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Class Public methods
from_trusted_xml(xml) Link
from_xml(xml, disallowed_types = nil) Link
Returns a Hash
containing a collection of pairs when the key is the node name and the value is its content
xml = <<-XML
<?xml version="1.0" encoding="UTF-8"?>
<hash>
<foo type="integer">1</foo>
<bar type="integer">2</bar>
</hash>
XML
hash = Hash.from_xml(xml)
# => {"hash"=>{"foo"=>1, "bar"=>2}}
DisallowedType
is raised if the XML contains attributes with type="yaml"
or type="symbol"
. Use Hash.from_trusted_xml
to parse this XML.
Custom disallowed_types
can also be passed in the form of an array.
xml = <<-XML
<?xml version="1.0" encoding="UTF-8"?>
<hash>
<foo type="integer">1</foo>
<bar type="string">"David"</bar>
</hash>
XML
hash = Hash.from_xml(xml, ['integer'])
# => ActiveSupport::XMLConverter::DisallowedType: Disallowed type attribute: "integer"
Note that passing custom disallowed types will override the default types, which are Symbol
and YAML.
Instance Public methods
assert_valid_keys(*valid_keys) Link
Validates all keys in a hash match *valid_keys
, raising ArgumentError
on a mismatch.
Note that keys are treated differently than HashWithIndifferentAccess
, meaning that string and symbol keys will not match.
{ name: 'Rob', years: '28' }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: :years. Valid keys are: :name, :age"
{ name: 'Rob', age: '28' }.assert_valid_keys('name', 'age') # => raises "ArgumentError: Unknown key: :name. Valid keys are: 'name', 'age'"
{ name: 'Rob', age: '28' }.assert_valid_keys(:name, :age) # => passes, raises nothing
# File activesupport/lib/active_support/core_ext/hash/keys.rb, line 48 def assert_valid_keys(*valid_keys) valid_keys.flatten! each_key do |k| unless valid_keys.include?(k) raise ArgumentError.new("Unknown key: #{k.inspect}. Valid keys are: #{valid_keys.map(&:inspect).join(', ')}") end end end
compact_blank!() Link
Removes all blank values from the Hash
in place and returns self. Uses Object#blank?
for determining if a value is blank.
h = { a: "", b: 1, c: nil, d: [], e: false, f: true }
h.compact_blank!
# => { b: 1, f: true }
deep_dup() Link
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"
deep_merge(other_hash, &block) Link
Returns a new hash with self
and other_hash
merged recursively.
h1 = { a: true, b: { c: [1, 2, 3] } }
h2 = { a: false, b: { x: [3, 4, 5] } }
h1.deep_merge(h2) # => { a: false, b: { c: [1, 2, 3], x: [3, 4, 5] } }
Like with Hash#merge in the standard library, a block can be provided to merge values:
h1 = { a: 100, b: 200, c: { c1: 100 } }
h2 = { b: 250, c: { c1: 200 } }
h1.deep_merge(h2) { |key, this_val, other_val| this_val + other_val }
# => { a: 100, b: 450, c: { c1: 300 } }
deep_merge!(other_hash, &block) Link
Same as deep_merge
, but modifies self
.
# File activesupport/lib/active_support/core_ext/hash/deep_merge.rb, line 23 def deep_merge!(other_hash, &block) merge!(other_hash) do |key, this_val, other_val| if this_val.is_a?(Hash) && other_val.is_a?(Hash) this_val.deep_merge(other_val, &block) elsif block_given? block.call(key, this_val, other_val) else other_val end end end
deep_stringify_keys() Link
Returns a new hash with all keys converted to strings. This includes the keys from the root hash and from all nested hashes and arrays.
hash = { person: { name: 'Rob', age: '28' } }
hash.deep_stringify_keys
# => {"person"=>{"name"=>"Rob", "age"=>"28"}}
deep_stringify_keys!() Link
Destructively converts all keys to strings. This includes the keys from the root hash and from all nested hashes and arrays.
deep_symbolize_keys() Link
Returns a new hash with all keys converted to symbols, as long as they respond to to_sym
. This includes the keys from the root hash and from all nested hashes and arrays.
hash = { 'person' => { 'name' => 'Rob', 'age' => '28' } }
hash.deep_symbolize_keys
# => {:person=>{:name=>"Rob", :age=>"28"}}
deep_symbolize_keys!() Link
Destructively converts all keys to symbols, as long as they respond to to_sym
. This includes the keys from the root hash and from all nested hashes and arrays.
deep_transform_keys(&block) Link
Returns a new hash with all keys converted by the block operation. This includes the keys from the root hash and from all nested hashes and arrays.
hash = { person: { name: 'Rob', age: '28' } }
hash.deep_transform_keys{ |key| key.to_s.upcase }
# => {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}
deep_transform_keys!(&block) Link
Destructively converts all keys by using the block operation. This includes the keys from the root hash and from all nested hashes and arrays.
deep_transform_values(&block) Link
Returns a new hash with all values converted by the block operation. This includes the values from the root hash and from all nested hashes and arrays.
hash = { person: { name: 'Rob', age: '28' } }
hash.deep_transform_values{ |value| value.to_s.upcase }
# => {person: {name: "ROB", age: "28"}}
deep_transform_values!(&block) Link
Destructively converts all values by using the block operation. This includes the values from the root hash and from all nested hashes and arrays.
except(*keys) Link
Returns a hash that includes everything except given keys.
hash = { a: true, b: false, c: nil }
hash.except(:c) # => { a: true, b: false }
hash.except(:a, :b) # => { c: nil }
hash # => { a: true, b: false, c: nil }
This is useful for limiting a set of parameters to everything but a few known toggles:
@person.update(params[:person].except(:admin))
except!(*keys) Link
Removes the given keys from hash and returns it.
hash = { a: true, b: false, c: nil }
hash.except!(:c) # => { a: true, b: false }
hash # => { a: true, b: false }
extract!(*keys) Link
Removes and returns the key/value pairs matching the given keys.
hash = { a: 1, b: 2, c: 3, d: 4 }
hash.extract!(:a, :b) # => {:a=>1, :b=>2}
hash # => {:c=>3, :d=>4}
extractable_options?() Link
nested_under_indifferent_access() Link
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 override 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
# => {"b"=>1}
reverse_merge(other_hash) Link
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.
reverse_merge!(other_hash) Link
Destructive reverse_merge
.
slice!(*keys) Link
Replaces the hash with only the given keys. Returns a hash containing the removed key/value pairs.
hash = { a: 1, b: 2, c: 3, d: 4 }
hash.slice!(:a, :b) # => {:c=>3, :d=>4}
hash # => {:a=>1, :b=>2}
stringify_keys() Link
Returns a new hash with all keys converted to strings.
hash = { name: 'Rob', age: '28' }
hash.stringify_keys
# => {"name"=>"Rob", "age"=>"28"}
stringify_keys!() Link
Destructively converts all keys to strings. Same as stringify_keys
, but modifies self
.
symbolize_keys() Link
Returns a new hash with all keys converted to symbols, as long as they respond to to_sym
.
hash = { 'name' => 'Rob', 'age' => '28' }
hash.symbolize_keys
# => {:name=>"Rob", :age=>"28"}
symbolize_keys!() Link
Destructively converts all keys to symbols, as long as they respond to to_sym
. Same as symbolize_keys
, but modifies self
.
to_query(namespace = nil) Link
Returns a string representation of the receiver suitable for use as a URL query string:
{name: 'David', nationality: 'Danish'}.to_query
# => "name=David&nationality=Danish"
An optional namespace can be passed to enclose key names:
{name: 'David', nationality: 'Danish'}.to_query('user')
# => "user%5Bname%5D=David&user%5Bnationality%5D=Danish"
The string pairs “key=value” that conform the query string are sorted lexicographically in ascending order.
# File activesupport/lib/active_support/core_ext/object/to_query.rb, line 75 def to_query(namespace = nil) query = filter_map do |key, value| unless (value.is_a?(Hash) || value.is_a?(Array)) && value.empty? value.to_query(namespace ? "#{namespace}[#{key}]" : key) end end query.sort! unless namespace.to_s.include?("[]") query.join("&") end
to_xml(options = {}) Link
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: lambda { |options, key| options[:builder].b(key) }}.to_xml # => "<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", "Integer" => "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 activesupport/lib/active_support/core_ext/hash/conversions.rb, line 74 def to_xml(options = {}) require "active_support/builder" unless defined?(Builder::XmlMarkup) 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.tag!(root) do each { |key, value| ActiveSupport::XmlMini.to_tag(key, value, options) } yield builder if block_given? end end
with_indifferent_access() Link
Returns an ActiveSupport::HashWithIndifferentAccess
out of its receiver:
{ a: 1 }.with_indifferent_access['a'] # => 1