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<title>When not to use mod_rewrite - Apache HTTP Server Version 2.4</title>
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<p>This document supplements the <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
<a href="../mod/mod_rewrite.html">reference documentation</a>. It describes
perhaps one of the most important concepts about <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> - namely,
when to avoid using it.</p>

<p><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> should be considered a last resort, when other
alternatives are found wanting. Using it when there are simpler
alternatives leads to configurations which are confusing, fragile, and
hard to maintain. Understanding what other alternatives are available is
a very important step towards <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> mastery.</p>

<p>Note that many of these examples won't work unchanged in your
particular server configuration, so it's important that you understand
them, rather than merely cutting and pasting the examples into your
configuration.</p>

<p>The most common situation in which <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> is
the right tool is when the very best solution requires access to the
server configuration files, and you don't have that access. Some
configuration directives are only available in the server configuration
file. So if you are in a hosting situation where you only have .htaccess
files to work with, you may need to resort to
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.</p>

</div>
<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif"> <a href="#redirect">Simple Redirection</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#alias">URL Aliasing</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#proxy">Simple Proxying</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#setenv">Environment Variable Testing</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#fallback-resource">Front Controller / Resource Routing</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#ifexpr">Conditional Configuration with Expressions</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#blocked-inline-images">Forbidding Image Hotlinking</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#blocking-of-robots">Blocking of Robots</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#host-deny">Denying Hosts in a Reject List</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#vhosts">Virtual Hosting</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#load-balancing">Load Balancing</a></li>
</ul><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="remapping.html">Redirection and remapping</a></li><li><a href="htaccess.html">Per-directory Rewrites</a></li><li><a href="flags.html">RewriteRule Flags</a></li><li><a href="vhosts.html">Virtual hosts</a></li><li><a href="rewritemap.html">Using RewriteMap</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 id="redirect">Simple Redirection <a title="Permanent link" href="#redirect" class="permalink">&para;</a></h2>


<p><code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code> provides the <code class="directive"><a href="../mod/mod_alias.html#redirect">Redirect</a></code> and <code class="directive"><a href="../mod/mod_alias.html#redirectmatch">RedirectMatch</a></code> directives, which provide a
means to redirect one URL to another. This kind of simple redirection of
one URL, or a class of URLs, to somewhere else, should be accomplished
using these directives rather than <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>. <code>RedirectMatch</code>
allows you to include a regular expression in your redirection criteria,
providing many of the benefits of using <code>RewriteRule</code>.</p>

<p>A common use for <code>RewriteRule</code> is to redirect an entire
class of URLs. For example, all URLs in the <code>/one</code> directory
must be redirected to <code>http://one.example.com/</code>, or perhaps
all <code>http</code> requests must be redirected to
<code>https</code>.</p>

<p>These situations are better handled by the <code>Redirect</code>
directive. Remember that <code>Redirect</code> preserves path
information. That is to say, a redirect for a URL <code>/one</code> will
also redirect all URLs under that, such as <code>/one/two.html</code>
and <code>/one/three/four.html</code>.</p>

<p>To redirect URLs under <code>/one</code> to
<code>http://one.example.com</code>, do the following:</p>

<pre class="prettyprint lang-config">Redirect "/one/" "http://one.example.com/"</pre>


<p>To redirect one hostname to another, for example
<code>example.com</code> to <code>www.example.com</code>, see the
<a href="remapping.html#canonicalhost">Canonical Hostnames</a>
recipe.</p>

<p>To redirect <code>http</code> URLs to <code>https</code>, a
<code class="directive"><a href="../mod/mod_alias.html#redirect">Redirect</a></code> in a dedicated
HTTP virtual host is the cleanest approach. See the
<a href="remapping.html#https-redirect">Forcing HTTPS</a> recipe for
the recommended configuration and the
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> alternative for <code>.htaccess</code>
use.</p>

    <div class="note"><h3>Processing order</h3>
    <p>If you do mix <code class="directive"><a href="../mod/mod_alias.html#redirect">Redirect</a></code>
    and <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> in the
    same context, be aware that their execution order depends on where
    they appear. In server/virtual-host context,
    <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> runs first; in per-directory context
    (<code>.htaccess</code>), <code class="module"><a href="../mod/mod_alias.html">mod_alias</a></code> runs first. See
    <a href="tech.html#order">Module Processing Order</a> for
    details.</p>
    </div>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="alias">URL Aliasing <a title="Permanent link" href="#alias" class="permalink">&para;</a></h2>
<p>The <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> directive
provides mapping from a URL-path to a directory - usually a directory outside
of your <code class="directive"><a href="../mod/core.html#documentroot">DocumentRoot</a></code>. Although it
is possible to perform this mapping with <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>,
<code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> is the preferred method, for
reasons of simplicity and performance.</p>

<div class="example"><h3>Using Alias</h3><pre class="prettyprint lang-config">Alias "/cats" "/var/www/virtualhosts/felines/htdocs"</pre>
</div>

<p>
The use of <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> to perform this mapping may be
appropriate when you do not have access to the server configuration
files. Alias may only be used in server or virtualhost context, and not
in a <code>.htaccess</code> file.
</p>

<p>Symbolic links would be another way to accomplish the same thing, if
you have <code>Options FollowSymLinks</code> enabled on your
server.</p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="proxy">Simple Proxying <a title="Permanent link" href="#proxy" class="permalink">&para;</a></h2>

<p><code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> provides the <a href="flags.html#flag_p">[P]</a> flag to pass rewritten URIs through
<code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code>.</p>

<pre class="prettyprint lang-config">RewriteRule "^/?images(.*)" "http://imageserver.local/images$1" [P]</pre>


<p>However, in many cases, when there is no actual pattern matching
needed, as in the example shown above, the <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code> directive is a better choice.
The example here could be rendered as:</p>

<pre class="prettyprint lang-config">ProxyPass "/images/" "http://imageserver.local/images/"</pre>


<p>Note that whether you use <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code> or <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code>, you'll still need to use the
<code class="directive"><a href="../mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code> directive to
catch redirects issued from the back-end server:</p>

<pre class="prettyprint lang-config">ProxyPassReverse "/images/" "http://imageserver.local/images/"</pre>


<p>You may need to use <code>RewriteRule</code> instead when there are
other <code>RewriteRule</code>s in effect in the same scope, as a
<code>RewriteRule</code> will usually take effect before a
<code>ProxyPass</code>, and so may preempt what you're trying to
accomplish.</p>

<p>One case where <code class="directive"><a href="../mod/mod_rewrite.html#rewriterule">RewriteRule</a></code>
is genuinely useful for proxying is when you want to proxy requests only
for content that doesn't exist locally - for example, during a migration
from one server to another:</p>

<pre class="prettyprint lang-config">RewriteCond "%{REQUEST_FILENAME}"       !-f
RewriteCond "%{REQUEST_FILENAME}"       !-d
RewriteRule "^/(.*)"                    "http://old.example.com/$1" [P]
ProxyPassReverse "/" "http://old.example.com/"</pre>


<p>In this example, requests for resources that haven't been migrated
yet are transparently proxied to the old server. As content is migrated,
the local files take precedence. Remember to always include a
<code class="directive"><a href="../mod/mod_proxy.html#proxypassreverse">ProxyPassReverse</a></code> directive to
ensure that any redirects issued by the backend are correctly passed on
to the client.</p>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="setenv">Environment Variable Testing <a title="Permanent link" href="#setenv" class="permalink">&para;</a></h2>

<p><code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> is frequently used to take a particular
action based on the presence or absence of a particular environment
variable or request header. This can be done more efficiently using the
<code class="directive"><a href="../mod/core.html#if">&lt;If&gt;</a></code> directive.</p>

<p>Consider, for example, the common scenario where
<code class="directive">RewriteRule</code> is used to enforce a canonical
hostname, such as <code>www.example.com</code> instead of
<code>example.com</code>. This can be done using the <code class="directive"><a href="../mod/core.html#if">&lt;If&gt;</a></code> directive, as shown here:</p>

<pre class="prettyprint lang-config">&lt;If "req('Host') != 'www.example.com'"&gt;
    Redirect "/" "http://www.example.com/"
&lt;/If&gt;</pre>


<p>This technique can be used to take actions based on any request
header, response header, or environment variable, replacing
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> in many common scenarios.</p>

<p>See especially the <a href="../expr.html">expression evaluation
documentation</a> for a overview of what types of expressions you can
use in <code class="directive"><a href="../mod/core.html#if">&lt;If&gt;</a></code> sections,
and in certain other directives.</p>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="fallback-resource">Front Controller / Resource Routing <a title="Permanent link" href="#fallback-resource" class="permalink">&para;</a></h2>

<p>A very common use of <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> is to route all
requests for non-existent resources to a single front controller script
(e.g. <code>index.php</code>). This is the basis of most modern web
framework routing.</p>

<p>The typical <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> approach is:</p>

<pre class="prettyprint lang-config">RewriteEngine On
RewriteCond "%{REQUEST_FILENAME}" !-f
RewriteCond "%{REQUEST_FILENAME}" !-d
RewriteRule "^(.*)$" "/index.php" [L]</pre>


<p>This can be accomplished far more simply with the
<code class="directive"><a href="../mod/mod_dir.html#fallbackresource">FallbackResource</a></code> directive:</p>

<pre class="prettyprint lang-config">FallbackResource /index.php</pre>


<p><code class="directive"><a href="../mod/mod_dir.html#fallbackresource">FallbackResource</a></code> does the
same thing - requests for existing files and directories are served
normally, while everything else is routed to the specified resource -
but without the overhead and complexity of the rewrite engine. It works
in both server configuration and <code>.htaccess</code> context.</p>

<p>To disable a <code>FallbackResource</code> set in a parent
directory:</p>

<pre class="prettyprint lang-config">FallbackResource disabled</pre>


</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="ifexpr">Conditional Configuration with Expressions <a title="Permanent link" href="#ifexpr" class="permalink">&para;</a></h2>

<p>Many uses of <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>
can be replaced by the
<code class="directive"><a href="../mod/core.html#if">&lt;If&gt;</a></code> directive, which
supports a rich <a href="../expr.html">expression syntax</a> and
integrates cleanly with other Apache directives.</p>

<p>Redirect based on a query string parameter:</p>

<pre class="prettyprint lang-config">&lt;If "%{QUERY_STRING} =~ /lang=fr/"&gt;
    Redirect "/welcome" "/bienvenue"
&lt;/If&gt;</pre>


<p>Restrict access by request method:</p>

<pre class="prettyprint lang-config">&lt;If "%{REQUEST_METHOD} IN {'DELETE', 'PUT', 'PATCH'}"&gt;
    Require ip 10.0.0.0/8
&lt;/If&gt;</pre>


<p>Block requests missing a Host header (HTTP/1.0 clients):</p>

<pre class="prettyprint lang-config">&lt;If "-z req('Host')"&gt;
    Require all denied
&lt;/If&gt;</pre>


<p>See the <a href="../expr.html">expression evaluation
documentation</a> for the full syntax available in
<code class="directive"><a href="../mod/core.html#if">&lt;If&gt;</a></code> blocks.</p>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="blocked-inline-images">Forbidding Image Hotlinking <a title="Permanent link" href="#blocked-inline-images" class="permalink">&para;</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>"Hotlinking" is the practice of other sites including your
      images inline in their pages, using your bandwidth to serve
      content for someone else's site. You can prevent this without
      <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>Use <code class="directive"><a href="../mod/mod_setenvif.html#setenvif">SetEnvIf</a></code>
      with <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>:</p>

      <pre class="prettyprint lang-config">SetEnvIf Referer example\.com localreferer
&lt;FilesMatch "\.(jpg|png|gif)$"&gt;
    Require env localreferer
&lt;/FilesMatch&gt;</pre>

    </dd>

    <dt>Discussion:</dt>

    <dd>
      <p>If you need more complex logic - such as serving an
      alternate image to hotlinkers instead of denying the request - you
      may need <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. The following examples
      rely on the <code>HTTP_REFERER</code> header, which is optional
      and can be spoofed. The <code>!^$</code> condition allows
      requests with no Referer header at all, so that users who type
      the URL directly, or whose browsers suppress the Referer, are
      not blocked.</p>

      <p>Deny the request outright:</p>

<pre class="prettyprint lang-config">RewriteCond "%{HTTP_REFERER}"  "!^$"
RewriteCond "%{HTTP_REFERER}"  "!www.example.com" [NC]
RewriteRule "\.(gif|jpg|png)$" "-"                [F,NC]</pre>


      <p>Serve an alternate image:</p>

<pre class="prettyprint lang-config">RewriteCond "%{HTTP_REFERER}"  "!^$"
RewriteCond "%{HTTP_REFERER}"  "!www.example.com"      [NC]
RewriteRule "\.(gif|jpg|png)$" "/images/go-away.png"   [R,NC]</pre>


    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="blocking-of-robots">Blocking of Robots <a title="Permanent link" href="#blocking-of-robots" class="permalink">&para;</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>You wish to block persistent requests from a particular robot
      or user agent that ignores your <code>/robots.txt</code>.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>Use <code class="directive"><a href="../mod/mod_setenvif.html#setenvifnocase">SetEnvIfNoCase</a></code>
      with <code class="directive"><a href="../mod/mod_authz_core.html#require">Require</a></code>:</p>

      <pre class="prettyprint lang-config">SetEnvIfNoCase User-Agent ^NameOfBadRobot goaway
&lt;Location "/secret/files"&gt;
    &lt;RequireAll&gt;
        Require all granted
        Require not env goaway
    &lt;/RequireAll&gt;
&lt;/Location&gt;</pre>

    </dd>

    <dt>Discussion:</dt>

    <dd>
      <p>Any technique that relies on the <code>USER_AGENT</code>
      string can be trivially circumvented, since that string can be
      changed by the client. If you are experiencing a sustained attack,
      you should consider blocking it at a higher level, such as at your
      firewall.</p>

      <p>If you need to combine user-agent and IP address matching,
      <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> can be used as a fallback:</p>

<pre class="prettyprint lang-config">RewriteCond "%{HTTP_USER_AGENT}"   "^NameOfBadRobot"
RewriteCond "%{REMOTE_ADDR}"       "=123\.45\.67\.[8-9]"
RewriteRule "^/secret/files/"      "-"                   [F]</pre>


    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="host-deny">Denying Hosts in a Reject List <a title="Permanent link" href="#host-deny" class="permalink">&para;</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>We wish to maintain a list of hosts and have those hosts
      blocked from accessing our server.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>For simple IP-based blocking, use
      <code class="directive"><a href="../mod/mod_authz_host.html#require">Require</a></code> directly:</p>

      <pre class="prettyprint lang-config">&lt;Location "/"&gt;
    Require all granted
    Require not ip 193.102.180.41
    Require not ip 192.76.162.40
&lt;/Location&gt;</pre>

    </dd>

    <dt>Discussion:</dt>

    <dd>
      <p>If you need a dynamic, file-based deny list (rather than
      enumerating addresses in the configuration), <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
      with a <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>
      can be used:</p>

<pre class="prettyprint lang-config">RewriteEngine on
RewriteMap    hosts-deny  "txt:/path/to/hosts.deny"
RewriteCond   "${hosts-deny:%{REMOTE_ADDR}|NOT-FOUND}" "!=NOT-FOUND" [OR]
RewriteCond   "${hosts-deny:%{REMOTE_HOST}|NOT-FOUND}" "!=NOT-FOUND"
RewriteRule   "^"                                      "-"           [F]</pre>


      <p>The map file contains one entry per line, with IP addresses or
      hostnames as keys and a dummy value (since
      <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code> requires
      key/value pairs):</p>

<div class="example"><p><code>
##  hosts.deny<br>
193.102.180.41 -<br>
192.76.162.40  -<br>
</code></p></div>

      <p>The second <code class="directive"><a href="../mod/mod_rewrite.html#rewritecond">RewriteCond</a></code>
      assumes <code>HostnameLookups</code> is enabled. If not, drop it
      and remove the <code>[OR]</code> flag from the first condition.</p>
    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="vhosts">Virtual Hosting <a title="Permanent link" href="#vhosts" class="permalink">&para;</a></h2>
<p>Although it is possible to handle <a href="vhosts.html">virtual hosts
with mod_rewrite</a>, it is seldom the right way. Creating individual
<code class="directive"><a href="../mod/core.html#virtualhost">&lt;VirtualHost&gt;</a></code> blocks is
almost always the right way to go. In the
event that you have an enormous number of virtual hosts, consider using
<code class="module"><a href="../mod/mod_vhost_alias.html">mod_vhost_alias</a></code> to create these hosts automatically.</p>

<p>Modules such as <code class="module"><a href="../mod/mod_macro.html">mod_macro</a></code> are
also useful for creating a large number of virtual hosts dynamically.</p>

<p>Using <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> for vitualhost creation may be
appropriate if you are using a hosting service that does not provide
you access to the server configuration files, and you are therefore
restricted to configuration using <code>.htaccess</code> files.</p>

<p>See the <a href="vhosts.html">virtual hosts with mod_rewrite</a>
document for more details on how you might accomplish this if it still
seems like the right approach.</p>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="section">
<h2 id="load-balancing">Load Balancing <a title="Permanent link" href="#load-balancing" class="permalink">&para;</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>We wish to distribute load across several back-end
      servers.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>Use <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>, which provides a
      flexible and featureful load-balancing solution. It supports
      several balancing algorithms, session stickiness, health checks,
      and dynamic configuration via the Balancer Manager - none of which
      are possible with a <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> approach.</p>

<pre class="prettyprint lang-config">&lt;Proxy "balancer://mycluster"&gt;
    BalancerMember "http://one.example.com"
    BalancerMember "http://two.example.com"
    BalancerMember "http://three.example.com"
&lt;/Proxy&gt;
ProxyPass        "/"  "balancer://mycluster/"
ProxyPassReverse "/"  "balancer://mycluster/"</pre>


    </dd>

    <dt>Discussion:</dt>
    <dd>

<p>It is possible to accomplish rudimentary random load balancing using
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code> with a <code>rnd</code>
<code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>:</p>

<pre class="prettyprint lang-config">RewriteEngine on
RewriteMap  lb       "rnd:/path/to/serverlist.txt"
RewriteRule "^/(.*)" "http://${lb:servers}/$1"     [P,L]</pre>


<p>However, <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> is far more flexible and
featureful than anything you can cobble together using
<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>, and is the recommended approach.</p>

    </dd>
  </dl>

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