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diff --git a/railties/doc/guides/html/caching_with_rails.html b/railties/doc/guides/html/caching_with_rails.html deleted file mode 100644 index 02cc981b0e..0000000000 --- a/railties/doc/guides/html/caching_with_rails.html +++ /dev/null @@ -1,480 +0,0 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"> -<head> - <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> - <title>Caching with Rails: An overview</title> - <!--[if lt IE 8]> - <script src="http://ie7-js.googlecode.com/svn/version/2.0(beta3)/IE8.js" type="text/javascript"></script> - <![endif]--> - <link href="stylesheets/base.css" media="screen" rel="Stylesheet" type="text/css" /> - <link href="stylesheets/forms.css" media="screen" rel="Stylesheet" type="text/css" /> - <link href="stylesheets/more.css" media="screen" rel="Stylesheet" type="text/css" /> -</head> -<body> - <div id="header" > - <div id="logo"> - <a href="index.html" title="Ruby on Rails"><img src="images/rails_logo_remix.gif" alt="Rails" height="140" width="110" /></a> - </div> - - <h1 id="site_title"><span>Ruby on Rails</span></h1> - <h2 id="site_title_tagline">Sustainable productivity for web-application development</h2> - - <ul id="navMain"> - <li class="first-child"><a href="http://www.rubyonrails.org/" title="Ruby on Rails" class="ruby_on_rails">Ruby on Rails</a></li> - <li><a class="manuals" href="index.html" title="Manuals Index">Guides Index</a></li> - </ul> - </div> - - <div id="container"> - - <div id="sidebar"> - <h2>Chapters</h2> - <ol> - <li> - <a href="#_basic_caching">Basic Caching</a> - <ul> - - <li><a href="#_page_caching">Page Caching</a></li> - - <li><a href="#_action_caching">Action Caching</a></li> - - <li><a href="#_fragment_caching">Fragment Caching</a></li> - - <li><a href="#_sweepers">Sweepers</a></li> - - <li><a href="#_sql_caching">SQL Caching</a></li> - - <li><a href="#_cache_stores">Cache stores</a></li> - - </ul> - </li> - <li> - <a href="#_conditional_get_support">Conditional GET support</a> - </li> - <li> - <a href="#_advanced_caching">Advanced Caching</a> - </li> - </ol> - </div> - - <div id="content"> - <h1>Caching with Rails: An overview</h1> - <div id="preamble">
-<div class="sectionbody">
-<div class="paragraph"><p>Everyone caches. This guide will teach you what you need to know about
-avoiding that expensive round-trip to your database and returning what you
-need to return to those hungry web clients in the shortest time possible.</p></div>
-</div>
-</div>
-<h2 id="_basic_caching">1. Basic Caching</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>This is an introduction to the three types of caching techniques that Rails
-provides by default without the use of any third party plugins.</p></div>
-<div class="paragraph"><p>To get started make sure <tt>config.action_controller.perform_caching</tt> is set
-to <tt>true</tt> for your environment. This flag is normally set in the
-corresponding config/environments/*.rb and caching is disabled by default
-there for development and test, and enabled for production.</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>config<span style="color: #990000">.</span>action_controller<span style="color: #990000">.</span>perform_caching <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #0000FF">true</span></span></tt></pre></div></div>
-<h3 id="_page_caching">1.1. Page Caching</h3>
-<div class="paragraph"><p>Page caching is a Rails mechanism which allows the request for a generated
-page to be fulfilled by the webserver, without ever having to go through the
-Rails stack at all. Obviously, this is super-fast. Unfortunately, it can’t be
-applied to every situation (such as pages that need authentication) and since
-the webserver is literally just serving a file from the filesystem, cache
-expiration is an issue that needs to be dealt with.</p></div>
-<div class="paragraph"><p>So, how do you enable this super-fast cache behavior? Simple, let’s say you
-have a controller called ProductsController and a <em>list</em> action that lists all
-the products</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ActionController
-
- caches_page <span style="color: #990000">:</span>index
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> index<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>The first time anyone requests products/index, Rails will generate a file
-called <tt>index.html</tt> and the webserver will then look for that file before it
-passes the next request for products/index to your Rails application.</p></div>
-<div class="paragraph"><p>By default, the page cache directory is set to Rails.public_path (which is
-usually set to <tt>RAILS_ROOT + "/public"</tt>) and this can be configured by
-changing the configuration setting <tt>config.action_controller.page_cache_directory</tt>.
-Changing the default from /public helps avoid naming conflicts, since you may
-want to put other static html in /public, but changing this will require web
-server reconfiguration to let the web server know where to serve the cached
-files from.</p></div>
-<div class="paragraph"><p>The Page Caching mechanism will automatically add a <tt>.html</tt> exxtension to
-requests for pages that do not have an extension to make it easy for the
-webserver to find those pages and this can be configured by changing the
-configuration setting <tt>config.action_controller.page_cache_extension</tt>.</p></div>
-<div class="paragraph"><p>In order to expire this page when a new product is added we could extend our
-example controler like this:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ActionController
-
- caches_page <span style="color: #990000">:</span>list
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> list<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> create
- expire_page <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>list
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>If you want a more complicated expiration scheme, you can use cache sweepers
-to expire cached objects when things change. This is covered in the section on Sweepers.</p></div>
-<h3 id="_action_caching">1.2. Action Caching</h3>
-<div class="paragraph"><p>One of the issues with Page Caching is that you cannot use it for pages that
-require to restrict access somehow. This is where Action Caching comes in.
-Action Caching works like Page Caching except for the fact that the incoming
-web request does go from the webserver to the Rails stack and Action Pack so
-that before filters can be run on it before the cache is served, so that
-authentication and other restrictions can be used while still serving the
-result of the output from a cached copy.</p></div>
-<div class="paragraph"><p>Clearing the cache works in the exact same way as with Page Caching.</p></div>
-<div class="paragraph"><p>Let’s say you only wanted authenticated users to edit or create a Product
-object, but still cache those pages:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ActionController
-
- before_filter <span style="color: #990000">:</span>authenticate<span style="color: #990000">,</span> <span style="color: #990000">:</span>only <span style="color: #990000">=></span> <span style="color: #990000">[</span> <span style="color: #990000">:</span>edit<span style="color: #990000">,</span> <span style="color: #990000">:</span>create <span style="color: #990000">]</span>
- caches_page <span style="color: #990000">:</span>list
- caches_action <span style="color: #990000">:</span>edit
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> list<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> create
- expire_page <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>list
- expire_action <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>edit
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> edit<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>And you can also use <tt>:if</tt> (or <tt>:unless</tt>) to pass a Proc that specifies when the
-action should be cached. Also, you can use <tt>:layout => false</tt> to cache without
-layout so that dynamic information in the layout such as logged in user info
-or the number of items in the cart can be left uncached. This feature is
-available as of Rails 2.2.</p></div>
-<div class="paragraph"><p>[More: more examples? Walk-through of Action Caching from request to response?
- Description of Rake tasks to clear cached files? Show example of
- subdomain caching? Talk about :cache_path, :if and assing blocks/Procs
- to expire_action?]</p></div>
-<h3 id="_fragment_caching">1.3. Fragment Caching</h3>
-<div class="paragraph"><p>Life would be perfect if we could get away with caching the entire contents of
-a page or action and serving it out to the world. Unfortunately, dynamic web
-applications usually build pages with a variety of components not all of which
-have the same caching characteristics. In order to address such a dynamically
-created page where different parts of the page need to be cached and expired
-differently Rails provides a mechanism called Fragment Caching.</p></div>
-<div class="paragraph"><p>Fragment Caching allows a fragment of view logic to be wrapped in a cache
-block and served out of the cache store when the next request comes in.</p></div>
-<div class="paragraph"><p>As an example, if you wanted to show all the orders placed on your website
-in real time and didn’t want to cache that part of the page, but did want
-to cache the part of the page which lists all products available, you
-could use this piece of code:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="color: #FF0000"><% Order.find_recent.each do |o| %></span>
- <span style="color: #FF0000"><%= o.buyer.name %></span> bought <span style="color: #FF0000"><% o.product.name %></span>
-<span style="color: #FF0000"><% end %></span>
-
-<span style="color: #FF0000"><% cache do %></span>
- All available products<span style="color: #990000">:</span>
- <span style="color: #FF0000"><% Product.find(:all).each do |p| %></span>
- <span style="color: #FF0000"><%= link_to p.name, product_url(p) %></span>
- <span style="color: #FF0000"><% end %></span>
-<span style="color: #FF0000"><% end %></span></tt></pre></div></div>
-<div class="paragraph"><p>The cache block in our example will bind to the action that called it and is
-written out to the same place as the Action Cache, which means that if you
-want to cache multiple fragments per action, you should provide an <tt>action_suffix</tt> to the cache call:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="color: #FF0000"><% cache(:action =></span> <span style="color: #FF0000">'recent'</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>action_suffix <span style="color: #990000">=></span> <span style="color: #FF0000">'all_products'</span><span style="color: #990000">)</span> <span style="font-weight: bold"><span style="color: #0000FF">do</span></span> <span style="color: #990000">%></span>
- All available products<span style="color: #990000">:</span></tt></pre></div></div>
-<div class="paragraph"><p>and you can expire it using the <tt>expire_fragment</tt> method, like so:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>expire_fragment<span style="color: #990000">(:</span>controller <span style="color: #990000">=></span> <span style="color: #FF0000">'products'</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #FF0000">'recent'</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>action_suffix <span style="color: #990000">=></span> 'all_products<span style="color: #990000">)</span></tt></pre></div></div>
-<div class="paragraph"><p>If you don’t want the cache block to bind to the action that called it, You can
-also use globally keyed fragments by calling the cache method with a key, like
-so:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="color: #FF0000"><% cache(:key =></span> <span style="color: #990000">[</span><span style="color: #FF0000">'all_available_products'</span><span style="color: #990000">,</span> <span style="color: #009900">@latest_product</span><span style="color: #990000">.</span>created_at<span style="color: #990000">].</span>join<span style="color: #990000">(</span><span style="color: #FF0000">':'</span><span style="color: #990000">))</span> <span style="font-weight: bold"><span style="color: #0000FF">do</span></span> <span style="color: #990000">%></span>
- All available products<span style="color: #990000">:</span></tt></pre></div></div>
-<div class="paragraph"><p>This fragment is then available to all actions in the ProductsController using
-the key and can be expired the same way:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>expire_fragment<span style="color: #990000">(:</span>key <span style="color: #990000">=></span> <span style="color: #990000">[</span><span style="color: #FF0000">'all_available_products'</span><span style="color: #990000">,</span> <span style="color: #009900">@latest_product</span><span style="color: #990000">.</span>created_at<span style="color: #990000">].</span>join<span style="color: #990000">(</span><span style="color: #FF0000">':'</span><span style="color: #990000">))</span></tt></pre></div></div>
-<h3 id="_sweepers">1.4. Sweepers</h3>
-<div class="paragraph"><p>Cache sweeping is a mechanism which allows you to get around having a ton of
-expire_{page,action,fragment} calls in your code by moving all the work
-required to expire cached content into a <tt>ActionController::Caching::Sweeper</tt>
-class that is an Observer and looks for changes to an object via callbacks,
-and when a change occurs it expires the caches associated with that object n
-an around or after filter.</p></div>
-<div class="paragraph"><p>Continuing with our Product controller example, we could rewrite it with a
-sweeper such as the following:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> StoreSweeper <span style="color: #990000"><</span> ActionController<span style="color: #990000">::</span>Caching<span style="color: #990000">::</span>Sweeper
- observe Product <span style="font-style: italic"><span style="color: #9A1900"># This sweeper is going to keep an eye on the Product model</span></span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># If our sweeper detects that a Product was created call this</span></span>
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> after_create<span style="color: #990000">(</span>product<span style="color: #990000">)</span>
- expire_cache_for<span style="color: #990000">(</span>product<span style="color: #990000">)</span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># If our sweeper detects that a Product was updated call this</span></span>
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> after_update<span style="color: #990000">(</span>product<span style="color: #990000">)</span>
- expire_cache_for<span style="color: #990000">(</span>product<span style="color: #990000">)</span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># If our sweeper detects that a Product was deleted call this</span></span>
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> after_destroy<span style="color: #990000">(</span>product<span style="color: #990000">)</span>
- expire_cache_for<span style="color: #990000">(</span>product<span style="color: #990000">)</span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- private
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> expire_cache_for<span style="color: #990000">(</span>record<span style="color: #990000">)</span>
- <span style="font-style: italic"><span style="color: #9A1900"># Expire the list page now that we added a new product</span></span>
- expire_page<span style="color: #990000">(:</span>controller <span style="color: #990000">=></span> <span style="color: #FF0000">'#{record}'</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #FF0000">'list'</span><span style="color: #990000">)</span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># Expire a fragment</span></span>
- expire_fragment<span style="color: #990000">(:</span>controller <span style="color: #990000">=></span> <span style="color: #FF0000">'#{record}'</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #FF0000">'recent'</span><span style="color: #990000">,</span> <span style="color: #990000">:</span>action_suffix <span style="color: #990000">=></span> <span style="color: #FF0000">'all_products'</span><span style="color: #990000">)</span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>Then we add it to our controller to tell it to call the sweeper when certain
-actions are called. So, if we wanted to expire the cached content for the
-list and edit actions when the create action was called, we could do the
-following:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ActionController
-
- before_filter <span style="color: #990000">:</span>authenticate<span style="color: #990000">,</span> <span style="color: #990000">:</span>only <span style="color: #990000">=></span> <span style="color: #990000">[</span> <span style="color: #990000">:</span>edit<span style="color: #990000">,</span> <span style="color: #990000">:</span>create <span style="color: #990000">]</span>
- caches_page <span style="color: #990000">:</span>list
- caches_action <span style="color: #990000">:</span>edit
- cache_sweeper <span style="color: #990000">:</span>store_sweeper<span style="color: #990000">,</span> <span style="color: #990000">:</span>only <span style="color: #990000">=></span> <span style="color: #990000">[</span> <span style="color: #990000">:</span>create <span style="color: #990000">]</span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> list<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> create
- expire_page <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>list
- expire_action <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>edit
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> edit<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<h3 id="_sql_caching">1.5. SQL Caching</h3>
-<div class="paragraph"><p>Query caching is a Rails feature that caches the result set returned by each
-query so that if Rails encounters the same query again for that request, it
-will used the cached result set as opposed to running the query against the
-database again.</p></div>
-<div class="paragraph"><p>For example:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ActionController
-
- before_filter <span style="color: #990000">:</span>authenticate<span style="color: #990000">,</span> <span style="color: #990000">:</span>only <span style="color: #990000">=></span> <span style="color: #990000">[</span> <span style="color: #990000">:</span>edit<span style="color: #990000">,</span> <span style="color: #990000">:</span>create <span style="color: #990000">]</span>
- caches_page <span style="color: #990000">:</span>list
- caches_action <span style="color: #990000">:</span>edit
- cache_sweeper <span style="color: #990000">:</span>store_sweeper<span style="color: #990000">,</span> <span style="color: #990000">:</span>only <span style="color: #990000">=></span> <span style="color: #990000">[</span> <span style="color: #990000">:</span>create <span style="color: #990000">]</span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> list
- <span style="font-style: italic"><span style="color: #9A1900"># Run a find query</span></span>
- Product<span style="color: #990000">.</span>find<span style="color: #990000">(:</span>all<span style="color: #990000">)</span>
-
- <span style="color: #990000">...</span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># Run the same query again</span></span>
- Product<span style="color: #990000">.</span>find<span style="color: #990000">(:</span>all<span style="color: #990000">)</span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> create
- expire_page <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>list
- expire_action <span style="color: #990000">:</span>action <span style="color: #990000">=></span> <span style="color: #990000">:</span>edit
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> edit<span style="color: #990000">;</span> <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>In the <em>list</em> action above, the result set returned by the first
-Product.find(:all) will be cached and will be used to avoid querying the
-database again the second time that finder is called.</p></div>
-<div class="paragraph"><p>Query caches are created at the start of an action and destroyed at the end of
-that action and thus persist only for the duration of the action.</p></div>
-<h3 id="_cache_stores">1.6. Cache stores</h3>
-<div class="paragraph"><p>Rails provides different stores for the cached data for action and fragment
-caches. Page caches are always stored on disk.</p></div>
-<div class="paragraph"><p>The cache stores provided include:</p></div>
-<div class="paragraph"><p>1) Memory store: Cached data is stored in the memory allocated to the Rails
- process, which is fine for WEBrick and for FCGI (if you
- don’t care that each FCGI process holds its own fragment
- store). It’s not suitable for CGI as the process is thrown
- away at the end of each request. It can potentially also
- take up a lot of memory since each process keeps all the
- caches in memory.</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>ActionController<span style="color: #990000">::</span>Base<span style="color: #990000">.</span>cache_store <span style="color: #990000">=</span> <span style="color: #990000">:</span>memory_store</tt></pre></div></div>
-<div class="paragraph"><p>2) File store: Cached data is stored on the disk, this is the default store
- and the default path for this store is: /tmp/cache. Works
- well for all types of environments and allows all processes
- running from the same application directory to access the
- cached content.</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>ActionController<span style="color: #990000">::</span>Base<span style="color: #990000">.</span>cache_store <span style="color: #990000">=</span> <span style="color: #990000">:</span>file_store<span style="color: #990000">,</span> <span style="color: #FF0000">"/path/to/cache/directory"</span></tt></pre></div></div>
-<div class="paragraph"><p>3) DRb store: Cached data is stored in a separate shared DRb process that all
- servers communicate with. This works for all environments and
- only keeps one cache around for all processes, but requires
- that you run and manage a separate DRb process.</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>ActionController<span style="color: #990000">::</span>Base<span style="color: #990000">.</span>cache_store <span style="color: #990000">=</span> <span style="color: #990000">:</span>drb_store<span style="color: #990000">,</span> <span style="color: #FF0000">"druby://localhost:9192"</span></tt></pre></div></div>
-<div class="paragraph"><p>4) MemCached store: Works like DRbStore, but uses Danga’s MemCache instead.
- Rails uses the bundled memcached-client gem by default.</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>ActionController<span style="color: #990000">::</span>Base<span style="color: #990000">.</span>cache_store <span style="color: #990000">=</span> <span style="color: #990000">:</span>mem_cache_store<span style="color: #990000">,</span> <span style="color: #FF0000">"localhost"</span></tt></pre></div></div>
-<div class="paragraph"><p>5) Custom store: You can define your own cache store (new in Rails 2.1)</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt>ActionController<span style="color: #990000">::</span>Base<span style="color: #990000">.</span>cache_store <span style="color: #990000">=</span> MyOwnStore<span style="color: #990000">.</span>new<span style="color: #990000">(</span><span style="color: #FF0000">"parameter"</span><span style="color: #990000">)</span></tt></pre></div></div>
-<div class="paragraph"><p><tt>Note: config.cache_store can be used in place of
-ActionController::Base.cache_store in your Rails::Initializer.run block in
-environment.rb</tt></p></div>
-</div>
-<h2 id="_conditional_get_support">2. Conditional GET support</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>Conditional GETs are a facility of the HTTP spec that provide a way for web
-servers to tell browsers that the response to a GET request hasn’t changed
-since the last request and can be safely pulled from the browser cache.</p></div>
-<div class="paragraph"><p>They work by using the HTTP_IF_NONE_MATCH and HTTP_IF_MODIFIED_SINCE headers to
-pass back and forth both a unique content identifier and the timestamp of when
-the content was last changed. If the browser makes a request where the content
-identifier (etag) or last modified since timestamp matches the server’s version
-then the server only needs to send back an empty response with a not modified
-status.</p></div>
-<div class="paragraph"><p>It is the server’s (i.e. our) responsibility to look for a last modified
-timestamp and the if-none-match header and determine whether or not to send
-back the full response. With conditional-get support in rails this is a pretty
-easy task:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ApplicationController
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> show
- <span style="color: #009900">@product</span> <span style="color: #990000">=</span> Product<span style="color: #990000">.</span>find<span style="color: #990000">(</span>params<span style="color: #990000">[:</span>id<span style="color: #990000">])</span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># If the request is stale according to the given timestamp and etag value</span></span>
- <span style="font-style: italic"><span style="color: #9A1900"># (i.e. it needs to be processed again) then execute this block</span></span>
- <span style="font-weight: bold"><span style="color: #0000FF">if</span></span> stale?<span style="color: #990000">(:</span>last_modified <span style="color: #990000">=></span> <span style="color: #009900">@product</span><span style="color: #990000">.</span>updated_at<span style="color: #990000">.</span>utc<span style="color: #990000">,</span> <span style="color: #990000">:</span>etag <span style="color: #990000">=></span> <span style="color: #009900">@product</span><span style="color: #990000">)</span>
- respond_to <span style="font-weight: bold"><span style="color: #0000FF">do</span></span> <span style="color: #990000">|</span>wants<span style="color: #990000">|</span>
- <span style="font-style: italic"><span style="color: #9A1900"># ... normal response processing</span></span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-
- <span style="font-style: italic"><span style="color: #9A1900"># If the request is fresh (i.e. it's not modified) then you don't need to do</span></span>
- <span style="font-style: italic"><span style="color: #9A1900"># anything. The default render checks for this using the parameters</span></span>
- <span style="font-style: italic"><span style="color: #9A1900"># used in the previous call to stale? and will automatically send a</span></span>
- <span style="font-style: italic"><span style="color: #9A1900"># :not_modified. So that's it, you're done.</span></span>
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-<div class="paragraph"><p>If you don’t have any special response processing and are using the default
-rendering mechanism (i.e. you’re not using respond_to or calling render
-yourself) then you’ve got an easy helper in fresh_when:</p></div>
-<div class="listingblock">
-<div class="content"><!-- Generator: GNU source-highlight 2.9
-by Lorenzo Bettini
-http://www.lorenzobettini.it
-http://www.gnu.org/software/src-highlite -->
-<pre><tt><span style="font-weight: bold"><span style="color: #0000FF">class</span></span> ProductsController <span style="color: #990000"><</span> ApplicationController
-
- <span style="font-style: italic"><span style="color: #9A1900"># This will automatically send back a :not_modified if the request is fresh,</span></span>
- <span style="font-style: italic"><span style="color: #9A1900"># and will render the default template (product.*) if it's stale.</span></span>
-
- <span style="font-weight: bold"><span style="color: #0000FF">def</span></span> show
- <span style="color: #009900">@product</span> <span style="color: #990000">=</span> Product<span style="color: #990000">.</span>find<span style="color: #990000">(</span>params<span style="color: #990000">[:</span>id<span style="color: #990000">])</span>
- fresh_when <span style="color: #990000">:</span>last_modified <span style="color: #990000">=></span> <span style="color: #009900">@product</span><span style="color: #990000">.</span>published_at<span style="color: #990000">.</span>utc<span style="color: #990000">,</span> <span style="color: #990000">:</span>etag <span style="color: #990000">=></span> <span style="color: #009900">@article</span>
- <span style="font-weight: bold"><span style="color: #0000FF">end</span></span>
-<span style="font-weight: bold"><span style="color: #0000FF">end</span></span></tt></pre></div></div>
-</div>
-<h2 id="_advanced_caching">3. Advanced Caching</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>Along with the built-in mechanisms outlined above, a number of excellent
-plugins exist to help with finer grained control over caching. These include
-Chris Wanstrath’s excellent cache_fu plugin (more info here:
-<a href="http://errtheblog.com/posts/57-kickin-ass-w-cachefu">http://errtheblog.com/posts/57-kickin-ass-w-cachefu</a>) and Evan Weaver’s
-interlock plugin (more info here:
-<a href="http://blog.evanweaver.com/articles/2007/12/13/better-rails-caching/">http://blog.evanweaver.com/articles/2007/12/13/better-rails-caching/</a>). Both
-of these plugins play nice with memcached and are a must-see for anyone
-seriously considering optimizing their caching needs.</p></div>
-</div>
- - </div> - </div> -</body> -</html> |