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
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)
Public Instance methods
auto_link(text, link = :all, href_options = {}, &block)

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://www.rubyonrails.org</a> and
    say hello to <a href="mailto:david@loudthinking.com">david@loudthinking.com</a>

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
     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 178
178:       def auto_link(text, link = :all, href_options = {}, &block)
179:         return '' if text.blank?
180:         case link
181:           when :all             then auto_link_urls(auto_link_email_addresses(text, &block), href_options, &block)
182:           when :email_addresses then auto_link_email_addresses(text, &block)
183:           when :urls            then auto_link_urls(text, href_options, &block)
184:         end
185:       end
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" %>
    # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 25
25:       def concat(string, binding)
26:         eval("_erbout", binding).concat(string)
27:       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 %>
     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 302
302:       def cycle(first_value, *values)
303:         if (values.last.instance_of? Hash)
304:           params = values.pop
305:           name = params[:name]
306:         else
307:           name = "default"
308:         end
309:         values.unshift(first_value)
310: 
311:         cycle = get_cycle(name)
312:         if (cycle.nil? || cycle.values != values)
313:           cycle = set_cycle(name, Cycle.new(*values))
314:         end
315:         return cycle.to_s
316:       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..."
    # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 62
62:       def excerpt(text, phrase, radius = 100, excerpt_string = "...")
63:         if text.nil? || phrase.nil? then return end
64:         phrase = Regexp.escape(phrase)
65: 
66:         if found_pos = text.chars =~ /(#{phrase})/i
67:           start_pos = [ found_pos - radius, 0 ].max
68:           end_pos   = [ found_pos + phrase.chars.length + radius, text.chars.length ].min
69: 
70:           prefix  = start_pos > 0 ? excerpt_string : ""
71:           postfix = end_pos < text.chars.length ? excerpt_string : ""
72: 
73:           prefix + text.chars[start_pos..end_pos].strip + postfix
74:         else
75:           nil
76:         end
77:       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</strong>
    # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 46
46:       def highlight(text, phrase, highlighter = '<strong class="highlight">\1</strong>')
47:         if phrase.blank? then return text end
48:         text.gsub(/(#{Regexp.escape(phrase)})/i, highlighter) unless text.nil?
49:       end
markdown(text)

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

     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 144
144:         def markdown(text)
145:           text.blank? ? "" : BlueCloth.new(text).to_html
146:         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
    # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 87
87:       def pluralize(count, singular, plural = nil)
88:          "#{count} " + if count == 1 || count == '1'
89:           singular
90:         elsif plural
91:           plural
92:         elsif Object.const_defined?("Inflector")
93:           Inflector.pluralize(singular)
94:         else
95:           singular + "s"
96:         end
97:       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.

     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 320
320:       def reset_cycle(name = "default")
321:         cycle = get_cycle(name)
322:         cycle.reset unless cycle.nil?
323:       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;/script>
  sanitize('<a href="javascript: sucker();">Click here for $100</a>')
   => <a>Click here for $100</a>
     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 221
221:       def sanitize(html)
222:         # only do this if absolutely necessary
223:         if html.index("<")
224:           tokenizer = HTML::Tokenizer.new(html)
225:           new_text = ""
226: 
227:           while token = tokenizer.next
228:             node = HTML::Node.parse(nil, 0, 0, token, false)
229:             new_text << case node
230:               when HTML::Tag
231:                 if VERBOTEN_TAGS.include?(node.name)
232:                   node.to_s.gsub(/</, "&lt;")
233:                 else
234:                   if node.closing != :close
235:                     node.attributes.delete_if { |attr,v| attr =~ VERBOTEN_ATTRS }
236:                     %w(href src).each do |attr|
237:                       node.attributes.delete attr if node.attributes[attr] =~ /^javascript:/i
238:                     end
239:                   end
240:                   node.to_s
241:                 end
242:               else
243:                 node.to_s.gsub(/</, "&lt;")
244:             end
245:           end
246: 
247:           html = new_text
248:         end
249: 
250:         html
251:       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.

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

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
     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 191
191:       def strip_links(text)
192:         text.gsub(/<a\b.*?>(.*?)<\/a>/mi, '\1')
193:       end
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.

     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 256
256:       def strip_tags(html)     
257:         return html if html.blank?
258:         if html.index("<")
259:           text = ""
260:           tokenizer = HTML::Tokenizer.new(html)
261: 
262:           while token = tokenizer.next
263:             node = HTML::Node.parse(nil, 0, 0, token, false)
264:             # result is only the content of any Text nodes
265:             text << node.to_s if node.class == HTML::Text  
266:           end
267:           # strip any comments, and if they have a newline at the end (ie. line with
268:           # only a comment) strip that too
269:           text.gsub(/<!--(.*?)-->[\n]?/m, "") 
270:         else
271:           html # already plain text
272:         end 
273:       end
textilize(text)

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

     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 114
114:         def textilize(text)
115:           if text.blank?
116:             ""
117:           else
118:             textilized = RedCloth.new(text, [ :hard_breaks ])
119:             textilized.hard_breaks = true if textilized.respond_to?("hard_breaks=")
120:             textilized.to_html
121:           end
122:         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.

     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 128
128:         def textilize_without_paragraph(text)
129:           textiled = textilize(text)
130:           if textiled[0..2] == "<p>" then textiled = textiled[3..-1] end
131:           if textiled[-4..-1] == "</p>" then textiled = textiled[0..-5] end
132:           return textiled
133:         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...
    # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 34
34:       def truncate(text, length = 30, truncate_string = "...")
35:         if text.nil? then return end
36:         l = length - truncate_string.chars.length
37:         text.chars.length > length ? text.chars[0...l] + truncate_string : text
38:       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
     # File vendor/rails/actionpack/lib/action_view/helpers/text_helper.rb, line 104
104:       def word_wrap(text, line_width = 80)
105:         text.gsub(/\n/, "\n\n").gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1\n").strip
106:       end