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><a href=\"http://example.com/\">Example</a></p>"
- C
- E
- H
- P
- R
- S
- T
- W
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.
Examples
<%
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
%>
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.
Example
# 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 %>
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.
Examples
# 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 actionpack/lib/action_view/helpers/text_helper.rb, line 317 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) unless cycle && cycle.values == values cycle = set_cycle(name, Cycle.new(*values)) end cycle.to_s end
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. The resulting string will be stripped in
any case. If the phrase isn’t found, nil is returned.
Examples
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
You can still use excerpt with the old API that accepts the
radius as its optional third and the ellipsis as
its optional forth parameter:
excerpt('This is an example', 'an', 5) # => ...s is an exam... excerpt('This is also an example', 'an', 8, '<chop> ') # => <chop> is also an example
# File actionpack/lib/action_view/helpers/text_helper.rb, line 157 def excerpt(text, phrase, *args) return unless text && phrase options = args.extract_options! unless args.empty? ActiveSupport::Deprecation.warn "Calling excerpt with radius and omission as arguments is deprecated. " "Please call with :radius => #{args[0]}#{", :omission => '#{args[1]}'" if args[1]} instead.", caller options[:radius] = args[0] || 100 options[:omission] = args[1] || "..." end options.reverse_merge!(:radius => 100, :omission => "...") phrase = Regexp.escape(phrase) return unless found_pos = text.mb_chars =~ %r(#{phrase})/ start_pos = [ found_pos - options[:radius], 0 ].max end_pos = [ [ found_pos + phrase.mb_chars.length + options[:radius] - 1, 0].max, text.mb_chars.length ].min prefix = start_pos > 0 ? options[:omission] : "" postfix = end_pos < text.mb_chars.length - 1 ? options[:omission] : "" prefix + text.mb_chars[start_pos..end_pos].strip + postfix end
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 ‘<strong
class=“highlight”>1</strong>’)
Examples
highlight('You searched for: rails', 'rails') # => You searched for: <strong class="highlight">rails</strong> 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>
You can still use highlight with the old API that accepts the
highlighter as its optional third parameter:
highlight('You searched for: rails', 'rails', '<a href="search?q=\1">\1</a>') # => You searched for: <a href="search?q=rails">rails</a>
# File actionpack/lib/action_view/helpers/text_helper.rb, line 111 def highlight(text, phrases, *args) options = args.extract_options! unless args.empty? ActiveSupport::Deprecation.warn "Calling highlight with a highlighter as an argument is deprecated. " "Please call with :highlighter => '#{args[0]}' instead.", caller options[:highlighter] = args[0] || '<strong class="highlight">\1</strong>' end options.reverse_merge!(:highlighter => '<strong class="highlight">\1</strong>') text = sanitize(text) unless options[:sanitize] == false if text.blank? || phrases.blank? text else match = Array(phrases).map { |p| Regexp.escape(p) }.join('|') text.gsub(%r(#{match})(?![^<]*?>)/, options[:highlighter]) end.html_safe end
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
Examples
pluralize(1, 'person') # => 1 person pluralize(2, 'person') # => 2 people pluralize(3, 'person', 'users') # => 3 users pluralize(0, 'person') # => 0 people
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.
Example
# 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>
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- Iffalse, does not sanitizetext.
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>" 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("<span>I'm allowed!</span> It's true.", {}, :sanitize => false) # => "<p><span>I'm allowed!</span> It's true.</p>"
# File actionpack/lib/action_view/helpers/text_helper.rb, line 266 def simple_format(text, html_options={}, options={}) text = '' if text.nil? text = text.dup start_tag = tag('p', html_options, true) text = sanitize(text) unless options[:sanitize] == false text = text.to_str text.gsub!(%r\r\n?/, "\n") # \r\n and \r -> \n text.gsub!(%r\n\n+/, "</p>\n\n#{start_tag}") # 2+ newline -> paragraph text.gsub!(%r([^\n]\n)(?=[^\n])/, '\1<br />') # 1 newline -> br text.insert 0, start_tag text.html_safe.safe_concat("</p>") end
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.
The result is not marked as HTML-safe, so will be subject to the default
escaping when used in views, unless wrapped by raw(). Care
should be taken if text contains HTML tags or entities, because truncation may
produce invalid HTML (such as unbalanced or
incomplete tags).
Examples
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>") # => "<p>Once upon a time in a wo..."
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).
Examples
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\n a successor to the throne turned out to be more trouble than anyone could have\n imagined... word_wrap('Once upon a time', :line_width => 8) # => Once upon\na time word_wrap('Once upon a time', :line_width => 1) # => Once\nupon\na\ntime
You can still use word_wrap with the old API that accepts the
line_width as its optional second parameter:
word_wrap('Once upon a time', 8) # => Once upon\na time
# File actionpack/lib/action_view/helpers/text_helper.rb, line 223 def word_wrap(text, *args) options = args.extract_options! unless args.blank? ActiveSupport::Deprecation.warn "Calling word_wrap with line_width as an argument is deprecated. " "Please call with :line_width => #{args[0]} instead.", caller options[:line_width] = args[0] || 80 end options.reverse_merge!(:line_width => 80) text.split("\n").collect do |line| line.length > options[:line_width] ? line.gsub(%r(.{1,#{options[:line_width]}})(\s+|$)/, "\\1\n").strip : line end * "\n" end