blocks|key|1591098|text|integer.ordinalize是我不久前偶然发现的一个小方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1591099|1.ordinalize+=+"1st"
3.ordinalize+=+"3rd"|code-block|syntax|javascript|1591100|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

integer.ordinalize is one little method that I just stumbled upon not to long ago.

<pre><code>1.ordinalize = "1st"
3.ordinalize = "3rd"
</code></pre>

blocks|key|1376335|text|我现在很喜欢div_for和content_tag_for|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1376336|<%25+div_for(@comment)+do+%25>
++
<%25+end+%25>|code-block|syntax|javascript|1376337|上面的代码呈现如下：|1376338|<div+id="comment_123"+class="comment">
++
</div>|1376339|想要CSS类为comment+other_class吗？没问题：|1376340|<%25+div_for(@comment,+:class+=>+'other_class')+do+%25>
++
<%25+end+%25>|1376341|想要一个span而不是一个div？没问题，content_tag_for来救你了！|1376342|<%25+content_tag_for(:span,+@comment)+do+%25>
<%25+end+%25>

#+Becomes...

<span+id="comment_123"+class="comment">
++
|1376343|如果你想给你的id加上前缀，content_tag_for也很棒。我用它来加载gif。|1376344|<%25+content_tag_for(:span,+@comment,+'loading')+do+%25>
++<%25=+image_tag+'loading.gif'+-%25>
<%25+end+%25>

#+Becomes...

<span+id="loading_comment_123"+class="comment">
++<img+src="loading.gif"+/>
|1376345|entityMap^0|6|7|E|F|0|0|0|0|7|J|0|0|L|F|0|0|7|2|E|F|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|17|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|18|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|19|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|1D|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|1E|8|@$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|U|3|V|5|H|7|1H|8|@]|D|@]|E|$I|J]]|$1|W|3|X|5|6|7|1I|8|@$9|1J|A|1K|B|C]|$9|1L|A|1M|B|C]]|D|@]|E|$]]|$1|Y|3|Z|5|H|7|1N|8|@]|D|@]|E|$I|J]]|$1|10|3|-4|5|6|7|1O|8|@]|D|@]|E|$]]]|11|$]]

I'm currently in love with <code>div_for</code> and <code>content_tag_for</code>

<pre><code>&lt;% div_for(@comment) do %&gt;
 &lt;!-- code to display your comment --&gt;
&lt;% end %&gt;
</code></pre>

The above code renders this:

<pre><code>&lt;div id="comment_123" class="comment"&gt;
 &lt;!-- code to display your comment --&gt;
&lt;/div&gt;
</code></pre>

Want the CSS class to be <code>comment other_class</code>? No problem:

<pre><code>&lt;% div_for(@comment, :class =&gt; 'other_class') do %&gt;
 &lt;!-- code to display your comment --&gt;
&lt;% end %&gt;
</code></pre>

Want a span and not a div? No problem, <code>content_tag_for</code> to the rescue!

<pre><code>&lt;% content_tag_for(:span, @comment) do %&gt;
&lt;% end %&gt;

# Becomes...

&lt;span id="comment_123" class="comment"&gt;
 &lt;!-- code to display your comment --&gt;
&lt;/span&gt;
</code></pre>

<code>content_tag_for</code> is also great if you want to prefix you <code>id</code>. I use it for loading gifs.

<pre><code>&lt;% content_tag_for(:span, @comment, 'loading') do %&gt;
 &lt;%= image_tag 'loading.gif' -%&gt;
&lt;% end %&gt;

# Becomes...

&lt;span id="loading_comment_123" class="comment"&gt;
 &lt;img src="loading.gif" /&gt;
&lt;/span&gt;
</code></pre>

blocks|key|1376154|text|要查看已安装的gem的列表，您可以运行：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1376155|gem+server|code-block|syntax|javascript|1376156|然后将你的浏览器指向：|1376157|http://localhost:8808|1376158|你会得到一个格式良好的get列表，其中包含指向rdoc、web和任何依赖项的链接。比…好得多：|1376159|gem+list|1376160|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

To see a list of gems that are installed, you can run:

<pre><code>gem server
</code></pre>

Then point your browser at:

<pre><code>http://localhost:8808
</code></pre>

You get a nicely formatted list of your gems with links to rdoc, the web and any dependencies. Much nicer than:

<pre><code>gem list
</code></pre>

blocks|key|1376045|text|您可以利用Ruby类定义处于活动状态以及Rails在生产环境中缓存类这一事实，以确保只有在应用程序启动时才从数据库获取常量数据。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1376046|例如，对于表示国家/地区的模型，您需要定义一个常量，该常量在装入类时执行Country.all查询：|offset|length|style|CODE|1376047|class+Country+<+ActiveRecord::Base
++COUNTRIES+=+self.all
++.
++.
++.
end|code-block|syntax|javascript|1376048|您可以通过引用Country::COUNTRIES在视图模板中(可能在选择帮助器中)使用此常量。例如：|1376049|<%25=+select_tag(:country,+options_for_select(Country::COUNTRIES))+%25>|1376050|entityMap^0|0|10|B|0|0|7|I|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@$D|U|E|V|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|W|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|X|8|@$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|O|3|P|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

You can take advantage of the fact that Ruby class definitions are active and that Rails caches classes in the production environment, to ensure that constant data is only fetched from the database when your application starts up.

For example, for a model that represents countries you'd define a constant that performs a <code>Country.all</code> query when the class is loaded:

<pre><code>class Country &lt; ActiveRecord::Base
 COUNTRIES = self.all
 .
 .
 .
end
</code></pre>

You can use this constant within a view template (perhaps within a select helper) by referring to <code>Country::COUNTRIES</code>. For example:

<pre><code>&lt;%= select_tag(:country, options_for_select(Country::COUNTRIES)) %&gt;
</code></pre>

blocks|key|1376210|text|在environment.rb中，您可以定义新的日期/时间格式，例如|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1376211|[Time::DATE_FORMATS,+Date::DATE_FORMATS].each+do+%7Cobj%7C
++obj[:dots]+=+"%25m.%25d.%25y"
end|code-block|syntax|javascript|1376212|所以在你的视图中，你可以使用：|1376213|Created:+<%25=+@my_object.created_at.to_s(:dots)+%25>|1376214|它将像这样打印：|1376215|Created:+06.21.09|1376216|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

in your environment.rb, you can define new date/time formats e.g.

<pre><code>[Time::DATE_FORMATS, Date::DATE_FORMATS].each do |obj|
 obj[:dots] = "%m.%d.%y"
end
</code></pre>

so then in your views you can use:

<pre><code>Created: &lt;%= @my_object.created_at.to_s(:dots) %&gt;
</code></pre>

which will print like:

<pre><code>Created: 06.21.09
</code></pre>

blocks|key|1375924|text|如果您有一个包含一些类方法和一些命名作用域的模型：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1375925|class+Animal+<+ActiveRecord::Base
++named_scope+'nocturnal',+:conditions+=>+{'nocturnal'+=>+true}
++named_scope+'carnivorous',+:conditions+=>+{'vegetarian'+=>+true}

++def+self.feed_all_with(food)
++++self.all.each+do+%7Canimal%7C
++++++animal.feed_with(food)
++++end
++end
end|code-block|syntax|javascript|1375926|然后，您可以通过命名作用域调用类方法：|1375927|if+night_time?
++Animal.nocturnal.carnivorous.feed_all_with(bacon)
end|1375928|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

If you have a model with some class methods and some named scopes:

<pre><code>class Animal &lt; ActiveRecord::Base
 named_scope 'nocturnal', :conditions =&gt; {'nocturnal' =&gt; true}
 named_scope 'carnivorous', :conditions =&gt; {'vegetarian' =&gt; true}

 def self.feed_all_with(food)
 self.all.each do |animal|
 animal.feed_with(food)
 end
 end
end
</code></pre>

Then you can call the class methods through the named scope:

<pre><code>if night_time?
 Animal.nocturnal.carnivorous.feed_all_with(bacon)
end
</code></pre>

blocks|key|1375772|text|Rails+2.3.x现在允许您执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1375773|render+@items|code-block|syntax|javascript|1375774|简单多了..|1375775|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Rails 2.3.x now allows you to do:

<pre><code>render @items
</code></pre>

much simpler..

blocks|key|1375696|text|我将从我最喜欢的一个开始。在使用集合调用partial时，您可以使用以下代码，而不是遍历集合并为每个项调用它：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1375697|render+:partial+=>+'items',+:collection+=>+@items|code-block|syntax|javascript|1375698|这将为每个项目调用一次partial，并在每次传递一个局部变量项目。你也不必担心零检查@items。|1375699|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I'll start with one of my favorites. When calling a partial with a collection, instead of looping through your collection and calling it for each item, you can use this:

<pre><code>render :partial =&gt; 'items', :collection =&gt; @items
</code></pre>

This will call the partial once per item, and pass a local variable item each time. You don't have to worry about nil checking @items either.

blocks|key|1591715|text|您可以为您的测试套件更改模型的行为。假设您定义了一些after_save方法，并且您不希望它出现在单元测试中。它是这样工作的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1591716|#+models/person.rb
class+Person+<+ActiveRecord::Base

++def+after_save
++++#+do+something+useful
++end

end


#+test/unit/person_test.rb
require+'test_helper'

class+PersonTest+<+ActiveSupport::TestCase

++class+::Person
++++def+after_save
++++++#+do+nothing
++++end
++end

++test+"something+interesting"+do
++++#+...
++end
end|code-block|syntax|javascript|1591717|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can change the behaviour of a model for your test suite. Say you have some after_save method defined and you do not want it to happen in your unit tests. This is how it works:

<pre><code># models/person.rb
class Person &lt; ActiveRecord::Base

 def after_save
 # do something useful
 end

end


# test/unit/person_test.rb
require 'test_helper'

class PersonTest &lt; ActiveSupport::TestCase

 class ::Person
 def after_save
 # do nothing
 end
 end

 test "something interesting" do
 # ...
 end
end
</code></pre>

blocks|key|1591764|text|有趣的是，数组有特殊的方法来访问它的42个元素|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1591765|a+=+[]
a.forty_two|code-block|syntax|javascript|1591766|http://railsapi.com/doc/rails-v2.3.8/classes/ActiveSupport/CoreExtensions/Array/Access.html#M003045|offset|length|1591767|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|2R|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|T|8|@]|9|@$I|U|J|V|1|W]]|A|$]]|$1|K|3|-4|5|6|7|X|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|H]]]]

Funny feature is that array has special method for accessing its 42 element

<pre><code>a = []
a.forty_two
</code></pre>

<a href="http://railsapi.com/doc/rails-v2.3.8/classes/ActiveSupport/CoreExtensions/Array/Access.html#M003045" rel="noreferrer">http://railsapi.com/doc/rails-v2.3.8/classes/ActiveSupport/CoreExtensions/Array/Access.html#M003045</a>

blocks|key|1375866|text|如果为资源添加工艺路线，请执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1375867|ActionController::Routing::Routes.draw+do+%7Cmap%7C
++map.resources+:maps
end|code-block|syntax|javascript|1375868|并注册其他mime类型：|1375869|Mime::Type.register+'application/vnd.google-earth.kml%2Bxml',+:kml|1375870|您不需要在控制器中使用respond_to块来为这些附加类型提供服务。相反，只需为特定类型创建视图，例如'show.kml.builder'或'index.kml.erb'。当接收到对'/maps.kml'或'/maps/1.kml'的请求时，Rails将呈现这些特定于类型的模板，并相应地设置响应类型。|offset|length|style|CODE|1375871|entityMap^0|0|0|0|0|B|A|1G|I|1Z|F|2K|B|2W|D|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@$M|X|N|Y|O|P]|$M|Z|N|10|O|P]|$M|11|N|12|O|P]|$M|13|N|14|O|P]|$M|15|N|16|O|P]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|R|$]]

If you add routing for a resource:

<pre><code>ActionController::Routing::Routes.draw do |map|
 map.resources :maps
end
</code></pre>

And register additional mime-types:

<pre><code>Mime::Type.register 'application/vnd.google-earth.kml+xml', :kml
</code></pre>

You don't need a <code>respond_to</code> block in your controller to serve these additional types. Instead, just create views for the specific types, for example <code>'show.kml.builder'</code> or <code>'index.kml.erb'</code>. Rails will render these type-specific templates when requests for <code>'/maps.kml'</code> or <code>'/maps/1.kml'</code> are received, setting the response type appropriately.

blocks|key|1591554|text|ActionView::Base.default_form_builder+=+MyFormBuilderClass|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1591555|在创建自己的表单构建器时非常有用。一个比手动传递更好的选择:构建器，无论是在视图中还是在您自己的custom_form_for帮助器中。|unstyled|offset|length|style|CODE|1591556|entityMap^0|0|1C|F|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@$G|O|H|P|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>ActionView::Base.default_form_builder = MyFormBuilderClass
</code></pre>

Very useful when you're creating your own form builders. A much better alternative to manually passing :builder, either in your views or in your own <code>custom_form_for</code> helper.

blocks|key|1591655|text|返回块是返回值的一个很好的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1591656|def+returns_a_hash(id)
++returning+Hash.new+do+%7Cresult%7C
+++result["id"]+=+id
++end
end|code-block|syntax|javascript|1591657|将返回一个哈希值。您也可以替换任何其他类型。|1591658|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

The returning block is a great way to return values:

<pre><code>def returns_a_hash(id)
 returning Hash.new do |result|
 result["id"] = id
 end
end
</code></pre>

Will return a hash. You can substitute any other types as well.

blocks|key|1591821|text|以编程方式使用rake路径打印所有内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1591822|Rails.application.routes|code-block|syntax|javascript|1591823|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Get everything printed with rake routes programmatically:

<pre><code>Rails.application.routes
</code></pre>

As a companion to <a href="https://stackoverflow.com/questions/63998/hidden-features-of-ruby">Hidden features of Ruby</a>. 

Try to keep it to Rails since the other is a better place for Ruby-specific examples. One per post please.

Hidden Features of Ruby on Rails

单元测试

数据库

作为的伙伴。尽量保持在Rails上，因为另一个地方更适合Ruby特定的示例。每个帖子请给我一个。

问Ruby on Rails的隐藏功能
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回答 14

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