class Hash
Constants
- DISALLOWED_XML_TYPES
Public Class Methods
# File lib/active_support/core_ext/hash/conversions.rb, line 101 def from_trusted_xml(xml) from_xml xml, [] end
# File lib/active_support/core_ext/hash/conversions.rb, line 97 def from_xml(xml, disallowed_types = nil) typecast_xml_value(unrename_keys(ActiveSupport::XmlMini.parse(xml)), disallowed_types) end
Private Class Methods
# File lib/active_support/core_ext/hash/conversions.rb, line 106 def typecast_xml_value(value, disallowed_types = nil) disallowed_types ||= DISALLOWED_XML_TYPES case value.class.to_s when 'Hash' if value.include?('type') && !value['type'].is_a?(Hash) && disallowed_types.include?(value['type']) raise DisallowedType, value['type'] end if value['type'] == 'array' _, entries = Array.wrap(value.detect { |k,v| not v.is_a?(String) }) if entries.nil? || (c = value['__content__'] && c.blank?) [] else case entries.class.to_s # something weird with classes not matching here. maybe singleton methods breaking is_a? when "Array" entries.collect { |v| typecast_xml_value(v, disallowed_types) } when "Hash" [typecast_xml_value(entries, disallowed_types)] else raise "can't typecast #{entries.inspect}" end end elsif value['type'] == 'file' || (value["__content__"] && (value.keys.size == 1 || value["__content__"].present?)) content = value["__content__"] if parser = ActiveSupport::XmlMini::PARSING[value["type"]] parser.arity == 1 ? parser.call(content) : parser.call(content, value) else content end elsif value['type'] == 'string' && value['nil'] != 'true' "" # blank or nil parsed values are represented by nil elsif value.blank? || value['nil'] == 'true' nil # If the type is the only element which makes it then # this still makes the value nil, except if type is # a XML node(where type['value'] is a Hash) elsif value['type'] && value.size == 1 && !value['type'].is_a?(::Hash) nil else xml_value = Hash[value.map { |k,v| [k, typecast_xml_value(v, disallowed_types)] }] # Turn { :files => { :file => #<StringIO> } into { :files => #<StringIO> } so it is compatible with # how multipart uploaded files from HTML appear xml_value["file"].is_a?(StringIO) ? xml_value["file"] : xml_value end when 'Array' value.map! { |i| typecast_xml_value(i, disallowed_types) } value.length > 1 ? value : value.first when 'String' value else raise "can't typecast #{value.class.name} - #{value.inspect}" end end
# File lib/active_support/core_ext/hash/conversions.rb, line 164 def unrename_keys(params) case params.class.to_s when "Hash" Hash[params.map { |k,v| [k.to_s.tr("-", "_"), unrename_keys(v)] } ] when "Array" params.map { |v| unrename_keys(v) } else params end end
Public Instance Methods
Validate all keys in a hash match *valid keys, raising ArgumentError on a mismatch. Note that keys are NOT treated indifferently, meaning if you use strings for keys but assert symbols as keys, this will fail.
Examples¶ ↑
{ :name => "Rob", :years => "28" }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: years" { :name => "Rob", :age => "28" }.assert_valid_keys("name", "age") # => raises "ArgumentError: Unknown key: name" { :name => "Rob", :age => "28" }.assert_valid_keys(:name, :age) # => passes, raises nothing
# File lib/active_support/core_ext/hash/keys.rb, line 48 def assert_valid_keys(*valid_keys) valid_keys.flatten! each_key do |k| raise(ArgumentError, "Unknown key: #{k}") unless valid_keys.include?(k) end end
Returns a deep copy of hash.
hash = { :a => { :b => 'b' } } dup = hash.deep_dup dup[:a][:c] = 'c' hash[:a][:c] #=> nil dup[:a][:c] #=> "c"
# File lib/active_support/core_ext/hash/deep_dup.rb, line 10 def deep_dup duplicate = self.dup duplicate.each_pair do |k,v| tv = duplicate[k] duplicate[k] = tv.is_a?(Hash) && v.is_a?(Hash) ? tv.deep_dup : v end duplicate end
Returns a new hash with self
and other_hash
merged recursively.
h1 = {:x => {:y => [4,5,6]}, :z => [7,8,9]} h2 = {:x => {:y => [7,8,9]}, :z => "xyz"} h1.deep_merge(h2) #=> { :x => {:y => [7, 8, 9]}, :z => "xyz" } h2.deep_merge(h1) #=> { :x => {:y => [4, 5, 6]}, :z => [7, 8, 9] }
# File lib/active_support/core_ext/hash/deep_merge.rb, line 9 def deep_merge(other_hash) dup.deep_merge!(other_hash) end
Same as deep_merge
, but modifies self
.
# File lib/active_support/core_ext/hash/deep_merge.rb, line 14 def deep_merge!(other_hash) other_hash.each_pair do |k,v| tv = self[k] self[k] = tv.is_a?(Hash) && v.is_a?(Hash) ? tv.deep_merge(v) : v end self end
Returns a hash that represents the difference between two hashes.
Examples:
{1 => 2}.diff(1 => 2) # => {} {1 => 2}.diff(1 => 3) # => {1 => 2} {}.diff(1 => 2) # => {1 => 2} {1 => 2, 3 => 4}.diff(1 => 2) # => {3 => 4}
# File lib/active_support/core_ext/hash/diff.rb, line 10 def diff(h2) dup.delete_if { |k, v| h2[k] == v }.merge!(h2.dup.delete_if { |k, v| has_key?(k) }) end
# File lib/active_support/json/encoding.rb, line 245 def encode_json(encoder) # values are encoded with use_options = false, because we don't want hash representations from ActiveModel to be # processed once again with as_json with options, as this could cause unexpected results (i.e. missing fields); # on the other hand, we need to run as_json on the elements, because the model representation may contain fields # like Time/Date in their original (not jsonified) form, etc. "{#{map { |k,v| "#{encoder.encode(k.to_s)}:#{encoder.encode(v, false)}" } * ','}}" end
Return a hash that includes everything but the given keys. This is useful for limiting a set of parameters to everything but a few known toggles:
@person.update_attributes(params[:person].except(:admin))
If the receiver responds to convert_key
, the method is called
on each of the arguments. This allows except
to play nice with
hashes with indifferent access for instance:
{:a => 1}.with_indifferent_access.except(:a) # => {} {:a => 1}.with_indifferent_access.except("a") # => {}
# File lib/active_support/core_ext/hash/except.rb, line 14 def except(*keys) dup.except!(*keys) end
Replaces the hash without the given keys.
# File lib/active_support/core_ext/hash/except.rb, line 19 def except!(*keys) keys.each { |key| delete(key) } self end
Removes and returns the key/value pairs matching the given keys.
{:a => 1, :b => 2, :c => 3, :d => 4}.extract!(:a, :b) # => {:a => 1, :b => 2}
# File lib/active_support/core_ext/hash/slice.rb, line 35 def extract!(*keys) result = {} keys.each {|key| result[key] = delete(key) } result end
By default, only instances of Hash itself are extractable. Subclasses of Hash may implement this method and return true to declare themselves as extractable. If a Hash is extractable, Array#extract_options! pops it from the Array when it is the last element of the Array.
# File lib/active_support/core_ext/array/extract_options.rb, line 7 def extractable_options? instance_of?(Hash) end
Called when object is nested under an object that receives with_indifferent_access.
This method will be called on the current object by the enclosing object
and is aliased to with_indifferent_access
by default. Subclasses of Hash may overwrite this
method to return self
if converting to an
ActiveSupport::HashWithIndifferentAccess
would not be
desirable.
b = {:b => 1} {:a => b}.with_indifferent_access["a"] # calls b.nested_under_indifferent_access
Merges the caller into other_hash
. For example,
options = options.reverse_merge(:size => 25, :velocity => 10)
is equivalent to
options = {:size => 25, :velocity => 10}.merge(options)
This is particularly useful for initializing an options hash with default values.
# File lib/active_support/core_ext/hash/reverse_merge.rb, line 12 def reverse_merge(other_hash) other_hash.merge(self) end
Destructive reverse_merge
.
# File lib/active_support/core_ext/hash/reverse_merge.rb, line 17 def reverse_merge!(other_hash) # right wins if there is no left merge!( other_hash ){|key,left,right| left } end
Slice a hash to include only the given keys. This is useful for limiting an options hash to valid keys before passing to a method:
def search(criteria = {}) assert_valid_keys(:mass, :velocity, :time) end search(options.slice(:mass, :velocity, :time))
If you have an array of keys you want to limit to, you should splat them:
valid_keys = [:mass, :velocity, :time] search(options.slice(*valid_keys))
# File lib/active_support/core_ext/hash/slice.rb, line 15 def slice(*keys) keys = keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true) hash = self.class.new keys.each { |k| hash[k] = self[k] if has_key?(k) } hash end
Replaces the hash with only the given keys. Returns a hash contained the removed key/value pairs
{:a => 1, :b => 2, :c => 3, :d => 4}.slice!(:a, :b) # => {:c => 3, :d => 4}
# File lib/active_support/core_ext/hash/slice.rb, line 25 def slice!(*keys) keys = keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true) omit = slice(*self.keys - keys) hash = slice(*keys) replace(hash) omit end
Return a new hash with all keys converted to strings.
{ :name => 'Rob', :years => '28' }.stringify_keys #=> { "name" => "Rob", "years" => "28" }
# File lib/active_support/core_ext/hash/keys.rb, line 6 def stringify_keys dup.stringify_keys! end
Destructively convert all keys to strings. Same as
stringify_keys
, but modifies self
.
# File lib/active_support/core_ext/hash/keys.rb, line 12 def stringify_keys! keys.each do |key| self[key.to_s] = delete(key) end self end
Return a new hash with all keys converted to symbols, as long as they
respond to to_sym
.
{ 'name' => 'Rob', 'years' => '28' }.symbolize_keys #=> { :name => "Rob", :years => "28" }
# File lib/active_support/core_ext/hash/keys.rb, line 24 def symbolize_keys dup.symbolize_keys! end
Destructively convert all keys to symbols, as long as they respond to
to_sym
. Same as symbolize_keys
, but modifies
self
.
# File lib/active_support/core_ext/hash/keys.rb, line 30 def symbolize_keys! keys.each do |key| self[(key.to_sym rescue key) || key] = delete(key) end self end
Returns a string representation of the receiver suitable for use as a URL query string:
{:name => 'David', :nationality => 'Danish'}.to_param # => "name=David&nationality=Danish"
An optional namespace can be passed to enclose the param names:
{:name => 'David', :nationality => 'Danish'}.to_param('user') # => "user[name]=David&user[nationality]=Danish"
The string pairs “key=value” that conform the query string are sorted lexicographically in ascending order.
This method is also aliased as to_query
.
# File lib/active_support/core_ext/object/to_param.rb, line 50 def to_param(namespace = nil) collect do |key, value| value.to_query(namespace ? "#{namespace}[#{key}]" : key) end.sort * '&' end
Returns a string containing an XML representation of its receiver:
{"foo" => 1, "bar" => 2}.to_xml # => # <?xml version="1.0" encoding="UTF-8"?> # <hash> # <foo type="integer">1</foo> # <bar type="integer">2</bar> # </hash>
To do so, the method loops over the pairs and builds nodes that depend on
the values. Given a pair key
, value
:
-
If
value
is a hash there's a recursive call withkey
as:root
. -
If
value
is an array there's a recursive call withkey
as:root
, andkey
singularized as:children
. -
If
value
is a callable object it must expect one or two arguments. Depending on the arity, the callable is invoked with theoptions
hash as first argument withkey
as:root
, andkey
singularized as second argument. The callable can add nodes by usingoptions[:builder]
."foo".to_xml(lambda { |options, key| options[:builder].b(key) }) # => "<b>foo</b>"
-
If
value
responds toto_xml
the method is invoked withkey
as:root
.class Foo def to_xml(options) options[:builder].bar "fooing!" end end {:foo => Foo.new}.to_xml(:skip_instruct => true) # => "<hash><bar>fooing!</bar></hash>"
-
Otherwise, a node with
key
as tag is created with a string representation ofvalue
as text node. Ifvalue
isnil
an attribute “nil” set to “true” is added. Unless the option:skip_types
exists and is true, an attribute “type” is added as well according to the following mapping:XML_TYPE_NAMES = { "Symbol" => "symbol", "Fixnum" => "integer", "Bignum" => "integer", "BigDecimal" => "decimal", "Float" => "float", "TrueClass" => "boolean", "FalseClass" => "boolean", "Date" => "date", "DateTime" => "datetime", "Time" => "datetime" }
By default the root node is “hash”, but that's configurable via the
:root
option.
The default XML builder is a fresh instance of
Builder::XmlMarkup
. You can configure your own builder with
the :builder
option. The method also accepts options like
:dasherize
and friends, they are forwarded to the builder.
# File lib/active_support/core_ext/hash/conversions.rb, line 69 def to_xml(options = {}) require 'active_support/builder' unless defined?(Builder) options = options.dup options[:indent] ||= 2 options[:root] ||= "hash" options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent]) builder = options[:builder] builder.instruct! unless options.delete(:skip_instruct) root = ActiveSupport::XmlMini.rename_key(options[:root].to_s, options) builder.__send__(:method_missing, root) do each { |key, value| ActiveSupport::XmlMini.to_tag(key, value, options) } yield builder if block_given? end end
Returns an ActiveSupport::HashWithIndifferentAccess
out of its
receiver:
{:a => 1}.with_indifferent_access["a"] # => 1
# File lib/active_support/core_ext/hash/indifferent_access.rb, line 8 def with_indifferent_access ActiveSupport::HashWithIndifferentAccess.new_from_hash_copying_default(self) end