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 valiation method.

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

Build Status

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, ...)
  • custom error messages

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

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

or

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

  validates :title, presence: true

  validates :preview, attached: true, size: { less_than: 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 Mime::Type.
class User < ApplicationRecord
  has_one_attached :avatar
  has_many_attached :photos

  validates :avatar, attached: true, content_type: :png # Mime[: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 ration 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

## Internationalization (I18n)

Active Storage Validations use I18n for errors messages. For this add there keys in your translation file:

```yml
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: "doesn't a square image"
      aspect_ratio_not_portrait: "doesn't contain a portrait image"
      aspect_ratio_not_landscape: "doesn't contain a landscape image"
      aspect_ratio_is_not: "doesn't contain aspect ratio of %{aspect_ratio}"
      aspect_ratio_unknown: "has an unknown aspect ratio"

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_type" containing the list of authorized content types.

It's 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'

And then execute:

$ bundle

Sample

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

Sample

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
  • add aspect ratio validation

Tests & Contributing

To run tests in root folder of gem:

  • BUNDLE_GEMFILE=gemfiles/rails_5_2.gemfile bundle exec rake test to run for Rails 5.2
  • BUNDLE_GEMFILE=gemfiles/rails_6.0.gemfile bundle exec rake test to run for Rails 6.0

To play with app cd test/dummy and rails s -b 0.0.0.0 (before rails db:migrate).

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 Rails issue. And according to commits it will be 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.