3 files changed, 30 insertions, 1 deletions
diff --git a/actionmailer/CHANGELOG.md b/actionmailer/CHANGELOG.md
index 97ff62fa87..b343e8b373 100644
--- a/actionmailer/CHANGELOG.md
+++ b/actionmailer/CHANGELOG.md
@@ -1,3 +1,12 @@
+*   Add `config.action_mailer.preview_enabled` configuration option.
+
+    This config option can be used to enable the mail preview in environments
+    other than development (such as staging).
+
+    Defaults to `true` in development and false elsewhere.
+
+    *Leonard Garvey*
+
 *   Allow preview interceptors to be registered through
     `config.action_mailer.preview_interceptors`.
 
diff --git a/actionmailer/lib/action_mailer/preview.rb b/actionmailer/lib/action_mailer/preview.rb
index 33a9faa7e7..f27fab1a0d 100644
--- a/actionmailer/lib/action_mailer/preview.rb
+++ b/actionmailer/lib/action_mailer/preview.rb
@@ -11,6 +11,14 @@ module ActionMailer
       #
       mattr_accessor :preview_path, instance_writer: false
 
+      # Enable or disable mailer previews through app configuration:
+      #
+      #     config.action_mailer.preview_enabled = true
+      #
+      # Defaults to true for development environment
+      #
+      mattr_accessor :preview_enabled, instance_writer: false
+
       # :nodoc:
       mattr_accessor :preview_interceptors, instance_writer: false
       self.preview_interceptors = []
@@ -94,6 +102,10 @@ module ActionMailer
           Base.preview_path
         end
 
+        def preview_enabled #:nodoc:
+          Base.preview_enabled
+        end
+
         def inform_preview_interceptors(message) #:nodoc:
           Base.preview_interceptors.each do |interceptor|
             interceptor.previewing_email(message)
diff --git a/actionmailer/lib/action_mailer/railtie.rb b/actionmailer/lib/action_mailer/railtie.rb
index 671551fa53..409a7a897a 100644
--- a/actionmailer/lib/action_mailer/railtie.rb
+++ b/actionmailer/lib/action_mailer/railtie.rb
@@ -18,8 +18,9 @@ module ActionMailer
       options.assets_dir      ||= paths["public"].first
       options.javascripts_dir ||= paths["public/javascripts"].first
       options.stylesheets_dir ||= paths["public/stylesheets"].first
+      options.preview_enabled = Rails.env.development? if options.preview_enabled.nil?
 
-      if Rails.env.development?
+      if options.preview_enabled
         options.preview_path  ||= defined?(Rails.root) ? "#{Rails.root}/test/mailers/previews" : nil
       end
 
@@ -37,6 +38,13 @@ module ActionMailer
         register_observers(options.delete(:observers))
 
         options.each { |k,v| send("#{k}=", v) }
+
+        if options.preview_enabled
+          app.routes.append do
+            get '/rails/mailers'         => "rails/mailers#index"
+            get '/rails/mailers/*path'   => "rails/mailers#preview"
+          end
+        end
       end
     end