validating_active_storage_attachments

🛡️ Validate Attachments in Models

Use built-in Active Storage validators to ensure files meet your requirements before saving. You can validate content types and file sizes directly in your model to prevent unwanted uploads and improve security.

class User < ApplicationRecord
  has_one_attached :avatar

  validates :avatar,
            attached: true,
            content_type: ['image/png', 'image/jpg', 'image/jpeg'],
            size: { less_than: 5.megabytes, message: 'should be under 5MB' }
end

This ensures only images of allowed types and sizes are accepted. If validation fails, errors will be added to avatar for easy display in views.