aboutsummaryrefslogtreecommitdiffstats
path: root/actionmailer/lib/action_mailer/base.rb
blob: 6056399cd21faa68008c4b54f7c5be5da59632d9 (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
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
require 'mail'
require 'action_mailer/queued_message'
require 'action_mailer/collector'
require 'active_support/core_ext/string/inflections'
require 'active_support/core_ext/hash/except'
require 'active_support/core_ext/module/anonymous'
require 'active_support/queueing'
require 'action_mailer/log_subscriber'

module ActionMailer
  # Action Mailer allows you to send email from your application using a mailer model and views.
  #
  # = Mailer Models
  #
  # To use Action Mailer, you need to create a mailer model.
  #
  #   $ rails generate mailer Notifier
  #
  # The generated model inherits from <tt>ActionMailer::Base</tt>. A mailer model defines methods
  # used to generate an email message. In these methods, you can setup variables to be used in
  # the mailer views, options on the mail itself such as the <tt>:from</tt> address, and attachments.
  #
  #   class Notifier < ActionMailer::Base
  #     default from: 'no-reply@example.com',
  #             return_path: 'system@example.com'
  #
  #     def welcome(recipient)
  #       @account = recipient
  #       mail(to: recipient.email_address_with_name,
  #            bcc: ["bcc@example.com", "Order Watcher <watcher@example.com>"])
  #     end
  #   end
  #
  # Within the mailer method, you have access to the following methods:
  #
  # * <tt>attachments[]=</tt> - Allows you to add attachments to your email in an intuitive
  #   manner; <tt>attachments['filename.png'] = File.read('path/to/filename.png')</tt>
  #
  # * <tt>attachments.inline[]=</tt> - Allows you to add an inline attachment to your email
  #   in the same manner as <tt>attachments[]=</tt>
  #
  # * <tt>headers[]=</tt> - Allows you to specify any header field in your email such
  #   as <tt>headers['X-No-Spam'] = 'True'</tt>. Note, while most fields like <tt>To:</tt>
  #   <tt>From:</tt> can only appear once in an email header, other fields like <tt>X-Anything</tt>
  #   can appear multiple times. If you want to change a field that can appear multiple times,
  #   you need to set it to nil first so that Mail knows you are replacing it and not adding
  #   another field of the same name.
  #
  # * <tt>headers(hash)</tt> - Allows you to specify multiple headers in your email such
  #   as <tt>headers({'X-No-Spam' => 'True', 'In-Reply-To' => '1234@message.id'})</tt>
  #
  # * <tt>mail</tt> - Allows you to specify email to be sent.
  #
  # The hash passed to the mail method allows you to specify any header that a Mail::Message
  # will accept (any valid Email header including optional fields).
  #
  # The mail method, if not passed a block, will inspect your views and send all the views with
  # the same name as the method, so the above action would send the +welcome.text.erb+ view
  # file as well as the +welcome.text.html.erb+ view file in a +multipart/alternative+ email.
  #
  # If you want to explicitly render only certain templates, pass a block:
  #
  #   mail(to: user.email) do |format|
  #     format.text
  #     format.html
  #   end
  #
  # The block syntax is also useful in providing information specific to a part:
  #
  #   mail(to: user.email) do |format|
  #     format.text(content_transfer_encoding: "base64")
  #     format.html
  #   end
  #
  # Or even to render a special view:
  #
  #   mail(to: user.email) do |format|
  #     format.text
  #     format.html { render "some_other_template" }
  #   end
  #
  # = Mailer views
  #
  # Like Action Controller, each mailer class has a corresponding view directory in which each
  # method of the class looks for a template with its name.
  #
  # To define a template to be used with a mailing, create an <tt>.erb</tt> file with the same
  # name as the method in your mailer model. For example, in the mailer defined above, the template at
  # <tt>app/views/notifier/welcome.text.erb</tt> would be used to generate the email.
  #
  # Variables defined in the model are accessible as instance variables in the view.
  #
  # Emails by default are sent in plain text, so a sample view for our model example might look like this:
  #
  #   Hi <%= @account.name %>,
  #   Thanks for joining our service! Please check back often.
  #
  # You can even use Action Pack helpers in these views. For example:
  #
  #   You got a new note!
  #   <%= truncate(@note.body, length: 25) %>
  #
  # If you need to access the subject, from or the recipients in the view, you can do that through message object:
  #
  #   You got a new note from <%= message.from %>!
  #   <%= truncate(@note.body, length: 25) %>
  #
  #
  # = Generating URLs
  #
  # URLs can be generated in mailer views using <tt>url_for</tt> or named routes. Unlike controllers from
  # Action Pack, the mailer instance doesn't have any context about the incoming request, so you'll need
  # to provide all of the details needed to generate a URL.
  #
  # When using <tt>url_for</tt> you'll need to provide the <tt>:host</tt>, <tt>:controller</tt>, and <tt>:action</tt>:
  #
  #   <%= url_for(host: "example.com", controller: "welcome", action: "greeting") %>
  #
  # When using named routes you only need to supply the <tt>:host</tt>:
  #
  #   <%= users_url(host: "example.com") %>
  #
  # You should use the <tt>named_route_url</tt> style (which generates absolute URLs) and avoid using the
  # <tt>named_route_path</tt> style (which generates relative URLs), since clients reading the mail will
  # have no concept of a current URL from which to determine a relative path.
  #
  # It is also possible to set a default host that will be used in all mailers by setting the <tt>:host</tt>
  # option as a configuration option in <tt>config/application.rb</tt>:
  #
  #   config.action_mailer.default_url_options = { host: "example.com" }
  #
  # When you decide to set a default <tt>:host</tt> for your mailers, then you need to make sure to use the
  # <tt>only_path: false</tt> option when using <tt>url_for</tt>. Since the <tt>url_for</tt> view helper
  # will generate relative URLs by default when a <tt>:host</tt> option isn't explicitly provided, passing
  # <tt>only_path: false</tt> will ensure that absolute URLs are generated.
  #
  # = Sending mail
  #
  # Once a mailer action and template are defined, you can deliver your message or create it and save it
  # for delivery later:
  #
  #   Notifier.welcome(david).deliver # sends the email
  #   mail = Notifier.welcome(david)  # => a Mail::Message object
  #   mail.deliver                    # sends the email
  #
  # You never instantiate your mailer class. Rather, you just call the method you defined on the class itself.
  #
  # = Multipart Emails
  #
  # Multipart messages can also be used implicitly because Action Mailer will automatically detect and use
  # multipart templates, where each template is named after the name of the action, followed by the content
  # type. Each such detected template will be added as a separate part to the message.
  #
  # For example, if the following templates exist:
  # * signup_notification.text.erb
  # * signup_notification.text.html.erb
  # * signup_notification.text.xml.builder
  # * signup_notification.text.yaml.erb
  #
  # Each would be rendered and added as a separate part to the message, with the corresponding content
  # type. The content type for the entire message is automatically set to <tt>multipart/alternative</tt>,
  # which indicates that the email contains multiple different representations of the same email
  # body. The same instance variables defined in the action are passed to all email templates.
  #
  # Implicit template rendering is not performed if any attachments or parts have been added to the email.
  # This means that you'll have to manually add each part to the email and set the content type of the email
  # to <tt>multipart/alternative</tt>.
  #
  # = Attachments
  #
  # Sending attachment in emails is easy:
  #
  #   class ApplicationMailer < ActionMailer::Base
  #     def welcome(recipient)
  #       attachments['free_book.pdf'] = File.read('path/to/file.pdf')
  #       mail(to: recipient, subject: "New account information")
  #     end
  #   end
  #
  # Which will (if it had both a <tt>welcome.text.erb</tt> and <tt>welcome.text.html.erb</tt>
  # template in the view directory), send a complete <tt>multipart/mixed</tt> email with two parts,
  # the first part being a <tt>multipart/alternative</tt> with the text and HTML email parts inside,
  # and the second being a <tt>application/pdf</tt> with a Base64 encoded copy of the file.pdf book
  # with the filename +free_book.pdf+.
  #
  # If you need to send attachments with no content, you need to create an empty view for it,
  # or add an empty body parameter like this:
  #
  #     class ApplicationMailer < ActionMailer::Base
  #       def welcome(recipient)
  #         attachments['free_book.pdf'] = File.read('path/to/file.pdf')
  #         mail(to: recipient, subject: "New account information", body: "")
  #       end
  #     end
  #
  # = Inline Attachments
  #
  # You can also specify that a file should be displayed inline with other HTML. This is useful
  # if you want to display a corporate logo or a photo.
  #
  #   class ApplicationMailer < ActionMailer::Base
  #     def welcome(recipient)
  #       attachments.inline['photo.png'] = File.read('path/to/photo.png')
  #       mail(to: recipient, subject: "Here is what we look like")
  #     end
  #   end
  #
  # And then to reference the image in the view, you create a <tt>welcome.html.erb</tt> file and
  # make a call to +image_tag+ passing in the attachment you want to display and then call
  # +url+ on the attachment to get the relative content id path for the image source:
  #
  #   <h1>Please Don't Cringe</h1>
  #
  #   <%= image_tag attachments['photo.png'].url -%>
  #
  # As we are using Action View's +image_tag+ method, you can pass in any other options you want:
  #
  #   <h1>Please Don't Cringe</h1>
  #
  #   <%= image_tag attachments['photo.png'].url, alt: 'Our Photo', class: 'photo' -%>
  #
  # = Observing and Intercepting Mails
  #
  # Action Mailer provides hooks into the Mail observer and interceptor methods. These allow you to
  # register classes that are called during the mail delivery life cycle.
  #
  # An observer class must implement the <tt>:delivered_email(message)</tt> method which will be
  # called once for every email sent after the email has been sent.
  #
  # An interceptor class must implement the <tt>:delivering_email(message)</tt> method which will be
  # called before the email is sent, allowing you to make modifications to the email before it hits
  # the delivery agents. Your class should make any needed modifications directly to the passed
  # in Mail::Message instance.
  #
  # = Default Hash
  #
  # Action Mailer provides some intelligent defaults for your emails, these are usually specified in a
  # default method inside the class definition:
  #
  #   class Notifier < ActionMailer::Base
  #     default sender: 'system@example.com'
  #   end
  #
  # You can pass in any header value that a <tt>Mail::Message</tt> accepts. Out of the box,
  # <tt>ActionMailer::Base</tt> sets the following:
  #
  # * <tt>mime_version: "1.0"</tt>
  # * <tt>charset:      "UTF-8",</tt>
  # * <tt>content_type: "text/plain",</tt>
  # * <tt>parts_order:  [ "text/plain", "text/enriched", "text/html" ]</tt>
  #
  # <tt>parts_order</tt> and <tt>charset</tt> are not actually valid <tt>Mail::Message</tt> header fields,
  # but Action Mailer translates them appropriately and sets the correct values.
  #
  # As you can pass in any header, you need to either quote the header as a string, or pass it in as
  # an underscored symbol, so the following will work:
  #
  #   class Notifier < ActionMailer::Base
  #     default 'Content-Transfer-Encoding' => '7bit',
  #             content_description: 'This is a description'
  #   end
  #
  # Finally, Action Mailer also supports passing <tt>Proc</tt> objects into the default hash, so you
  # can define methods that evaluate as the message is being generated:
  #
  #   class Notifier < ActionMailer::Base
  #     default 'X-Special-Header' => Proc.new { my_method }
  #
  #     private
  #
  #       def my_method
  #         'some complex call'
  #       end
  #   end
  #
  # Note that the proc is evaluated right at the start of the mail message generation, so if you
  # set something in the defaults using a proc, and then set the same thing inside of your
  # mailer method, it will get over written by the mailer method.
  #
  # It is also possible to set these default options that will be used in all mailers through
  # the <tt>default_options=</tt> configuration in <tt>config/application.rb</tt>:
  #
  #    config.action_mailer.default_options = { from: "no-reply@example.org" }
  #
  # = Callbacks
  #
  # You can specify callbacks using before_action and after_action for configuring your messages.
  # This may be useful, for example, when you want to add default inline attachments for all
  # messages sent out by a certain mailer class:
  #
  #   class Notifier < ActionMailer::Base
  #     before_action :add_inline_attachment!
  #
  #     def welcome
  #       mail
  #     end
  #
  #     private
  #
  #       def add_inline_attachment!
  #         attachments.inline["footer.jpg"] = File.read('/path/to/filename.jpg')
  #       end
  #   end
  #
  # Callbacks in ActionMailer are implemented using AbstractController::Callbacks, so you
  # can define and configure callbacks in the same manner that you would use callbacks in
  # classes that inherit from ActionController::Base.
  #
  # Note that unless you have a specific reason to do so, you should prefer using before_action
  # rather than after_action in your ActionMailer classes so that headers are parsed properly.
  #
  # = Configuration options
  #
  # These options are specified on the class level, like
  # <tt>ActionMailer::Base.raise_delivery_errors = true</tt>
  #
  # * <tt>default</tt> - You can pass this in at a class level as well as within the class itself as
  #   per the above section.
  #
  # * <tt>logger</tt> - the logger is used for generating information on the mailing run if available.
  #   Can be set to nil for no logging. Compatible with both Ruby's own Logger and Log4r loggers.
  #
  # * <tt>smtp_settings</tt> - Allows detailed configuration for <tt>:smtp</tt> delivery method:
  #   * <tt>:address</tt> - Allows you to use a remote mail server. Just change it from its default
  #     "localhost" setting.
  #   * <tt>:port</tt> - On the off chance that your mail server doesn't run on port 25, you can change it.
  #   * <tt>:domain</tt> - If you need to specify a HELO domain, you can do it here.
  #   * <tt>:user_name</tt> - If your mail server requires authentication, set the username in this setting.
  #   * <tt>:password</tt> - If your mail server requires authentication, set the password in this setting.
  #   * <tt>:authentication</tt> - If your mail server requires authentication, you need to specify the
  #     authentication type here.
  #     This is a symbol and one of <tt>:plain</tt> (will send the password in the clear), <tt>:login</tt> (will
  #     send password Base64 encoded) or <tt>:cram_md5</tt> (combines a Challenge/Response mechanism to exchange
  #     information and a cryptographic Message Digest 5 algorithm to hash important information)
  #   * <tt>:enable_starttls_auto</tt> - When set to true, detects if STARTTLS is enabled in your SMTP server
  #     and starts to use it.
  #   * <tt>:openssl_verify_mode</tt> - When using TLS, you can set how OpenSSL checks the certificate. This is
  #     really useful if you need to validate a self-signed and/or a wildcard certificate. You can use the name
  #     of an OpenSSL verify constant ('none', 'peer', 'client_once','fail_if_no_peer_cert') or directly the
  #     constant  (OpenSSL::SSL::VERIFY_NONE, OpenSSL::SSL::VERIFY_PEER,...).
  #
  # * <tt>sendmail_settings</tt> - Allows you to override options for the <tt>:sendmail</tt> delivery method.
  #   * <tt>:location</tt> - The location of the sendmail executable. Defaults to <tt>/usr/sbin/sendmail</tt>.
  #   * <tt>:arguments</tt> - The command line arguments. Defaults to <tt>-i -t</tt> with <tt>-f sender@address</tt>
  #     added automatically before the message is sent.
  #
  # * <tt>file_settings</tt> - Allows you to override options for the <tt>:file</tt> delivery method.
  #   * <tt>:location</tt> - The directory into which emails will be written. Defaults to the application
  #     <tt>tmp/mails</tt>.
  #
  # * <tt>raise_delivery_errors</tt> - Whether or not errors should be raised if the email fails to be delivered.
  #
  # * <tt>delivery_method</tt> - Defines a delivery method. Possible values are <tt>:smtp</tt> (default),
  #   <tt>:sendmail</tt>, <tt>:test</tt>, and <tt>:file</tt>. Or you may provide a custom delivery method
  #   object e.g. MyOwnDeliveryMethodClass. See the Mail gem documentation on the interface you need to
  #   implement for a custom delivery agent.
  #
  # * <tt>perform_deliveries</tt> - Determines whether emails are actually sent from Action Mailer when you
  #   call <tt>.deliver</tt> on an mail message or on an Action Mailer method. This is on by default but can
  #   be turned off to aid in functional testing.
  #
  # * <tt>deliveries</tt> - Keeps an array of all the emails sent out through the Action Mailer with
  #   <tt>delivery_method :test</tt>. Most useful for unit and functional testing.
  #
  # * <tt>queue</> - The queue that will be used to deliver the mail. The queue should expect a job that responds to <tt>run</tt>.
  class Base < AbstractController::Base
    include DeliveryMethods
    abstract!

    include AbstractController::Logger
    include AbstractController::Rendering
    include AbstractController::Layouts
    include AbstractController::Helpers
    include AbstractController::Translation
    include AbstractController::AssetPaths
    include AbstractController::Callbacks

    self.protected_instance_variables = [:@_action_has_layout]

    helper ActionMailer::MailHelper

    private_class_method :new #:nodoc:

    class_attribute :default_params
    self.default_params = {
      mime_version: "1.0",
      charset:      "UTF-8",
      content_type: "text/plain",
      parts_order:  [ "text/plain", "text/enriched", "text/html" ]
    }.freeze

    class_attribute :queue
    self.queue = ActiveSupport::SynchronousQueue.new

    class << self
      # Register one or more Observers which will be notified when mail is delivered.
      def register_observers(*observers)
        observers.flatten.compact.each { |observer| register_observer(observer) }
      end

      # Register one or more Interceptors which will be called before mail is sent.
      def register_interceptors(*interceptors)
        interceptors.flatten.compact.each { |interceptor| register_interceptor(interceptor) }
      end

      # Register an Observer which will be notified when mail is delivered.
      # Either a class or a string can be passed in as the Observer. If a string is passed in
      # it will be <tt>constantize</tt>d.
      def register_observer(observer)
        delivery_observer = (observer.is_a?(String) ? observer.constantize : observer)
        Mail.register_observer(delivery_observer)
      end

      # Register an Interceptor which will be called before mail is sent.
      # Either a class or a string can be passed in as the Interceptor. If a string is passed in
      # it will be <tt>constantize</tt>d.
      def register_interceptor(interceptor)
        delivery_interceptor = (interceptor.is_a?(String) ? interceptor.constantize : interceptor)
        Mail.register_interceptor(delivery_interceptor)
      end

      def mailer_name
        @mailer_name ||= anonymous? ? "anonymous" : name.underscore
      end
      attr_writer :mailer_name
      alias :controller_path :mailer_name

      def default(value = nil)
        self.default_params = default_params.merge(value).freeze if value
        default_params
      end
      # Allows to set defaults through app configuration:
      #
      #    config.action_mailer.default_options = { from: "no-reply@example.org" }
      alias :default_options= :default

      # Receives a raw email, parses it into an email object, decodes it,
      # instantiates a new mailer, and passes the email object to the mailer
      # object's +receive+ method. If you want your mailer to be able to
      # process incoming messages, you'll need to implement a +receive+
      # method that accepts the raw email string as a parameter:
      #
      #   class MyMailer < ActionMailer::Base
      #     def receive(mail)
      #       ...
      #     end
      #   end
      def receive(raw_mail)
        ActiveSupport::Notifications.instrument("receive.action_mailer") do |payload|
          mail = Mail.new(raw_mail)
          set_payload_for_mail(payload, mail)
          new.receive(mail)
        end
      end

      # Wraps an email delivery inside of Active Support Notifications instrumentation. This
      # method is actually called by the <tt>Mail::Message</tt> object itself through a callback
      # when you call <tt>:deliver</tt> on the Mail::Message, calling +deliver_mail+ directly
      # and passing a Mail::Message will do nothing except tell the logger you sent the email.
      def deliver_mail(mail) #:nodoc:
        ActiveSupport::Notifications.instrument("deliver.action_mailer") do |payload|
          set_payload_for_mail(payload, mail)
          yield # Let Mail do the delivery actions
        end
      end

      def respond_to?(method, include_private = false) #:nodoc:
        super || action_methods.include?(method.to_s)
      end

    protected

      def set_payload_for_mail(payload, mail) #:nodoc:
        payload[:mailer]     = name
        payload[:message_id] = mail.message_id
        payload[:subject]    = mail.subject
        payload[:to]         = mail.to
        payload[:from]       = mail.from
        payload[:bcc]        = mail.bcc if mail.bcc.present?
        payload[:cc]         = mail.cc  if mail.cc.present?
        payload[:date]       = mail.date
        payload[:mail]       = mail.encoded
      end

      def method_missing(method_name, *args)
        if action_methods.include?(method_name.to_s)
          QueuedMessage.new(queue, self, method_name, *args)
        else
          super
        end
      end
    end

    attr_internal :message

    # Instantiate a new mailer object. If +method_name+ is not +nil+, the mailer
    # will be initialized according to the named method. If not, the mailer will
    # remain uninitialized (useful when you only need to invoke the "receive"
    # method, for instance).
    def initialize(method_name=nil, *args)
      super()
      @_mail_was_called = false
      @_message = Mail.new
      process(method_name, *args) if method_name
    end

    def process(*args) #:nodoc:
      lookup_context.skip_default_locale!

      super
      @_message = NullMail.new unless @_mail_was_called
    end

    class NullMail #:nodoc:
      def body; '' end

      def method_missing(*args)
        nil
      end
    end

    def mailer_name
      self.class.mailer_name
    end

    # Allows you to pass random and unusual headers to the new <tt>Mail::Message</tt> object
    # which will add them to itself.
    #
    #   headers['X-Special-Domain-Specific-Header'] = "SecretValue"
    #
    # You can also pass a hash into headers of header field names and values, which
    # will then be set on the Mail::Message object:
    #
    #   headers 'X-Special-Domain-Specific-Header' => "SecretValue",
    #           'In-Reply-To' => incoming.message_id
    #
    # The resulting Mail::Message will have the following in its header:
    #
    #   X-Special-Domain-Specific-Header: SecretValue
    def headers(args=nil)
      if args
        @_message.headers(args)
      else
        @_message
      end
    end

    # Allows you to add attachments to an email, like so:
    #
    #  mail.attachments['filename.jpg'] = File.read('/path/to/filename.jpg')
    #
    # If you do this, then Mail will take the file name and work out the mime type
    # set the Content-Type, Content-Disposition, Content-Transfer-Encoding and
    # base64 encode the contents of the attachment all for you.
    #
    # You can also specify overrides if you want by passing a hash instead of a string:
    #
    #  mail.attachments['filename.jpg'] = {mime_type: 'application/x-gzip',
    #                                      content: File.read('/path/to/filename.jpg')}
    #
    # If you want to use a different encoding than Base64, you can pass an encoding in,
    # but then it is up to you to pass in the content pre-encoded, and don't expect
    # Mail to know how to decode this data:
    #
    #  file_content = SpecialEncode(File.read('/path/to/filename.jpg'))
    #  mail.attachments['filename.jpg'] = {mime_type: 'application/x-gzip',
    #                                      encoding: 'SpecialEncoding',
    #                                      content: file_content }
    #
    # You can also search for specific attachments:
    #
    #  # By Filename
    #  mail.attachments['filename.jpg']   # => Mail::Part object or nil
    #
    #  # or by index
    #  mail.attachments[0]                # => Mail::Part (first attachment)
    #
    def attachments
      @_message.attachments
    end

    # The main method that creates the message and renders the email templates. There are
    # two ways to call this method, with a block, or without a block.
    #
    # Both methods accept a headers hash. This hash allows you to specify the most used headers
    # in an email message, these are:
    #
    # * <tt>:subject</tt> - The subject of the message, if this is omitted, Action Mailer will
    #   ask the Rails I18n class for a translated <tt>:subject</tt> in the scope of
    #   <tt>[mailer_scope, action_name]</tt> or if this is missing, will translate the
    #   humanized version of the <tt>action_name</tt>
    # * <tt>:to</tt> - Who the message is destined for, can be a string of addresses, or an array
    #   of addresses.
    # * <tt>:from</tt> - Who the message is from
    # * <tt>:cc</tt> - Who you would like to Carbon-Copy on this email, can be a string of addresses,
    #   or an array of addresses.
    # * <tt>:bcc</tt> - Who you would like to Blind-Carbon-Copy on this email, can be a string of
    #   addresses, or an array of addresses.
    # * <tt>:reply_to</tt> - Who to set the Reply-To header of the email to.
    # * <tt>:date</tt> - The date to say the email was sent on.
    #
    # You can set default values for any of the above headers (except :date) by using the <tt>default</tt>
    # class method:
    #
    #  class Notifier < ActionMailer::Base
    #    self.default from: 'no-reply@test.lindsaar.net',
    #                 bcc: 'email_logger@test.lindsaar.net',
    #                 reply_to: 'bounces@test.lindsaar.net'
    #  end
    #
    # If you need other headers not listed above, you can either pass them in
    # as part of the headers hash or use the <tt>headers['name'] = value</tt>
    # method.
    #
    # When a <tt>:return_path</tt> is specified as header, that value will be used as the 'envelope from'
    # address for the Mail message. Setting this is useful when you want delivery notifications
    # sent to a different address than the one in <tt>:from</tt>. Mail will actually use the
    # <tt>:return_path</tt> in preference to the <tt>:sender</tt> in preference to the <tt>:from</tt>
    # field for the 'envelope from' value.
    #
    # If you do not pass a block to the +mail+ method, it will find all templates in the
    # view paths using by default the mailer name and the method name that it is being
    # called from, it will then create parts for each of these templates intelligently,
    # making educated guesses on correct content type and sequence, and return a fully
    # prepared Mail::Message ready to call <tt>:deliver</tt> on to send.
    #
    # For example:
    #
    #   class Notifier < ActionMailer::Base
    #     default from: 'no-reply@test.lindsaar.net',
    #
    #     def welcome
    #       mail(to: 'mikel@test.lindsaar.net')
    #     end
    #   end
    #
    # Will look for all templates at "app/views/notifier" with name "welcome".
    # If no welcome template exists, it will raise an ActionView::MissingTemplate error.
    #
    # However, those can be customized:
    #
    #   mail(template_path: 'notifications', template_name: 'another')
    #
    # And now it will look for all templates at "app/views/notifications" with name "another".
    #
    # If you do pass a block, you can render specific templates of your choice:
    #
    #   mail(to: 'mikel@test.lindsaar.net') do |format|
    #     format.text
    #     format.html
    #   end
    #
    # You can even render text directly without using a template:
    #
    #   mail(to: 'mikel@test.lindsaar.net') do |format|
    #     format.text { render text: "Hello Mikel!" }
    #     format.html { render text: "<h1>Hello Mikel!</h1>" }
    #   end
    #
    # Which will render a <tt>multipart/alternative</tt> email with <tt>text/plain</tt> and
    # <tt>text/html</tt> parts.
    #
    # The block syntax also allows you to customize the part headers if desired:
    #
    #   mail(to: 'mikel@test.lindsaar.net') do |format|
    #     format.text(content_transfer_encoding: "base64")
    #     format.html
    #   end
    #
    def mail(headers={}, &block)
      @_mail_was_called = true
      m = @_message

      # At the beginning, do not consider class default for content_type
      content_type = headers[:content_type]

      # Call all the procs (if any)
      class_default = self.class.default
      default_values = class_default.merge(class_default) do |k,v|
        v.respond_to?(:to_proc) ? instance_eval(&v) : v
      end

      # Handle defaults
      headers = headers.reverse_merge(default_values)
      headers[:subject] ||= default_i18n_subject

      # Apply charset at the beginning so all fields are properly quoted
      m.charset = charset = headers[:charset]

      # Set configure delivery behavior
      wrap_delivery_behavior!(headers.delete(:delivery_method),headers.delete(:delivery_method_options))

      # Assign all headers except parts_order, content_type and body
      assignable = headers.except(:parts_order, :content_type, :body, :template_name, :template_path)
      assignable.each { |k, v| m[k] = v }

      # Render the templates and blocks
      responses = collect_responses(headers, &block)
      create_parts_from_responses(m, responses)

      # Setup content type, reapply charset and handle parts order
      m.content_type = set_content_type(m, content_type, headers[:content_type])
      m.charset      = charset

      if m.multipart?
        m.body.set_sort_order(headers[:parts_order])
        m.body.sort_parts!
      end

      m
    end

  protected

    def set_content_type(m, user_content_type, class_default)
      params = m.content_type_parameters || {}
      case
      when user_content_type.present?
        user_content_type
      when m.has_attachments?
        if m.attachments.detect { |a| a.inline? }
          ["multipart", "related", params]
        else
          ["multipart", "mixed", params]
        end
      when m.multipart?
        ["multipart", "alternative", params]
      else
        m.content_type || class_default
      end
    end

    # Translates the +subject+ using Rails I18n class under <tt>[mailer_scope, action_name]</tt> scope.
    # If it does not find a translation for the +subject+ under the specified scope it will default to a
    # humanized version of the <tt>action_name</tt>.
    def default_i18n_subject #:nodoc:
      mailer_scope = self.class.mailer_name.tr('/', '.')
      I18n.t(:subject, scope: [mailer_scope, action_name], default: action_name.humanize)
    end

    def collect_responses(headers) #:nodoc:
      responses = []

      if block_given?
        collector = ActionMailer::Collector.new(lookup_context) { render(action_name) }
        yield(collector)
        responses = collector.responses
      elsif headers[:body]
        responses << {
          body: headers.delete(:body),
          content_type: self.class.default[:content_type] || "text/plain"
        }
      else
        templates_path = headers.delete(:template_path) || self.class.mailer_name
        templates_name = headers.delete(:template_name) || action_name

        each_template(templates_path, templates_name) do |template|
          self.formats = template.formats

          responses << {
            body: render(template: template),
            content_type: template.type.to_s
          }
        end
      end

      responses
    end

    def each_template(paths, name, &block) #:nodoc:
      templates = lookup_context.find_all(name, Array(paths))
      if templates.empty?
        raise ActionView::MissingTemplate.new([paths], name, [paths], false, 'mailer')
      else
        templates.uniq { |t| t.formats }.each(&block)
      end
    end

    def create_parts_from_responses(m, responses) #:nodoc:
      if responses.size == 1 && !m.has_attachments?
        responses[0].each { |k,v| m[k] = v }
      elsif responses.size > 1 && m.has_attachments?
        container = Mail::Part.new
        container.content_type = "multipart/alternative"
        responses.each { |r| insert_part(container, r, m.charset) }
        m.add_part(container)
      else
        responses.each { |r| insert_part(m, r, m.charset) }
      end
    end

    def insert_part(container, response, charset) #:nodoc:
      response[:charset] ||= charset
      part = Mail::Part.new(response)
      container.add_part(part)
    end

    ActiveSupport.run_load_hooks(:action_mailer, self)
  end
end