class Hashie::Mash
Mash
allows you to create pseudo-objects that have method-like accessors for hash keys. This is useful for such implementations as an API-accessing library that wants to fake robust objects without the overhead of actually doing so. Think of it as OpenStruct with some additional goodies.
A Mash
will look at the methods you pass it and perform operations based on the following rules:
-
No punctuation: Returns the value of the hash for that key, or nil if none exists.
-
Assignment (
=
): Sets the attribute of the given method name. -
Truthiness (
?
): Returns true or false depending on the truthiness of the attribute, or false if the key is not set. -
Bang (
!
): Forces the existence of this key, used for deep Mashes. Think of it as “touch” for mashes. -
Under Bang (
_
): Like Bang, but returns a newMash
rather than creating a key. Used to test existance in deep Mashes.
Basic Example¶ ↑
mash = Mash.new mash.name? # => false mash.name = "Bob" mash.name # => "Bob" mash.name? # => true
Hash
Conversion Example¶ ↑
hash = {:a => {:b => 23, :d => {:e => "abc"}}, :f => [{:g => 44, :h => 29}, 12]} mash = Mash.new(hash) mash.a.b # => 23 mash.a.d.e # => "abc" mash.f.first.g # => 44 mash.f.last # => 12
Bang Example¶ ↑
mash = Mash.new mash.author # => nil mash.author! # => <Mash> mash = Mash.new mash.author!.name = "Michael Bleigh" mash.author # => <Mash name="Michael Bleigh">
Under Bang Example¶ ↑
mash = Mash.new mash.author # => nil mash.author_ # => <Mash> mash.author_.name # => nil mash = Mash.new mash.author_.name = "Michael Bleigh" (assigned to temp object) mash.author # => <Mash>
Constants
- ALLOWED_SUFFIXES
Public Class Methods
# File lib/hashie/mash.rb, line 71 def self.load(path, options = {}) @_mashes ||= new return @_mashes[path] if @_mashes.key?(path) raise ArgumentError, "The following file doesn't exist: #{path}" unless File.file?(path) options = options.dup parser = options.delete(:parser) { Hashie::Extensions::Parsers::YamlErbParser } @_mashes[path] = new(parser.perform(path, options)).freeze end
If you pass in an existing hash, it will convert it to a Mash
including recursively descending into arrays and hashes, converting them as well.
# File lib/hashie/mash.rb, line 101 def initialize(source_hash = nil, default = nil, &blk) deep_update(source_hash) if source_hash default ? super(default) : super(&blk) end
Creates a new anonymous subclass with key conflict warnings disabled. You may pass an array of method symbols to restrict the disabled warnings to. Hashie::Mash.quiet
.new(hash) all warnings disabled. Hashie::Mash.quiet
(:zip).new(hash) only zip warning is disabled.
# File lib/hashie/mash.rb, line 112 def self.quiet(*method_keys) @memoized_classes ||= {} @memoized_classes[method_keys] ||= Class.new(self) do disable_warnings(*method_keys) end end
Public Instance Methods
Assigns a value to a key
# File lib/hashie/mash.rb, line 262 def assign_property(name, value) self[name] = value end
Returns a new instance of the class it was called on, with nil values removed.
# File lib/hashie/mash.rb, line 341 def compact self.class.new(super) end
Retrieves an attribute set in the Mash
. Will convert any key passed in to a string before retrieving.
# File lib/hashie/mash.rb, line 126 def custom_reader(key) default_proc.call(self, key) if default_proc && !key?(key) value = regular_reader(convert_key(key)) yield value if block_given? value end
Performs a deep_update
on a duplicate of the current mash.
# File lib/hashie/mash.rb, line 213 def deep_merge(*other_hashes, &blk) dup.deep_update(*other_hashes, &blk) end
Recursively merges this mash with the passed in hash, merging each hash in the hierarchy.
# File lib/hashie/mash.rb, line 219 def deep_update(*other_hashes, &blk) other_hashes.each do |other_hash| _deep_update(other_hash, &blk) end self end
# File lib/hashie/mash.rb, line 169 def delete(key) super(convert_key(key)) end
# File lib/hashie/mash.rb, line 329 def dig(*keys) super(*keys.map { |key| convert_key(key) }) end
Duplicates the current mash as a new mash.
# File lib/hashie/mash.rb, line 198 def dup self.class.new(self, default, &default_proc) end
play nice with ActiveSupport Array#extract_options!
# File lib/hashie/mash.rb, line 319 def extractable_options? true end
# File lib/hashie/mash.rb, line 165 def fetch(key, *args) super(convert_key(key), *args) end
This is the bang method reader, it will return a new Mash
if there isn’t a value already assigned to the key requested.
# File lib/hashie/mash.rb, line 148 def initializing_reader(key) ck = convert_key(key) regular_writer(ck, self.class.new) unless key?(ck) regular_reader(ck) end
Returns a new instance of the class it was called on, using its keys as values, and its values as keys. The new values and keys will always be strings.
# File lib/hashie/mash.rb, line 180 def invert self.class.new(super) end
# File lib/hashie/mash.rb, line 203 def key?(key) super(convert_key(key)) end
Alias these lexically so they get the correctly defined deep_merge
and deep_update
based on ruby version.
# File lib/hashie/mash.rb, line 301 def method_missing(method_name, *args, &blk) # rubocop:disable Style/MethodMissing return self.[](method_name, &blk) if key?(method_name) name, suffix = method_name_and_suffix(method_name) case suffix when '='.freeze assign_property(name, args.first) when '?'.freeze !!self[name] when '!'.freeze initializing_reader(name) when '_'.freeze underbang_reader(name) else self[method_name] end end
# File lib/hashie/mash.rb, line 296 def prefix_method?(method_name) method_name = method_name.to_s method_name.end_with?(*ALLOWED_SUFFIXES) && key?(method_name.chop) end
Returns a new instance of the class it was called on, containing elements for which the given block returns false.
# File lib/hashie/mash.rb, line 186 def reject(&blk) self.class.new(super(&blk)) end
# File lib/hashie/mash.rb, line 280 def replace(other_hash) (keys - other_hash.keys).each { |key| delete(key) } other_hash.each { |key, value| self[key] = value } self end
# File lib/hashie/mash.rb, line 286 def respond_to_missing?(method_name, *args) return true if key?(method_name) suffix = method_suffix(method_name) if suffix true else super end end
another ActiveSupport method, see issue #270
# File lib/hashie/mash.rb, line 324 def reverse_merge(other_hash) self.class.new(other_hash).merge(self) end
Returns a new instance of the class it was called on, containing elements for which the given block returns true.
# File lib/hashie/mash.rb, line 192 def select(&blk) self.class.new(super(&blk)) end
Performs a shallow_update
on a duplicate of the current mash
# File lib/hashie/mash.rb, line 267 def shallow_merge(other_hash) dup.shallow_update(other_hash) end
Merges (non-recursively) the hash from the argument, changing the receiving hash
# File lib/hashie/mash.rb, line 273 def shallow_update(other_hash) other_hash.each_pair do |k, v| regular_writer(convert_key(k), convert_value(v, true)) end self end
# File lib/hashie/mash.rb, line 347 def slice(*keys) string_keys = keys.map { |key| convert_key(key) } self.class.new(super(*string_keys)) end
# File lib/hashie/mash.rb, line 82 def to_module(mash_method_name = :settings) mash = self Module.new do |m| m.send :define_method, mash_method_name.to_sym do mash end end end
# File lib/hashie/mash.rb, line 352 def transform_keys(&blk) self.class.new(super(&blk)) end
# File lib/hashie/mash.rb, line 335 def transform_values(&blk) self.class.new(super(&blk)) end
This is the under bang method reader, it will return a temporary new Mash
if there isn’t a value already assigned to the key requested.
# File lib/hashie/mash.rb, line 156 def underbang_reader(key) ck = convert_key(key) if key?(ck) regular_reader(ck) else self.class.new end end
# File lib/hashie/mash.rb, line 173 def values_at(*keys) super(*keys.map { |key| convert_key(key) }) end
# File lib/hashie/mash.rb, line 91 def with_accessors! extend Hashie::Extensions::Mash::DefineAccessors end
Protected Instance Methods
# File lib/hashie/mash.rb, line 359 def method_name_and_suffix(method_name) method_name = method_name.to_s if method_name.end_with?(*ALLOWED_SUFFIXES) [method_name[0..-2], method_name[-1]] else [method_name[0..-1], nil] end end
# File lib/hashie/mash.rb, line 368 def method_suffix(method_name) method_name = method_name.to_s method_name[-1] if method_name.end_with?(*ALLOWED_SUFFIXES) end
Private Instance Methods
# File lib/hashie/mash.rb, line 247 def _deep_update(other_hash, &blk) other_hash.each_pair do |k, v| key = convert_key(k) if v.is_a?(::Hash) && key?(key) && regular_reader(key).is_a?(Mash) custom_reader(key).deep_update(v, &blk) else value = convert_value(v, true) value = convert_value(yield(key, self[k], value), true) if blk && key?(k) custom_writer(key, value, false) end end end
# File lib/hashie/mash.rb, line 395 def log_built_in_message(method_key) return if self.class.disable_warnings?(method_key) method_information = Hashie::Utils.method_information(method(method_key)) Hashie.logger.warn( 'You are setting a key that conflicts with a built-in method ' \ "#{self.class}##{method_key} #{method_information}. " \ 'This can cause unexpected behavior when accessing the key as a ' \ 'property. You can still access the key via the #[] method.' ) end
# File lib/hashie/mash.rb, line 408 def log_collision?(method_key) return unless respond_to?(method_key) _, suffix = method_name_and_suffix(method_key) (!suffix || suffix == '='.freeze) && !self.class.disable_warnings?(method_key) && !(regular_key?(method_key) || regular_key?(method_key.to_s)) end