Active Storage Validations

If you are using active_storage gem and you want to add simple validations for it, like presence or content_type you need to write a custom validation method.

This gems doing it for you. Just use attached: true or content_type: 'image/png' validation.

What it can do

validates if file(s) attached
validates content type
validates size of files
validates dimension of images/videos
validates number of uploaded files (min/max required)
validates aspect ratio (if square, portrait, landscape, is_16_9, ...)
validates if file can be processed by MiniMagick or Vips
custom error messages
allow procs for dynamic determination of values

Usage

For example you have a model like this and you want to add validation.

class User < ApplicationRecord
  has_one_attached :avatar
  has_many_attached :photos
  has_one_attached :image

  validates :name, presence: true

  validates :avatar, attached: true, content_type: 'image/png',
                                     dimension: { width: 200, height: 200 }
  validates :photos, attached: true, content_type: ['image/png', 'image/jpeg'],
                                     dimension: { width: { min: 800, max: 2400 },
                                                  height: { min: 600, max: 1800 }, message: 'is not given between dimension' }
  validates :image, attached: true,
                    processable_image: true,
                    content_type: ['image/png', 'image/jpeg'],
                    aspect_ratio: :landscape
end

class Project < ApplicationRecord
  has_one_attached :logo
  has_one_attached :preview
  has_one_attached :attachment
  has_many_attached :documents

  validates :title, presence: true

  validates :logo, attached: true, size: { less_than: 100.megabytes , message: 'is too large' }
  validates :preview, attached: true, size: { between: 1.kilobyte..100.megabytes , message: 'is not given between size' }
  validates :attachment, attached: true, content_type: { in: 'application/pdf', message: 'is not a PDF' }
  validates :documents, limit: { min: 1, max: 3 }
end

More examples

Content type validation using symbols. In order to infer the correct mime type from the symbol, the types must be registered with Marcel::EXTENSIONS (MimeMagic::EXTENSIONS for Rails <= 6.1.3).

class User < ApplicationRecord
  has_one_attached :avatar
  has_many_attached :photos

  validates :avatar, attached: true, content_type: :png # Marcel::Magic.by_extension(:png).to_s => 'image/png'
                                                        # Rails <= 6.1.3; MimeMagic.by_extension(:png).to_s => 'image/png'
  # or
  validates :photos, attached: true, content_type: [:png, :jpg, :jpeg]
  # or
  validates :avatar, content_type: /\Aimage\/.*\z/
end

Dimension validation with width, height and in.

class User < ApplicationRecord
  has_one_attached :avatar
  has_many_attached :photos

  validates :avatar, dimension: { width: { in: 80..100 }, message: 'is not given between dimension' }
  validates :photos, dimension: { height: { in: 600..1800 } }
end

Dimension validation with min and max range for width and height:

class User < ApplicationRecord
  has_one_attached :avatar
  has_many_attached :photos

  validates :avatar, dimension: { min: 200..100 }
  # Equivalent to:
  # validates :avatar, dimension: { width: { min: 200 }, height: { min: 100  } }
  validates :photos, dimension: { min: 200..100, max: 400..200 }
  # Equivalent to:
  # validates :avatar, dimension: { width: { min: 200, max: 400 }, height: { min: 100, max: 200  } }
end

Aspect ratio validation:

class User < ApplicationRecord
  has_one_attached :avatar
  has_one_attached :photo
  has_many_attached :photos

  validates :avatar, aspect_ratio: :square
  validates :photo, aspect_ratio: :landscape

  # you can also pass dynamic aspect ratio, like :is_4_3, :is_16_9, etc
  validates :photos, aspect_ratio: :is_4_3
end

Proc Usage:

Procs can be used instead of values in all the above examples. They will be called on every validation.

class User < ApplicationRecord
  has_many_attached :proc_files

  validates :proc_files, limit: { max: -> (record) { record.admin? ? 100 : 10 } }
end

Internationalization (I18n)

Active Storage Validations uses I18n for error messages. For this, add these keys in your translation file:

en:
  errors:
    messages:
      content_type_invalid: "has an invalid content type"
      file_size_out_of_range: "size %{file_size} is not between required range"
      limit_out_of_range: "total number is out of range"
      image_metadata_missing: "is not a valid image"
      dimension_min_inclusion: "must be greater than or equal to %{width} x %{height} pixel."
      dimension_max_inclusion: "must be less than or equal to %{width} x %{height} pixel."
      dimension_width_inclusion: "width is not included between %{min} and %{max} pixel."
      dimension_height_inclusion: "height is not included between %{min} and %{max} pixel."
      dimension_width_greater_than_or_equal_to: "width must be greater than or equal to %{length} pixel."
      dimension_height_greater_than_or_equal_to: "height must be greater than or equal to %{length} pixel."
      dimension_width_less_than_or_equal_to: "width must be less than or equal to %{length} pixel."
      dimension_height_less_than_or_equal_to: "height must be less than or equal to %{length} pixel."
      dimension_width_equal_to: "width must be equal to %{length} pixel."
      dimension_height_equal_to: "height must be equal to %{length} pixel."
      aspect_ratio_not_square: "must be a square image"
      aspect_ratio_not_portrait: "must be a portrait image"
      aspect_ratio_not_landscape: "must be a landscape image"
      aspect_ratio_is_not: "must have an aspect ratio of %{aspect_ratio}"
      aspect_ratio_unknown: "has an unknown aspect ratio"
      image_not_processable: "is not a valid image"

In some cases, Active Storage Validations provides variables to help you customize messages:

The "content_type_invalid" key has two variables that you can use, a variable named "content_type" containing the content type of the send file and a variable named "authorized_types" containing the list of authorized content types.

The variables are not used by default to leave the choice to the user.

For example :

content_type_invalid: "has an invalid content type : %{content_type}"

Also the "limit_out_of_range" key supports two variables the "min" and "max".

For example :

limit_out_of_range: "total number is out of range. range: [%{min}, %{max}]"

Installation

Add this line to your application's Gemfile:

# Rails 5.2 and Rails 6
gem 'active_storage_validations'

# Optional, to use :dimension validator or :aspect_ratio validator
gem 'mini_magick', '>= 4.9.5'
# Or
gem 'ruby-vips', '>= 2.1.0'

And then execute:

$ bundle

Sample

Very simple example of validation with file attached, content type check and custom error message.

Test matchers

Provides RSpec-compatible and Minitest-compatible matchers for testing the validators.

RSpec

In spec_helper.rb, you'll need to require the matchers:

require 'active_storage_validations/matchers'

And include the module:

RSpec.configure do |config|
  config.include ActiveStorageValidations::Matchers
end

Example (Note that the options are chainable):

describe User do
  it { is_expected.to validate_attached_of(:avatar) }

  it { is_expected.to validate_content_type_of(:avatar).allowing('image/png', 'image/gif') }
  it { is_expected.to validate_content_type_of(:avatar).rejecting('text/plain', 'text/xml') }

  it { is_expected.to validate_dimensions_of(:avatar).width(250) }
  it { is_expected.to validate_dimensions_of(:avatar).height(200) }
  it { is_expected.to validate_dimensions_of(:avatar).width(250).height(200).with_message('Invalid dimensions.') }
  it { is_expected.to validate_dimensions_of(:avatar).width_min(200) }
  it { is_expected.to validate_dimensions_of(:avatar).width_max(500) }
  it { is_expected.to validate_dimensions_of(:avatar).height_min(100) }
  it { is_expected.to validate_dimensions_of(:avatar).height_max(300) }
  it { is_expected.to validate_dimensions_of(:avatar).width_between(200..500) }
  it { is_expected.to validate_dimensions_of(:avatar).height_between(100..300) }

  it { is_expected.to validate_size_of(:avatar).less_than(50.kilobytes) }
  it { is_expected.to validate_size_of(:avatar).less_than_or_equal_to(50.kilobytes) }
  it { is_expected.to validate_size_of(:avatar).greater_than(1.kilobyte) }
  it { is_expected.to validate_size_of(:avatar).greater_than_or_equal_to(1.kilobyte) }
  it { is_expected.to validate_size_of(:avatar).between(100..500.kilobytes) }
end

Minitest

To use the following syntax, make sure you have the shoulda-context gem up and running. To make use of the matchers you need to require the matchers:

require 'active_storage_validations/matchers'

And extend the module:

class ActiveSupport::TestCase
  extend ActiveStorageValidations::Matchers
end

Example (Note that the options are chainable):

class UserTest < ActiveSupport::TestCase
  should validate_attached_of(:avatar)

  should validate_content_type_of(:avatar).allowing('image/png', 'image/gif')
  should validate_content_type_of(:avatar).rejecting('text/plain', 'text/xml')

  should validate_dimensions_of(:avatar).width(250)
  should validate_dimensions_of(:avatar).height(200)
  should validate_dimensions_of(:avatar).width(250).height(200).with_message('Invalid dimensions.')
  should validate_dimensions_of(:avatar).width_min(200)
  should validate_dimensions_of(:avatar).width_max(500)
  should validate_dimensions_of(:avatar).height_min(100)
  should validate_dimensions_of(:avatar).height_max(300)
  should validate_dimensions_of(:avatar).width_between(200..500)
  should validate_dimensions_of(:avatar).height_between(100..300)

  should validate_size_of(:avatar).less_than(50.kilobytes)
  should validate_size_of(:avatar).less_than_or_equal_to(50.kilobytes)
  should validate_size_of(:avatar).greater_than(1.kilobyte)
  should validate_size_of(:avatar).greater_than_or_equal_to(1.kilobyte)
  should validate_size_of(:avatar).between(100..500.kilobytes)
end

Todo

verify with remote storages (s3, etc)
verify how it works with direct upload
better error message when content_size is invalid
add more translations

Tests & Contributing

To run tests in root folder of gem:

BUNDLE_GEMFILE=gemfiles/rails_6_0.gemfile bundle exec rake test to run for Rails 6.0
BUNDLE_GEMFILE=gemfiles/rails_6_1.gemfile bundle exec rake test to run for Rails 6.1
BUNDLE_GEMFILE=gemfiles/rails_7_0.gemfile bundle exec rake test to run for Rails 7.0
BUNDLE_GEMFILE=gemfiles/rails_next.gemfile bundle exec rake test to run for Rails main branch

Snippet to run in console:

BUNDLE_GEMFILE=gemfiles/rails_6_0.gemfile bundle
BUNDLE_GEMFILE=gemfiles/rails_6_1.gemfile bundle
BUNDLE_GEMFILE=gemfiles/rails_7_0.gemfile bundle
BUNDLE_GEMFILE=gemfiles/rails_next.gemfile bundle
BUNDLE_GEMFILE=gemfiles/rails_6_0.gemfile bundle exec rake test
BUNDLE_GEMFILE=gemfiles/rails_6_1.gemfile bundle exec rake test
BUNDLE_GEMFILE=gemfiles/rails_7_0.gemfile bundle exec rake test
BUNDLE_GEMFILE=gemfiles/rails_next.gemfile bundle exec rake test

Known issues

There is an issue in Rails which it possible to get if you have added a validation and generating for example an image preview of attachments. It can be fixed with this:

  <% if @user.avatar.attached? && @user.avatar.attachment.blob.present? && @user.avatar.attachment.blob.persisted? %>
    <%= image_tag @user.avatar %>
  <% end %>

This is a Rails issue, and is fixed in Rails 6.

Contributing

You are welcome to contribute.

Contributors (BIG THANK YOU)

License

The gem is available as open source under the terms of the MIT License.

suke/active_storage_validations