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 51: def concat(string) 52: output_buffer << string 53: 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 345 345: def current_cycle(name = "default") 346: cycle = get_cycle(name) 347: cycle.current_value if cycle 348: 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 317 317: def cycle(first_value, *values) 318: if (values.last.instance_of? Hash) 319: params = values.pop 320: name = params[:name] 321: else 322: name = "default" 323: end 324: values.unshift(first_value) 325: 326: cycle = get_cycle(name) 327: unless cycle && cycle.values == values 328: cycle = set_cycle(name, Cycle.new(*values)) 329: end 330: cycle.to_s 331: 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 157 157: def excerpt(text, phrase, *args) 158: return unless text && phrase 159: 160: options = args.extract_options! 161: unless args.empty? 162: 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 163: 164: options[:radius] = args[0] || 100 165: options[:omission] = args[1] || "..." 166: end 167: options.reverse_merge!(:radius => 100, :omission => "...") 168: 169: phrase = Regexp.escape(phrase) 170: return unless found_pos = text.mb_chars =~ /(#{phrase})/ 171: 172: start_pos = [ found_pos - options[:radius], 0 ].max 173: end_pos = [ [ found_pos + phrase.mb_chars.length + options[:radius] - 1, 0].max, text.mb_chars.length ].min 174: 175: prefix = start_pos > 0 ? options[:omission] : "" 176: postfix = end_pos < text.mb_chars.length - 1 ? options[:omission] : "" 177: 178: prefix + text.mb_chars[start_pos..end_pos].strip + postfix 179: 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 ’1’)
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 111 111: def highlight(text, phrases, *args) 112: options = args.extract_options! 113: unless args.empty? 114: ActiveSupport::Deprecation.warn "Calling highlight with a highlighter as an argument is deprecated. " "Please call with :highlighter => '#{args[0]}' instead.", caller 115: 116: options[:highlighter] = args[0] || '<strong class="highlight">\1</strong>' 117: end 118: options.reverse_merge!(:highlighter => '<strong class="highlight">\1</strong>') 119: 120: text = sanitize(text) unless options[:sanitize] == false 121: if text.blank? || phrases.blank? 122: text 123: else 124: match = Array(phrases).map { |p| Regexp.escape(p) }.join('|') 125: text.gsub(/(#{match})(?![^<]*?>)/, options[:highlighter]) 126: end.html_safe 127: 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 198 198: def pluralize(count, singular, plural = nil) 199: "#{count || 0} " + ((count == 1 || count =~ /^1(\.0+)?$/) ? singular : (plural || singular.pluralize)) 200: 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 369 369: def reset_cycle(name = "default") 370: cycle = get_cycle(name) 371: cycle.reset if cycle 372: end
# File lib/action_view/helpers/text_helper.rb, line 55 55: def safe_concat(string) 56: output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string) 57: 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 266 266: def simple_format(text, html_options={}, options={}) 267: text = '' if text.nil? 268: text = text.dup 269: start_tag = tag('p', html_options, true) 270: text = sanitize(text) unless options[:sanitize] == false 271: text = text.to_str 272: text.gsub!(/\r\n?/, "\n") # \r\n and \r -> \n 273: text.gsub!(/\n\n+/, "</p>\n\n#{start_tag}") # 2+ newline -> paragraph 274: text.gsub!(/([^\n]\n)(?=[^\n])/, '\1<br />') # 1 newline -> br 275: text.insert 0, start_tag 276: text.html_safe.safe_concat("</p>") 277: 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 85: def truncate(text, options = {}) 86: options.reverse_merge!(:length => 30) 87: text.truncate(options.delete(:length), options) if text 88: 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 223 223: def word_wrap(text, *args) 224: options = args.extract_options! 225: unless args.blank? 226: ActiveSupport::Deprecation.warn "Calling word_wrap with line_width as an argument is deprecated. " "Please call with :line_width => #{args[0]} instead.", caller 227: 228: options[:line_width] = args[0] || 80 229: end 230: options.reverse_merge!(:line_width => 80) 231: 232: text.split("\n").collect do |line| 233: line.length > options[:line_width] ? line.gsub(/(.{1,#{options[:line_width]}})(\s+|$)/, "\\1\n").strip : line 234: end * "\n" 235: 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 415 415: def get_cycle(name) 416: @_cycles = Hash.new unless defined?(@_cycles) 417: return @_cycles[name] 418: end
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