```ruby
class RunFile < ActiveRecord::Base
  has_many :runs, dependent: :restrict_with_exception, primary_key: :digest, foreign_key: :run_file_digest

  validates :digest, presence: true, uniqueness: true
  validates :file, presence: true

  def self.for_file(file)
    if file.respond_to?(:read)
      file_text = file.read
      if file_text.include?("\0")
        RunFile.for_binary(file_text)
      else
        RunFile.for_text(file_text)
      end
    end
  end

  def self.for_text(file_text)
    digest = Digest::SHA256.hexdigest(file_text)
    where(digest: digest).first_or_create(file: file_text)
  end

  def self.for_binary(file_text)
    digest = Digest::SHA256.hexdigest(file_text)
    where(digest: digest).first_or_create(file: RunFile.unpack_binary(file_text))
  end

  def self.random
    RunFile.offset(rand(RunFile.count)).first
  end

  def self.unpack_binary(file_text)
    file_text.unpack("C*")
  end

  def self.pack_binary(character_array)
    character_array[1..-1].split(", ").map(&:to_i).pack("C*")
  end
end
```

Stop scanning the whole file to check if llanfair
user
```ruby
class RunFile < ActiveRecord::Base
  has_many :runs, dependent: :restrict_with_exception, primary_key: :digest, foreign_key: :run_file_digest

  validates :digest, presence: true, uniqueness: true
  validates :file, presence: true

  def self.for_file(file)
    if file.respond_to?(:read)
      file_text = file.read
      if file_text[8..29] == "org.fenix.llanfair.Run"
        RunFile.for_binary(file_text)
      else
        RunFile.for_text(file_text)
      end
    end
  end

  def self.for_text(file_text)
    digest = Digest::SHA256.hexdigest(file_text)
    where(digest: digest).first_or_create(file: file_text)
  end

  def self.for_binary(file_text)
    digest = Digest::SHA256.hexdigest(file_text)
    where(digest: digest).first_or_create(file: RunFile.unpack_binary(file_text))
  end

  def self.random
    RunFile.offset(rand(RunFile.count)).first
  end

  def self.unpack_binary(file_text)
    file_text.unpack("C*")
  end

  def self.pack_binary(character_array)
    character_array[1..-1].split(", ").map(&:to_i).pack("C*")
  end
end
```
assistant