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author | Colm MacCarthaigh <colm@apache.org> | 2005-08-24 10:18:45 +0200 |
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committer | Colm MacCarthaigh <colm@apache.org> | 2005-08-24 10:18:45 +0200 |
commit | 60a8931fa6096cf41df8ca5a53569741f675ba90 (patch) | |
tree | 9f507f4d212c2e3885596af4bf6f0fd4e716f6f6 /docs | |
parent | Update transformation (diff) | |
download | apache2-60a8931fa6096cf41df8ca5a53569741f675ba90.tar.xz apache2-60a8931fa6096cf41df8ca5a53569741f675ba90.zip |
Remove over-zealous and invalid use of <indent></indent> in the Caching
User-guide.
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@239563 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'docs')
-rw-r--r-- | docs/manual/caching.html.en | 39 | ||||
-rw-r--r-- | docs/manual/caching.xml | 39 |
2 files changed, 0 insertions, 78 deletions
diff --git a/docs/manual/caching.html.en b/docs/manual/caching.html.en index 0f7dfb8326..414d48a027 100644 --- a/docs/manual/caching.html.en +++ b/docs/manual/caching.html.en @@ -112,8 +112,6 @@ <h3>Improving Cache Hits</h3> - <span class="indent"> - <p>When caching locally generated content, ensuring that <code class="directive"><a href="./mod/core.html#usecanonicalname">UseCanonicalName</a></code> is set to <code>On</code> can dramatically improve the ratio of cache hits. This @@ -139,13 +137,11 @@ <p>If you are using Server Side Includes, and want the benefit of speedy serves from the cache, you should use <code>virtual</code> include types.</p> - </span> <h3>Expiry Periods</h3> - <span class="indent"> <p>The default expiry period for cached entities is one hour, however this can be easily over-ridden by using the <code class="directive"><a href="./mod/mod_cache.html#cachedefaultexpire">CacheDefaultExpire</a></code> directive. This default is only used when the original source of the content does not @@ -160,14 +156,12 @@ <p>The maximum expiry period may also be controlled by using the <code class="directive"><a href="./mod/mod_cache.html#cachemaxexpire">CacheMaxExpire</a></code>.</p> - </span> <h3>A Brief Guide to Conditional Requests</h3> - <span class="indent"> <p>When content expires from the cache and is re-requested from the backend or content provider, rather than pass on the original request, Aoache will use a conditional request instead.</p> @@ -203,13 +197,11 @@ from the cache if it has not changed. As long as reading from the cache store is faster than reading from the backend (e.g. an in-memory cache compared to reading from disk).</p> - </span> <h3>What Can be Cached?</h3> - <span class="indent"> <p>As mentioned already, the two styles of caching in Apache work differently, <code class="module"><a href="./mod/mod_file_cache.html">mod_file_cache</a></code> caching maintains file contents as they were when Apache was started. When a request is @@ -260,15 +252,11 @@ <li>A response will not be stored if it includes a "Vary:" header containing the match-all "*".</li> </ol> - - </span> <h3>What Should Not be Cached?</h3> - <span class="indent"> - <p>In short, any content which is highly time-sensitive, or which varies depending on the particulars of the request that are not covered by HTTP negotiation, should not be cached.</p> @@ -280,13 +268,11 @@ <p>If on the other hand, the content served differs depending on the values of various HTTP headers, it is possible that it might be possible to cache it intelligently through the use of a "Vary" header.</p> - </span> <h3>Variable/Negotiated Content</h3> - <span class="indent"> <p>If a response with a "Vary" header is received by <code class="module"><a href="./mod/mod_cache.html">mod_cache</a></code> when requesting content by the backend it will attempt to handle it intelligently. If possible, @@ -303,7 +289,6 @@ Vary: negotiate,accept-language,accept-charset <p><code class="module"><a href="./mod/mod_cache.html">mod_cache</a></code> will only serve the cached content to requesters with matching accept-language and accept-charset headers matching those of the original request.</p> - </span> </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> @@ -314,7 +299,6 @@ Vary: negotiate,accept-language,accept-charset <h3>Local exploits</h3> - <span class="indent"> <p>As requests to end-users can be served from the cache, the cache itself can become a target for those wishing to deface or interfere with content. It is important to bear in mind that the cache must at all @@ -332,15 +316,12 @@ Vary: negotiate,accept-language,accept-charset using <code class="module"><a href="./mod/mod_disk_cache.html">mod_disk_cache</a></code> you should bear this in mind - ensure you upgrade Apache when security upgrades are announced and run CGI processes as a non-Apache user using <a href="suexec.html">suEXEC</a> if possible.</p> - </span> <h3>Cache Poisoning</h3> - <span class="indent"> - <p>When running Apache as a caching proxy server, there is also the potential for so-called cache poisoning. Cache Poisoning is a broad term for attacks in which an attacker causes the proxy server to @@ -358,7 +339,6 @@ Vary: negotiate,accept-language,accept-charset a series of requests, and to exploit a vulnerability on an origin webserver such that the attacker can entirely control the content retrieved by the proxy.</p> - </span> </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> <div class="section"> @@ -375,7 +355,6 @@ Vary: negotiate,accept-language,accept-charset <h3>CacheFile</h3> - <span class="indent"> <p>The most basic form of caching present in Apache is the file-handle caching provided by <code class="module"><a href="./mod/mod_file_cache.html">mod_file_cache</a></code>. Rather than caching file-contents, this cache maintains a table of open file descriptors. Files @@ -406,13 +385,11 @@ Vary: negotiate,accept-language,accept-charset will have been deleted, and not show up on the filesystem, extra free space will not be recovered until Apache is stopped and the file descriptor closed.</p> - </span> <h3>CacheEnable fd</h3> - <span class="indent"> <p><code class="module"><a href="./mod/mod_mem_cache.html">mod_mem_cache</a></code> also provides its own file-handle caching scheme, which can be enabled via the <code class="directive"><a href="./mod/mod_cache.html#cacheenable">CacheEnable</a></code> directive.</p> @@ -422,8 +399,6 @@ Vary: negotiate,accept-language,accept-charset <p>As with all of <code class="module"><a href="./mod/mod_cache.html">mod_cache</a></code> this type of file-handle caching is intelligent, and handles will not be maintained beyond the expiry time of the cached content.</p> - - </span> </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> <div class="section"> @@ -452,7 +427,6 @@ Vary: negotiate,accept-language,accept-charset <h3>Operating System Caching</h3> - <span class="indent"> <p>Almost all modern operating systems cache file-data in memory managed directly by the kernel. This is a powerful feature, and for the most part operating systems get it right. For example, on Linux, let's look at @@ -482,7 +456,6 @@ sys 0m0.000s</pre></div> deleted or modified, it can automatically remove file contents from the cache when neccessary. This is a big advantage over Apache's in-memory caching which has no way of knowing when a file has changed.</p> - </span> <p>Despite the performance and advantages of automatic operating system @@ -497,7 +470,6 @@ sys 0m0.000s</pre></div> <h3>MMapStatic Caching</h3> - <span class="indent"> <p><code class="module"><a href="./mod/mod_file_cache.html">mod_file_cache</a></code> provides the <code class="directive"><a href="./mod/mod_file_cache.html#mmapstatic">MMapStatic</a></code> directive, which allows you to have Apache map a static file's contents into memory at @@ -517,14 +489,11 @@ sys 0m0.000s</pre></div> process will replicate this memory, so it is critically important to ensure that the files mapped are not so large as to cause the system to swap memory.</p> - </span> - <h3>mod_mem_cache Caching</h3> - <span class="indent"> <p><code class="module"><a href="./mod/mod_mem_cache.html">mod_mem_cache</a></code> provides a HTTP-aware intelligent in-memory cache. It also uses heap memory directly, which means that even if <var>MMap</var> is not supported on your system, @@ -538,9 +507,6 @@ CacheEnable mem / # Limit the size of the cache to 1 Megabyte MCacheSize 1024</pre></div> - - </span> - </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div> <div class="section"> @@ -571,7 +537,6 @@ CacheDirLength 1</pre></div> <h3>Understanding the Cache-Store</h3> - <span class="indent"> <p>To store items in the cache, <code class="module"><a href="./mod/mod_disk_cache.html">mod_disk_cache</a></code> creates a 22 character hash of the url being requested. Thie hash incorporates the hostname, protocol, port, path and any CGI arguments to the URL, @@ -622,13 +587,11 @@ CacheDirLength 1</pre></div> ".vary" directory will be created for the url in question. This directory will have multiple ".data" files corresponding to the differently negotiated content.</p> - </span> <h3>Maintaining the Disk Cache</h3> - <span class="indent"> <p>Although <code class="module"><a href="./mod/mod_disk_cache.html">mod_disk_cache</a></code> will remove cached content as it is expired, it does not maintain any information on the total size of the cache or how little free space may be left.</p> @@ -655,8 +618,6 @@ CacheDirLength 1</pre></div> to how much space is used you should ensure that <a href="programs/htcacheclean.html">htcacheclean</a> is configured to leave enough "grow room" following a clean.</p> - - </span> </div></div> diff --git a/docs/manual/caching.xml b/docs/manual/caching.xml index 9115cdcd50..8d53c9dd13 100644 --- a/docs/manual/caching.xml +++ b/docs/manual/caching.xml @@ -127,8 +127,6 @@ <section> <title>Improving Cache Hits</title> - <indent> - <p>When caching locally generated content, ensuring that <directive module="core">UseCanonicalName</directive> is set to <code>On</code> can dramatically improve the ratio of cache hits. This @@ -156,13 +154,11 @@ <p>If you are using Server Side Includes, and want the benefit of speedy serves from the cache, you should use <code>virtual</code> include types.</p> - </indent> </section> <section> <title>Expiry Periods</title> - <indent> <p>The default expiry period for cached entities is one hour, however this can be easily over-ridden by using the <directive module="mod_cache">CacheDefaultExpire</directive> directive. This @@ -179,14 +175,12 @@ <p>The maximum expiry period may also be controlled by using the <directive module="mod_cache">CacheMaxExpire</directive>.</p> - </indent> </section> <section> <title>A Brief Guide to Conditional Requests</title> - <indent> <p>When content expires from the cache and is re-requested from the backend or content provider, rather than pass on the original request, Aoache will use a conditional request instead.</p> @@ -222,13 +216,11 @@ from the cache if it has not changed. As long as reading from the cache store is faster than reading from the backend (e.g. an in-memory cache compared to reading from disk).</p> - </indent> </section> <section> <title>What Can be Cached?</title> - <indent> <p>As mentioned already, the two styles of caching in Apache work differently, <module>mod_file_cache</module> caching maintains file contents as they were when Apache was started. When a request is @@ -281,15 +273,11 @@ <li>A response will not be stored if it includes a "Vary:" header containing the match-all "*".</li> </ol> - - </indent> </section> <section> <title>What Should Not be Cached?</title> - <indent> - <p>In short, any content which is highly time-sensitive, or which varies depending on the particulars of the request that are not covered by HTTP negotiation, should not be cached.</p> @@ -301,13 +289,11 @@ <p>If on the other hand, the content served differs depending on the values of various HTTP headers, it is possible that it might be possible to cache it intelligently through the use of a "Vary" header.</p> - </indent> </section> <section> <title>Variable/Negotiated Content</title> - <indent> <p>If a response with a "Vary" header is received by <module>mod_cache</module> when requesting content by the backend it will attempt to handle it intelligently. If possible, @@ -324,7 +310,6 @@ Vary: negotiate,accept-language,accept-charset <p><module>mod_cache</module> will only serve the cached content to requesters with matching accept-language and accept-charset headers matching those of the original request.</p> - </indent> </section> </section> @@ -335,7 +320,6 @@ Vary: negotiate,accept-language,accept-charset <section> <title>Local exploits</title> - <indent> <p>As requests to end-users can be served from the cache, the cache itself can become a target for those wishing to deface or interfere with content. It is important to bear in mind that the cache must at all @@ -354,15 +338,12 @@ Vary: negotiate,accept-language,accept-charset ensure you upgrade Apache when security upgrades are announced and run CGI processes as a non-Apache user using <a href="suexec.html">suEXEC</a> if possible.</p> - </indent> </section> <section> <title>Cache Poisoning</title> - <indent> - <p>When running Apache as a caching proxy server, there is also the potential for so-called cache poisoning. Cache Poisoning is a broad term for attacks in which an attacker causes the proxy server to @@ -380,7 +361,6 @@ Vary: negotiate,accept-language,accept-charset a series of requests, and to exploit a vulnerability on an origin webserver such that the attacker can entirely control the content retrieved by the proxy.</p> - </indent> </section> </section> @@ -407,7 +387,6 @@ Vary: negotiate,accept-language,accept-charset <section> <title>CacheFile</title> - <indent> <p>The most basic form of caching present in Apache is the file-handle caching provided by <module>mod_file_cache</module>. Rather than caching file-contents, this cache maintains a table of open file descriptors. Files @@ -440,13 +419,11 @@ Vary: negotiate,accept-language,accept-charset will have been deleted, and not show up on the filesystem, extra free space will not be recovered until Apache is stopped and the file descriptor closed.</p> - </indent> </section> <section> <title>CacheEnable fd</title> - <indent> <p><module>mod_mem_cache</module> also provides its own file-handle caching scheme, which can be enabled via the <directive module="mod_cache">CacheEnable</directive> directive.</p> @@ -458,8 +435,6 @@ Vary: negotiate,accept-language,accept-charset <p>As with all of <module>mod_cache</module> this type of file-handle caching is intelligent, and handles will not be maintained beyond the expiry time of the cached content.</p> - - </indent> </section> </section> @@ -498,7 +473,6 @@ Vary: negotiate,accept-language,accept-charset <section> <title>Operating System Caching</title> - <indent> <p>Almost all modern operating systems cache file-data in memory managed directly by the kernel. This is a powerful feature, and for the most part operating systems get it right. For example, on Linux, let's look at @@ -529,7 +503,6 @@ sys 0m0.000s</pre> deleted or modified, it can automatically remove file contents from the cache when neccessary. This is a big advantage over Apache's in-memory caching which has no way of knowing when a file has changed.</p> - </indent> </section> <p>Despite the performance and advantages of automatic operating system @@ -544,7 +517,6 @@ sys 0m0.000s</pre> <section> <title>MMapStatic Caching</title> - <indent> <p><module>mod_file_cache</module> provides the <directive module="mod_file_cache">MMapStatic</directive> directive, which allows you to have Apache map a static file's contents into memory at @@ -566,14 +538,11 @@ sys 0m0.000s</pre> process will replicate this memory, so it is critically important to ensure that the files mapped are not so large as to cause the system to swap memory.</p> - </indent> - </section> <section> <title>mod_mem_cache Caching</title> - <indent> <p><module>mod_mem_cache</module> provides a HTTP-aware intelligent in-memory cache. It also uses heap memory directly, which means that even if <var>MMap</var> is not supported on your system, @@ -588,9 +557,6 @@ CacheEnable mem / # Limit the size of the cache to 1 Megabyte MCacheSize 1024</pre> </example> - - </indent> - </section> </section> @@ -631,7 +597,6 @@ CacheDirLength 1</pre> <section> <title>Understanding the Cache-Store</title> - <indent> <p>To store items in the cache, <module>mod_disk_cache</module> creates a 22 character hash of the url being requested. Thie hash incorporates the hostname, protocol, port, path and any CGI arguments to the URL, @@ -682,13 +647,11 @@ CacheDirLength 1</pre> ".vary" directory will be created for the url in question. This directory will have multiple ".data" files corresponding to the differently negotiated content.</p> - </indent> </section> <section> <title>Maintaining the Disk Cache</title> - <indent> <p>Although <module>mod_disk_cache</module> will remove cached content as it is expired, it does not maintain any information on the total size of the cache or how little free space may be left.</p> @@ -719,8 +682,6 @@ CacheDirLength 1</pre> to how much space is used you should ensure that <a href="programs/htcacheclean.html">htcacheclean</a> is configured to leave enough "grow room" following a clean.</p> - - </indent> </section> </section> |