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 that generate HTML output sanitize the given input by default, 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
- ActionView::Helpers::SanitizeHelper
- ActionView::Helpers::TagHelper
- ActionView::Helpers::OutputSafetyHelper
Instance Public methods
concat(string) Link
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
%>
current_cycle(name = "default") 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 %>
cycle(first_value, *values) Link
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 actionview/lib/action_view/helpers/text_helper.rb, line 358 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
excerpt(text, phrase, options = {}) Link
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 actionview/lib/action_view/helpers/text_helper.rb, line 179 def excerpt(text, phrase, options = {}) return unless text && phrase separator = options.fetch(:separator, nil) || "" case phrase when Regexp regex = phrase else regex = /#{Regexp.escape(phrase)}/i end return unless matches = text.match(regex) phrase = matches[0] unless separator.empty? text.split(separator).each do |value| if value.match?(regex) phrase = value break end end end first_part, second_part = text.split(phrase, 2) prefix, first_part = cut_excerpt_part(:first, first_part, separator, options) postfix, second_part = cut_excerpt_part(:second, second_part, separator, options) affix = [first_part, separator, phrase, separator, second_part].join.strip [prefix, affix, postfix].join end
highlight(text, phrases, options = {}, &block) Link
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>
) or passing a block that receives each matched term. By default text
is sanitized to prevent possible XSS attacks. If the input is trustworthy, passing false for :sanitize
will turn sanitizing off.
highlight('You searched for: rails', 'rails')
# => You searched for: <mark>rails</mark>
highlight('You searched for: rails', /for|rails/)
# => You searched <mark>for</mark>: <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>
highlight('You searched for: rails', 'rails') { |match| link_to(search_path(q: match, match)) }
# => You searched for: <a href="search?q=rails">rails</a>
highlight('<a href="javascript:alert(\'no!\')">ruby</a> on rails', 'rails', sanitize: false)
# => <a href="javascript:alert('no!')">ruby</a> on <mark>rails</mark>
# File actionview/lib/action_view/helpers/text_helper.rb, line 136 def highlight(text, phrases, options = {}, &block) text = sanitize(text) if options.fetch(:sanitize, true) if text.blank? || phrases.blank? text || "" else match = Array(phrases).map do |p| Regexp === p ? p.to_s : Regexp.escape(p) end.join("|") if block_given? text.gsub(/(#{match})(?![^<]*?>)/i, &block) else highlighter = options.fetch(:highlighter, '<mark>\1</mark>') text.gsub(/(#{match})(?![^<]*?>)/i, highlighter) end end.html_safe end
pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale) Link
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 for the given locale, which defaults to I18n.locale
The word will be pluralized using rules defined for the locale (you must define your own inflection rules for languages other than English). See ActiveSupport::Inflector.pluralize
pluralize(1, 'person')
# => 1 person
pluralize(2, 'person')
# => 2 people
pluralize(3, 'person', plural: 'users')
# => 3 users
pluralize(0, 'person')
# => 0 people
pluralize(2, 'Person', locale: :de)
# => 2 Personen
# File actionview/lib/action_view/helpers/text_helper.rb, line 234 def pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale) word = if count == 1 || count.to_s.match?(/^1(\.0+)?$/) singular else plural || singular.pluralize(locale) end "#{count || 0} #{word}" end
reset_cycle(name = "default") Link
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>
safe_concat(string) Link
simple_format(text, html_options = {}, options = {}) Link
Returns text
transformed into HTML using simple formatting rules. Two or more consecutive newlines (\n\n
or \r\n\r\n
) are considered a paragraph and wrapped in <p>
tags. One newline (\n
or \r\n
) is considered 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!</blink> It's true.</p>"
# File actionview/lib/action_view/helpers/text_helper.rb, line 306 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, raw(paragraph), html_options) }.join("\n\n").html_safe end end
truncate(text, options = {}, &block) Link
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("<p>Once upon a time in a world far far away</p>", escape: false)
# => "<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 actionview/lib/action_view/helpers/text_helper.rb, line 98 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
word_wrap(text, line_width: 80, break_sequence: "\n") Link
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
You can also specify a custom +break_sequence+ ("\n" by default)
word_wrap('Once upon a time', line_width: 1, break_sequence: "\r\n")
# => Once\r\nupon\r\na\r\ntime
# File actionview/lib/action_view/helpers/text_helper.rb, line 264 def word_wrap(text, line_width: 80, break_sequence: "\n") text.split("\n").collect! do |line| line.length > line_width ? line.gsub(/(.{1,#{line_width}})(\s+|$)/, "\\1#{break_sequence}").rstrip : line end * break_sequence end