The TextHelper Module provides a set of methods for filtering, formatting and transforming strings that can reduce the amount of inline Ruby code in your views. These helper methods extend ActionView making them callable within your template files as shown in the following example which truncates the title of each post to 10 characters.

<% @posts.each do |post| %>
  # post == 'This is my title'
  Title: <%= truncate(post.title, 10) %>
<% end %>
 => Title: This is my...
Methods
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Constants
VERBOTEN_TAGS = %w(form script plaintext) unless defined?(VERBOTEN_TAGS)
 
VERBOTEN_ATTRS = /^on/i unless defined?(VERBOTEN_ATTRS)
 
AUTO_LINK_RE = %r{ ( # leading text <\w+.*?>| # leading HTML tag, or [^=!:'"/]| # leading punctuation, or ^ # beginning of line ) ( (?:https?://)| # protocol spec, or (?:www\.) # www.* ) ( [-\w]+ # subdomain or domain (?:\.[-\w]+)* # remaining subdomains or domain (?::\d+)? # port (?:/(?:(?:[~\w\+%-]|(?:[,.;:][^\s$]))+)?)* # path (?:\?[\w\+%&=.;-]+)? # query string (?:\#[\w\-]*)? # trailing anchor ) ([[:punct:]]|\s|<|$) # trailing text }x unless const_defined?(:AUTO_LINK_RE)
 
Instance Public methods

Turns all urls and email addresses into clickable links. The link parameter will limit what should be linked. You can add html attributes to the links using href_options. Options for link are :all (default), :email_addresses, and :urls.

auto_link("Go to http://www.rubyonrails.org and say hello to david@loudthinking.com") =>
  Go to <a href="http://www.rubyonrails.org">http:/%rwww.rubyonrails.org</a> and
  say hello to <a href="mailto:david@loudthinking.com">david@loudthinking.com<%ra>

If a block is given, each url and email address is yielded and the result is used as the link text.

auto_link(post.body, :all, :target => '_blank') do |text|
  truncate(text, 15)
end

Source: show

concat(string, binding)

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 code block, you can use the concat method.

<% concat "hello", binding %>

is equivalent to using:

<%= "hello" %>

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 25
def concat(string, binding)
  eval("_erbout", binding).concat(string)
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:

<% @items.each do |item| %>
  <tr class="<%= cycle("even", "odd") -%>">
    <td>item</td>
  </tr>
<% end %>

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. You can manually reset a cycle by calling #reset_cycle and passing the name of the cycle.

 <% @items.each do |item| %>
   <tr class="<%= cycle("even", "odd", :name => "row_class")
     <td>
       <% item.values.each do |value| %>
         <span style="color:<%= cycle("red", "green", "blue", :name => "colors") -%>">
           value
         </span>
       <% end %>
       <% reset_cycle("colors") %>
     </td>
  </tr>
<% end %>

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 302
def cycle(first_value, *values)
  if (values.last.instance_of? Hash)
    params = values.pop
    name = params[:name]
  else
    name = "default"
  end
  values.unshift(first_value)

  cycle = get_cycle(name)
  if (cycle.nil? || cycle.values != values)
    cycle = set_cycle(name, Cycle.new(*values))
  end
  return cycle.to_s
end
excerpt(text, phrase, radius = 100, excerpt_string = "...")

Extracts an excerpt from text that matches the first instance of phrase. The radius expands the excerpt on each side of phrase by the number of characters defined in radius. If the excerpt radius overflows the beginning or end of the text, then the excerpt_string will be prepended/appended accordingly. If the phrase isn’t found, nil is returned.

excerpt('This is an example', 'an', 5) 
 => "...s is an examp..."

excerpt('This is an example', 'is', 5) 
 => "This is an..."

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 62
def excerpt(text, phrase, radius = 100, excerpt_string = "...")
  if text.nil? || phrase.nil? then return end
  phrase = Regexp.escape(phrase)

  if found_pos = text.chars =~ %r(#{phrase})/
    start_pos = [ found_pos - radius, 0 ].max
    end_pos   = [ found_pos + phrase.chars.length + radius, text.chars.length ].min

    prefix  = start_pos > 0 ? excerpt_string : ""
    postfix = end_pos < text.chars.length ? excerpt_string : ""

    prefix + text.chars[start_pos..end_pos].strip + postfix
  else
    nil
  end
end
highlight(text, phrase, highlighter = '<strong class="highlight">\1</strong>')

Highlights phrase everywhere it is found 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.

highlight('You searched for: rails', 'rails')  
 => You searched for: <strong class="highlight">rails<%rstrong>

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 46
def highlight(text, phrase, highlighter = '<strong class="highlight">\1</strong>')
  if phrase.blank? then return text end
  text.gsub(%r(#{Regexp.escape(phrase)})/, highlighter) unless text.nil?
end
markdown(text)

Returns the text with all the Markdown codes turned into HTML tags. This method is only available if BlueCloth is available.

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 144
def markdown(text)
  text.blank? ? "" : BlueCloth.new(text).to_html
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, if the ActiveSupport Inflector is loaded, it will use the Inflector to determine the plural form, otherwise it will just add an ‘s’ to the singular word.

pluralize(1, 'person')  => 1 person
pluralize(2, 'person')  => 2 people
pluralize(3, 'person', 'users')  => 3 users

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 87
def pluralize(count, singular, plural = nil)
   "#{count} " + if count == 1 || count == '1'
    singular
  elsif plural
    plural
  elsif Object.const_defined?("Inflector")
    Inflector.pluralize(singular)
  else
    singular + "s"
  end
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.

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 320
def reset_cycle(name = "default")
  cycle = get_cycle(name)
  cycle.reset unless cycle.nil?
end
sanitize(html)

Sanitizes the html by converting <form> and <script> tags into regular text, and removing all “onxxx” attributes (so that arbitrary Javascript cannot be executed). It also removes href= and src= attributes that start with “javascript:”. You can modify what gets sanitized by defining VERBOTEN_TAGS and VERBOTEN_ATTRS before this Module is loaded.

sanitize('<script> do_nasty_stuff() </script>')
 => &lt;script> do_nasty_stuff() &lt;%rscript>
sanitize('<a href="javascript: sucker();">Click here for $100</a>')
 => <a>Click here for $100</a>

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 221
def sanitize(html)
  # only do this if absolutely necessary
  if html.index("<")
    tokenizer = HTML::Tokenizer.new(html)
    new_text = ""

    while token = tokenizer.next
      node = HTML::Node.parse(nil, 0, 0, token, false)
      new_text << case node
        when HTML::Tag
          if VERBOTEN_TAGS.include?(node.name)
            node.to_s.gsub(%r</, "&lt;")
          else
            if node.closing != :close
              node.attributes.delete_if { |attr,v| attr =~ VERBOTEN_ATTRS }
              %w(href src).each do |attr|
                node.attributes.delete attr if node.attributes[attr] =~ %r^javascript:/
              end
            end
            node.to_s
          end
        else
          node.to_s.gsub(%r</, "&lt;")
      end
    end

    html = new_text
  end

  html
end
simple_format(text)

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.

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 156
def simple_format(text)
  content_tag 'p', text.to_s.
    gsub(%r\r\n?/, "\n").                    # \r\n and \r -> \n
    gsub(%r\n\n+/, "</p>\n\n<p>").           # 2+ newline  -> paragraph
    gsub(%r([^\n]\n)(?=[^\n])/, '\1<br />')  # 1 newline   -> br
end

Strips link tags from text leaving just the link label.

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

Source: show

strip_tags(html)

Strips all HTML tags from the html, including comments. This uses the html-scanner tokenizer and so its HTML parsing ability is limited by that of html-scanner.

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 256
def strip_tags(html)     
  return html if html.blank?
  if html.index("<")
    text = ""
    tokenizer = HTML::Tokenizer.new(html)

    while token = tokenizer.next
      node = HTML::Node.parse(nil, 0, 0, token, false)
      # result is only the content of any Text nodes
      text << node.to_s if node.class == HTML::Text  
    end
    # strip any comments, and if they have a newline at the end (ie. line with
    # only a comment) strip that too
    text.gsub(%r<!--(.*?)-->[\n]?/, "") 
  else
    html # already plain text
  end 
end
textilize(text)

Returns the text with all the Textile codes turned into HTML tags. This method is only available if RedCloth is available.

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 114
def textilize(text)
  if text.blank?
    ""
  else
    textilized = RedCloth.new(text, [ :hard_breaks ])
    textilized.hard_breaks = true if textilized.respond_to?("hard_breaks=")
    textilized.to_html
  end
end
textilize_without_paragraph(text)

Returns the text with all the Textile codes turned into HTML tags, but without the bounding <p> tag that RedCloth adds. This method is only available if RedCloth is available.

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 128
def textilize_without_paragraph(text)
  textiled = textilize(text)
  if textiled[0..2] == "<p>" then textiled = textiled[3..-1] end
  if textiled[-4..-1] == "</p>" then textiled = textiled[0..-5] end
  return textiled
end
truncate(text, length = 30, truncate_string = "...")

If text is longer than length, text will be truncated to the length of length and the last three characters will be replaced with the truncate_string.

truncate("Once upon a time in a world far far away", 14)  
 => Once upon a...

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 34
def truncate(text, length = 30, truncate_string = "...")
  if text.nil? then return end
  l = length - truncate_string.chars.length
  text.chars.length > length ? text.chars[0...l] + truncate_string : text
end
word_wrap(text, line_width = 80)

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.

word_wrap('Once upon a time', 4)
 => Once\nupon\na\ntime

Source: show 

# File rails/actionpack/lib/action_view/helpers/text_helper.rb, line 104
def word_wrap(text, line_width = 80)
  text.gsub(%r\n/, "\n\n").gsub(%r(.{1,#{line_width}})(\s+|$)/, "\\1\n").strip
end