Module: Flagsmith::Engine::Utils::HashFunc

Included in:
FeatureState, Segments::Evaluator
Defined in:
lib/flagsmith/engine/utils/hash_func.rb

Overview

HashFunction

Instance Method Summary collapse

Instance Method Details

#hashed_percentage_for_object_ids(object_ids, iterations = 1) ⇒ Object

Given a list of object ids, get a floating point number between 0 (inclusive) and 100 (exclusive) based on the hash of those ids. This should give the same value every time for any list of ids.

:param object_ids: list of object ids to calculate the hash for :param iterations: num times to include each id in the generated string to hash :return: (float) number between 0 (inclusive) and 100 (exclusive)



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# File 'lib/flagsmith/engine/utils/hash_func.rb', line 17

def hashed_percentage_for_object_ids(object_ids, iterations = 1)
  to_hash = (object_ids.map(&:to_s) * iterations).flatten.join(',')

  hashed_value = Digest::MD5.hexdigest(to_hash.encode('utf-8'))
  hashed_value_as_int = hashed_value.to_i(16)
  value = ((hashed_value_as_int % 9999).to_f / 9998) * 100

  # since we want a number between 0 (inclusive) and 100 (exclusive), in the
  # unlikely case that we get the exact number 100, we call the method again
  # and increase the number of iterations to ensure we get a different result
  return hashed_percentage_for_object_ids(object_ids, iterations + 1) if value == 100

  value
end