aboutsummaryrefslogtreecommitdiffstats
path: root/actionview/lib/action_view/helpers/text_helper.rb
blob: 34138de00e5b01c0ff8dfdedbcfbcd83a89ec30c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
# frozen_string_literal: true

require "active_support/core_ext/string/filters"
require "active_support/core_ext/array/extract_options"

module ActionView
  # = Action View Text Helpers
  module Helpers #:nodoc:
    # 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>&lt;a href=\"http://example.com/\"&gt;Example&lt;/a&gt;</p>"
    module TextHelper
      extend ActiveSupport::Concern

      include SanitizeHelper
      include TagHelper
      include OutputSafetyHelper

      # 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
      #   %>
      def concat(string)
        output_buffer << string
      end

      def safe_concat(string)
        output_buffer.respond_to?(:safe_concat) ? output_buffer.safe_concat(string) : concat(string)
      end

      # Truncates a given +text+ after a given <tt>:length</tt> if +text+ is longer than <tt>:length</tt>
      # (defaults to 30). The last characters will be replaced with the <tt>:omission</tt> (defaults to "...")
      # for a total length not exceeding <tt>:length</tt>.
      #
      # Pass a <tt>:separator</tt> 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 <tt>:escape</tt> 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>")
      #   # => "&lt;p&gt;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>"
      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

      # Highlights one or more +phrases+ everywhere in +text+ by inserting it into
      # a <tt>:highlighter</tt> string. The highlighter can be specialized by passing <tt>:highlighter</tt>
      # as a single-quoted string with <tt>\1</tt> 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 <tt>:sanitize</tt> 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>
      def highlight(text, phrases, options = {})
        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) { |found| yield found }
          else
            highlighter = options.fetch(:highlighter, '<mark>\1</mark>')
            text.gsub(/(#{match})(?![^<]*?>)/i, highlighter)
          end
        end.html_safe
      end

      # Extracts an excerpt from +text+ that matches the first instance of +phrase+.
      # The <tt>:radius</tt> option expands the excerpt on each side of the first occurrence of +phrase+ by the number of characters
      # defined in <tt>:radius</tt> (which defaults to 100). If the excerpt radius overflows the beginning or end of the +text+,
      # then the <tt>:omission</tt> option (which defaults to "...") will be prepended/appended accordingly. Use the
      # <tt>:separator</tt> 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...
      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

      # 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
      def pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale)
        word = if (count == 1 || count =~ /^1(\.0+)?$/)
          singular
        else
          plural || singular.pluralize(locale)
        end

        "#{count || 0} #{word}"
      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
      #
      #   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
      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}").strip : line
        end * break_sequence
      end

      # Returns +text+ transformed into HTML using simple formatting rules.
      # Two or more consecutive newlines(<tt>\n\n</tt> or <tt>\r\n\r\n</tt>) are
      # considered a paragraph and wrapped in <tt><p></tt> tags. One newline
      # (<tt>\n</tt> or <tt>\r\n</tt>) is considered a linebreak and a
      # <tt><br /></tt> tag is appended. This method does not remove the
      # newlines from the +text+.
      #
      # You can pass any HTML attributes into <tt>html_options</tt>. These
      # will be added to all created paragraphs.
      #
      # ==== Options
      # * <tt>:sanitize</tt> - If +false+, does not sanitize +text+.
      # * <tt>:wrapper_tag</tt> - String representing the wrapper tag, defaults to <tt>"p"</tt>
      #
      # ==== 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>"
      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

      # 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 <tt>:name</tt> key will create a
      # named cycle. The default name for a cycle without a +:name+ key is
      # <tt>"default"</tt>. 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 %>
      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

      # 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 %>
      def current_cycle(name = "default")
        cycle = get_cycle(name)
        cycle.current_value if cycle
      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>
      def reset_cycle(name = "default")
        cycle = get_cycle(name)
        cycle.reset if cycle
      end

      class Cycle #:nodoc:
        attr_reader :values

        def initialize(first_value, *values)
          @values = values.unshift(first_value)
          reset
        end

        def reset
          @index = 0
        end

        def current_value
          @values[previous_index].to_s
        end

        def to_s
          value = @values[@index].to_s
          @index = next_index
          value
        end

        private

          def next_index
            step_index(1)
          end

          def previous_index
            step_index(-1)
          end

          def step_index(n)
            (@index + n) % @values.size
          end
      end

      private
        # 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.
        def get_cycle(name)
          @_cycles = Hash.new unless defined?(@_cycles)
          @_cycles[name]
        end

        def set_cycle(name, cycle_object)
          @_cycles = Hash.new unless defined?(@_cycles)
          @_cycles[name] = cycle_object
        end

        def split_paragraphs(text)
          return [] if text.blank?

          text.to_str.gsub(/\r\n?/, "\n").split(/\n\n+/).map! do |t|
            t.gsub!(/([^\n]\n)(?=[^\n])/, '\1<br />') || t
          end
        end

        def cut_excerpt_part(part_position, part, separator, options)
          return "", "" unless part

          radius   = options.fetch(:radius, 100)
          omission = options.fetch(:omission, "...")

          part = part.split(separator)
          part.delete("")
          affix = part.size > radius ? omission : ""

          part = if part_position == :first
            drop_index = [part.length - radius, 0].max
            part.drop(drop_index)
          else
            part.first(radius)
          end

          return affix, part.join(separator)
        end
    end
  end
end