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to_json.cr
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to_json.cr
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class Object
def to_json : String
String.build do |str|
to_json str
end
end
def to_json(io : IO) : Nil
JSON.build(io) do |json|
to_json(json)
end
end
def to_pretty_json(indent : String = " ") : String
String.build do |str|
to_pretty_json str, indent: indent
end
end
def to_pretty_json(io : IO, indent : String = " ") : Nil
JSON.build(io, indent: indent) do |json|
to_json(json)
end
end
end
struct Nil
def to_json(json : JSON::Builder) : Nil
json.null
end
def to_json_object_key : String
""
end
end
struct Bool
def to_json(json : JSON::Builder) : Nil
json.bool(self)
end
end
struct Int
def to_json(json : JSON::Builder) : Nil
json.number(self)
end
def to_json_object_key : String
to_s
end
end
struct Float
def to_json(json : JSON::Builder) : Nil
json.number(self)
end
def to_json_object_key : String
to_s
end
end
class String
def to_json(json : JSON::Builder) : Nil
json.string(self)
end
def to_json_object_key : String
self
end
end
struct Path
def to_json(json : JSON::Builder) : Nil
@name.to_json(json)
end
def to_json_object_key
@name
end
end
struct Symbol
def to_json(json : JSON::Builder) : Nil
json.string(to_s)
end
def to_json_object_key : String
to_s
end
end
class Array
def to_json(json : JSON::Builder) : Nil
json.array do
each &.to_json(json)
end
end
end
class Deque
def to_json(json : JSON::Builder) : Nil
json.array do
each &.to_json(json)
end
end
end
struct Set
def to_json(json : JSON::Builder) : Nil
json.array do
each &.to_json(json)
end
end
end
module Iterator(T)
# Converts the content of an iterator into a JSON array in lazy way.
# See `Iterator#from_json` for an example.
def to_json(json : JSON::Builder)
json.array do
each &.to_json(json)
end
end
end
class Hash
# Serializes this Hash into JSON.
#
# Keys are serialized by invoking `to_json_object_key` on them.
# Values are serialized with the usual `to_json(json : JSON::Builder)`
# method.
def to_json(json : JSON::Builder) : Nil
json.object do
each do |key, value|
json.field key.to_json_object_key do
value.to_json(json)
end
end
end
end
end
struct Tuple
def to_json(json : JSON::Builder) : Nil
json.array do
{% for i in 0...T.size %}
self[{{i}}].to_json(json)
{% end %}
end
end
end
struct NamedTuple
def to_json(json : JSON::Builder)
json.object do
{% for key in T.keys %}
json.field {{key.stringify}} do
self[{{key.symbolize}}].to_json(json)
end
{% end %}
end
end
end
struct Time::Format
def to_json(value : Time, json : JSON::Builder) : Nil
format(value).to_json(json)
end
end
struct Enum
# Serializes this enum member by name.
#
# For non-flags enums, the serialization is a JSON string. The value is the
# member name (see `#to_s`) transformed with `String#underscore`.
#
# ```
# enum Stages
# INITIAL
# SECOND_STAGE
# end
#
# Stages::INITIAL.to_json # => %("initial")
# Stages::SECOND_STAGE.to_json # => %("second_stage")
# ```
#
# For flags enums, the serialization is a JSON array including every flagged
# member individually serialized in the same way as a member of a non-flags enum.
# `None` is serialized as an empty array, `All` as an array containing
# all members.
#
# ```
# @[Flags]
# enum Sides
# LEFT
# RIGHT
# end
#
# Sides::LEFT.to_json # => %(["left"])
# (Sides::LEFT | Sides::RIGHT).to_json # => %(["left","right"])
# Sides::All.to_json # => %(["left","right"])
# Sides::None.to_json # => %([])
# ```
#
# `ValueConverter.to_json` offers a different serialization strategy based on the
# member value.
def to_json(json : JSON::Builder)
{% if @type.annotation(Flags) %}
json.array do
each do |member, _value|
json.string(member.to_s.underscore)
end
end
{% else %}
json.string(to_s.underscore)
{% end %}
end
end
module Enum::ValueConverter(T)
def self.to_json(value : T)
String.build do |io|
to_json(value, io)
end
end
def self.to_json(value : T, io : IO)
JSON.build(io) do |json|
to_json(value, json)
end
end
# Serializes enum member *member* by value.
#
# For both flags enums and non-flags enums, the value of the enum member is
# used for serialization.
#
# ```
# enum Stages
# INITIAL
# SECOND_STAGE
# end
#
# Enum::ValueConverter.to_json(Stages::INITIAL) # => %(0)
# Enum::ValueConverter.to_json(Stages::SECOND_STAGE) # => %(1)
#
# @[Flags]
# enum Sides
# LEFT
# RIGHT
# end
#
# Enum::ValueConverter.to_json(Sides::LEFT) # => %(1)
# Enum::ValueConverter.to_json(Sides::LEFT | Sides::RIGHT) # => %(3)
# Enum::ValueConverter.to_json(Sides::All) # => %(3)
# Enum::ValueConverter.to_json(Sides::None) # => %(0)
# ```
#
# `Enum#to_json` offers a different serialization strategy based on the member
# name.
def self.to_json(member : T, json : JSON::Builder)
json.scalar(member.value)
end
end
struct Time
# Emits a string formatted according to [RFC 3339](https://tools.ietf.org/html/rfc3339)
# ([ISO 8601](http://xml.coverpages.org/ISO-FDIS-8601.pdf) profile).
#
# The JSON format itself does not specify a time data type, this method just
# assumes that a string holding a RFC 3339 time format will be interpreted as
# a time value.
#
# See `#from_json` for reference.
def to_json(json : JSON::Builder) : Nil
json.string(Time::Format::RFC_3339.format(self, fraction_digits: 0))
end
end
# Converter to be used with `JSON::Serializable`
# to serialize the elements of an `Array(T)` with the custom converter.
#
# ```
# require "json"
#
# class TimestampArray
# include JSON::Serializable
#
# @[JSON::Field(converter: JSON::ArrayConverter(Time::EpochConverter))]
# property dates : Array(Time)
# end
#
# timestamp = TimestampArray.from_json(%({"dates":[1459859781,1567628762]}))
# timestamp.dates # => [2016-04-05 12:36:21 UTC, 2019-09-04 20:26:02 UTC]
# timestamp.to_json # => %({"dates":[1459859781,1567628762]})
# ```
#
# `JSON::ArrayConverter.new` should be used if the nested converter is also an
# instance instead of a type.
#
# ```
# require "json"
#
# class TimestampArray
# include JSON::Serializable
#
# @[JSON::Field(converter: JSON::ArrayConverter.new(Time::Format.new("%b %-d, %Y")))]
# property dates : Array(Time)
# end
#
# timestamp = TimestampArray.from_json(%({"dates":["Apr 5, 2016","Sep 4, 2019"]}))
# timestamp.dates # => [2016-04-05 00:00:00 UTC, 2019-09-04 00:00:00 UTC]
# timestamp.to_json # => %({"dates":["Apr 5, 2016","Sep 4, 2019"]})
# ```
#
# This implies that `JSON::ArrayConverter(T)` and
# `JSON::ArrayConverter(T.class).new(T)` perform the same serializations.
module JSON::ArrayConverter(Converter)
private struct WithInstance(T)
def initialize(@converter : T)
end
def to_json(values : Array, builder : JSON::Builder)
builder.array do
values.each do |value|
@converter.to_json(value, builder)
end
end
end
end
def self.new(converter : Converter)
WithInstance.new(converter)
end
def self.to_json(values : Array, builder : JSON::Builder)
WithInstance.new(Converter).to_json(values, builder)
end
end
# Converter to be used with `JSON::Serializable`
# to serialize the values of a `Hash(String, V)` with the custom converter.
#
# ```
# require "json"
#
# class TimestampHash
# include JSON::Serializable
#
# @[JSON::Field(converter: JSON::HashValueConverter(Time::EpochConverter))]
# property birthdays : Hash(String, Time)
# end
#
# timestamp = TimestampHash.from_json(%({"birthdays":{"foo":1459859781,"bar":1567628762}}))
# timestamp.birthdays # => {"foo" => 2016-04-05 12:36:21 UTC, "bar" => 2019-09-04 20:26:02 UTC)}
# timestamp.to_json # => {"birthdays":{"foo":1459859781,"bar":1567628762}}
# ```
#
# `JSON::HashValueConverter.new` should be used if the nested converter is also
# an instance instead of a type.
#
# ```
# require "json"
#
# class TimestampHash
# include JSON::Serializable
#
# @[JSON::Field(converter: JSON::HashValueConverter.new(Time::Format.new("%b %-d, %Y")))]
# property birthdays : Hash(String, Time)
# end
#
# timestamp = TimestampHash.from_json(%({"birthdays":{"foo":"Apr 5, 2016","bar":"Sep 4, 2019"}}))
# timestamp.birthdays # => {"foo" => 2016-04-05 00:00:00 UTC, "bar" => 2019-09-04 00:00:00 UTC)}
# timestamp.to_json # => {"birthdays":{"foo":"Apr 5, 2016","bar":"Sep 4, 2019"}}
# ```
#
# This implies that `JSON::HashValueConverter(T)` and
# `JSON::HashValueConverter(T.class).new(T)` perform the same serializations.
module JSON::HashValueConverter(Converter)
private struct WithInstance(T)
def initialize(@converter : T)
end
def to_json(values : Hash, builder : JSON::Builder)
builder.object do
values.each do |key, value|
builder.field key.to_json_object_key do
@converter.to_json(value, builder)
end
end
end
end
end
def self.new(converter : Converter)
WithInstance.new(converter)
end
def self.to_json(values : Hash, builder : JSON::Builder)
WithInstance.new(Converter).to_json(values, builder)
end
end
# Converter to be used with `JSON::Serializable` and `YAML::Serializable`
# to serialize a `Time` instance as the number of seconds
# since the unix epoch. See `Time#to_unix`.
#
# ```
# require "json"
#
# class Person
# include JSON::Serializable
#
# @[JSON::Field(converter: Time::EpochConverter)]
# property birth_date : Time
# end
#
# person = Person.from_json(%({"birth_date": 1459859781}))
# person.birth_date # => 2016-04-05 12:36:21 UTC
# person.to_json # => %({"birth_date":1459859781})
# ```
module Time::EpochConverter
def self.to_json(value : Time, json : JSON::Builder) : Nil
json.number(value.to_unix)
end
end
# Converter to be used with `JSON::Serializable` and `YAML::Serializable`
# to serialize a `Time` instance as the number of milliseconds
# since the unix epoch. See `Time#to_unix_ms`.
#
# ```
# require "json"
#
# class Timestamp
# include JSON::Serializable
#
# @[JSON::Field(converter: Time::EpochMillisConverter)]
# property value : Time
# end
#
# timestamp = Timestamp.from_json(%({"value": 1459860483856}))
# timestamp.value # => 2016-04-05 12:48:03.856 UTC
# timestamp.to_json # => %({"value":1459860483856})
# ```
module Time::EpochMillisConverter
def self.to_json(value : Time, json : JSON::Builder) : Nil
json.number(value.to_unix_ms)
end
end
# Converter to be used with `JSON::Serializable` to read the raw
# value of a JSON object property as a `String`.
#
# It can be useful to read ints and floats without losing precision,
# or to read an object and deserialize it later based on some
# condition.
#
# ```
# require "json"
#
# class Raw
# include JSON::Serializable
#
# @[JSON::Field(converter: String::RawConverter)]
# property value : String
# end
#
# raw = Raw.from_json(%({"value": 123456789876543212345678987654321}))
# raw.value # => "123456789876543212345678987654321"
# raw.to_json # => %({"value":123456789876543212345678987654321})
# ```
module String::RawConverter
def self.to_json(value : String, json : JSON::Builder) : Nil
json.raw(value)
end
end