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From rbo...@apache.org
Subject svn commit: r832094 [3/4] - /httpd/httpd/trunk/docs/manual/rewrite/
Date Mon, 02 Nov 2009 20:36:32 GMT
Modified: httpd/httpd/trunk/docs/manual/rewrite/rewrite_guide_advanced.html.en
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/rewrite/rewrite_guide_advanced.html.en?rev=832094&r1=832093&r2=832094&view=diff
==============================================================================
--- httpd/httpd/trunk/docs/manual/rewrite/rewrite_guide_advanced.html.en (original)
+++ httpd/httpd/trunk/docs/manual/rewrite/rewrite_guide_advanced.html.en Mon Nov  2 20:36:30 2009
@@ -41,1251 +41,11 @@
     avoids many problems.</div>
 
   </div>
-<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#cluster">Web Cluster with Consistent URL Space</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#structuredhomedirs">Structured Homedirs</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#filereorg">Filesystem Reorganization</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#redirect404">Redirect Failing URLs to Another Web Server</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#archive-access-multiplexer">Archive Access Multiplexer</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#browser-dependent-content">Browser Dependent Content</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#dynamic-mirror">Dynamic Mirror</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#reverse-dynamic-mirror">Reverse Dynamic Mirror</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#retrieve-missing-data">Retrieve Missing Data from Intranet</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#load-balancing">Load Balancing</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#new-mime-type">New MIME-type, New Service</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#on-the-fly-content">On-the-fly Content-Regeneration</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#autorefresh">Document With Autorefresh</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#mass-virtual-hosting">Mass Virtual Hosting</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#host-deny">Host Deny</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#proxy-deny">Proxy Deny</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#special-authentication">Special Authentication Variant</a></li>
-<li><img alt="" src="../images/down.gif" /> <a href="#referer-deflector">Referer-based Deflector</a></li>
-</ul><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module
+<div id="quickview"><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module
 documentation</a></li><li><a href="intro.html">mod_rewrite
 introduction</a></li><li><a href="rewrite_guide.html">Rewrite Guide - useful
 examples</a></li><li><a href="tech.html">Technical details</a></li></ul></div>
-<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="cluster" id="cluster">Web Cluster with Consistent URL Space</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>We want to create a homogeneous and consistent URL
-          layout across all WWW servers on an Intranet web cluster, i.e.,
-          all URLs (by definition server-local and thus
-          server-dependent!) become server <em>independent</em>!
-          What we want is to give the WWW namespace a single consistent
-          layout: no URL should refer to
-          any particular target server. The cluster itself
-          should connect users automatically to a physical target
-          host as needed, invisibly.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>First, the knowledge of the target servers comes from
-          (distributed) external maps which contain information on
-          where our users, groups, and entities reside. They have the
-          form:</p>
-
-<div class="example"><pre>
-user1  server_of_user1
-user2  server_of_user2
-:      :
-</pre></div>
-
-          <p>We put them into files <code>map.xxx-to-host</code>.
-          Second we need to instruct all servers to redirect URLs
-          of the forms:</p>
-
-<div class="example"><pre>
-/u/user/anypath
-/g/group/anypath
-/e/entity/anypath
-</pre></div>
-
-          <p>to</p>
-
-<div class="example"><pre>
-http://physical-host/u/user/anypath
-http://physical-host/g/group/anypath
-http://physical-host/e/entity/anypath
-</pre></div>
-
-          <p>when any URL path need not be valid on every server. The
-          following ruleset does this for us with the help of the map
-          files (assuming that server0 is a default server which
-          will be used if a user has no entry in the map):</p>
-
-<div class="example"><pre>
-RewriteEngine on
-
-RewriteMap      user-to-host   txt:/path/to/map.user-to-host
-RewriteMap     group-to-host   txt:/path/to/map.group-to-host
-RewriteMap    entity-to-host   txt:/path/to/map.entity-to-host
-
-RewriteRule   ^/u/<strong>([^/]+)</strong>/?(.*)   http://<strong>${user-to-host:$1|server0}</strong>/u/$1/$2
-RewriteRule   ^/g/<strong>([^/]+)</strong>/?(.*)  http://<strong>${group-to-host:$1|server0}</strong>/g/$1/$2
-RewriteRule   ^/e/<strong>([^/]+)</strong>/?(.*) http://<strong>${entity-to-host:$1|server0}</strong>/e/$1/$2
-
-RewriteRule   ^/([uge])/([^/]+)/?$          /$1/$2/.www/
-RewriteRule   ^/([uge])/([^/]+)/([^.]+.+)   /$1/$2/.www/$3\
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="structuredhomedirs" id="structuredhomedirs">Structured Homedirs</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Some sites with thousands of users use a
-          structured homedir layout, <em>i.e.</em> each homedir is in a
-          subdirectory which begins (for instance) with the first
-          character of the username. So, <code>/~foo/anypath</code>
-          is <code>/home/<strong>f</strong>/foo/.www/anypath</code>
-          while <code>/~bar/anypath</code> is
-          <code>/home/<strong>b</strong>/bar/.www/anypath</code>.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>We use the following ruleset to expand the tilde URLs
-          into the above layout.</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteRule   ^/~(<strong>([a-z])</strong>[a-z0-9]+)(.*)  /home/<strong>$2</strong>/$1/.www$3
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="filereorg" id="filereorg">Filesystem Reorganization</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>This really is a hardcore example: a killer application
-          which heavily uses per-directory
-          <code>RewriteRules</code> to get a smooth look and feel
-          on the Web while its data structure is never touched or
-          adjusted. Background: <strong><em>net.sw</em></strong> is
-          my archive of freely available Unix software packages,
-          which I started to collect in 1992. It is both my hobby
-          and job to do this, because while I'm studying computer
-          science I have also worked for many years as a system and
-          network administrator in my spare time. Every week I need
-          some sort of software so I created a deep hierarchy of
-          directories where I stored the packages:</p>
-
-<div class="example"><pre>
-drwxrwxr-x   2 netsw  users    512 Aug  3 18:39 Audio/
-drwxrwxr-x   2 netsw  users    512 Jul  9 14:37 Benchmark/
-drwxrwxr-x  12 netsw  users    512 Jul  9 00:34 Crypto/
-drwxrwxr-x   5 netsw  users    512 Jul  9 00:41 Database/
-drwxrwxr-x   4 netsw  users    512 Jul 30 19:25 Dicts/
-drwxrwxr-x  10 netsw  users    512 Jul  9 01:54 Graphic/
-drwxrwxr-x   5 netsw  users    512 Jul  9 01:58 Hackers/
-drwxrwxr-x   8 netsw  users    512 Jul  9 03:19 InfoSys/
-drwxrwxr-x   3 netsw  users    512 Jul  9 03:21 Math/
-drwxrwxr-x   3 netsw  users    512 Jul  9 03:24 Misc/
-drwxrwxr-x   9 netsw  users    512 Aug  1 16:33 Network/
-drwxrwxr-x   2 netsw  users    512 Jul  9 05:53 Office/
-drwxrwxr-x   7 netsw  users    512 Jul  9 09:24 SoftEng/
-drwxrwxr-x   7 netsw  users    512 Jul  9 12:17 System/
-drwxrwxr-x  12 netsw  users    512 Aug  3 20:15 Typesetting/
-drwxrwxr-x  10 netsw  users    512 Jul  9 14:08 X11/
-</pre></div>
-
-          <p>In July 1996 I decided to make this archive public to
-          the world via a nice Web interface. "Nice" means that I
-          wanted to offer an interface where you can browse
-          directly through the archive hierarchy. And "nice" means
-          that I didn't want to change anything inside this
-          hierarchy - not even by putting some CGI scripts at the
-          top of it. Why? Because the above structure should later be
-          accessible via FTP as well, and I didn't want any
-          Web or CGI stuff mixed in there.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>The solution has two parts: The first is a set of CGI
-          scripts which create all the pages at all directory
-          levels on-the-fly. I put them under
-          <code>/e/netsw/.www/</code> as follows:</p>
-
-<div class="example"><pre>
--rw-r--r--   1 netsw  users    1318 Aug  1 18:10 .wwwacl
-drwxr-xr-x  18 netsw  users     512 Aug  5 15:51 DATA/
--rw-rw-rw-   1 netsw  users  372982 Aug  5 16:35 LOGFILE
--rw-r--r--   1 netsw  users     659 Aug  4 09:27 TODO
--rw-r--r--   1 netsw  users    5697 Aug  1 18:01 netsw-about.html
--rwxr-xr-x   1 netsw  users     579 Aug  2 10:33 netsw-access.pl
--rwxr-xr-x   1 netsw  users    1532 Aug  1 17:35 netsw-changes.cgi
--rwxr-xr-x   1 netsw  users    2866 Aug  5 14:49 netsw-home.cgi
-drwxr-xr-x   2 netsw  users     512 Jul  8 23:47 netsw-img/
--rwxr-xr-x   1 netsw  users   24050 Aug  5 15:49 netsw-lsdir.cgi
--rwxr-xr-x   1 netsw  users    1589 Aug  3 18:43 netsw-search.cgi
--rwxr-xr-x   1 netsw  users    1885 Aug  1 17:41 netsw-tree.cgi
--rw-r--r--   1 netsw  users     234 Jul 30 16:35 netsw-unlimit.lst
-</pre></div>
-
-          <p>The <code>DATA/</code> subdirectory holds the above
-          directory structure, <em>i.e.</em> the real
-          <strong><em>net.sw</em></strong> stuff, and gets
-          automatically updated via <code>rdist</code> from time to
-          time. The second part of the problem remains: how to link
-          these two structures together into one smooth-looking URL
-          tree? We want to hide the <code>DATA/</code> directory
-          from the user while running the appropriate CGI scripts
-          for the various URLs. Here is the solution: first I put
-          the following into the per-directory configuration file
-          in the <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code>
-          of the server to rewrite the public URL path
-          <code>/net.sw/</code> to the internal path
-          <code>/e/netsw</code>:</p>
-
-<div class="example"><pre>
-RewriteRule  ^net.sw$       net.sw/        [R]
-RewriteRule  ^net.sw/(.*)$  e/netsw/$1
-</pre></div>
-
-          <p>The first rule is for requests which miss the trailing
-          slash! The second rule does the real thing. And then
-          comes the killer configuration which stays in the
-          per-directory config file
-          <code>/e/netsw/.www/.wwwacl</code>:</p>
-
-<div class="example"><pre>
-Options       ExecCGI FollowSymLinks Includes MultiViews
-
-RewriteEngine on
-
-#  we are reached via /net.sw/ prefix
-RewriteBase   /net.sw/
-
-#  first we rewrite the root dir to
-#  the handling cgi script
-RewriteRule   ^$                       netsw-home.cgi     [L]
-RewriteRule   ^index\.html$            netsw-home.cgi     [L]
-
-#  strip out the subdirs when
-#  the browser requests us from perdir pages
-RewriteRule   ^.+/(netsw-[^/]+/.+)$    $1                 [L]
-
-#  and now break the rewriting for local files
-RewriteRule   ^netsw-home\.cgi.*       -                  [L]
-RewriteRule   ^netsw-changes\.cgi.*    -                  [L]
-RewriteRule   ^netsw-search\.cgi.*     -                  [L]
-RewriteRule   ^netsw-tree\.cgi$        -                  [L]
-RewriteRule   ^netsw-about\.html$      -                  [L]
-RewriteRule   ^netsw-img/.*$           -                  [L]
-
-#  anything else is a subdir which gets handled
-#  by another cgi script
-RewriteRule   !^netsw-lsdir\.cgi.*     -                  [C]
-RewriteRule   (.*)                     netsw-lsdir.cgi/$1
-</pre></div>
-
-          <p>Some hints for interpretation:</p>
-
-          <ol>
-            <li>Notice the <code>L</code> (last) flag and no
-            substitution field ('<code>-</code>') in the fourth part</li>
-
-            <li>Notice the <code>!</code> (not) character and
-            the <code>C</code> (chain) flag at the first rule
-            in the last part</li>
-
-            <li>Notice the catch-all pattern in the last rule</li>
-          </ol>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="redirect404" id="redirect404">Redirect Failing URLs to Another Web Server</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>A typical FAQ about URL rewriting is how to redirect
-          failing requests on webserver A to webserver B. Usually
-          this is done via <code class="directive"><a href="../mod/core.html#errordocument">ErrorDocument</a></code> CGI scripts in Perl, but
-          there is also a <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> solution.
-          But note that this performs more poorly than using an
-          <code class="directive"><a href="../mod/core.html#errordocument">ErrorDocument</a></code>
-          CGI script!</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>The first solution has the best performance but less
-          flexibility, and is less safe:</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteCond   %{DOCUMENT_ROOT/%{REQUEST_URI} <strong>!-f</strong>
-RewriteRule   ^(.+)                             http://<strong>webserverB</strong>.dom/$1
-</pre></div>
-
-          <p>The problem here is that this will only work for pages
-          inside the <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code>. While you can add more
-          Conditions (for instance to also handle homedirs, etc.)
-          there is a better variant:</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteCond   %{REQUEST_URI} <strong>!-U</strong>
-RewriteRule   ^(.+)          http://<strong>webserverB</strong>.dom/$1
-</pre></div>
-
-          <p>This uses the URL look-ahead feature of <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.
-          The result is that this will work for all types of URLs
-          and is safe. But it does have a performance impact on
-          the web server, because for every request there is one
-          more internal subrequest. So, if your web server runs on a
-          powerful CPU, use this one. If it is a slow machine, use
-          the first approach or better an <code class="directive"><a href="../mod/core.html#errordocument">ErrorDocument</a></code> CGI script.</p>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="archive-access-multiplexer" id="archive-access-multiplexer">Archive Access Multiplexer</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Do you know the great CPAN (Comprehensive Perl Archive
-          Network) under <a href="http://www.perl.com/CPAN">http://www.perl.com/CPAN</a>?
-          CPAN automatically redirects browsers to one of many FTP
-          servers around the world (generally one near the requesting
-          client); each server carries a full CPAN mirror. This is
-          effectively an FTP access multiplexing service.
-          CPAN runs via CGI scripts, but how could a similar approach
-          be implemented via <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>?</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>First we notice that as of version 3.0.0,
-          <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> can
-          also use the "<code>ftp:</code>" scheme on redirects.
-          And second, the location approximation can be done by a
-          <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>
-          over the top-level domain of the client.
-          With a tricky chained ruleset we can use this top-level
-          domain as a key to our multiplexing map.</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteMap    multiplex                txt:/path/to/map.cxan
-RewriteRule   ^/CxAN/(.*)              %{REMOTE_HOST}::$1                 [C]
-RewriteRule   ^.+\.<strong>([a-zA-Z]+)</strong>::(.*)$  ${multiplex:<strong>$1</strong>|ftp.default.dom}$2  [R,L]
-</pre></div>
-
-<div class="example"><pre>
-##
-##  map.cxan -- Multiplexing Map for CxAN
-##
-
-de        ftp://ftp.cxan.de/CxAN/
-uk        ftp://ftp.cxan.uk/CxAN/
-com       ftp://ftp.cxan.com/CxAN/
- :
-##EOF##
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="browser-dependent-content" id="browser-dependent-content">Browser Dependent Content</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>At least for important top-level pages it is sometimes
-          necessary to provide the optimum of browser dependent
-          content, i.e., one has to provide one version for
-          current browsers, a different version for the Lynx and text-mode
-          browsers, and another for other browsers.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>We cannot use content negotiation because the browsers do
-          not provide their type in that form. Instead we have to
-          act on the HTTP header "User-Agent". The following config
-          does the following: If the HTTP header "User-Agent"
-          begins with "Mozilla/3", the page <code>foo.html</code>
-          is rewritten to <code>foo.NS.html</code> and the
-          rewriting stops. If the browser is "Lynx" or "Mozilla" of
-          version 1 or 2, the URL becomes <code>foo.20.html</code>.
-          All other browsers receive page <code>foo.32.html</code>.
-          This is done with the following ruleset:</p>
-
-<div class="example"><pre>
-RewriteCond %{HTTP_USER_AGENT}  ^<strong>Mozilla/3</strong>.*
-RewriteRule ^foo\.html$         foo.<strong>NS</strong>.html          [<strong>L</strong>]
-
-RewriteCond %{HTTP_USER_AGENT}  ^<strong>Lynx/</strong>.*         [OR]
-RewriteCond %{HTTP_USER_AGENT}  ^<strong>Mozilla/[12]</strong>.*
-RewriteRule ^foo\.html$         foo.<strong>20</strong>.html          [<strong>L</strong>]
-
-RewriteRule ^foo\.html$         foo.<strong>32</strong>.html          [<strong>L</strong>]
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="dynamic-mirror" id="dynamic-mirror">Dynamic Mirror</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Assume there are nice web pages on remote hosts we want
-          to bring into our namespace. For FTP servers we would use
-          the <code>mirror</code> program which actually maintains an
-          explicit up-to-date copy of the remote data on the local
-          machine. For a web server we could use the program
-          <code>webcopy</code> which runs via HTTP. But both
-          techniques have a major drawback: The local copy is
-          always only as up-to-date as the last time we ran the program. It
-          would be much better if the mirror was not a static one we
-          have to establish explicitly. Instead we want a dynamic
-          mirror with data which gets updated automatically
-          as needed on the remote host(s).</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>To provide this feature we map the remote web page or even
-          the complete remote web area to our namespace by the use
-          of the <dfn>Proxy Throughput</dfn> feature
-          (flag <code>[P]</code>):</p>
-
-<div class="example"><pre>
-RewriteEngine  on
-RewriteBase    /~quux/
-RewriteRule    ^<strong>hotsheet/</strong>(.*)$  <strong>http://www.tstimpreso.com/hotsheet/</strong>$1  [<strong>P</strong>]
-</pre></div>
-
-<div class="example"><pre>
-RewriteEngine  on
-RewriteBase    /~quux/
-RewriteRule    ^<strong>usa-news\.html</strong>$   <strong>http://www.quux-corp.com/news/index.html</strong>  [<strong>P</strong>]
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="reverse-dynamic-mirror" id="reverse-dynamic-mirror">Reverse Dynamic Mirror</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>...</dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-<div class="example"><pre>
-RewriteEngine on
-RewriteCond   /mirror/of/remotesite/$1           -U
-RewriteRule   ^http://www\.remotesite\.com/(.*)$ /mirror/of/remotesite/$1
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="retrieve-missing-data" id="retrieve-missing-data">Retrieve Missing Data from Intranet</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>This is a tricky way of virtually running a corporate
-          (external) Internet web server
-          (<code>www.quux-corp.dom</code>), while actually keeping
-          and maintaining its data on an (internal) Intranet web server
-          (<code>www2.quux-corp.dom</code>) which is protected by a
-          firewall. The trick is that the external web server retrieves
-          the requested data on-the-fly from the internal
-          one.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>First, we must make sure that our firewall still
-          protects the internal web server and only the
-          external web server is allowed to retrieve data from it.
-          On a packet-filtering firewall, for instance, we could
-          configure a firewall ruleset like the following:</p>
-
-<div class="example"><pre>
-<strong>ALLOW</strong> Host www.quux-corp.dom Port &gt;1024 --&gt; Host www2.quux-corp.dom Port <strong>80</strong>
-<strong>DENY</strong>  Host *                 Port *     --&gt; Host www2.quux-corp.dom Port <strong>80</strong>
-</pre></div>
-
-          <p>Just adjust it to your actual configuration syntax.
-          Now we can establish the <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
-          rules which request the missing data in the background
-          through the proxy throughput feature:</p>
-
-<div class="example"><pre>
-RewriteRule ^/~([^/]+)/?(.*)          /home/$1/.www/$2 [C]
-# REQUEST_FILENAME usage below is correct in this per-server context example 
-# because the rule that references REQUEST_FILENAME is chained to a rule that
-# sets REQUEST_FILENAME. 
-RewriteCond %{REQUEST_FILENAME}       <strong>!-f</strong>
-RewriteCond %{REQUEST_FILENAME}       <strong>!-d</strong>
-RewriteRule ^/home/([^/]+)/.www/?(.*) http://<strong>www2</strong>.quux-corp.dom/~$1/pub/$2 [<strong>P</strong>]
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="load-balancing" id="load-balancing">Load Balancing</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Suppose we want to load balance the traffic to
-          <code>www.example.com</code> over <code>www[0-5].example.com</code>
-          (a total of 6 servers). How can this be done?</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>There are many possible solutions for this problem.
-          We will first discuss a common DNS-based method,
-          and then one based on <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>:</p>
-
-          <ol>
-            <li>
-              <strong>DNS Round-Robin</strong>
-
-              <p>The simplest method for load-balancing is to use
-              DNS round-robin.
-              Here you just configure <code>www[0-9].example.com</code>
-              as usual in your DNS with A (address) records, e.g.,</p>
-
-<div class="example"><pre>
-www0   IN  A       1.2.3.1
-www1   IN  A       1.2.3.2
-www2   IN  A       1.2.3.3
-www3   IN  A       1.2.3.4
-www4   IN  A       1.2.3.5
-www5   IN  A       1.2.3.6
-</pre></div>
-
-              <p>Then you additionally add the following entries:</p>
-
-<div class="example"><pre>
-www   IN  A       1.2.3.1
-www   IN  A       1.2.3.2
-www   IN  A       1.2.3.3
-www   IN  A       1.2.3.4
-www   IN  A       1.2.3.5
-</pre></div>
-
-              <p>Now when <code>www.example.com</code> gets
-              resolved, <code>BIND</code> gives out <code>www0-www5</code>
-              - but in a permutated (rotated) order every time.
-              This way the clients are spread over the various
-              servers. But notice that this is not a perfect load
-              balancing scheme, because DNS resolutions are
-              cached by clients and other nameservers, so
-              once a client has resolved <code>www.example.com</code>
-              to a particular <code>wwwN.example.com</code>, all its
-              subsequent requests will continue to go to the same
-              IP (and thus a single server), rather than being
-              distributed across the other available servers. But the
-              overall result is
-              okay because the requests are collectively
-              spread over the various web servers.</p>
-            </li>
-
-            <li>
-              <strong>DNS Load-Balancing</strong>
-
-              <p>A sophisticated DNS-based method for
-              load-balancing is to use the program
-              <code>lbnamed</code> which can be found at <a href="http://www.stanford.edu/~riepel/lbnamed/">
-              http://www.stanford.edu/~riepel/lbnamed/</a>.
-              It is a Perl 5 program which, in conjunction with auxiliary
-              tools, provides real load-balancing via
-              DNS.</p>
-            </li>
-
-            <li>
-              <strong>Proxy Throughput Round-Robin</strong>
-
-              <p>In this variant we use <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
-              and its proxy throughput feature. First we dedicate
-              <code>www0.example.com</code> to be actually
-              <code>www.example.com</code> by using a single</p>
-
-<div class="example"><pre>
-www    IN  CNAME   www0.example.com.
-</pre></div>
-
-              <p>entry in the DNS. Then we convert
-              <code>www0.example.com</code> to a proxy-only server,
-              i.e., we configure this machine so all arriving URLs
-              are simply passed through its internal proxy to one of
-              the 5 other servers (<code>www1-www5</code>). To
-              accomplish this we first establish a ruleset which
-              contacts a load balancing script <code>lb.pl</code>
-              for all URLs.</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteMap    lb      prg:/path/to/lb.pl
-RewriteRule   ^/(.+)$ ${lb:$1}           [P,L]
-</pre></div>
-
-              <p>Then we write <code>lb.pl</code>:</p>
-
-<div class="example"><pre>
-#!/path/to/perl
-##
-##  lb.pl -- load balancing script
-##
-
-$| = 1;
-
-$name   = "www";     # the hostname base
-$first  = 1;         # the first server (not 0 here, because 0 is myself)
-$last   = 5;         # the last server in the round-robin
-$domain = "foo.dom"; # the domainname
-
-$cnt = 0;
-while (&lt;STDIN&gt;) {
-    $cnt = (($cnt+1) % ($last+1-$first));
-    $server = sprintf("%s%d.%s", $name, $cnt+$first, $domain);
-    print "http://$server/$_";
-}
-
-##EOF##
-</pre></div>
-
-              <div class="note">A last notice: Why is this useful? Seems like
-              <code>www0.example.com</code> still is overloaded? The
-              answer is yes, it is overloaded, but with plain proxy
-              throughput requests, only! All SSI, CGI, ePerl, etc.
-              processing is handled done on the other machines.
-              For a complicated site, this may work well. The biggest
-              risk here is that www0 is now a single point of failure --
-              if it crashes, the other servers are inaccessible.</div>
-            </li>
-
-            <li>
-              <strong>Dedicated Load Balancers</strong>
-
-              <p>There are more sophisticated solutions, as well. Cisco,
-              F5, and several other companies sell hardware load
-              balancers (typically used in pairs for redundancy), which
-              offer sophisticated load balancing and auto-failover
-              features. There are software packages which offer similar
-              features on commodity hardware, as well. If you have
-              enough money or need, check these out. The <a href="http://vegan.net/lb/">lb-l mailing list</a> is a
-              good place to research.</p>
-            </li>
-          </ol>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="new-mime-type" id="new-mime-type">New MIME-type, New Service</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>On the net there are many nifty CGI programs. But
-          their usage is usually boring, so a lot of webmasters
-          don't use them. Even Apache's Action handler feature for
-          MIME-types is only appropriate when the CGI programs
-          don't need special URLs (actually <code>PATH_INFO</code>
-          and <code>QUERY_STRINGS</code>) as their input. First,
-          let us configure a new file type with extension
-          <code>.scgi</code> (for secure CGI) which will be processed
-          by the popular <code>cgiwrap</code> program. The problem
-          here is that for instance if we use a Homogeneous URL Layout
-          (see above) a file inside the user homedirs might have a URL
-          like <code>/u/user/foo/bar.scgi</code>, but
-          <code>cgiwrap</code> needs URLs in the form
-          <code>/~user/foo/bar.scgi/</code>. The following rule
-          solves the problem:</p>
-
-<div class="example"><pre>
-RewriteRule ^/[uge]/<strong>([^/]+)</strong>/\.www/(.+)\.scgi(.*) ...
-... /internal/cgi/user/cgiwrap/~<strong>$1</strong>/$2.scgi$3  [NS,<strong>T=application/x-http-cgi</strong>]
-</pre></div>
-
-          <p>Or assume we have some more nifty programs:
-          <code>wwwlog</code> (which displays the
-          <code>access.log</code> for a URL subtree) and
-          <code>wwwidx</code> (which runs Glimpse on a URL
-          subtree). We have to provide the URL area to these
-          programs so they know which area they are really working with.
-          But usually this is complicated, because they may still be
-          requested by the alternate URL form, i.e., typically we would
-          run the <code>swwidx</code> program from within
-          <code>/u/user/foo/</code> via hyperlink to</p>
-
-<div class="example"><pre>
-/internal/cgi/user/swwidx?i=/u/user/foo/
-</pre></div>
-
-          <p>which is ugly, because we have to hard-code
-          <strong>both</strong> the location of the area
-          <strong>and</strong> the location of the CGI inside the
-          hyperlink. When we have to reorganize, we spend a
-          lot of time changing the various hyperlinks.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>The solution here is to provide a special new URL format
-          which automatically leads to the proper CGI invocation.
-          We configure the following:</p>
-
-<div class="example"><pre>
-RewriteRule   ^/([uge])/([^/]+)(/?.*)/\*  /internal/cgi/user/wwwidx?i=/$1/$2$3/
-RewriteRule   ^/([uge])/([^/]+)(/?.*):log /internal/cgi/user/wwwlog?f=/$1/$2$3
-</pre></div>
-
-          <p>Now the hyperlink to search at
-          <code>/u/user/foo/</code> reads only</p>
-
-<div class="example"><pre>
-HREF="*"
-</pre></div>
-
-          <p>which internally gets automatically transformed to</p>
-
-<div class="example"><pre>
-/internal/cgi/user/wwwidx?i=/u/user/foo/
-</pre></div>
-
-          <p>The same approach leads to an invocation for the
-          access log CGI program when the hyperlink
-          <code>:log</code> gets used.</p>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="on-the-fly-content" id="on-the-fly-content">On-the-fly Content-Regeneration</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Here comes a really esoteric feature: Dynamically
-          generated but statically served pages, i.e., pages should be
-          delivered as pure static pages (read from the filesystem
-          and just passed through), but they have to be generated
-          dynamically by the web server if missing. This way you can
-          have CGI-generated pages which are statically served unless an
-          admin (or a <code>cron</code> job) removes the static contents. Then the
-          contents gets refreshed.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          This is done via the following ruleset:
-
-<div class="example"><pre>
-# This example is valid in per-directory context only
-RewriteCond %{REQUEST_FILENAME}   <strong>!-s</strong>
-RewriteRule ^page\.<strong>html</strong>$          page.<strong>cgi</strong>   [T=application/x-httpd-cgi,L]
-</pre></div>
-
-          <p>Here a request for <code>page.html</code> leads to an
-          internal run of a corresponding <code>page.cgi</code> if
-          <code>page.html</code> is missing or has filesize
-          null. The trick here is that <code>page.cgi</code> is a
-          CGI script which (additionally to its <code>STDOUT</code>)
-          writes its output to the file <code>page.html</code>.
-          Once it has completed, the server sends out
-          <code>page.html</code>. When the webmaster wants to force
-          a refresh of the contents, he just removes
-          <code>page.html</code> (typically from <code>cron</code>).</p>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="autorefresh" id="autorefresh">Document With Autorefresh</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Wouldn't it be nice, while creating a complex web page, if
-          the web browser would automatically refresh the page every
-          time we save a new version from within our editor?
-          Impossible?</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>No! We just combine the MIME multipart feature, the
-          web server NPH feature, and the URL manipulation power of
-          <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. First, we establish a new
-          URL feature: Adding just <code>:refresh</code> to any
-          URL causes the 'page' to be refreshed every time it is
-          updated on the filesystem.</p>
-
-<div class="example"><pre>
-RewriteRule   ^(/[uge]/[^/]+/?.*):refresh  /internal/cgi/apache/nph-refresh?f=$1
-</pre></div>
-
-          <p>Now when we reference the URL</p>
-
-<div class="example"><pre>
-/u/foo/bar/page.html:refresh
-</pre></div>
-
-          <p>this leads to the internal invocation of the URL</p>
-
-<div class="example"><pre>
-/internal/cgi/apache/nph-refresh?f=/u/foo/bar/page.html
-</pre></div>
-
-          <p>The only missing part is the NPH-CGI script. Although
-          one would usually say "left as an exercise to the reader"
-          ;-) I will provide this, too.</p>
-
-<div class="example"><pre>
-#!/sw/bin/perl
-##
-##  nph-refresh -- NPH/CGI script for auto refreshing pages
-##  Copyright (c) 1997 Ralf S. Engelschall, All Rights Reserved.
-##
-$| = 1;
-
-#   split the QUERY_STRING variable
-@pairs = split(/&amp;/, $ENV{'QUERY_STRING'});
-foreach $pair (@pairs) {
-    ($name, $value) = split(/=/, $pair);
-    $name =~ tr/A-Z/a-z/;
-    $name = 'QS_' . $name;
-    $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
-    eval "\$$name = \"$value\"";
-}
-$QS_s = 1 if ($QS_s eq '');
-$QS_n = 3600 if ($QS_n eq '');
-if ($QS_f eq '') {
-    print "HTTP/1.0 200 OK\n";
-    print "Content-type: text/html\n\n";
-    print "&amp;lt;b&amp;gt;ERROR&amp;lt;/b&amp;gt;: No file given\n";
-    exit(0);
-}
-if (! -f $QS_f) {
-    print "HTTP/1.0 200 OK\n";
-    print "Content-type: text/html\n\n";
-    print "&amp;lt;b&amp;gt;ERROR&amp;lt;/b&amp;gt;: File $QS_f not found\n";
-    exit(0);
-}
-
-sub print_http_headers_multipart_begin {
-    print "HTTP/1.0 200 OK\n";
-    $bound = "ThisRandomString12345";
-    print "Content-type: multipart/x-mixed-replace;boundary=$bound\n";
-    &amp;print_http_headers_multipart_next;
-}
-
-sub print_http_headers_multipart_next {
-    print "\n--$bound\n";
-}
-
-sub print_http_headers_multipart_end {
-    print "\n--$bound--\n";
-}
-
-sub displayhtml {
-    local($buffer) = @_;
-    $len = length($buffer);
-    print "Content-type: text/html\n";
-    print "Content-length: $len\n\n";
-    print $buffer;
-}
-
-sub readfile {
-    local($file) = @_;
-    local(*FP, $size, $buffer, $bytes);
-    ($x, $x, $x, $x, $x, $x, $x, $size) = stat($file);
-    $size = sprintf("%d", $size);
-    open(FP, "&amp;lt;$file");
-    $bytes = sysread(FP, $buffer, $size);
-    close(FP);
-    return $buffer;
-}
-
-$buffer = &amp;readfile($QS_f);
-&amp;print_http_headers_multipart_begin;
-&amp;displayhtml($buffer);
-
-sub mystat {
-    local($file) = $_[0];
-    local($time);
-
-    ($x, $x, $x, $x, $x, $x, $x, $x, $x, $mtime) = stat($file);
-    return $mtime;
-}
-
-$mtimeL = &amp;mystat($QS_f);
-$mtime = $mtime;
-for ($n = 0; $n &amp;lt; $QS_n; $n++) {
-    while (1) {
-        $mtime = &amp;mystat($QS_f);
-        if ($mtime ne $mtimeL) {
-            $mtimeL = $mtime;
-            sleep(2);
-            $buffer = &amp;readfile($QS_f);
-            &amp;print_http_headers_multipart_next;
-            &amp;displayhtml($buffer);
-            sleep(5);
-            $mtimeL = &amp;mystat($QS_f);
-            last;
-        }
-        sleep($QS_s);
-    }
-}
-
-&amp;print_http_headers_multipart_end;
-
-exit(0);
-
-##EOF##
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="mass-virtual-hosting" id="mass-virtual-hosting">Mass Virtual Hosting</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>The <code class="directive"><a href="../mod/core.html#virtualhost">&lt;VirtualHost&gt;</a></code> feature of Apache is nice
-          and works great when you just have a few dozen
-          virtual hosts. But when you are an ISP and have hundreds of
-          virtual hosts, this feature is suboptimal.</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>To provide this feature we map the remote web page or even
-          the complete remote web area to our namespace using the
-          <dfn>Proxy Throughput</dfn> feature (flag <code>[P]</code>):</p>
-
-<div class="example"><pre>
-##
-##  vhost.map
-##
-www.vhost1.dom:80  /path/to/docroot/vhost1
-www.vhost2.dom:80  /path/to/docroot/vhost2
-     :
-www.vhostN.dom:80  /path/to/docroot/vhostN
-</pre></div>
-
-<div class="example"><pre>
-##
-##  httpd.conf
-##
-    :
-#   use the canonical hostname on redirects, etc.
-UseCanonicalName on
-
-    :
-#   add the virtual host in front of the CLF-format
-CustomLog  /path/to/access_log  "%{VHOST}e %h %l %u %t \"%r\" %&gt;s %b"
-    :
-
-#   enable the rewriting engine in the main server
-RewriteEngine on
-
-#   define two maps: one for fixing the URL and one which defines
-#   the available virtual hosts with their corresponding
-#   DocumentRoot.
-RewriteMap    lowercase    int:tolower
-RewriteMap    vhost        txt:/path/to/vhost.map
-
-#   Now do the actual virtual host mapping
-#   via a huge and complicated single rule:
-#
-#   1. make sure we don't map for common locations
-RewriteCond   %{REQUEST_URI}  !^/commonurl1/.*
-RewriteCond   %{REQUEST_URI}  !^/commonurl2/.*
-    :
-RewriteCond   %{REQUEST_URI}  !^/commonurlN/.*
-#
-#   2. make sure we have a Host header, because
-#      currently our approach only supports
-#      virtual hosting through this header
-RewriteCond   %{HTTP_HOST}  !^$
-#
-#   3. lowercase the hostname
-RewriteCond   ${lowercase:%{HTTP_HOST}|NONE}  ^(.+)$
-#
-#   4. lookup this hostname in vhost.map and
-#      remember it only when it is a path
-#      (and not "NONE" from above)
-RewriteCond   ${vhost:%1}  ^(/.*)$
-#
-#   5. finally we can map the URL to its docroot location
-#      and remember the virtual host for logging purposes
-RewriteRule   ^/(.*)$   %1/$1  [E=VHOST:${lowercase:%{HTTP_HOST}}]
-    :
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="host-deny" id="host-deny">Host Deny</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>How can we forbid a list of externally configured hosts
-          from using our server?</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>For Apache &gt;= 1.3b6:</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteMap    hosts-deny  txt:/path/to/hosts.deny
-RewriteCond   ${hosts-deny:%{REMOTE_HOST}|NOT-FOUND} !=NOT-FOUND [OR]
-RewriteCond   ${hosts-deny:%{REMOTE_ADDR}|NOT-FOUND} !=NOT-FOUND
-RewriteRule   ^/.*  -  [F]
-</pre></div>
-
-          <p>For Apache &lt;= 1.3b6:</p>
-
-<div class="example"><pre>
-RewriteEngine on
-RewriteMap    hosts-deny  txt:/path/to/hosts.deny
-RewriteRule   ^/(.*)$ ${hosts-deny:%{REMOTE_HOST}|NOT-FOUND}/$1
-RewriteRule   !^NOT-FOUND/.* - [F]
-RewriteRule   ^NOT-FOUND/(.*)$ ${hosts-deny:%{REMOTE_ADDR}|NOT-FOUND}/$1
-RewriteRule   !^NOT-FOUND/.* - [F]
-RewriteRule   ^NOT-FOUND/(.*)$ /$1
-</pre></div>
-
-<div class="example"><pre>
-##
-##  hosts.deny
-##
-##  ATTENTION! This is a map, not a list, even when we treat it as such.
-##             mod_rewrite parses it for key/value pairs, so at least a
-##             dummy value "-" must be present for each entry.
-##
-
-193.102.180.41 -
-bsdti1.sdm.de  -
-192.76.162.40  -
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="proxy-deny" id="proxy-deny">Proxy Deny</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>How can we forbid a certain host or even a user of a
-          special host from using the Apache proxy?</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>We first have to make sure <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
-          is below(!) <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> in the Configuration
-          file when compiling the Apache web server. This way it gets
-          called <em>before</em> <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>. Then we
-          configure the following for a host-dependent deny...</p>
-
-<div class="example"><pre>
-RewriteCond %{REMOTE_HOST} <strong>^badhost\.mydomain\.com$</strong>
-RewriteRule !^http://[^/.]\.mydomain.com.*  - [F]
-</pre></div>
-
-          <p>...and this one for a user@host-dependent deny:</p>
-
-<div class="example"><pre>
-RewriteCond %{REMOTE_IDENT}@%{REMOTE_HOST}  <strong>^badguy@badhost\.mydomain\.com$</strong>
-RewriteRule !^http://[^/.]\.mydomain.com.*  - [F]
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="special-authentication" id="special-authentication">Special Authentication Variant</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>Sometimes very special authentication is needed, for
-          instance authentication which checks for a set of
-          explicitly configured users. Only these should receive
-          access and without explicit prompting (which would occur
-          when using Basic Auth via <code class="module"><a href="../mod/mod_auth_basic.html">mod_auth_basic</a></code>).</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>We use a list of rewrite conditions to exclude all except
-          our friends:</p>
-
-<div class="example"><pre>
-RewriteCond %{REMOTE_IDENT}@%{REMOTE_HOST} <strong>!^friend1@client1.quux-corp\.com$</strong>
-RewriteCond %{REMOTE_IDENT}@%{REMOTE_HOST} <strong>!^friend2</strong>@client2.quux-corp\.com$
-RewriteCond %{REMOTE_IDENT}@%{REMOTE_HOST} <strong>!^friend3</strong>@client3.quux-corp\.com$
-RewriteRule ^/~quux/only-for-friends/      -                                 [F]
-</pre></div>
-        </dd>
-      </dl>
-
-    </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
-<div class="section">
-<h2><a name="referer-deflector" id="referer-deflector">Referer-based Deflector</a></h2>
-
-      
-
-      <dl>
-        <dt>Description:</dt>
-
-        <dd>
-          <p>How can we program a flexible URL Deflector which acts
-          on the "Referer" HTTP header and can be configured with as
-          many referring pages as we like?</p>
-        </dd>
-
-        <dt>Solution:</dt>
-
-        <dd>
-          <p>Use the following really tricky ruleset...</p>
-
-<div class="example"><pre>
-RewriteMap  deflector txt:/path/to/deflector.map
-
-RewriteCond %{HTTP_REFERER} !=""
-RewriteCond ${deflector:%{HTTP_REFERER}} ^-$
-RewriteRule ^.* %{HTTP_REFERER} [R,L]
-
-RewriteCond %{HTTP_REFERER} !=""
-RewriteCond ${deflector:%{HTTP_REFERER}|NOT-FOUND} !=NOT-FOUND
-RewriteRule ^.* ${deflector:%{HTTP_REFERER}} [R,L]
-</pre></div>
-
-          <p>... in conjunction with a corresponding rewrite
-          map:</p>
-
-<div class="example"><pre>
-##
-##  deflector.map
-##
-
-http://www.badguys.com/bad/index.html    -
-http://www.badguys.com/bad/index2.html   -
-http://www.badguys.com/bad/index3.html   http://somewhere.com/
-</pre></div>
-
-          <p>This automatically redirects the request back to the
-          referring page (when "<code>-</code>" is used as the value
-          in the map) or to a specific URL (when an URL is specified
-          in the map as the second argument).</p>
-        </dd>
-      </dl>
-
-    </div></div>
+</div>
 <div class="bottomlang">
 <p><span>Available Languages: </span><a href="../en/rewrite/rewrite_guide_advanced.html" title="English">&nbsp;en&nbsp;</a> |
 <a href="../fr/rewrite/rewrite_guide_advanced.html" hreflang="fr" rel="alternate" title="Fran├žais">&nbsp;fr&nbsp;</a></p>



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