Add audio uploads (#11123)

* Add audio uploads

Fix #4827

Accept uploads of OGG, WAV, FLAC, OPUS and MP3 files, and converts
them to OGG. Media attachments get a new `audio` type. In the UI,
audio uploads are displayed identically to video uploads.

* Improve code style

1 files changed, 43 insertions, 21 deletions

diff --git a/app/models/media_attachment.rb b/app/models/media_attachment.rb
index ab794faa0..5ca218411 100644
--- a/app/models/media_attachment.rb
+++ b/app/models/media_attachment.rb
@@ -24,14 +24,16 @@
 class MediaAttachment < ApplicationRecord
   self.inheritance_column = nil
 
-  enum type: [:image, :gifv, :video, :unknown]
+  enum type: [:image, :gifv, :video, :unknown, :audio]
 
   IMAGE_FILE_EXTENSIONS = ['.jpg', '.jpeg', '.png', '.gif', '.webp'].freeze
   VIDEO_FILE_EXTENSIONS = ['.webm', '.mp4', '.m4v', '.mov'].freeze
+  AUDIO_FILE_EXTENSIONS = ['.ogg', '.oga', '.mp3', '.wav', '.flac', '.opus'].freeze
 
   IMAGE_MIME_TYPES             = ['image/jpeg', 'image/png', 'image/gif', 'image/webp'].freeze
   VIDEO_MIME_TYPES             = ['video/webm', 'video/mp4', 'video/quicktime'].freeze
   VIDEO_CONVERTIBLE_MIME_TYPES = ['video/webm', 'video/quicktime'].freeze
+  AUDIO_MIME_TYPES             = ['audio/wave', 'audio/wav', 'audio/x-wav', 'audio/x-pn-wave', 'audio/ogg', 'audio/mpeg', 'audio/webm', 'audio/flac'].freeze
 
   BLURHASH_OPTIONS = {
     x_comp: 4,
@@ -65,6 +67,13 @@ class MediaAttachment < ApplicationRecord
     },
   }.freeze
 
+  AUDIO_STYLES = {
+    original: {
+      format: 'ogg',
+      convert_options: {},
+    },
+  }.freeze
+
   VIDEO_FORMAT = {
     format: 'mp4',
     convert_options: {
@@ -83,6 +92,11 @@ class MediaAttachment < ApplicationRecord
     },
   }.freeze
 
+  VIDEO_CONVERTED_STYLES = {
+    small: VIDEO_STYLES[:small],
+    original: VIDEO_FORMAT,
+  }.freeze
+
   IMAGE_LIMIT = 8.megabytes
   VIDEO_LIMIT = 40.megabytes
 
@@ -95,9 +109,9 @@ class MediaAttachment < ApplicationRecord
                     processors: ->(f) { file_processors f },
                     convert_options: { all: '-quality 90 -strip' }
 
-  validates_attachment_content_type :file, content_type: IMAGE_MIME_TYPES + VIDEO_MIME_TYPES
-  validates_attachment_size :file, less_than: IMAGE_LIMIT, unless: :video_or_gifv?
-  validates_attachment_size :file, less_than: VIDEO_LIMIT, if: :video_or_gifv?
+  validates_attachment_content_type :file, content_type: IMAGE_MIME_TYPES + VIDEO_MIME_TYPES + AUDIO_MIME_TYPES
+  validates_attachment_size :file, less_than: IMAGE_LIMIT, unless: :larger_media_format?
+  validates_attachment_size :file, less_than: VIDEO_LIMIT, if: :larger_media_format?
   remotable_attachment :file, VIDEO_LIMIT
 
   include Attachmentable
@@ -120,8 +134,12 @@ class MediaAttachment < ApplicationRecord
     file.blank? && remote_url.present?
   end
 
-  def video_or_gifv?
-    video? || gifv?
+  def larger_media_format?
+    video? || gifv? || audio?
+  end
+
+  def audio_or_video?
+    audio? || video?
   end
 
   def to_param
@@ -156,28 +174,24 @@ class MediaAttachment < ApplicationRecord
     private
 
     def file_styles(f)
-      if f.instance.file_content_type == 'image/gif'
-        {
-          small: IMAGE_STYLES[:small],
-          original: VIDEO_FORMAT,
-        }
-      elsif IMAGE_MIME_TYPES.include? f.instance.file_content_type
+      if f.instance.file_content_type == 'image/gif' || VIDEO_CONVERTIBLE_MIME_TYPES.include?(f.instance.file_content_type)
+        VIDEO_CONVERTED_STYLES
+      elsif IMAGE_MIME_TYPES.include?(f.instance.file_content_type)
         IMAGE_STYLES
-      elsif VIDEO_CONVERTIBLE_MIME_TYPES.include?(f.instance.file_content_type)
-        {
-          small: VIDEO_STYLES[:small],
-          original: VIDEO_FORMAT,
-        }
-      else
+      elsif VIDEO_MIME_TYPES.include?(f.instance.file_content_type)
         VIDEO_STYLES
+      else
+        AUDIO_STYLES
       end
     end
 
     def file_processors(f)
       if f.file_content_type == 'image/gif'
         [:gif_transcoder, :blurhash_transcoder]
-      elsif VIDEO_MIME_TYPES.include? f.file_content_type
+      elsif VIDEO_MIME_TYPES.include?(f.file_content_type)
         [:video_transcoder, :blurhash_transcoder]
+      elsif AUDIO_MIME_TYPES.include?(f.file_content_type)
+        [:transcoder]
       else
         [:lazy_thumbnail, :blurhash_transcoder]
       end
@@ -202,7 +216,15 @@ class MediaAttachment < ApplicationRecord
   end
 
   def set_type_and_extension
-    self.type = VIDEO_MIME_TYPES.include?(file_content_type) ? :video : :image
+    self.type = begin
+      if VIDEO_MIME_TYPES.include?(file_content_type)
+        :video
+      elsif AUDIO_MIME_TYPES.include?(file_content_type)
+        :audio
+      else
+        :image
+      end
+    end
   end
 
   def set_meta
@@ -245,7 +267,7 @@ class MediaAttachment < ApplicationRecord
       frame_rate: movie.frame_rate,
       duration: movie.duration,
       bitrate: movie.bitrate,
-    }
+    }.compact
   end
 
   def reset_parent_cache