Module: Smplkit::Flags::JsonLogicEvaluator

Defined in:

lib/smplkit/flags/client.rb

Overview

Vendored minimal JSON Logic evaluator covering the operators the smplkit platform ships in flag rules.

Stays in-tree so the Ruby SDK doesn’t depend on the json_logic gem being correct — the Java SDK followed the same pattern. Operators supported: ==, !=, <, <=, >, >=, in, var, and, or, !, if, missing, none.

Class Method Summary

• .apply(logic, data) ⇒ Object
• .compare(values, data) ⇒ Object
• .eval_if(values, data) ⇒ Object
• .eval_in(values, data) ⇒ Object
• .eval_missing(values, data) ⇒ Object
• .present?(value) ⇒ Boolean
• .resolve_var(path, data, default = nil) ⇒ Object
• .truthy?(value) ⇒ Boolean

Class Method Details

.apply(logic, data) ⇒ Object

# File 'lib/smplkit/flags/client.rb', line 393

def apply(logic, data)
  return logic unless logic.is_a?(Hash)
  return logic if logic.empty?

  op, values = logic.first
  values = [values] unless values.is_a?(Array)

  case op
  when "var"
    resolve_var(values[0], data, values[1])
  when "and"
    values.reduce(true) { |acc, v| acc && truthy?(apply(v, data)) }
  when "or"
    values.reduce(false) { |acc, v| acc || truthy?(apply(v, data)) }
  when "!"
    !truthy?(apply(values[0], data))
  when "if"
    eval_if(values, data)
  when "==", "==="
    apply(values[0], data) == apply(values[1], data)
  when "!=", "!=="
    apply(values[0], data) != apply(values[1], data)
  when "<"
    compare(values, data) { |a, b| a < b }
  when "<="
    compare(values, data) { |a, b| a <= b }
  when ">"
    compare(values, data) { |a, b| a > b }
  when ">="
    compare(values, data) { |a, b| a >= b }
  when "in"
    eval_in(values, data)
  when "missing"
    eval_missing(values, data)
  when "none"
    values_arr = apply(values[0], data) || []
    inner = values[1]
    values_arr.is_a?(Array) && values_arr.none? { |item| truthy?(apply(inner, item)) }
  else
    false
  end
end

.compare(values, data) ⇒ Object

# File 'lib/smplkit/flags/client.rb', line 463

def compare(values, data)
  applied = values.map { |v| apply(v, data) }
  return false if applied.any?(&:nil?)

  if applied.length == 2
    yield(applied[0], applied[1])
  elsif applied.length == 3
    yield(applied[0], applied[1]) && yield(applied[1], applied[2])
  else
    false
  end
rescue ArgumentError, TypeError
  false
end

.eval_if(values, data) ⇒ Object

# File 'lib/smplkit/flags/client.rb', line 478

def eval_if(values, data)
  i = 0
  while i + 1 < values.length
    return apply(values[i + 1], data) if truthy?(apply(values[i], data))

    i += 2
  end
  i < values.length ? apply(values[i], data) : nil
end

.eval_in(values, data) ⇒ Object

# File 'lib/smplkit/flags/client.rb', line 488

def eval_in(values, data)
  needle = apply(values[0], data)
  haystack = apply(values[1], data)
  return false if haystack.nil?

  haystack.include?(needle)
rescue NoMethodError, TypeError
  false
end

.eval_missing(values, data) ⇒ Object

# File 'lib/smplkit/flags/client.rb', line 498

def eval_missing(values, data)
  keys = values.is_a?(Array) ? values.flatten : [values]
  keys.reject { |k| present?(resolve_var(k, data)) }
end

.present?(value) ⇒ Boolean

Returns:

• (Boolean)

# File 'lib/smplkit/flags/client.rb', line 503

def present?(value)
  !(value.nil? || value == "")
end

.resolve_var(path, data, default = nil) ⇒ Object

# File 'lib/smplkit/flags/client.rb', line 446

def resolve_var(path, data, default = nil)
  return data if path.nil? || path == "" || path == []

  keys = path.is_a?(Array) ? path : path.to_s.split(".")
  keys.reduce(data) do |scope, key|
    break default if scope.nil?

    if scope.is_a?(Hash)
      scope[key] || scope[key.to_s] || scope[key.to_sym]
    elsif scope.is_a?(Array) && key.to_s =~ /\A\d+\z/
      scope[key.to_i]
    else
      default
    end
  end || default
end

.truthy?(value) ⇒ Boolean

Returns:

• (Boolean)

# File 'lib/smplkit/flags/client.rb', line 436

def truthy?(value)
  return false if value.nil?
  return false if value == false
  return false if value.is_a?(Numeric) && value.zero?
  return false if value == ""
  return false if value == []

  true
end