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
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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 %>
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 %>
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 actionpack/lib/action_view/helpers/text_helper.rb, line 310 def cycle(first_value, *values) options = values.extract_options! name = options.fetch(:name, 'default') 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. Use the :separator
option to
choose the delimitation. 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 excerpt('This is a very beautiful morning', 'very', separator: ' ', radius: 1) # => ...a very beautiful...
# File actionpack/lib/action_view/helpers/text_helper.rb, line 150 def excerpt(text, phrase, options = {}) return unless text && phrase separator = options.fetch(:separator, "") phrase = Regexp.escape(phrase) regex = /#{phrase}/ return unless matches = text.match(regex) phrase = matches[0] text.split(separator).each do |value| if value.match(regex) regex = phrase = value break end end first_part, second_part = text.split(regex, 2) prefix, first_part = cut_excerpt_part(:first, first_part, separator, options) postfix, second_part = cut_excerpt_part(:second, second_part, separator, options) prefix + (first_part + separator + phrase + separator + second_part).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
‘<mark>1</mark>’)
highlight('You searched for: rails', 'rails') # => You searched for: <mark>rails</mark> 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>
# File actionpack/lib/action_view/helpers/text_helper.rb, line 114 def highlight(text, phrases, options = {}) text = sanitize(text) if options.fetch(:sanitize, true) if text.blank? || phrases.blank? text else highlighter = options.fetch(:highlighter, '<mark>\1</mark>') match = Array(phrases).map { |p| Regexp.escape(p) }.join('|') text.gsub(/(#{match})(?![^<]*?>)/, 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
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>
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
. -
:wrapper_tag
- String representing the wrapper tag, defaults to"p"
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>" simple_format(my_text, {}, wrapper_tag: "div") # => "<div>Here is some basic text...\n<br />...with a line break.</div>" 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("<blink>Unblinkable.</blink>") # => "<p>Unblinkable.</p>" simple_format("<blink>Blinkable!</blink> It's true.", {}, sanitize: false) # => "<p><blink>Blinkable!</span> It's true.</p>"
# File actionpack/lib/action_view/helpers/text_helper.rb, line 258 def simple_format(text, html_options = {}, options = {}) wrapper_tag = options.fetch(:wrapper_tag, :p) text = sanitize(text) if options.fetch(:sanitize, true) paragraphs = split_paragraphs(text) if paragraphs.empty? content_tag(wrapper_tag, nil, html_options) else paragraphs.map { |paragraph| content_tag(wrapper_tag, paragraph, html_options, options[:sanitize]) }.join("\n\n").html_safe end 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.
Pass a block if you want to show extra content when the text is truncated.
The result is marked as HTML-safe, but it is escaped by default, unless
:escape
is false
. 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..." truncate("Once upon a time in a world far far away") { link_to "Continue", "#" } # => "Once upon a time in a wo...<a href="#">Continue</a>"
# File actionpack/lib/action_view/helpers/text_helper.rb, line 87 def truncate(text, options = {}, &block) if text length = options.fetch(:length, 30) content = text.truncate(length, options) content = options[:escape] == false ? content.html_safe : ERB::Util.html_escape(content) content << capture(&block) if block_given? && text.length > length content end 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\na successor to the throne turned out to be more trouble than anyone could have\nimagined... word_wrap('Once upon a time', line_width: 8) # => Once\nupon a\ntime word_wrap('Once upon a time', line_width: 1) # => Once\nupon\na\ntime
# File actionpack/lib/action_view/helpers/text_helper.rb, line 215 def word_wrap(text, options = {}) line_width = options.fetch(:line_width, 80) text.split("\n").collect do |line| line.length > line_width ? line.gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1\n").strip : line end * "\n" end