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

Parameters:

  • the key or array of keys you would like to be coerced.

  • the class into which you want the key(s) coerced.



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# File 'lib/hashie/extensions/coercion.rb', line 63

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

Parameters:

  • the type you would like coerced.

  • the class into which you would like the value coerced.

  • (defaults to: {})

    a customizable set of options

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 102

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 78

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

#key_coercions ⇒ Object

Returns a hash of any existing key coercions.



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# File 'lib/hashie/extensions/coercion.rb', line 72

def key_coercions
  @key_coercions || {}
end

#lenient_value_coercions ⇒ Object

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



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# File 'lib/hashie/extensions/coercion.rb', line 120

def lenient_value_coercions
  @value_coercions || {}
end

#strict_value_coercions ⇒ Object

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



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# File 'lib/hashie/extensions/coercion.rb', line 116

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 125

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