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 that generate HTML output sanitize the given input by default, 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

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
%>
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 54
      def concat(string)
        output_buffer << string
      end
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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 %>
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 378
      def current_cycle(name = "default")
        cycle = get_cycle(name)
        cycle.current_value if cycle
      end
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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 %>
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 354
      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
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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...
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 175
      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)
              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
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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. By default text is sanitized to prevent possible XSS attacks. If the input is trustworthy, passing false for :sanitize will turn sanitizing off.

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>

highlight('<a href="javascript:alert(\'no!\')">ruby</a> on rails', 'rails', sanitize: false)
# => <a href="javascript:alert('no!')">ruby</a> on <mark>rails</mark>
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 132
      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
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pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale)

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 for the given locale, which defaults to I18n.locale

The word will be pluralized using rules defined for the locale (you must define your own inflection rules for languages other than English). See ActiveSupport::Inflector.pluralize

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

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

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

pluralize(0, 'person')
# => 0 people

pluralize(2, 'Person', locale: :de)
# => 2 Personen
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 230
      def pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale)
        word = if count == 1 || count.to_s.match?(/^1(\.0+)?$/)
          singular
        else
          plural || singular.pluralize(locale)
        end

        "#{count || 0} #{word}"
      end
🔎 See on GitHub

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>
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 401
      def reset_cycle(name = "default")
        cycle = get_cycle(name)
        cycle.reset if cycle
      end
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safe_concat(string)

📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 58
      def safe_concat(string)
        output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string)
      end
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simple_format(text, html_options = {}, options = {})

Returns text transformed into HTML using simple formatting rules. Two or more consecutive newlines(\n\n or \r\n\r\n) are considered a paragraph and wrapped in <p> tags. One newline (\n or \r\n) is considered 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>"
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 302
      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
🔎 See on GitHub

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>"
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 94
      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
🔎 See on GitHub

word_wrap(text, line_width: 80, break_sequence: "\n")

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

You can also specify a custom +break_sequence+ ("\n" by default)

word_wrap('Once upon a time', line_width: 1, break_sequence: "\r\n")
# => Once\r\nupon\r\na\r\ntime
📝 Source code
# File actionview/lib/action_view/helpers/text_helper.rb, line 260
      def word_wrap(text, line_width: 80, break_sequence: "\n")
        text.split("\n").collect! do |line|
          line.length > line_width ? line.gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1#{break_sequence}").rstrip : line
        end * break_sequence
      end
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