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    <p>If you're looking for a way to associate complex logic with a particular view so that the logic is executed every time that view is created, even if it's generated with methods that don't exist yet, you can use Rails helpers. Every controller has a helper associated with it. For example, if you have a file <code>app/controllers/my_controller.rb</code>, Rails will automatically look for a file called <code>app/helpers/my_helper.rb</code>.</p> <p>Any methods defined in a helper are available to views that are created by the associated controller. So, for example, let's say you have this controller:</p> <pre><code>def MyController &lt; ApplicationController # snip ... def my_action @var = "some value" end end </code></pre> <p>and a view <code>app/views/my/my_action.html.erb</code>:</p> <pre><code>&lt;% variable1 = Model1.where(some conditions) %&gt; &lt;% variable2 = Model2.where(some other conditions) %&gt; &lt;% variable3 = Model3.where(some third conditions) %&gt; &lt;%= "#{variable1} #{variable2} #{variable3} #{@var} %&gt; </code></pre> <p>You can refactor the code that accesses the models into <code>app/helpers/my_helper.rb</code>:</p> <pre><code>module MyHelper def get_variable1() return Model1.where(some conditions) end def get_variable2() return Model2.where(some other conditions) end def get_variable3() return Model3.where(some third conditions) end end </code></pre> <p>And refactor your view like this:</p> <pre><code>&lt;% variable1 = get_variable1() %&gt; &lt;% variable2 = get_variable2() %&gt; &lt;% variable3 = get_variable3() %&gt; &lt;%= "#{variable1} #{variable2} #{variable3} #{@var} %&gt; </code></pre> <p>Without having to modify your controller.</p>
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    1. POIs it bad to have fat views in rails?
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    1. USKevin
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    1. COI asked this question and got a similar answer: http://stackoverflow.com/questions/17152262/call-a-controller-method-automatically-when-rendering-a-partial
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    2. COHelpers are really supposed to be for generating snippets of HTML, not for data access. Consider if you have to call the same helper more than once; now you are making the same call to the database twice. I would prefer seeing all data access at the controller level.
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