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.
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>"
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 lib/action_view/helpers/text_helper.rb, line 51 def concat(string) output_buffer << string end
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 lib/action_view/helpers/text_helper.rb, line 345 def current_cycle(name = "default") cycle = get_cycle(name) cycle.current_value if cycle 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.
# 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 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.
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 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 =~ /(#{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>')
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 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(/(#{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
pluralize(1, 'person') # => 1 person pluralize(2, 'person') # => 2 people pluralize(3, 'person', 'users') # => 3 users pluralize(0, 'person') # => 0 people
# File lib/action_view/helpers/text_helper.rb, line 198 def pluralize(count, singular, plural = nil) "#{count || 0} " + ((count == 1 || count =~ /^1(\.0+)?$/) ? singular : (plural || singular.pluralize)) end
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 lib/action_view/helpers/text_helper.rb, line 369 def reset_cycle(name = "default") cycle = get_cycle(name) cycle.reset if cycle end
# File lib/action_view/helpers/text_helper.rb, line 55 def safe_concat(string) output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string) end
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.
:sanitize
- If false
, does not sanitize
text
.
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 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\n?/, "\n") # \r\n and \r -> \n text.gsub!(/\n\n+/, "</p>\n\n#{start_tag}") # 2+ newline -> paragraph text.gsub!(/([^\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).
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..."
# File lib/action_view/helpers/text_helper.rb, line 85 def truncate(text, options = {}) options.reverse_merge!(:length => 30) text.truncate(options.delete(:length), options) if text end
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\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 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(/(.{1,#{options[:line_width]}})(\s+|$)/, "\\1\n").strip : line end * "\n" end
The cycle helpers need to store the cycles in a place that is guaranteed to be reset every time a page is rendered, so it uses an instance variable of ActionView::Base.
# File lib/action_view/helpers/text_helper.rb, line 415 def get_cycle(name) @_cycles = Hash.new unless defined?(@_cycles) return @_cycles[name] end
# File lib/action_view/helpers/text_helper.rb, line 420 def set_cycle(name, cycle_object) @_cycles = Hash.new unless defined?(@_cycles) @_cycles[name] = cycle_object end