Action View Helpers

distance_of_time_in_words(Time.current, 15.seconds.from_now)  
# => 1분 미만
distance_of_time_in_words(Time.current, 15.seconds.from_now, include_seconds: true)
# => 20초 미만

time_ago_in_words(3.minutes.from_now) # => 3분

number_to_currency(1234567890.50) # => ₩1,234,567,890.50

number_to_human(1234)    # => 1.23 천
number_to_human(1234567) # => 1.23 백만

number_to_human_size(1234)    # => 1.21 KB
number_to_human_size(1234567) # => 1.18 MB

number_to_percentage(100, precision: 0) # => 100%

number_to_phone(1235551234) # => 123-555-1234 

number_with_delimiter(12345678) # => 12,345,678

number_with_precision(111.2345)               # => 111.235
number_with_precision(111.2345, precision: 2) # => 111.23

excerpt("This is a very beautiful morning", "very", separator: " ", radius: 1)
# => ...a very beautiful...

excerpt("This is also an example", "an", radius: 8, omission: "<chop> ")
# => <chop> is also an example

pluralize(1, "person") # => 1 person 
pluralize(2, "person") # => 2 people
pluralize(3, "person", plural: "users") # => 3 users

truncate("Once upon a time in a world far far away")
# => "Once upon a time in a world..."

truncate("Once upon a time in a world far far away", length: 17) 
# => "Once upon a ti..."

truncate("one-two-three-four-five", length: 20, separator: "-")
# => "one-two-three..."

truncate("And they found that many people were sleeping better.", length: 25, omission: "... (continued)")
# => "And they f... (continued)"

truncate("<p>Once upon a time in a world far far away</p>", escape: false)
# => "<p>Once upon a time in a wo..."

word_wrap("Once upon a time", line_width: 8)
# => 주어진 line_width에 맞춰 줄바꿈된 문자열:
# => "Once\nupon a\ntime"

<%= button_to "로그인", sign_in_path %>

<form method="post" action="/sessions" class="button_to">
  <input type="submit" value="로그인" />
</form>

<% if current_page?(controller: 'profiles', action: 'show') %>
  <strong>현재 profile 페이지에 있습니다</strong>
<% end %>

link_to "Profile", @profile
# => <a href="/profiles/1">Profile</a>

link_to "Book", @book # 복합 기본키 [:author_id, :id]가 주어진 경우
# => <a href="/books/2_1">Book</a>

link_to "Profiles", profiles_path
# => <a href="/profiles">Profiles</a>

link_to nil, "https://example.com"
# => <a href="https://example.com">https://example.com</a>

link_to "Articles", articles_path, id: "articles", class: "article__container"
# => <a href="/articles" class="article__container" id="articles">Articles</a>

<%= link_to @profile do %>
  <strong><%= @profile.name %></strong> -- <span>확인해보세요!</span>
<% end %>

<a href="/profiles/1">
  <strong>David</strong> -- <span>확인해보세요!</span>
</a>

mail_to "john_doe@gmail.com"
# => <a href="mailto:john_doe@gmail.com">john_doe@gmail.com</a>

mail_to "me@john_doe.com", cc: "me@jane_doe.com", 
        subject: "이것은 예제 이메일입니다"  
# => <a href="mailto:"me@john_doe.com?cc=me@jane_doe.com&subject=This%20is%20an%20example%20email">"me@john_doe.com</a>

url_for @profile
# => /profiles/1

url_for [ @hotel, @booking, page: 2, line: 3 ]
# => /hotels/1/bookings/1?line=3&page=2

url_for @post # composite primary key [:blog_id, :id]가 주어진 경우
# => /posts/1_2

sanitize @article.body

sanitize @article.body, tags: %w(table tr td), attributes: %w(id class style)

# config/application.rb
class Application < Rails::Application
  config.action_view.sanitized_allowed_tags = %w(table tr td)
end

sanitize_css("background-color: red; color: white; font-size: 16px;")

strip_links("<a href='https://rubyonrails.org'>Ruby on Rails</a>")
# => Ruby on Rails

strip_links("이메일: <a href='mailto:me@email.com'>me@email.com</a>")
# => 이메일: me@email.com.

strip_links("블로그: <a href='http://myblog.com/'>방문</a>.")
# => 블로그: 방문.

strip_tags("Strip <i>these</i> tags!")
# => Strip these tags!

strip_tags("<b>Bold</b> no more! <a href='more.html'>See more</a>")
# => Bold no more! See more

strip_links('<<a href="https://example.org">잘못된 & 링크</a>')
# => &lt;잘못된 &amp; 링크

config.asset_host = "assets.example.com"

image_tag("rails.png")
# => <img src="//assets.example.com/images/rails.png" />

audio_tag("sound")
# => <audio src="/audios/sound"></audio>

audio_tag("sound.wav", "sound.mid") 
# => <audio><source src="/audios/sound.wav" /><source src="/audios/sound.mid" /></audio>

audio_tag("sound", controls: true)
# => <audio controls="controls" src="/audios/sound"></audio>

auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", { title: "RSS Feed" })
# => RSS Feed를 자동으로 찾을 수 있도록 하는 link 태그를 반환합니다 <link rel="alternate" type="application/rss+xml" title="RSS Feed" href="http://www.example.com/feed.rss" />

favicon_link_tag 
# => <link href="/assets/favicon.ico" rel="icon" type="image/x-icon" /> 

image_tag("icon.png")
# => <img src="/assets/icon.png" />

image_tag("icon.png", size: "16x10", alt: "글 수정")
# => <img src="/assets/icon.png" width="16" height="10" alt="글 수정" />

javascript_include_tag("common")
# => <script src="/assets/common.js"></script>

javascript_include_tag("common", async: true)
# => <script src="/assets/common.js" async="async"></script>

picture_tag("icon.webp", "icon.png")

<picture>
  <source srcset="/assets/icon.webp" type="image/webp" />
  <source srcset="/assets/icon.png" type="image/png" />
  <img src="/assets/icon.png" />
</picture>

preload_link_tag("application.css")
# => <link rel="preload" href="/assets/application.css" as="style" type="text/css" />

stylesheet_link_tag("application")
# => <link href="/assets/application.css" rel="stylesheet" />

stylesheet_link_tag("application", media: "all")
# => <link href="/assets/application.css" media="all" rel="stylesheet" />

video_tag("trailer")
# => <video src="/videos/trailer"></video>

video_tag(["trailer.ogg", "trailer.flv"])
# => <video><source src="/videos/trailer.ogg" /><source src="/videos/trailer.flv" /></video>

video_tag("trailer", controls: true)
# => <video controls="controls" src="/videos/trailer"></video>

<%# app/views/users/greeting.html.erb %>
내 이름은 <%= current_user.name %>이고, "우리 웹사이트에 오신 것을 환영합니다!"라고 말하고 싶습니다!

<script>
  var greeting = "<%= escape_javascript render('users/greeting') %>";
  alert(`안녕하세요, ${greeting}`);
</script>

javascript_tag("alert('All is good')", type: "application/javascript")

<script type="application/javascript">
//<![CDATA[
alert('모두 잘 되었습니다')
//]]>
</script>

<%= javascript_tag type: "application/javascript" do %>
  alert("내 앱에 오신 것을 환영합니다!")
<% end %>

tag.some_tag_name(선택적 content, options)

tag.h1 "All titles fit to print"
# => <h1>All titles fit to print</h1>

tag.div "Hello, world!"
# => <div>Hello, world!</div>

tag.section class: %w( kitties puppies )
# => <section class="kitties puppies"></section>

tag.div data: { user_id: 123 }
# => <div data-user-id="123"></div>

token_list("cats", "dogs")
# => "cats dogs"

token_list(nil, false, 123, "", "foo", { bar: true })
# => "123 foo bar"

mobile, alignment = true, "center"
token_list("flex items-#{alignment}", "flex-col": mobile)
# => "flex items-center flex-col"
class_names("flex items-#{alignment}", "flex-col": mobile) # using the alias
# => "flex items-center flex-col"

<% @greeting = capture do %>
  <p>환영합니다! 현재 날짜와 시간은 <%= Time.current %>입니다</p>
<% end %>

<html>
  <head>
    <title>환영합니다!</title>
  </head>
  <body>
    <%= @greeting %>
  </body>
</html>

@greeting
# => "제 반짝이는 새 웹 페이지에 오신 것을 환영합니다! 현재 날짜와 시간은 2018-09-06 11:09:16 -0500 입니다"

<%# app/views/users/special_page.html.erb %>
<% content_for(:html_title) { "특별 페이지 제목" } %>

<%# app/views/layouts/application.html.erb %>
<html>
  <head>
    <title><%= content_for?(:html_title) ? yield(:html_title) : "기본 제목" %></title>
  </head>
</html>

# app/helpers/title_helper.rb
module TitleHelper
  def html_title
    content_for(:html_title) || "기본 제목"
  end
end

<% benchmark "데이터 파일 처리" do %>
  <%= expensive_files_operation %>
<% end %>

<% cache do %>
  <%= render "application/footer" %>
<% end %>

<% @articles.each do |article| %>
  <% cache article do %>
    <%= render article %>
  <% end %>
<% end %>

views/articles/index:bea67108094918eeba32cd4a6f786301/articles/1

# config/routes.rb
resources :articles

# app/controllers/articles_controller.rb
def index
  @articles = Article.all

  respond_to do |format|
    format.html
    format.atom
  end
end

# app/views/articles/index.atom.builder
atom_feed do |feed|
  feed.title("기사 목록")
  feed.updated(@articles.first.created_at)

  @articles.each do |article|
    feed.entry(article) do |entry|
      entry.title(article.title)
      entry.content(article.body, type: "html")

      entry.author do |author|
        author.name(article.author_name)
      end
    end
  end
end

my_hash = { "first" => 1, "second" => "two", "third" => [1, 2, 3] }
debug(my_hash)

<pre class="debug_dump">---
first: 1
second: two
third:
- 1
- 2
- 3
</pre>