Use Active Storage to handle cached attachments

This fixes a few issues we've had for years.

First, when attaching an image and then sending a form with validation
errors, the image preview would not be rendered when the form was
displayed once again. Now it's rendered as expected.

Second, when attaching an image, removing it, and attaching a new
one, browsers were displaying the image preview of the first one. That's
because Paperclip generated the same URL from both files (as they both
had the same hash data and prefix). Browsers usually cache images and
render the cached image when getting the same URL.

Since now we're storing each image in a different Blob, the images have
different URLs and so the preview of the second one is correctly
displayed.

Finally, when users downloaded a document, they were getting files with
a very long hexadecimal hash as filename. Now they get the original
filename.

app/controllers/direct_uploads_controller.rb

@@ -15,9 +15,9 @@ class DirectUploadsController < ApplicationController
       @direct_upload.relation.set_cached_attachment_from_attachment
 
       render json: { cached_attachment: @direct_upload.relation.cached_attachment,
-                     filename: @direct_upload.relation.attachment.original_filename,
+                     filename: @direct_upload.relation.storage_attachment.filename.to_s,
                      destroy_link: render_destroy_upload_link(@direct_upload),
-                     attachment_url: @direct_upload.relation.attachment.url }
+                     attachment_url: polymorphic_path(@direct_upload.relation.storage_attachment) }
     else
       render json: { errors: @direct_upload.errors[:attachment].join(", ") },
              status: :unprocessable_entity

app/models/concerns/attachable.rb

@@ -9,14 +9,10 @@ module Attachable
     # Paperclip do not allow to use Procs on valiations definition
     do_not_validate_attachment_file_type :attachment
     validate :attachment_presence
-    validate :validate_attachment_content_type,         if: -> { attachment.present? }
-    validate :validate_attachment_size,                 if: -> { attachment.present? }
+    validate :validate_attachment_content_type,         if: -> { storage_attachment.attached? }
+    validate :validate_attachment_size,                 if: -> { storage_attachment.attached? }
 
-    before_save :set_attachment_from_cached_attachment, if: -> { cached_attachment.present? }
-
-    Paperclip.interpolates :prefix do |attachment, style|
-      attachment.instance.prefix(attachment, style)
-    end
+    before_validation :set_attachment_from_cached_attachment, if: -> { cached_attachment.present? }
   end
 
   def association_class
@@ -26,29 +22,37 @@ module Attachable
   end
 
   def set_cached_attachment_from_attachment
-    self.cached_attachment = if filesystem_storage?
-                               attachment.path
-                             else
-                               attachment.url
-                             end
+    self.cached_attachment = storage_attachment.signed_id
   end
 
   def set_attachment_from_cached_attachment
+    self.storage_attachment = cached_attachment
+
     if filesystem_storage?
-      File.open(cached_attachment) { |file| self.attachment = file }
+      File.open(file_path) do |file|
+        self.paperclip_attachment = file
+      end
     else
-      self.attachment = URI.parse(cached_attachment).open
+      self.paperclip_attachment = URI.parse(cached_attachment).open
     end
   end
 
-  def prefix(attachment, _style)
-    if attachment.instance.persisted?
-      ":attachment/:id_partition"
+  def attachment_content_type
+    storage_attachment.blob.content_type if storage_attachment.attached?
+  end
+
+  def attachment_file_size
+    if storage_attachment.attached?
+      storage_attachment.blob.byte_size
     else
-      "cached_attachments/user/#{attachment.instance.user_id}"
+      0
     end
   end
 
+  def file_path
+    ActiveStorage::Blob.service.path_for(storage_attachment.blob.key)
+  end
+
   private
 
     def filesystem_storage?
@@ -73,7 +77,7 @@ module Attachable
     end
 
     def attachment_presence
-      if attachment.blank? && cached_attachment.blank?
+      unless storage_attachment.attached?
         errors.add(:attachment, I18n.t("errors.messages.blank"))
       end
     end

app/models/concerns/has_attachment.rb

@@ -5,18 +5,21 @@ module HasAttachment
     def has_attachment(attribute, paperclip_options = {})
       has_one_attached :"storage_#{attribute}"
 
-      has_attached_file attribute, paperclip_options
-      alias_method :"paperclip_#{attribute}=", :"#{attribute}="
-
-      define_method :"#{attribute}=" do |file|
-        if file.is_a?(IO) || file.is_a?(Tempfile) && !file.is_a?(Ckeditor::Http::QqFile)
+      define_method :"storage_#{attribute}=" do |file|
+        if file.is_a?(IO)
           send(:"storage_#{attribute}").attach(io: file, filename: File.basename(file.path))
         elsif file.nil?
           send(:"storage_#{attribute}").detach
         else
           send(:"storage_#{attribute}").attach(file)
         end
+      end
 
+      has_attached_file attribute, paperclip_options
+      alias_method :"paperclip_#{attribute}=", :"#{attribute}="
+
+      define_method :"#{attribute}=" do |file|
+        send(:"storage_#{attribute}=", file)
         send(:"paperclip_#{attribute}=", file)
       end
     end

app/models/direct_upload.rb

@@ -34,7 +34,7 @@ class DirectUpload
   end
 
   def save_attachment
-    @relation.attachment.save
+    @relation.storage_attachment.blob.save!
   end
 
   def persisted?
@@ -53,7 +53,7 @@ class DirectUpload
 
     def relation_attributtes
       {
-        paperclip_attachment: @attachment,
+        storage_attachment: @attachment,
         cached_attachment: @cached_attachment,
         user: @user
       }

app/models/document.rb

@@ -1,7 +1,7 @@
 class Document < ApplicationRecord
   include Attachable
 
-  has_attachment :attachment, url: "/system/:class/:prefix/:style/:hash.:extension",
+  has_attachment :attachment, url: "/system/:class/:attachment/:id_partition/:style/:hash.:extension",
                               hash_data: ":class/:style/:custom_hash_data",
                               use_timestamp: false,
                               hash_secret: Rails.application.secrets.secret_key_base

app/models/image.rb

@@ -6,7 +6,7 @@ class Image < ApplicationRecord
                                 medium: "300x300#",
                                 thumb: "140x245#"
                               },
-                              url: "/system/:class/:prefix/:style/:hash.:extension",
+                              url: "/system/:class/:attachment/:id_partition/:style/:hash.:extension",
                               hash_data: ":class/:style",
                               use_timestamp: false,
                               hash_secret: Rails.application.secrets.secret_key_base
@@ -27,7 +27,7 @@ class Image < ApplicationRecord
   validates :user_id, presence: true
   validates :imageable_id, presence: true,         if: -> { persisted? }
   validates :imageable_type, presence: true,       if: -> { persisted? }
-  validate :validate_image_dimensions, if: -> { attachment.present? && attachment.dirty? }
+  validate :validate_image_dimensions, if: -> { storage_attachment.attached? && storage_attachment.new_record? }
 
   def self.max_file_size
     Setting["uploads.images.max_size"].to_i
@@ -68,14 +68,17 @@ class Image < ApplicationRecord
     end
 
     def validate_image_dimensions
-      if attachment_of_valid_content_type?
+      if accepted_content_types.include?(attachment_content_type)
         return true if imageable_class == Widget::Card
 
-        dimensions = Paperclip::Geometry.from_file(attachment.queued_for_write[:original].path)
+        storage_attachment.analyze unless storage_attachment.analyzed?
+
+        width = storage_attachment.metadata[:width]
+        height = storage_attachment.metadata[:height]
         min_width = Setting["uploads.images.min_width"].to_i
         min_height = Setting["uploads.images.min_height"].to_i
-        errors.add(:attachment, :min_image_width, required_min_width: min_width) if dimensions.width < min_width
-        errors.add(:attachment, :min_image_height, required_min_height: min_height) if dimensions.height < min_height
+        errors.add(:attachment, :min_image_width, required_min_width: min_width) if width < min_width
+        errors.add(:attachment, :min_image_height, required_min_height: min_height) if height < min_height
       end
     end
 
@@ -93,8 +96,4 @@ class Image < ApplicationRecord
         end
       end
     end
-
-    def attachment_of_valid_content_type?
-      attachment.present? && accepted_content_types.include?(attachment_content_type)
-    end
 end