Return errors as json objects instead of strings

app/controllers/albums_controller.rb

@@ -29,20 +29,20 @@ def create
     if @album.save
       render json: transform_album_for_json(@album), status: :created
     else
-      render json: @album.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@album), status: :unprocessable_content
     end
   end
 
   def update
     if @album.update(transformed_attributes)
       render json: transform_album_for_json(@album), status: :ok
     else
-      render json: @album.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@album), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @album.errors, status: :unprocessable_content unless @album.destroy
+    render json: transform_errors_for_json(@album), status: :unprocessable_content unless @album.destroy
   end
 
   def destroy_empty
@@ -51,7 +51,7 @@ def destroy_empty
   end
 
   def merge
-    render json: @album.errors, status: :unprocessable_content unless @album.merge(Album.find(params.expect(:source_id)))
+    render json: transform_errors_for_json(@album), status: :unprocessable_content unless @album.merge(Album.find(params.expect(:source_id)))
   end
 
   private

app/controllers/application_controller.rb

@@ -2,6 +2,9 @@ class ApplicationController < ActionController::API
   include Pundit::Authorization
   include ActionController::HttpAuthentication::Token::ControllerMethods
 
+  # This map only includes the type of validation errors that we could have inside the app
+  ERROR_TYPE_MAP = { blank: :required, taken: :not_unique }.freeze
+
   etag { params[:page] }
   etag { params[:per_page] }
 
@@ -42,6 +45,15 @@ def stale?(scope:, **)
     super(etag:, **)
   end
 
+  def transform_error_for_json(error)
+    { attribute: error.attribute, type: ERROR_TYPE_MAP[error.type] }
+  end
+
+  # This method expects an instance of a class that includes `ActiveModel::Errors`
+  def transform_errors_for_json(object)
+    { errors: object.errors.errors.map { transform_error_for_json(it) } }
+  end
+
   private
 
   def authenticate_user
@@ -52,16 +64,11 @@ def authenticate_user
   end
 
   def user_not_authorized(exc)
-    policy_name = exc.policy.class.to_s.underscore
-
     status = current_user.present? ? :forbidden : :unauthorized
-    render json: { status => [I18n.t("#{policy_name}.#{exc.query}",
-                                     scope: 'pundit',
-                                     default: :default)] },
-           status:
+    render json: { errors: [{ policy: exc.policy.class.to_s.underscore, type: status, action: exc.query }] }, status:
   end
 
   def model_not_found(exc)
-    render json: { not_found: ["#{exc.model.pluralize.downcase}.not-found"] }, status: :not_found
+    render json: { errors: [{ model: exc.model.downcase, type: :not_found }] }, status: :not_found
   end
 end

app/controllers/artists_controller.rb

@@ -26,20 +26,20 @@ def create
     if @artist.save
       render json: transform_artist_for_json(@artist), status: :created
     else
-      render json: @artist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@artist), status: :unprocessable_content
     end
   end
 
   def update
     if @artist.update(transformed_attributes)
       render json: transform_artist_for_json(@artist), status: :ok
     else
-      render json: @artist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@artist), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @artist.errors, status: :unprocessable_content unless @artist.destroy
+    render json: transform_errors_for_json(@artist), status: :unprocessable_content unless @artist.destroy
   end
 
   def destroy_empty
@@ -51,7 +51,7 @@ def destroy_empty
   end
 
   def merge
-    render json: @artist.errors, status: :unprocessable_content unless @artist.merge(Artist.find(params.expect(:source_id)))
+    render json: transform_errors_for_json(@artist), status: :unprocessable_content unless @artist.merge(Artist.find(params.expect(:source_id)))
   end
 
   private

app/controllers/auth_tokens_controller.rb

@@ -19,8 +19,7 @@ def create
 
     user = User.find_by(name: params[:name])
     unless user.try(:authenticate, params[:password])
-      render json: { unauthorized: [I18n.t('auth_tokens.create.wrong_credentials')] },
-             status: :unauthorized
+      render json: { errors: [{ attribute: :base, type: :wrong_credentials }] }, status: :unauthorized
       return
     end
 
@@ -33,12 +32,12 @@ def create
     if @auth_token.save
       render json: transform_auth_token_for_json_with_token(@auth_token), status: :created
     else
-      render json: @auth_token.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@auth_token), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @auth_token.errors, status: :unprocessable_content unless @auth_token.destroy
+    render json: transform_errors_for_json(@auth_token), status: :unprocessable_content unless @auth_token.destroy
   end
 
   private

app/controllers/codec_conversions_controller.rb

@@ -23,20 +23,20 @@ def create
     if @codec_conversion.save
       render json: transform_codec_conversion_for_json(@codec_conversion), status: :created
     else
-      render json: @codec_conversion.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec_conversion), status: :unprocessable_content
     end
   end
 
   def update
     if @codec_conversion.update(permitted_attributes(CodecConversion))
       render json: transform_codec_conversion_for_json(@codec_conversion), status: :ok
     else
-      render json: @codec_conversion.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec_conversion), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @codec_conversion.errors, status: :unprocessable_content unless @codec_conversion.destroy
+    render json: transform_errors_for_json(@codec_conversion), status: :unprocessable_content unless @codec_conversion.destroy
   end
 
   private

app/controllers/codecs_controller.rb

@@ -21,20 +21,20 @@ def create
     if @codec.save
       render json: transform_codec_for_json(@codec), status: :created
     else
-      render json: @codec.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec), status: :unprocessable_content
     end
   end
 
   def update
     if @codec.update(permitted_attributes(@codec))
       render json: transform_codec_for_json(@codec), status: :ok
     else
-      render json: @codec.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@codec), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @codec.errors, status: :unprocessable_content unless @codec.destroy
+    render json: transform_errors_for_json(@codec), status: :unprocessable_content unless @codec.destroy
   end
 
   private

app/controllers/cover_filenames_controller.rb

@@ -21,12 +21,12 @@ def create
     if @cover_filename.save
       render json: transform_cover_filename_for_json(@cover_filename), status: :created
     else
-      render json: @cover_filename.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@cover_filename), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @cover_filename.errors, status: :unprocessable_content unless @cover_filename.destroy
+    render json: transform_errors_for_json(@cover_filename), status: :unprocessable_content unless @cover_filename.destroy
   end
 
   private

app/controllers/genres_controller.rb

@@ -21,20 +21,20 @@ def create
     if @genre.save
       render json: transform_genre_for_json(@genre), status: :created
     else
-      render json: @genre.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@genre), status: :unprocessable_content
     end
   end
 
   def update
     if @genre.update(permitted_attributes(@genre))
       render json: transform_genre_for_json(@genre), status: :ok
     else
-      render json: @genre.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@genre), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @genre.errors, status: :unprocessable_content unless @genre.destroy
+    render json: transform_errors_for_json(@genre), status: :unprocessable_content unless @genre.destroy
   end
 
   def destroy_empty

app/controllers/image_types_controller.rb

@@ -21,20 +21,20 @@ def create
     if @image_type.save
       render json: transform_image_type_for_json(@image_type), status: :created
     else
-      render json: @image_type.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@image_type), status: :unprocessable_content
     end
   end
 
   def update
     if @image_type.update(permitted_attributes(@image_type))
       render json: transform_image_type_for_json(@image_type), status: :ok
     else
-      render json: @image_type.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@image_type), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @image_type.errors, status: :unprocessable_content unless @image_type.destroy
+    render json: transform_errors_for_json(@image_type), status: :unprocessable_content unless @image_type.destroy
   end
 
   private

app/controllers/labels_controller.rb

@@ -21,20 +21,20 @@ def create
     if @label.save
       render json: transform_label_for_json(@label), status: :created
     else
-      render json: @label.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@label), status: :unprocessable_content
     end
   end
 
   def update
     if @label.update(permitted_attributes(@label))
       render json: transform_label_for_json(@label), status: :ok
     else
-      render json: @label.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@label), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @label.errors, status: :unprocessable_content unless @label.destroy
+    render json: transform_errors_for_json(@label), status: :unprocessable_content unless @label.destroy
   end
 
   def destroy_empty

app/controllers/locations_controller.rb

@@ -21,12 +21,12 @@ def create
     if @location.save
       render json: transform_location_for_json(@location), status: :created
     else
-      render json: @location.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@location), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @location.errors, status: :unprocessable_content unless @location.destroy
+    render json: transform_errors_for_json(@location), status: :unprocessable_content unless @location.destroy
   end
 
   private

app/controllers/playlists_controller.rb

@@ -21,26 +21,26 @@ def create
     if @playlist.save
       render json: transform_playlist_for_json(@playlist), status: :created
     else
-      render json: @playlist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@playlist), status: :unprocessable_content
     end
   end
 
   def update
     if @playlist.update(permitted_attributes(@playlist))
       render json: transform_playlist_for_json(@playlist), status: :ok
     else
-      render json: @playlist.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@playlist), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @playlist.errors, status: :unprocessable_content unless @playlist.destroy
+    render json: transform_errors_for_json(@playlist), status: :unprocessable_content unless @playlist.destroy
   end
 
   def add_item
     @item = @playlist.items.create(permitted_attributes(@playlist))
 
-    render json: @item.errors, status: :unprocessable_content unless @item.save
+    render json: transform_errors_for_json(@item), status: :unprocessable_content unless @item.save
   end
 
   private

app/controllers/plays_controller.rb

@@ -20,7 +20,7 @@ def create
     if @play.save
       render json: transform_play_for_json(@play), status: :created
     else
-      render json: @play.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@play), status: :unprocessable_content
     end
   end
 

app/controllers/tracks_controller.rb

@@ -26,20 +26,20 @@ def create
     if @track.save
       render json: transform_track_for_json(@track), status: :created
     else
-      render json: @track.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@track), status: :unprocessable_content
     end
   end
 
   def update
     if @track.update(transformed_attributes)
       render json: transform_track_for_json(@track), status: :ok
     else
-      render json: @track.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@track), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @track.errors, status: :unprocessable_content unless @track.destroy
+    render json: transform_errors_for_json(@track), status: :unprocessable_content unless @track.destroy
   end
 
   def destroy_empty

app/controllers/users_controller.rb

@@ -21,28 +21,27 @@ def create
     if @user.save
       render json: transform_user_for_json(@user), status: :created
     else
-      render json: @user.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@user), status: :unprocessable_content
     end
   end
 
   def update
     if @user == current_user &&
        params[:user][:password].present? &&
        !@user.try(:authenticate, params[:user][:current_password])
-      render json: { unauthorized: [I18n.t('users.current_password_is_incorrect')] },
-             status: :unauthorized
+      render json: { errors: [{ attribute: :base, type: :incorrect_password }] }, status: :unauthorized
       return
     end
 
     if @user.update(permitted_attributes(@user))
       render json: transform_user_for_json(@user), status: :ok
     else
-      render json: @user.errors, status: :unprocessable_content
+      render json: transform_errors_for_json(@user), status: :unprocessable_content
     end
   end
 
   def destroy
-    render json: @user.errors, status: :unprocessable_content unless @user.destroy
+    render json: transform_errors_for_json(@user), status: :unprocessable_content unless @user.destroy
   end
 
   private