Add ImageValidator

app/models/account.rb

@@ -6,14 +6,6 @@ class Account < ApplicationRecord
 
   NICKNAME_RE = /\A[a-z][_a-z0-9]*[a-z0-9]\z/.freeze
 
-  AVATAR_MAX_SIZE = 1.megabyte
-
-  AVATAR_CONTENT_TYPES = %w[
-    image/png
-    image/jpeg
-    image/gif
-  ].freeze
-
   self.role_cname = 'Role'
   self.role_table_name = 'roles'
   self.strict_rolify = false
@@ -76,8 +68,7 @@ class Account < ApplicationRecord
 
   validates :biography, allow_nil: true, length: { in: 3..10_000 }
 
-  validate :avatar_size_is_valid
+  validates :avatar, allow_nil: true, image: true
-  validate :avatar_content_type_is_valid
 
   ###########
   # Methods #
@@ -137,18 +128,4 @@ private
     self.public_name = public_name&.strip
     self.biography   = biography&.strip
   end
-
-  def avatar_size_is_valid
-    return unless avatar.attached?
-    return if avatar.blob.byte_size <= AVATAR_MAX_SIZE
-
-    errors.add :avatar, :size
-  end
-
-  def avatar_content_type_is_valid
-    return unless avatar.attached?
-    return if avatar.blob.content_type.in? AVATAR_CONTENT_TYPES
-
-    errors.add :avatar, :format, content_type: avatar.blob.content_type
-  end
 end

app/validators/application_each_validator.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+class ApplicationEachValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    self.class::Validation.new(self, record, attribute, value).call
+  end
+
+  class Validation
+    attr_reader :value
+
+    delegate :options, to: :@validator
+
+    def initialize(validator, record, attribute, value)
+      @validator = validator
+      @record    = record
+      @attribute = attribute
+      @value     = value
+    end
+
+    def call
+      catch :stop_validating do
+        perform
+      end
+    end
+
+    def perform
+      raise NotImplementedError, "#{self.class}#perform"
+    end
+
+    def error(*args)
+      @record.errors.add @attribute, *args
+    end
+
+    def error!(*args)
+      error(*args)
+      throw :stop_validating
+    end
+  end
+end

app/validators/image_validator.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class ImageValidator < ApplicationEachValidator
+  class Validation < Validation
+    MAX_SIZE = 1.megabyte
+
+    CONTENT_TYPES = %w[
+      image/png
+      image/jpeg
+      image/gif
+    ].freeze
+
+    delegate :blob, to: :value
+
+    delegate :content_type, :byte_size, to: :blob
+
+    def perform
+      return unless value.attached?
+
+      unless content_type.in? CONTENT_TYPES
+        error :image_format, content_type: content_type
+      end
+
+      error :image_size unless byte_size <= MAX_SIZE
+    end
+  end
+end

config/application.rb

@@ -41,6 +41,11 @@ module Partynest
     # Fully qualified domain name.
     config.site_domain = 'libertarian-party.com'
 
+    # Custom directories with classes and modules you want to be autoloadable.
+    config.autoload_paths += [
+      config.root.join('app', 'validators'),
+    ]
+
     # Email which all mail is set from.
     config.noreply_email_address = "no-reply@#{config.site_domain}"
     config.noreply_email_contact =

config/locales/activerecord/en.yml

@@ -108,9 +108,6 @@ en:
         unlock_token: Unlock token
         updated_at: Updated at
     errors:
-      models:
+      messages:
-        account:
+        image_size: 'has too big size'
-          attributes:
+        image_format: 'has invalid format: %{content_type}'
-            avatar:
-              size: 'has too big size'
-              format: 'has invalid format: %{content_type}'

config/locales/activerecord/ru.yml

@@ -108,9 +108,6 @@ ru:
         unlock_token: Токен разблокировки
         updated_at: Дата обновления
     errors:
-      models:
+      messages:
-        account:
+        image_size: 'имеет слишком большой размер'
-          attributes:
+        image_format: 'имеет неверный формат: %{content_type}'
-            avatar:
-              size: 'имеет слишком большой размер'
-              format: 'имеет неверный формат: %{content_type}'

spec/validators/image_validator_spec.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe ImageValidator do
+  pending "add some examples to (or delete) #{__FILE__}"
+end