aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_view/helpers/url_helper.rb
blob: 1145f348c2ecbb381e3a5ff42c0a3f1b81125951 (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
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
require 'action_view/helpers/javascript_helper'
require 'active_support/core_ext/array/access'
require 'active_support/core_ext/hash/keys'
require 'active_support/core_ext/string/output_safety'
require 'action_dispatch'

module ActionView
  # = Action View URL Helpers
  module Helpers #:nodoc:
    # Provides a set of methods for making links and getting URLs that
    # depend on the routing subsystem (see ActionDispatch::Routing).
    # This allows you to use the same format for links in views
    # and controllers.
    module UrlHelper
      # This helper may be included in any class that includes the
      # URL helpers of a routes (routes.url_helpers). Some methods
      # provided here will only work in the context of a request
      # (link_to_unless_current, for instance), which must be provided
      # as a method called #request on the context.

      extend ActiveSupport::Concern

      include ActionDispatch::Routing::UrlFor
      include TagHelper

      # We need to override url_optoins, _routes_context
      # and optimize_routes_generation? to consider the controller.

      def url_options #:nodoc:
        return super unless controller.respond_to?(:url_options)
        controller.url_options
      end

      def _routes_context #:nodoc:
        controller
      end
      protected :_routes_context

      def optimize_routes_generation? #:nodoc:
        controller.respond_to?(:optimize_routes_generation?) ?
          controller.optimize_routes_generation? : super
      end
      protected :optimize_routes_generation?

      # Returns the URL for the set of +options+ provided. This takes the
      # same options as +url_for+ in Action Controller (see the
      # documentation for <tt>ActionController::Base#url_for</tt>). Note that by default
      # <tt>:only_path</tt> is <tt>true</tt> so you'll get the relative "/controller/action"
      # instead of the fully qualified URL like "http://example.com/controller/action".
      #
      # ==== Options
      # * <tt>:anchor</tt> - Specifies the anchor name to be appended to the path.
      # * <tt>:only_path</tt> - If true, returns the relative URL (omitting the protocol, host name, and port) (<tt>true</tt> by default unless <tt>:host</tt> is specified).
      # * <tt>:trailing_slash</tt> - If true, adds a trailing slash, as in "/archive/2005/". Note that this
      #   is currently not recommended since it breaks caching.
      # * <tt>:host</tt> - Overrides the default (current) host if provided.
      # * <tt>:protocol</tt> - Overrides the default (current) protocol if provided.
      # * <tt>:user</tt> - Inline HTTP authentication (only plucked out if <tt>:password</tt> is also present).
      # * <tt>:password</tt> - Inline HTTP authentication (only plucked out if <tt>:user</tt> is also present).
      #
      # ==== Relying on named routes
      #
      # Passing a record (like an Active Record) instead of a Hash as the options parameter will
      # trigger the named route for that record. The lookup will happen on the name of the class. So passing a
      # Workshop object will attempt to use the +workshop_path+ route. If you have a nested route, such as
      # +admin_workshop_path+ you'll have to call that explicitly (it's impossible for +url_for+ to guess that route).
      #
      # ==== Examples
      #   <%= url_for(:action => 'index') %>
      #   # => /blog/
      #
      #   <%= url_for(:action => 'find', :controller => 'books') %>
      #   # => /books/find
      #
      #   <%= url_for(:action => 'login', :controller => 'members', :only_path => false, :protocol => 'https') %>
      #   # => https://www.example.com/members/login/
      #
      #   <%= url_for(:action => 'play', :anchor => 'player') %>
      #   # => /messages/play/#player
      #
      #   <%= url_for(:action => 'jump', :anchor => 'tax&ship') %>
      #   # => /testing/jump/#tax&ship
      #
      #   <%= url_for(Workshop.new) %>
      #   # relies on Workshop answering a persisted? call (and in this case returning false)
      #   # => /workshops
      #
      #   <%= url_for(@workshop) %>
      #   # calls @workshop.to_param which by default returns the id
      #   # => /workshops/5
      #
      #   # to_param can be re-defined in a model to provide different URL names:
      #   # => /workshops/1-workshop-name
      #
      #   <%= url_for("http://www.example.com") %>
      #   # => http://www.example.com
      #
      #   <%= url_for(:back) %>
      #   # if request.env["HTTP_REFERER"] is set to "http://www.example.com"
      #   # => http://www.example.com
      #
      #   <%= url_for(:back) %>
      #   # if request.env["HTTP_REFERER"] is not set or is blank
      #   # => javascript:history.back()
      def url_for(options = nil)
        case options
        when String
          options
        when nil, Hash
          options ||= {}
          options = options.symbolize_keys.reverse_merge!(:only_path => options[:host].nil?)
          super
        when :back
          controller.request.env["HTTP_REFERER"] || 'javascript:history.back()'
        else
          polymorphic_path(options)
        end
      end

      # Creates a link tag of the given +name+ using a URL created by the set of +options+.
      # See the valid options in the documentation for +url_for+. It's also possible to
      # pass a String instead of an options hash, which generates a link tag that uses the
      # value of the String as the href for the link. Using a <tt>:back</tt> Symbol instead
      # of an options hash will generate a link to the referrer (a JavaScript back link
      # will be used in place of a referrer if none exists). If +nil+ is passed as the name
      # the value of the link itself will become the name.
      #
      # ==== Signatures
      #
      #   link_to(body, url, html_options = {})
      #     # url is a String; you can use URL helpers like
      #     # posts_path
      #
      #   link_to(body, url_options = {}, html_options = {})
      #     # url_options, except :confirm or :method,
      #     # is passed to url_for
      #
      #   link_to(options = {}, html_options = {}) do
      #     # name
      #   end
      #
      #   link_to(url, html_options = {}) do
      #     # name
      #   end
      #
      # ==== Options
      # * <tt>:confirm => 'question?'</tt> - This will allow the unobtrusive JavaScript
      #   driver to prompt with the question specified. If the user accepts, the link is
      #   processed normally, otherwise no action is taken.
      # * <tt>:method => symbol of HTTP verb</tt> - This modifier will dynamically
      #   create an HTML form and immediately submit the form for processing using
      #   the HTTP verb specified. Useful for having links perform a POST operation
      #   in dangerous actions like deleting a record (which search bots can follow
      #   while spidering your site). Supported verbs are <tt>:post</tt>, <tt>:delete</tt>, <tt>:patch</tt>, and <tt>:put</tt>.
      #   Note that if the user has JavaScript disabled, the request will fall back
      #   to using GET. If <tt>:href => '#'</tt> is used and the user has JavaScript
      #   disabled clicking the link will have no effect. If you are relying on the
      #   POST behavior, you should check for it in your controller's action by using
      #   the request object's methods for <tt>post?</tt>, <tt>delete?</tt>, <tt>:patch</tt>, or <tt>put?</tt>.
      # * <tt>:remote => true</tt> - This will allow the unobtrusive JavaScript
      #   driver to make an Ajax request to the URL in question instead of following
      #   the link. The drivers each provide mechanisms for listening for the
      #   completion of the Ajax request and performing JavaScript operations once
      #   they're complete
      #
      # ==== Examples
      # Because it relies on +url_for+, +link_to+ supports both older-style controller/action/id arguments
      # and newer RESTful routes. Current Rails style favors RESTful routes whenever possible, so base
      # your application on resources and use
      #
      #   link_to "Profile", profile_path(@profile)
      #   # => <a href="/profiles/1">Profile</a>
      #
      # or the even pithier
      #
      #   link_to "Profile", @profile
      #   # => <a href="/profiles/1">Profile</a>
      #
      # in place of the older more verbose, non-resource-oriented
      #
      #   link_to "Profile", :controller => "profiles", :action => "show", :id => @profile
      #   # => <a href="/profiles/show/1">Profile</a>
      #
      # Similarly,
      #
      #   link_to "Profiles", profiles_path
      #   # => <a href="/profiles">Profiles</a>
      #
      # is better than
      #
      #   link_to "Profiles", :controller => "profiles"
      #   # => <a href="/profiles">Profiles</a>
      #
      # You can use a block as well if your link target is hard to fit into the name parameter. ERB example:
      #
      #   <%= link_to(@profile) do %>
      #     <strong><%= @profile.name %></strong> -- <span>Check it out!</span>
      #   <% end %>
      #   # => <a href="/profiles/1">
      #          <strong>David</strong> -- <span>Check it out!</span>
      #        </a>
      #
      # Classes and ids for CSS are easy to produce:
      #
      #   link_to "Articles", articles_path, :id => "news", :class => "article"
      #   # => <a href="/articles" class="article" id="news">Articles</a>
      #
      # Be careful when using the older argument style, as an extra literal hash is needed:
      #
      #   link_to "Articles", { :controller => "articles" }, :id => "news", :class => "article"
      #   # => <a href="/articles" class="article" id="news">Articles</a>
      #
      # Leaving the hash off gives the wrong link:
      #
      #   link_to "WRONG!", :controller => "articles", :id => "news", :class => "article"
      #   # => <a href="/articles/index/news?class=article">WRONG!</a>
      #
      # +link_to+ can also produce links with anchors or query strings:
      #
      #   link_to "Comment wall", profile_path(@profile, :anchor => "wall")
      #   # => <a href="/profiles/1#wall">Comment wall</a>
      #
      #   link_to "Ruby on Rails search", :controller => "searches", :query => "ruby on rails"
      #   # => <a href="/searches?query=ruby+on+rails">Ruby on Rails search</a>
      #
      #   link_to "Nonsense search", searches_path(:foo => "bar", :baz => "quux")
      #   # => <a href="/searches?foo=bar&amp;baz=quux">Nonsense search</a>
      #
      # The two options specific to +link_to+ (<tt>:confirm</tt> and <tt>:method</tt>) are used as follows:
      #
      #   link_to "Visit Other Site", "http://www.rubyonrails.org/", :confirm => "Are you sure?"
      #   # => <a href="http://www.rubyonrails.org/" data-confirm="Are you sure?"">Visit Other Site</a>
      #
      #   link_to("Destroy", "http://www.example.com", :method => :delete, :confirm => "Are you sure?")
      #   # => <a href='http://www.example.com' rel="nofollow" data-method="delete" data-confirm="Are you sure?">Destroy</a>
      def link_to(*args, &block)
        if block_given?
          options      = args.first || {}
          html_options = args.second
          link_to(capture(&block), options, html_options)
        else
          name         = args[0]
          options      = args[1] || {}
          html_options = args[2]

          html_options = convert_options_to_data_attributes(options, html_options)
          url = url_for(options)

          href = html_options['href']
          tag_options = tag_options(html_options)

          href_attr = "href=\"#{ERB::Util.html_escape(url)}\"" unless href
          "<a #{href_attr}#{tag_options}>#{ERB::Util.html_escape(name || url)}</a>".html_safe
        end
      end

      # Generates a form containing a single button that submits to the URL created
      # by the set of +options+. This is the safest method to ensure links that
      # cause changes to your data are not triggered by search bots or accelerators.
      # If the HTML button does not work with your layout, you can also consider
      # using the +link_to+ method with the <tt>:method</tt> modifier as described in
      # the +link_to+ documentation.
      #
      # By default, the generated form element has a class name of <tt>button_to</tt>
      # to allow styling of the form itself and its children. This can be changed
      # using the <tt>:form_class</tt> modifier within +html_options+. You can control
      # the form submission and input element behavior using +html_options+.
      # This method accepts the <tt>:method</tt> and <tt>:confirm</tt> modifiers
      # described in the +link_to+ documentation. If no <tt>:method</tt> modifier
      # is given, it will default to performing a POST operation. You can also
      # disable the button by passing <tt>:disabled => true</tt> in +html_options+.
      # If you are using RESTful routes, you can pass the <tt>:method</tt>
      # to change the HTTP verb used to submit the form.
      #
      # ==== Options
      # The +options+ hash accepts the same options as +url_for+.
      #
      # There are a few special +html_options+:
      # * <tt>:method</tt> - Symbol of HTTP verb. Supported verbs are <tt>:post</tt>, <tt>:get</tt>,
      #   <tt>:delete</tt>, <tt>:patch</tt>, and <tt>:put</tt>. By default it will be <tt>:post</tt>.
      # * <tt>:disabled</tt> - If set to true, it will generate a disabled button.
      # * <tt>:confirm</tt> - This will use the unobtrusive JavaScript driver to
      #   prompt with the question specified. If the user accepts, the link is
      #   processed normally, otherwise no action is taken.
      # * <tt>:remote</tt> -  If set to true, will allow the Unobtrusive JavaScript drivers to control the
      #   submit behavior. By default this behavior is an ajax submit.
      # * <tt>:form</tt> - This hash will be form attributes
      # * <tt>:form_class</tt> - This controls the class of the form within which the submit button will
      #   be placed
      #
      # ==== Examples
      #   <%= button_to "New", :action => "new" %>
      #   # => "<form method="post" action="/controller/new" class="button_to">
      #   #      <div><input value="New" type="submit" /></div>
      #   #    </form>"
      #
      #
      #   <%= button_to "New", :action => "new", :form_class => "new-thing" %>
      #   # => "<form method="post" action="/controller/new" class="new-thing">
      #   #      <div><input value="New" type="submit" /></div>
      #   #    </form>"
      #
      #
      #   <%= button_to "Create", :action => "create", :remote => true, :form => { "data-type" => "json" } %>
      #   # => "<form method="post" action="/images/create" class="button_to" data-remote="true" data-type="json">
      #   #      <div>
      #   #        <input value="Create" type="submit" />
      #   #        <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
      #   #      </div>
      #   #    </form>"
      #
      #
      #   <%= button_to "Delete Image", { :action => "delete", :id => @image.id },
      #             :confirm => "Are you sure?", :method => :delete %>
      #   # => "<form method="post" action="/images/delete/1" class="button_to">
      #   #      <div>
      #   #        <input type="hidden" name="_method" value="delete" />
      #   #        <input data-confirm='Are you sure?' value="Delete Image" type="submit" />
      #   #        <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
      #   #      </div>
      #   #    </form>"
      #
      #
      #   <%= button_to('Destroy', 'http://www.example.com', :confirm => 'Are you sure?',
      #             :method => "delete", :remote => true, :disable_with => 'loading...') %>
      #   # => "<form class='button_to' method='post' action='http://www.example.com' data-remote='true'>
      #   #       <div>
      #   #         <input name='_method' value='delete' type='hidden' />
      #   #         <input value='Destroy' type='submit' disable_with='loading...' data-confirm='Are you sure?' />
      #   #         <input name="authenticity_token" type="hidden" value="10f2163b45388899ad4d5ae948988266befcb6c3d1b2451cf657a0c293d605a6"/>
      #   #       </div>
      #   #     </form>"
      #   #
      def button_to(name, options = {}, html_options = {})
        html_options = html_options.stringify_keys
        convert_boolean_attributes!(html_options, %w(disabled))

        url    = options.is_a?(String) ? options : url_for(options)
        remote = html_options.delete('remote')

        method     = html_options.delete('method').to_s
        method_tag = %w{patch put delete}.include?(method) ? method_tag(method) : ''.html_safe

        form_method  = method == 'get' ? 'get' : 'post'
        form_options = html_options.delete('form') || {}
        form_options[:class] ||= html_options.delete('form_class') || 'button_to'
        form_options.merge!(:method => form_method, :action => url)
        form_options.merge!("data-remote" => "true") if remote

        request_token_tag = form_method == 'post' ? token_tag : ''

        html_options = convert_options_to_data_attributes(options, html_options)
        html_options.merge!("type" => "submit", "value" => name || url)

        inner_tags = method_tag.safe_concat tag('input', html_options).safe_concat request_token_tag
        content_tag('form', content_tag('div', inner_tags), form_options)
      end


      # Creates a link tag of the given +name+ using a URL created by the set of
      # +options+ unless the current request URI is the same as the links, in
      # which case only the name is returned (or the given block is yielded, if
      # one exists). You can give +link_to_unless_current+ a block which will
      # specialize the default behavior (e.g., show a "Start Here" link rather
      # than the link's text).
      #
      # ==== Examples
      # Let's say you have a navigation menu...
      #
      #   <ul id="navbar">
      #     <li><%= link_to_unless_current("Home", { :action => "index" }) %></li>
      #     <li><%= link_to_unless_current("About Us", { :action => "about" }) %></li>
      #   </ul>
      #
      # If in the "about" action, it will render...
      #
      #   <ul id="navbar">
      #     <li><a href="/controller/index">Home</a></li>
      #     <li>About Us</li>
      #   </ul>
      #
      # ...but if in the "index" action, it will render:
      #
      #   <ul id="navbar">
      #     <li>Home</li>
      #     <li><a href="/controller/about">About Us</a></li>
      #   </ul>
      #
      # The implicit block given to +link_to_unless_current+ is evaluated if the current
      # action is the action given. So, if we had a comments page and wanted to render a
      # "Go Back" link instead of a link to the comments page, we could do something like this...
      #
      #    <%=
      #        link_to_unless_current("Comment", { :controller => "comments", :action => "new" }) do
      #           link_to("Go back", { :controller => "posts", :action => "index" })
      #        end
      #     %>
      def link_to_unless_current(name, options = {}, html_options = {}, &block)
        link_to_unless current_page?(options), name, options, html_options, &block
      end

      # Creates a link tag of the given +name+ using a URL created by the set of
      # +options+ unless +condition+ is true, in which case only the name is
      # returned. To specialize the default behavior (i.e., show a login link rather
      # than just the plaintext link text), you can pass a block that
      # accepts the name or the full argument list for +link_to_unless+.
      #
      # ==== Examples
      #   <%= link_to_unless(@current_user.nil?, "Reply", { :action => "reply" }) %>
      #   # If the user is logged in...
      #   # => <a href="/controller/reply/">Reply</a>
      #
      #   <%=
      #      link_to_unless(@current_user.nil?, "Reply", { :action => "reply" }) do |name|
      #        link_to(name, { :controller => "accounts", :action => "signup" })
      #      end
      #   %>
      #   # If the user is logged in...
      #   # => <a href="/controller/reply/">Reply</a>
      #   # If not...
      #   # => <a href="/accounts/signup">Reply</a>
      def link_to_unless(condition, name, options = {}, html_options = {}, &block)
        if condition
          if block_given?
            block.arity <= 1 ? capture(name, &block) : capture(name, options, html_options, &block)
          else
            name
          end
        else
          link_to(name, options, html_options)
        end
      end

      # Creates a link tag of the given +name+ using a URL created by the set of
      # +options+ if +condition+ is true, otherwise only the name is
      # returned. To specialize the default behavior, you can pass a block that
      # accepts the name or the full argument list for +link_to_unless+ (see the examples
      # in +link_to_unless+).
      #
      # ==== Examples
      #   <%= link_to_if(@current_user.nil?, "Login", { :controller => "sessions", :action => "new" }) %>
      #   # If the user isn't logged in...
      #   # => <a href="/sessions/new/">Login</a>
      #
      #   <%=
      #      link_to_if(@current_user.nil?, "Login", { :controller => "sessions", :action => "new" }) do
      #        link_to(@current_user.login, { :controller => "accounts", :action => "show", :id => @current_user })
      #      end
      #   %>
      #   # If the user isn't logged in...
      #   # => <a href="/sessions/new/">Login</a>
      #   # If they are logged in...
      #   # => <a href="/accounts/show/3">my_username</a>
      def link_to_if(condition, name, options = {}, html_options = {}, &block)
        link_to_unless !condition, name, options, html_options, &block
      end

      # Creates a mailto link tag to the specified +email_address+, which is
      # also used as the name of the link unless +name+ is specified. Additional
      # HTML attributes for the link can be passed in +html_options+.
      #
      # +mail_to+ has several methods for hindering email harvesters and customizing
      # the email itself by passing special keys to +html_options+.
      #
      # ==== Options
      # * <tt>:encode</tt> - This key will accept the strings "javascript" or "hex".
      #   Passing "javascript" will dynamically create and encode the mailto link then
      #   eval it into the DOM of the page. This method will not show the link on
      #   the page if the user has JavaScript disabled. Passing "hex" will hex
      #   encode the +email_address+ before outputting the mailto link.
      # * <tt>:replace_at</tt> - When the link +name+ isn't provided, the
      #   +email_address+ is used for the link label. You can use this option to
      #   obfuscate the +email_address+ by substituting the @ sign with the string
      #   given as the value.
      # * <tt>:replace_dot</tt> - When the link +name+ isn't provided, the
      #   +email_address+ is used for the link label. You can use this option to
      #   obfuscate the +email_address+ by substituting the . in the email with the
      #   string given as the value.
      # * <tt>:subject</tt> - Preset the subject line of the email.
      # * <tt>:body</tt> - Preset the body of the email.
      # * <tt>:cc</tt> - Carbon Copy additional recipients on the email.
      # * <tt>:bcc</tt> - Blind Carbon Copy additional recipients on the email.
      #
      # ==== Examples
      #   mail_to "me@domain.com"
      #   # => <a href="mailto:me@domain.com">me@domain.com</a>
      #
      #   mail_to "me@domain.com", "My email", :encode => "javascript"
      #   # => <script>eval(decodeURIComponent('%64%6f%63...%27%29%3b'))</script>
      #
      #   mail_to "me@domain.com", "My email", :encode => "hex"
      #   # => <a href="mailto:%6d%65@%64%6f%6d%61%69%6e.%63%6f%6d">My email</a>
      #
      #   mail_to "me@domain.com", nil, :replace_at => "_at_", :replace_dot => "_dot_", :class => "email"
      #   # => <a href="mailto:me@domain.com" class="email">me_at_domain_dot_com</a>
      #
      #   mail_to "me@domain.com", "My email", :cc => "ccaddress@domain.com",
      #            :subject => "This is an example email"
      #   # => <a href="mailto:me@domain.com?cc=ccaddress@domain.com&subject=This%20is%20an%20example%20email">My email</a>
      def mail_to(email_address, name = nil, html_options = {})
        email_address = ERB::Util.html_escape(email_address)

        html_options = html_options.stringify_keys
        encode = html_options.delete("encode").to_s

        extras = %w{ cc bcc body subject }.map { |item|
          option = html_options.delete(item) || next
          "#{item}=#{Rack::Utils.escape_path(option)}"
        }.compact
        extras = extras.empty? ? '' : '?' + ERB::Util.html_escape(extras.join('&'))

        email_address_obfuscated = email_address.to_str
        email_address_obfuscated.gsub!(/@/, html_options.delete("replace_at")) if html_options.key?("replace_at")
        email_address_obfuscated.gsub!(/\./, html_options.delete("replace_dot")) if html_options.key?("replace_dot")
        case encode
        when "javascript"
          string = ''
          html   = content_tag("a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe))
          html   = escape_javascript(html.to_str)
          "document.write('#{html}');".each_byte do |c|
            string << sprintf("%%%x", c)
          end
          "<script>eval(decodeURIComponent('#{string}'))</script>".html_safe
        when "hex"
          email_address_encoded = email_address_obfuscated.unpack('C*').map {|c|
            sprintf("&#%d;", c)
          }.join

          string = 'mailto:'.unpack('C*').map { |c|
            sprintf("&#%d;", c)
          }.join + email_address.unpack('C*').map { |c|
            char = c.chr
            char =~ /\w/ ? sprintf("%%%x", c) : char
          }.join

          content_tag "a", name || email_address_encoded.html_safe, html_options.merge("href" => "#{string}#{extras}".html_safe)
        else
          content_tag "a", name || email_address_obfuscated.html_safe, html_options.merge("href" => "mailto:#{email_address}#{extras}".html_safe)
        end
      end

      # True if the current request URI was generated by the given +options+.
      #
      # ==== Examples
      # Let's say we're in the <tt>/shop/checkout?order=desc</tt> action.
      #
      #   current_page?(:action => 'process')
      #   # => false
      #
      #   current_page?(:controller => 'shop', :action => 'checkout')
      #   # => true
      #
      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'asc')
      #   # => false
      #
      #   current_page?(:action => 'checkout')
      #   # => true
      #
      #   current_page?(:controller => 'library', :action => 'checkout')
      #   # => false
      #
      # Let's say we're in the <tt>/shop/checkout?order=desc&page=1</tt> action.
      #
      #   current_page?(:action => 'process')
      #   # => false
      #
      #   current_page?(:controller => 'shop', :action => 'checkout')
      #   # => true
      #
      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page => '1')
      #   # => true
      #
      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page => '2')
      #   # => false
      #
      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc')
      #   # => false
      #
      #   current_page?(:action => 'checkout')
      #   # => true
      #
      #   current_page?(:controller => 'library', :action => 'checkout')
      #   # => false
      #
      # Let's say we're in the <tt>/products</tt> action with method POST in case of invalid product.
      #
      #   current_page?(:controller => 'product', :action => 'index')
      #   # => false
      #
      def current_page?(options)
        unless request
          raise "You cannot use helpers that need to determine the current " \
                "page unless your view context provides a Request object " \
                "in a #request method"
        end

        return false unless request.get?

        url_string = url_for(options)

        # We ignore any extra parameters in the request_uri if the
        # submitted url doesn't have any either. This lets the function
        # work with things like ?order=asc
        request_uri = url_string.index("?") ? request.fullpath : request.path

        if url_string =~ /^\w+:\/\//
          url_string == "#{request.protocol}#{request.host_with_port}#{request_uri}"
        else
          url_string == request_uri
        end
      end

      private
        def convert_options_to_data_attributes(options, html_options)
          if html_options
            html_options = html_options.stringify_keys
            html_options['data-remote'] = 'true' if link_to_remote_options?(options) || link_to_remote_options?(html_options)

            disable_with = html_options.delete("disable_with")
            confirm = html_options.delete('confirm')
            method  = html_options.delete('method')

            html_options["data-disable-with"] = disable_with if disable_with
            html_options["data-confirm"] = confirm if confirm
            add_method_to_attributes!(html_options, method) if method

            html_options
          else
            link_to_remote_options?(options) ? {'data-remote' => 'true'} : {}
          end
        end

        def link_to_remote_options?(options)
          options.is_a?(Hash) && options.delete('remote')
        end

        def add_method_to_attributes!(html_options, method)
          if method && method.to_s.downcase != "get" && html_options["rel"] !~ /nofollow/
            html_options["rel"] = "#{html_options["rel"]} nofollow".lstrip
          end
          html_options["data-method"] = method
        end

        # Processes the +html_options+ hash, converting the boolean
        # attributes from true/false form into the form required by
        # HTML/XHTML. (An attribute is considered to be boolean if
        # its name is listed in the given +bool_attrs+ array.)
        #
        # More specifically, for each boolean attribute in +html_options+
        # given as:
        #
        #   "attr" => bool_value
        #
        # if the associated +bool_value+ evaluates to true, it is
        # replaced with the attribute's name; otherwise the attribute is
        # removed from the +html_options+ hash. (See the XHTML 1.0 spec,
        # section 4.5 "Attribute Minimization" for more:
        # http://www.w3.org/TR/xhtml1/#h-4.5)
        #
        # Returns the updated +html_options+ hash, which is also modified
        # in place.
        #
        # Example:
        #
        #   convert_boolean_attributes!( html_options,
        #                                %w( checked disabled readonly ) )
        def convert_boolean_attributes!(html_options, bool_attrs)
          bool_attrs.each { |x| html_options[x] = x if html_options.delete(x) }
          html_options
        end

        def token_tag(token=nil)
          if token == false || !protect_against_forgery?
            ''
          else
            token ||= form_authenticity_token
            tag(:input, :type => "hidden", :name => request_forgery_protection_token.to_s, :value => token)
          end
        end

        def method_tag(method)
          tag('input', :type => 'hidden', :name => '_method', :value => method.to_s)
        end
    end
  end
end