ActiveStorage File Attachment Validation

Well, it ain't pretty, but this may be necessary until they bake in some validation:

  validate :logo_validation  def logo_validation    if logo.attached?      if logo.blob.byte_size > 1000000        logo.purge        errors[:base] << 'Too big'      elsif !logo.blob.content_type.starts_with?('image/')        logo.purge        errors[:base] << 'Wrong format'      end    end  end

ActiveStorage doesn't support validations right now. According to https://github.com/rails/rails/issues/31656.

Update:

Rails 6 will support ActiveStorage validations.

https://github.com/rails/rails/commit/e8682c5bf051517b0b265e446aa1a7eccfd47bf7

Uploaded files assigned to a record are persisted to storage when the recordis saved instead of immediately.In Rails 5.2, the following causes an uploaded file in `params[:avatar]` tobe stored:```ruby@user.avatar = params[:avatar]```In Rails 6, the uploaded file is stored when `@user` is successfully saved.

You can use awesome https://github.com/musaffa/file_validators gem

class Profile < ActiveRecord::Base  has_one_attached :avatar  validates :avatar, file_size: { less_than_or_equal_to: 100.kilobytes },    file_content_type: { allow: ['image/jpeg', 'image/png'] }end

I'm using it with form object so I'm not 100% sure it is working directly with AR but it should...