Merge pull request rails#49863 from yogeshjain999/service-as-proc

Allow accepting `service` as a proc in `has_one_attached` and `has_many_attached`

Author: jonathanhefner

activestorage/CHANGELOG.md

@@ -1,2 +1,5 @@
+*   Allow accepting `service` as a proc as well in `has_one_attached` and `has_many_attached`.
+
+    *Yogesh Khater*
 
 Please check [7-1-stable](https://github.com/rails/rails/blob/7-1-stable/activestorage/CHANGELOG.md) for previous changes.

activestorage/app/models/active_storage/blob.rb

@@ -17,10 +17,6 @@
 # update a blob's metadata on a subsequent pass, but you should not update the key or change the uploaded file.
 # If you need to create a derivative or otherwise change the blob, simply create a new blob and purge the old one.
 class ActiveStorage::Blob < ActiveStorage::Record
-  include Analyzable
-  include Identifiable
-  include Representable
-
   self.table_name = "active_storage_blobs"
 
   MINIMUM_TOKEN_LENGTH = 28
@@ -155,8 +151,28 @@ def compose(blobs, filename:, content_type: nil, metadata: nil)
         combined_blob.save!
       end
     end
+
+    def validate_service_configuration(service_name, model_class, association_name) # :nodoc:
+      if service_name
+        services.fetch(service_name) do
+          raise ArgumentError, "Cannot configure service #{service_name.inspect} for #{model_class}##{association_name}"
+        end
+      else
+        validate_global_service_configuration
+      end
+    end
+
+    def validate_global_service_configuration # :nodoc:
+      if connected? && table_exists? && Rails.configuration.active_storage.service.nil?
+        raise RuntimeError, "Missing Active Storage service name. Specify Active Storage service name for config.active_storage.service in config/environments/#{Rails.env}.rb"
+      end
+    end
   end
 
+  include Analyzable
+  include Identifiable
+  include Representable
+
   # Returns a signed ID for this blob that's suitable for reference on the client-side without fear of tampering.
   def signed_id(purpose: :blob_id, expires_in: nil, expires_at: nil)
     super

activestorage/lib/active_storage/attached/changes/create_one.rb

@@ -118,7 +118,12 @@ def find_or_build_blob
       end
 
       def attachment_service_name
-        record.attachment_reflections[name].options[:service_name]
+        service_name = record.attachment_reflections[name].options[:service_name]
+        if service_name.is_a?(Proc)
+          service_name = service_name.call(record)
+          ActiveStorage::Blob.validate_service_configuration(service_name, record.class, name)
+        end
+        service_name
       end
   end
 end

activestorage/lib/active_storage/attached/model.rb

@@ -78,12 +78,18 @@ module Attached::Model
       # (i.e. destroyed) whenever the record is destroyed.
       #
       # If you need the attachment to use a service which differs from the globally configured one,
-      # pass the +:service+ option. For instance:
+      # pass the +:service+ option. For example:
       #
       #   class User < ActiveRecord::Base
       #     has_one_attached :avatar, service: :s3
       #   end
       #
+      # +:service+ can also be specified as a proc, and it will be called with the model instance:
+      #
+      #   class User < ActiveRecord::Base
+      #     has_one_attached :avatar, service: ->(user) { user.in_europe_region? ? :s3_europe : :s3_usa }
+      #   end
+      #
       # If you need to enable +strict_loading+ to prevent lazy loading of attachment,
       # pass the +:strict_loading+ option. You can do:
       #
@@ -92,7 +98,7 @@ module Attached::Model
       #   end
       #
       def has_one_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
-        validate_service_configuration(name, service)
+        ActiveStorage::Blob.validate_service_configuration(service, self, name) unless service.is_a?(Proc)
 
         generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
           # frozen_string_literal: true
@@ -163,12 +169,18 @@ def #{name}=(attachable)
       # (i.e. destroyed) whenever the record is destroyed.
       #
       # If you need the attachment to use a service which differs from the globally configured one,
-      # pass the +:service+ option. For instance:
+      # pass the +:service+ option. For example:
       #
       #   class Gallery < ActiveRecord::Base
       #     has_many_attached :photos, service: :s3
       #   end
       #
+      # +:service+ can also be specified as a proc, and it will be called with the model instance:
+      #
+      #   class Gallery < ActiveRecord::Base
+      #     has_many_attached :photos, service: ->(gallery) { gallery.personal? ? :personal_s3 : :s3 }
+      #   end
+      #
       # If you need to enable +strict_loading+ to prevent lazy loading of attachments,
       # pass the +:strict_loading+ option. You can do:
       #
@@ -177,7 +189,7 @@ def #{name}=(attachable)
       #   end
       #
       def has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
-        validate_service_configuration(name, service)
+        ActiveStorage::Blob.validate_service_configuration(service, self, name) unless service.is_a?(Proc)
 
         generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
           # frozen_string_literal: true
@@ -223,23 +235,6 @@ def #{name}=(attachables)
         yield reflection if block_given?
         ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
       end
-
-      private
-        def validate_service_configuration(association_name, service)
-          if service.present?
-            ActiveStorage::Blob.services.fetch(service) do
-              raise ArgumentError, "Cannot configure service :#{service} for #{name}##{association_name}"
-            end
-          else
-            validate_global_service_configuration
-          end
-        end
-
-        def validate_global_service_configuration
-          if connected? && ActiveStorage::Blob.table_exists? && Rails.configuration.active_storage.service.nil?
-            raise RuntimeError, "Missing Active Storage service name. Specify Active Storage service name for config.active_storage.service in config/environments/#{Rails.env}.rb"
-          end
-        end
     end
 
     def attachment_changes # :nodoc:

activestorage/test/models/attached/many_test.rb

@@ -772,6 +772,23 @@ def highlights
     end
   end
 
+  test "attaching a new blob from an uploaded file with a service defined at runtime" do
+    extra_attached = Class.new(User) do
+      def self.name; superclass.name; end
+
+      has_many_attached :signatures, service: ->(user) { "disk_#{user.mirror_region}" }
+
+      def mirror_region
+        :mirror_2
+      end
+    end
+
+    @user = @user.becomes(extra_attached)
+
+    @user.signatures.attach fixture_file_upload("cropped.pdf")
+    assert_equal :disk_mirror_2, @user.signatures.first.service.name
+  end
+
   test "attaching blobs to a persisted, unchanged, and valid record, returns the attachments" do
     @user.highlights.attach create_blob(filename: "racecar.jpg")
     return_value = @user.highlights.attach create_blob(filename: "funky.jpg"), create_blob(filename: "town.jpg")
@@ -823,6 +840,20 @@ def highlights
     assert_match(/Cannot configure service :unknown for User#featured_photos/, error.message)
   end
 
+  test "raises error when misconfigured service is defined at runtime" do
+    extra_attached = Class.new(User) do
+      def self.name; superclass.name; end
+
+      has_many_attached :featured_vlogs, service: ->(*) { :unknown }
+    end
+
+    @user = @user.becomes(extra_attached)
+
+    assert_raises match: /Cannot configure service :unknown for .+#featured_vlog/ do
+      @user.featured_vlogs.attach fixture_file_upload("video.mp4")
+    end
+  end
+
   test "creating variation by variation name" do
     assert_no_enqueued_jobs only: ActiveStorage::TransformJob do
       @user.highlights_with_variants.attach fixture_file_upload("racecar.jpg")

activestorage/test/models/attached/one_test.rb

@@ -743,6 +743,23 @@ def avatar
     end
   end
 
+  test "attaching a new blob from an uploaded file with a service defined at runtime" do
+    extra_attached = Class.new(User) do
+      def self.name; superclass.name; end
+
+      has_one_attached :signature, service: ->(user) { "disk_#{user.mirror_region}" }
+
+      def mirror_region
+        :mirror_2
+      end
+    end
+
+    @user = @user.becomes(extra_attached)
+
+    @user.signature.attach fixture_file_upload("cropped.pdf")
+    assert_equal :disk_mirror_2, @user.signature.service.name
+  end
+
   test "raises error when global service configuration is missing" do
     Rails.configuration.active_storage.stub(:service, nil) do
       error = assert_raises RuntimeError do
@@ -765,6 +782,20 @@ def avatar
     assert_match(/Cannot configure service :unknown for User#featured_photo/, error.message)
   end
 
+  test "raises error when misconfigured service is defined at runtime" do
+    extra_attached = Class.new(User) do
+      def self.name; superclass.name; end
+
+      has_one_attached :featured_vlog, service: ->(*) { :unknown }
+    end
+
+    @user = @user.becomes(extra_attached)
+
+    assert_raises match: /Cannot configure service :unknown for .+#featured_vlog/ do
+      @user.featured_vlog.attach fixture_file_upload("video.mp4")
+    end
+  end
+
   test "creating variation by variation name" do
     @user.avatar_with_variants.attach fixture_file_upload("racecar.jpg")
     variant = @user.avatar_with_variants.variant(:thumb).processed