Module: Hashie::Extensions::Coercion::ClassMethods

Defined in:
lib/hashie/extensions/coercion.rb

Instance Method Summary collapse

Instance Method Details

#coerce_key(*attrs) ⇒ Object Also known as: coerce_keys

Set up a coercion rule such that any time the specified key is set it will be coerced into the specified class. Coercion will occur by first attempting to call Class.coerce and then by calling Class.new with the value as an argument in either case.

Examples:

Coerce a "user" subhash into a User object

class Tweet < Hash
  include Hashie::Extensions::Coercion
  coerce_key :user, User
end

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# File 'lib/hashie/extensions/coercion.rb', line 50

def coerce_key(*attrs)
  @key_coercions ||= {}
  into = attrs.pop
  attrs.each { |key| @key_coercions[key] = into }
end

#coerce_value(from, into, options = {}) ⇒ Object

Set up a coercion rule such that any time a value of the specified type is set it will be coerced into the specified class.

Examples:

Coerce all hashes into this special type of hash

class SpecialHash < Hash
  include Hashie::Extensions::Coercion
  coerce_value Hash, SpecialHash

  def initialize(hash = {})
    super
    hash.each_pair do |k,v|
      self[k] = v
    end
  end
end

Options Hash (options):

  • :strict (Boolean) — default: true

    whether use exact source class only or include ancestors


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# File 'lib/hashie/extensions/coercion.rb', line 89

def coerce_value(from, into, options = {})
  options = {:strict => true}.merge(options)

  if options[:strict]
    (@strict_value_coercions ||= {})[from] = into
  else
    while from.superclass && from.superclass != Object
      (@lenient_value_coercions ||= {})[from] = into
      from = from.superclass
    end
  end
end

#key_coercion(key) ⇒ Object

Returns the specific key coercion for the specified key, if one exists.


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# File 'lib/hashie/extensions/coercion.rb', line 65

def key_coercion(key)
  key_coercions[key.to_sym]
end

#key_coercionsObject

Returns a hash of any existing key coercions.


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# File 'lib/hashie/extensions/coercion.rb', line 59

def key_coercions
  @key_coercions || {}
end

#lenient_value_coercionsObject

Return all value coercions that have the :strict rule as false.


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# File 'lib/hashie/extensions/coercion.rb', line 105

def lenient_value_coercions; @value_coercions || {} end

#strict_value_coercionsObject

Return all value coercions that have the :strict rule as true.


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# File 'lib/hashie/extensions/coercion.rb', line 103

def strict_value_coercions; @strict_value_coercions || {} end

#value_coercion(value) ⇒ Object

Fetch the value coercion, if any, for the specified object.


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# File 'lib/hashie/extensions/coercion.rb', line 108

def value_coercion(value)
  from = value.class
  strict_value_coercions[from] || lenient_value_coercions[from]
end