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rails--rails/activesupport/lib/active_support/json/encoding.rb
2011-05-11 16:22:35 +02:00

287 lines
8.9 KiB
Ruby

require 'active_support/core_ext/object/to_json'
require 'active_support/core_ext/module/delegation'
require 'active_support/deprecation'
require 'active_support/json/variable'
require 'active_support/ordered_hash'
require 'bigdecimal'
require 'active_support/core_ext/big_decimal/conversions' # for #to_s
require 'active_support/core_ext/array/wrap'
require 'active_support/core_ext/hash/except'
require 'active_support/core_ext/hash/slice'
require 'active_support/core_ext/object/instance_variables'
require 'time'
require 'active_support/core_ext/time/conversions'
require 'active_support/core_ext/date_time/conversions'
require 'active_support/core_ext/date/conversions'
module ActiveSupport
class << self
delegate :use_standard_json_time_format, :use_standard_json_time_format=,
:escape_html_entities_in_json, :escape_html_entities_in_json=,
:to => :'ActiveSupport::JSON::Encoding'
end
module JSON
# matches YAML-formatted dates
DATE_REGEX = /^(?:\d{4}-\d{2}-\d{2}|\d{4}-\d{1,2}-\d{1,2}[T \t]+\d{1,2}:\d{2}:\d{2}(\.[0-9]*)?(([ \t]*)Z|[-+]\d{2}?(:\d{2})?))$/
# Dumps object in JSON (JavaScript Object Notation). See www.json.org for more info.
def self.encode(value, options = nil)
Encoding::Encoder.new(options).encode(value)
end
module Encoding #:nodoc:
class CircularReferenceError < StandardError; end
class Encoder
attr_reader :options
def initialize(options = nil)
@options = options
@seen = []
end
def encode(value, use_options = true)
check_for_circular_references(value) do
jsonified = use_options ? value.as_json(options_for(value)) : value.as_json
jsonified.encode_json(self)
end
end
# like encode, but only calls as_json, without encoding to string
def as_json(value)
check_for_circular_references(value) do
value.as_json(options_for(value))
end
end
def options_for(value)
if value.is_a?(Array) || value.is_a?(Hash)
# hashes and arrays need to get encoder in the options, so that they can detect circular references
(options || {}).merge(:encoder => self)
else
options
end
end
def escape(string)
Encoding.escape(string)
end
private
def check_for_circular_references(value)
if @seen.any? { |object| object.equal?(value) }
raise CircularReferenceError, 'object references itself'
end
@seen.unshift value
yield
ensure
@seen.shift
end
end
ESCAPED_CHARS = {
"\x00" => '\u0000', "\x01" => '\u0001', "\x02" => '\u0002',
"\x03" => '\u0003', "\x04" => '\u0004', "\x05" => '\u0005',
"\x06" => '\u0006', "\x07" => '\u0007', "\x0B" => '\u000B',
"\x0E" => '\u000E', "\x0F" => '\u000F', "\x10" => '\u0010',
"\x11" => '\u0011', "\x12" => '\u0012', "\x13" => '\u0013',
"\x14" => '\u0014', "\x15" => '\u0015', "\x16" => '\u0016',
"\x17" => '\u0017', "\x18" => '\u0018', "\x19" => '\u0019',
"\x1A" => '\u001A', "\x1B" => '\u001B', "\x1C" => '\u001C',
"\x1D" => '\u001D', "\x1E" => '\u001E', "\x1F" => '\u001F',
"\010" => '\b',
"\f" => '\f',
"\n" => '\n',
"\r" => '\r',
"\t" => '\t',
'"' => '\"',
'\\' => '\\\\',
'>' => '\u003E',
'<' => '\u003C',
'&' => '\u0026' }
class << self
# If true, use ISO 8601 format for dates and times. Otherwise, fall back to the Active Support legacy format.
attr_accessor :use_standard_json_time_format
attr_accessor :escape_regex
attr_reader :escape_html_entities_in_json
def escape_html_entities_in_json=(value)
self.escape_regex = \
if @escape_html_entities_in_json = value
/[\x00-\x1F"\\><&]/
else
/[\x00-\x1F"\\]/
end
end
def escape(string)
if string.respond_to?(:force_encoding)
string = string.encode(::Encoding::UTF_8, :undef => :replace).force_encoding(::Encoding::BINARY)
end
json = string.
gsub(escape_regex) { |s| ESCAPED_CHARS[s] }.
gsub(/([\xC0-\xDF][\x80-\xBF]|
[\xE0-\xEF][\x80-\xBF]{2}|
[\xF0-\xF7][\x80-\xBF]{3})+/nx) { |s|
s.unpack("U*").pack("n*").unpack("H*")[0].gsub(/.{4}/n, '\\\\u\&')
}
json = %("#{json}")
json.force_encoding(::Encoding::UTF_8) if json.respond_to?(:force_encoding)
json
end
end
self.use_standard_json_time_format = true
self.escape_html_entities_in_json = false
end
CircularReferenceError = Deprecation::DeprecatedConstantProxy.new('ActiveSupport::JSON::CircularReferenceError', Encoding::CircularReferenceError)
end
end
class Object
def as_json(options = nil) #:nodoc:
if respond_to?(:to_hash)
to_hash
else
instance_values
end
end
end
class Struct
def as_json(options = nil) #:nodoc:
Hash[members.zip(values)]
end
end
class TrueClass
AS_JSON = ActiveSupport::JSON::Variable.new('true').freeze
def as_json(options = nil) AS_JSON end #:nodoc:
end
class FalseClass
AS_JSON = ActiveSupport::JSON::Variable.new('false').freeze
def as_json(options = nil) AS_JSON end #:nodoc:
end
class NilClass
AS_JSON = ActiveSupport::JSON::Variable.new('null').freeze
def as_json(options = nil) AS_JSON end #:nodoc:
end
class String
def as_json(options = nil) self end #:nodoc:
def encode_json(encoder) encoder.escape(self) end #:nodoc:
end
class Symbol
def as_json(options = nil) to_s end #:nodoc:
end
class Numeric
def as_json(options = nil) self end #:nodoc:
def encode_json(encoder) to_s end #:nodoc:
end
class BigDecimal
# A BigDecimal would be naturally represented as a JSON number. Most libraries,
# however, parse non-integer JSON numbers directly as floats. Clients using
# those libraries would get in general a wrong number and no way to recover
# other than manually inspecting the string with the JSON code itself.
#
# That's why a JSON string is returned. The JSON literal is not numeric, but if
# the other end knows by contract that the data is supposed to be a BigDecimal,
# it still has the chance to post-process the string and get the real value.
def as_json(options = nil) to_s end #:nodoc:
end
class Regexp
def as_json(options = nil) to_s end #:nodoc:
end
module Enumerable
def as_json(options = nil) #:nodoc:
to_a.as_json(options)
end
end
class Array
def as_json(options = nil) #:nodoc:
# use encoder as a proxy to call as_json on all elements, to protect from circular references
encoder = options && options[:encoder] || ActiveSupport::JSON::Encoding::Encoder.new(options)
map { |v| encoder.as_json(v) }
end
def encode_json(encoder) #:nodoc:
# we assume here that the encoder has already run as_json on self and the elements, so we run encode_json directly
"[#{map { |v| v.encode_json(encoder) } * ','}]"
end
end
class Hash
def as_json(options = nil) #:nodoc:
# create a subset of the hash by applying :only or :except
subset = if options
if attrs = options[:only]
slice(*Array.wrap(attrs))
elsif attrs = options[:except]
except(*Array.wrap(attrs))
else
self
end
else
self
end
# use encoder as a proxy to call as_json on all values in the subset, to protect from circular references
encoder = options && options[:encoder] || ActiveSupport::JSON::Encoding::Encoder.new(options)
result = self.is_a?(ActiveSupport::OrderedHash) ? ActiveSupport::OrderedHash : Hash
result[subset.map { |k, v| [k.to_s, encoder.as_json(v)] }]
end
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
end
class Time
def as_json(options = nil) #:nodoc:
if ActiveSupport.use_standard_json_time_format
xmlschema
else
%(#{strftime("%Y/%m/%d %H:%M:%S")} #{formatted_offset(false)})
end
end
end
class Date
def as_json(options = nil) #:nodoc:
if ActiveSupport.use_standard_json_time_format
strftime("%Y-%m-%d")
else
strftime("%Y/%m/%d")
end
end
end
class DateTime
def as_json(options = nil) #:nodoc:
if ActiveSupport.use_standard_json_time_format
xmlschema
else
strftime('%Y/%m/%d %H:%M:%S %z')
end
end
end