer 2

Your indentation does not reflect the semantic association of the RewriteRule and RewriteCond directives.
The conditions
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
only apply if the URI pattern is ^images/([^\?]+)$. What you need is logically flip this and or at least skip the 10 following rules for these to apply for all URI patterns:
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [SKIP=10]
See my article More on using Rewrite rules in .htaccess files for more details.