Class: MoneyFormatValidator

Inherits:
ActiveModel::EachValidator
  • Object
show all
Defined in:
app/validators/money_format_validator.rb

Overview

Validate fields to look like currency values

NOTE: Currently limited to USD/CAD values.

Options:

  • ‘exclude_cents = true|false` determines if amount can have cents (default false)

  • ‘allow_negative = true|false` determines if amount can be negative (default false)

A blank value is considered valid (use presence validator to check for that)

Examples

validates :amount, money_format: true                 # optional
validates :amount, money_format: { exclude_cents: true, allow_negative: true }
validates :amount, money_format: true, presence: true # required

Constant Summary collapse

MONEY_REGEX = 
/\A[-+]?\d+(\.\d{1,2})?\z/

Instance Method Summary collapse

Instance Method Details

#validate_each(record, attr_name, value) ⇒ Object 



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# File 'app/validators/money_format_validator.rb', line 21

def validate_each(record, attr_name, value)
  if defined?(ActiveRecord::Base) && record.kind_of?(ActiveRecord::Base)
    # need to get the actual value being set because BigDecimal will convert
    # "invalid" to 0.0 making it impossible to validate
    value = record.send("#{attr_name}_before_type_cast".to_sym)
  end
  return if value.blank?

  # Need to first convert BigDecimal to floating point representation of string
  if value.kind_of?(BigDecimal)
    value = value.to_s("F")
  end

  # Finally convert any other types to string and clean off whitespace
  value = value.to_s.strip

  # Regex seems a bit odd to use here (vs converting to BigDeciaml) but we need
  # to check for values that BigDecimal can't represent (e.g., "badvalue") so
  # for now this works.
  record.errors.add(attr_name, :money_format, options) unless value =~ MONEY_REGEX

  # Check if value has cents but shouldn't
  if options[:exclude_cents] && value_has_cents?(value)
    record.errors.add(attr_name, :money_format_has_cents)
  end

  # Check if value is negative but shouldn't
  if value_is_negative?(value)
    record.errors.add(attr_name, :money_format_is_negative) unless options[:allow_negative]
  end
end

#value_has_cents?(value) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/validators/money_format_validator.rb', line 53

def value_has_cents?(value)
  BigDecimal.new(value.to_i) != BigDecimal.new(value)
end

#value_is_negative?(value) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/validators/money_format_validator.rb', line 57

def value_is_negative?(value)
  value.to_i < 0
end