You are viewing a plain text version of this content. The canonical link for it is here.
Posted to cvs@httpd.apache.org by mi...@apache.org on 2009/10/03 01:48:23 UTC
svn commit: r821203 [1/2] - in /httpd/httpd/trunk/docs/manual/mod:
directives.html.en mod_cache.html.en quickreference.html.en
Author: minfrin
Date: Fri Oct 2 23:48:23 2009
New Revision: 821203
URL: http://svn.apache.org/viewvc?rev=821203&view=rev
Log:
Update transformations.
Modified:
httpd/httpd/trunk/docs/manual/mod/directives.html.en
httpd/httpd/trunk/docs/manual/mod/mod_cache.html.en
httpd/httpd/trunk/docs/manual/mod/quickreference.html.en
Modified: httpd/httpd/trunk/docs/manual/mod/directives.html.en
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/mod/directives.html.en?rev=821203&r1=821202&r2=821203&view=diff
==============================================================================
--- httpd/httpd/trunk/docs/manual/mod/directives.html.en (original)
+++ httpd/httpd/trunk/docs/manual/mod/directives.html.en Fri Oct 2 23:48:23 2009
@@ -154,6 +154,7 @@
<li><a href="mod_cache.html#cacheminexpire">CacheMinExpire</a></li>
<li><a href="mod_disk_cache.html#cacheminfilesize">CacheMinFileSize</a></li>
<li><a href="mod_negotiation.html#cachenegotiateddocs">CacheNegotiatedDocs</a></li>
+<li><a href="mod_cache.html#cachequickhandler">CacheQuickHandler</a></li>
<li><a href="mod_disk_cache.html#cacheroot">CacheRoot</a></li>
<li><a href="mod_cache.html#cachestorenostore">CacheStoreNoStore</a></li>
<li><a href="mod_cache.html#cachestoreprivate">CacheStorePrivate</a></li>
Modified: httpd/httpd/trunk/docs/manual/mod/mod_cache.html.en
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/mod/mod_cache.html.en?rev=821203&r1=821202&r2=821203&view=diff
==============================================================================
--- httpd/httpd/trunk/docs/manual/mod/mod_cache.html.en (original)
+++ httpd/httpd/trunk/docs/manual/mod/mod_cache.html.en Fri Oct 2 23:48:23 2009
@@ -31,10 +31,11 @@
<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_cache.c</td></tr></table>
<h3>Summary</h3>
- <div class="warning">This module should be used with care and
- can be used to circumvent <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> and <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> directives. You
- should not enable caching for any content to which you wish
- to limit access by client host name, address or environment
+ <div class="warning">This module should be used with care, as when the
+ <code class="directive"><a href="#cachequickhandler">CacheQuickHandler</a></code> directive is
+ in its default value of <strong>on</strong>, the <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> and <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> directives will be circumvented.
+ You should not enable quick handler caching for any content to which you
+ wish to limit access by client host name, address or environment
variable.</div>
<p><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> implements an <a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a> compliant HTTP
@@ -68,6 +69,7 @@
<li><img alt="" src="../images/down.gif" /> <a href="#cachelockpath">CacheLockPath</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#cachemaxexpire">CacheMaxExpire</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#cacheminexpire">CacheMinExpire</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#cachequickhandler">CacheQuickHandler</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#cachestorenostore">CacheStoreNoStore</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#cachestoreprivate">CacheStorePrivate</a></li>
</ul>
@@ -76,6 +78,7 @@
<li><img alt="" src="../images/down.gif" /> <a href="#related">Related Modules and Directives</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#sampleconf">Sample Configuration</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#thunderingherd">Avoiding the Thundering Herd</a></li>
+<li><img alt="" src="../images/down.gif" /> <a href="#finecontrol">Fine Control with the CACHE Filter</a></li>
</ul><h3>See also</h3>
<ul class="seealso">
<li><a href="../caching.html">Caching Guide</a></li>
@@ -174,6 +177,71 @@
</IfModule>
</code></p></div>
+</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="section">
+<h2><a name="finecontrol" id="finecontrol">Fine Control with the CACHE Filter</a></h2>
+ <p>Under the default mode of cache operation, the cache runs as a quick handler,
+ short circuiting the majority of server processing and offering the highest
+ cache performance available.</p>
+
+ <p>In this mode, the cache <strong>bolts onto</strong> the front of the server,
+ acting as if a free standing RFC2616 caching proxy had been placed in front of
+ the server.</p>
+
+ <p>While this mode offers the best performance, the administrator may find that
+ under certain circumstances they may want to perform further processing on the
+ request after the request is cached, such as to inject personalisation into the
+ cached page, or to apply authorisation restrictions to the content. Under these
+ circumstances, an administrator is often forced to place independent reverse
+ proxy servers either behind or in front of the caching server to achieve this.</p>
+
+ <p>To solve this problem the <code class="directive"><a href="#cachequickhandler ">CacheQuickHandler
+ </a></code> directive can be set to <strong>off</strong>, and the server will
+ process all phases normally handled by a non cached request, including the
+ <strong>authentication and authorisation</strong> phases.</p>
+
+ <p>In addition, the administrator may optionally specify the <strong>precise point
+ within the filter chain</strong> where caching is to take place by adding the
+ <strong>CACHE</strong> filter to the output filter chain.</p>
+
+ <p>For example, to cache content before applying compression to the response,
+ place the <strong>CACHE</strong> filter before the <strong>DEFLATE</strong>
+ filter as in the example below:</p>
+
+ <div class="example"><p><code>
+ # Cache content before optional compression<br />
+ CacheQuickHandler off<br />
+ AddOutputFilterByType CACHE;DEFLATE text/plain<br /><br />
+ </code></p></div>
+
+ <p>Another option is to have content cached before personalisation is applied
+ by <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> (or another content processing filter). In this
+ example templates containing tags understood by
+ <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> are cached before being parsed:</p>
+
+ <div class="example"><p><code>
+ # Cache content before mod_include and mod_deflate<br />
+ CacheQuickHandler off<br />
+ AddOutputFilterByType CACHE;INCLUDES;DEFLATE text/html<br /><br />
+ </code></p></div>
+
+ <p>You may place the <strong>CACHE</strong> filter anywhere you wish within the
+ filter chain. In this example, content is cached after being parsed by
+ <code class="module"><a href="../mod/mod_include.html">mod_include</a></code>, but before being processed by
+ <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code>:</p>
+
+ <div class="example"><p><code>
+ # Cache content between mod_include and mod_deflate<br />
+ CacheQuickHandler off<br />
+ AddOutputFilterByType INCLUDES;CACHE;DEFLATE text/html<br /><br />
+ </code></p></div>
+
+ <div class="warning"><h3>Warning:</h3>If the location of the
+ <strong>CACHE</strong> filter in the filter chain is changed for any reason,
+ you may need to <strong>flush your cache</strong> to ensure that your data
+ served remains consistent. <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> is not in a position
+ to enforce this for you.</div>
+
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="CacheDefaultExpire" id="CacheDefaultExpire">CacheDefaultExpire</a> <a name="cachedefaultexpire" id="cachedefaultexpire">Directive</a></h2>
@@ -582,6 +650,51 @@
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
+<div class="directive-section"><h2><a name="CacheQuickHandler" id="CacheQuickHandler">CacheQuickHandler</a> <a name="cachequickhandler" id="cachequickhandler">Directive</a></h2>
+<table class="directive">
+<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Run the cache from the quick handler.</td></tr>
+<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheQuickHandler <var>on|off</var></code></td></tr>
+<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheQuickHandler on</code></td></tr>
+<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
+<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
+<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr>
+</table>
+ <p>The <code class="directive"><a href="#cachequickhandler">CacheQuickHandler</a></code> directive
+ controls the phase in which the cache is handled.</p>
+
+ <p>In the default enabled configuration, the cache operates within the quick
+ handler phase. This phase short circuits the majority of server processing,
+ and represents the most performant mode of operation for a typical server.
+ The cache <strong>bolts onto</strong> the front of the server, and the
+ majority of server processing is avoided.</p>
+
+ <p>When disabled, the cache operates as a normal handler, and is subject to
+ the full set of phases when handling a server request. While this mode is
+ slower than the default, it allows the cache to be used in cases where full
+ processing is required, such as when content is subject to authorisation.</p>
+
+ <div class="example"><p><code>
+ # Run cache as a normal handler<br />
+ CacheQuickHandler off<br /><br />
+ </code></p></div>
+
+ <p>It is also possible, when the quick handler is disabled, for the
+ administrator to choose the precise location within the filter chain where
+ caching is to be performed, by adding the <strong>CACHE</strong> filter to
+ the chain.</p>
+
+ <div class="example"><p><code>
+ # Cache content before mod_include and mod_deflate<br />
+ CacheQuickHandler off<br />
+ AddOutputFilterByType CACHE;INCLUDES;DEFLATE text/html<br /><br />
+ </code></p></div>
+
+ <p>If the CACHE filter is specified more than once, the last instance will
+ apply.</p>
+
+
+</div>
+<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="CacheStoreNoStore" id="CacheStoreNoStore">CacheStoreNoStore</a> <a name="cachestorenostore" id="cachestorenostore">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Attempt to cache requests or responses that have been marked as no-store.</td></tr>