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The TextHelper module provides a set of methods for filtering, formatting and transforming strings, which can reduce the amount of inline Ruby code in your views. These helper methods extend Action View making them callable within your template files.

Sanitization

Most text helpers by default sanitize the given content, but do not escape it. This means HTML tags will appear in the page but all malicious code will be removed. Let's look at some examples using the simple_format method:

simple_format('<a href="http://example.com/">Example</a>')
# => "<p><a href=\"http://example.com/\">Example</a></p>"

simple_format('<a href="javascript:alert(\'no!\')">Example</a>')
# => "<p><a>Example</a></p>"

If you want to escape all content, you should invoke the h method before calling the text helper.

simple_format h('<a href="http://example.com/">Example</a>')
# => "<p>&lt;a href=\"http://example.com/\"&gt;Example&lt;/a&gt;</p>"
Methods
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Included Modules
Instance Public methods
concat(string)

The preferred method of outputting text in your views is to use the <%= “text” %> eRuby syntax. The regular puts and print methods do not operate as expected in an eRuby code block. If you absolutely must output text within a non-output code block (i.e., <% %>), you can use the concat method.

<%
    concat "hello"
    # is the equivalent of <%= "hello" %>

    if logged_in
      concat "Logged in!"
    else
      concat link_to('login', action: :login)
    end
    # will either display "Logged in!" or a login link
%>
# File actionview/lib/action_view/helpers/text_helper.rb, line 52
def concat(string)
  output_buffer << string
end
current_cycle(name = "default")

Returns the current cycle string after a cycle has been started. Useful for complex table highlighting or any other design need which requires the current cycle string in more than one place.

# Alternate background colors
@items = [1,2,3,4]
<% @items.each do |item| %>
  <div style="background-color:<%= cycle("red","white","blue") %>">
    <span style="background-color:<%= current_cycle %>"><%= item %></span>
  </div>
<% end %>
# File actionview/lib/action_view/helpers/text_helper.rb, line 359
def current_cycle(name = "default")
  cycle = get_cycle(name)
  cycle.current_value if cycle
end
cycle(first_value, *values)

Creates a Cycle object whose to_s method cycles through elements of an array every time it is called. This can be used for example, to alternate classes for table rows. You can use named cycles to allow nesting in loops. Passing a Hash as the last parameter with a :name key will create a named cycle. The default name for a cycle without a :name key is "default". You can manually reset a cycle by calling #reset_cycle and passing the name of the cycle. The current cycle string can be obtained anytime using the #current_cycle method.

 # Alternate CSS classes for even and odd numbers...
 @items = [1,2,3,4]
 <table>
 <% @items.each do |item| %>
   <tr class="<%= cycle("odd", "even") -%>">
     <td>item</td>
   </tr>
 <% end %>
 </table>

 # Cycle CSS classes for rows, and text colors for values within each row
 @items = x = [{first: 'Robert', middle: 'Daniel', last: 'James'},
              {first: 'Emily', middle: 'Shannon', maiden: 'Pike', last: 'Hicks'},
             {first: 'June', middle: 'Dae', last: 'Jones'}]
 <% @items.each do |item| %>
   <tr class="<%= cycle("odd", "even", name: "row_class") -%>">
     <td>
       <% item.values.each do |value| %>
         <%# Create a named cycle "colors" %>
         <span style="color:<%= cycle("red", "green", "blue", name: "colors") -%>">
           <%= value %>
         </span>
       <% end %>
       <% reset_cycle("colors") %>
     </td>
  </tr>
<% end %>
# File actionview/lib/action_view/helpers/text_helper.rb, line 335
def cycle(first_value, *values)
  options = values.extract_options!
  name = options.fetch(:name, 'default')

  values.unshift(*first_value)

  cycle = get_cycle(name)
  unless cycle && cycle.values == values
    cycle = set_cycle(name, Cycle.new(*values))
  end
  cycle.to_s
end
excerpt(text, phrase, options = {})

Extracts an excerpt from text that matches the first instance of phrase. The :radius option expands the excerpt on each side of the first occurrence of phrase by the number of characters defined in :radius (which defaults to 100). If the excerpt radius overflows the beginning or end of the text, then the :omission option (which defaults to “…”) will be prepended/appended accordingly. Use the :separator option to choose the delimitation. The resulting string will be stripped in any case. If the phrase isn't found, nil is returned.

excerpt('This is an example', 'an', radius: 5)
# => ...s is an exam...

excerpt('This is an example', 'is', radius: 5)
# => This is a...

excerpt('This is an example', 'is')
# => This is an example

excerpt('This next thing is an example', 'ex', radius: 2)
# => ...next...

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

excerpt('This is a very beautiful morning', 'very', separator: ' ', radius: 1)
# => ...a very beautiful...
# File actionview/lib/action_view/helpers/text_helper.rb, line 168
def excerpt(text, phrase, options = {})
  return unless text && phrase

  separator = options.fetch(:separator, nil) || ""
  case phrase
  when Regexp
    regex = phrase
  else
    regex = /#{Regexp.escape(phrase)}/i
  end

  return unless matches = text.match(regex)
  phrase = matches[0]

  unless separator.empty?
    text.split(separator).each do |value|
      if value.match(regex)
        regex = phrase = value
        break
      end
    end
  end

  first_part, second_part = text.split(phrase, 2)

  prefix, first_part   = cut_excerpt_part(:first, first_part, separator, options)
  postfix, second_part = cut_excerpt_part(:second, second_part, separator, options)

  affix = [first_part, separator, phrase, separator, second_part].join.strip
  [prefix, affix, postfix].join
end
highlight(text, phrases, options = {})

Highlights one or more phrases everywhere in text by inserting it into a :highlighter string. The highlighter can be specialized by passing :highlighter as a single-quoted string with \1 where the phrase is to be inserted (defaults to '<mark>1</mark>') or passing a block that receives each matched term.

highlight('You searched for: rails', 'rails')
# => You searched for: <mark>rails</mark>

highlight('You searched for: rails', /for|rails/)
# => You searched <mark>for</mark>: <mark>rails</mark>

highlight('You searched for: ruby, rails, dhh', 'actionpack')
# => You searched for: ruby, rails, dhh

highlight('You searched for: rails', ['for', 'rails'], highlighter: '<em>\1</em>')
# => You searched <em>for</em>: <em>rails</em>

highlight('You searched for: rails', 'rails', highlighter: '<a href="search?q=\1">\1</a>')
# => You searched for: <a href="search?q=rails">rails</a>

highlight('You searched for: rails', 'rails') { |match| link_to(search_path(q: match, match)) }
# => You searched for: <a href="search?q=rails">rails</a>
# File actionview/lib/action_view/helpers/text_helper.rb, line 125
def highlight(text, phrases, options = {})
  text = sanitize(text) if options.fetch(:sanitize, true)

  if text.blank? || phrases.blank?
    text
  else
    match = Array(phrases).map do |p|
      Regexp === p ? p.to_s : Regexp.escape(p)
    end.join('|')

    if block_given?
      text.gsub(/(#{match})(?![^<]*?>)/i) { |found| yield found }
    else
      highlighter = options.fetch(:highlighter, '<mark>\1</mark>')
      text.gsub(/(#{match})(?![^<]*?>)/i, highlighter)
    end
  end.html_safe
end
pluralize(count, singular, plural = nil)

Attempts to pluralize the singular word unless count is 1. If plural is supplied, it will use that when count is > 1, otherwise it will use the Inflector to determine the plural form.

pluralize(1, 'person')
# => 1 person

pluralize(2, 'person')
# => 2 people

pluralize(3, 'person', 'users')
# => 3 users

pluralize(0, 'person')
# => 0 people
# File actionview/lib/action_view/helpers/text_helper.rb, line 215
def pluralize(count, singular, plural = nil)
  word = if (count == 1 || count =~ /^1(\.0+)?$/)
    singular
  else
    plural || singular.pluralize
  end

  "#{count || 0} #{word}"
end
reset_cycle(name = "default")

Resets a cycle so that it starts from the first element the next time it is called. Pass in name to reset a named cycle.

# Alternate CSS classes for even and odd numbers...
@items = [[1,2,3,4], [5,6,3], [3,4,5,6,7,4]]
<table>
<% @items.each do |item| %>
  <tr class="<%= cycle("even", "odd") -%>">
      <% item.each do |value| %>
        <span style="color:<%= cycle("#333", "#666", "#999", name: "colors") -%>">
          <%= value %>
        </span>
      <% end %>

      <% reset_cycle("colors") %>
  </tr>
<% end %>
</table>
# File actionview/lib/action_view/helpers/text_helper.rb, line 382
def reset_cycle(name = "default")
  cycle = get_cycle(name)
  cycle.reset if cycle
end
safe_concat(string)
# File actionview/lib/action_view/helpers/text_helper.rb, line 56
def safe_concat(string)
  output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string)
end
simple_format(text, html_options = {}, options = {})

Returns text transformed into HTML using simple formatting rules. Two or more consecutive newlines(\n\n) are considered as a paragraph and wrapped in <p> tags. One newline (\n) is considered as a linebreak and a <br /> tag is appended. This method does not remove the newlines from the text.

You can pass any HTML attributes into html_options. These will be added to all created paragraphs.

Options

  • :sanitize - If false, does not sanitize text.

  • :wrapper_tag - String representing the wrapper tag, defaults to "p"

Examples

my_text = "Here is some basic text...\n...with a line break."

simple_format(my_text)
# => "<p>Here is some basic text...\n<br />...with a line break.</p>"

simple_format(my_text, {}, wrapper_tag: "div")
# => "<div>Here is some basic text...\n<br />...with a line break.</div>"

more_text = "We want to put a paragraph...\n\n...right there."

simple_format(more_text)
# => "<p>We want to put a paragraph...</p>\n\n<p>...right there.</p>"

simple_format("Look ma! A class!", class: 'description')
# => "<p class='description'>Look ma! A class!</p>"

simple_format("<blink>Unblinkable.</blink>")
# => "<p>Unblinkable.</p>"

simple_format("<blink>Blinkable!</blink> It's true.", {}, sanitize: false)
# => "<p><blink>Blinkable!</blink> It's true.</p>"
# File actionview/lib/action_view/helpers/text_helper.rb, line 283
def simple_format(text, html_options = {}, options = {})
  wrapper_tag = options.fetch(:wrapper_tag, :p)

  text = sanitize(text) if options.fetch(:sanitize, true)
  paragraphs = split_paragraphs(text)

  if paragraphs.empty?
    content_tag(wrapper_tag, nil, html_options)
  else
    paragraphs.map! { |paragraph|
      content_tag(wrapper_tag, raw(paragraph), html_options)
    }.join("\n\n").html_safe
  end
end
truncate(text, options = {}, &block)

Truncates a given text after a given :length if text is longer than :length (defaults to 30). The last characters will be replaced with the :omission (defaults to “…”) for a total length not exceeding :length.

Pass a :separator to truncate text at a natural break.

Pass a block if you want to show extra content when the text is truncated.

The result is marked as HTML-safe, but it is escaped by default, unless :escape is false. Care should be taken if text contains HTML tags or entities, because truncation may produce invalid HTML (such as unbalanced or incomplete tags).

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

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>")
# => "&lt;p&gt;Once upon a time in a wo..."

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

truncate("Once upon a time in a world far far away") { link_to "Continue", "#" }
# => "Once upon a time in a wo...<a href="#">Continue</a>"
# File actionview/lib/action_view/helpers/text_helper.rb, line 92
def truncate(text, options = {}, &block)
  if text
    length  = options.fetch(:length, 30)

    content = text.truncate(length, options)
    content = options[:escape] == false ? content.html_safe : ERB::Util.html_escape(content)
    content << capture(&block) if block_given? && text.length > length
    content
  end
end
word_wrap(text, options = {})

Wraps the text into lines no longer than line_width width. This method breaks on the first whitespace character that does not exceed line_width (which is 80 by default).

word_wrap('Once upon a time')
# => Once upon a time

word_wrap('Once upon a time, in a kingdom called Far Far Away, a king fell ill, and finding a successor to the throne turned out to be more trouble than anyone could have imagined...')
# => Once upon a time, in a kingdom called Far Far Away, a king fell ill, and finding\na successor to the throne turned out to be more trouble than anyone could have\nimagined...

word_wrap('Once upon a time', line_width: 8)
# => Once\nupon a\ntime

word_wrap('Once upon a time', line_width: 1)
# => Once\nupon\na\ntime
# File actionview/lib/action_view/helpers/text_helper.rb, line 240
def word_wrap(text, options = {})
  line_width = options.fetch(:line_width, 80)

  text.split("\n").collect! do |line|
    line.length > line_width ? line.gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1\n").strip : line
  end * "\n"
end