JSON Schema based serializer
Add this line to your application's Gemfile:
gem 'json-schema-serializer'And then execute:
$ bundle
Or install it yourself as:
$ gem install json-schema-serializer
require "json/schema/serializer"
schema = {
type: "object",
properties: {
id: { type: "integer" },
name: { type: "string" },
fuzzy: { type: ["string", "integer", "null"] },
},
required: ["id"],
}
serializer = JSON::Schema::Serializer.new(schema)
serializer.serialize({id: "42", name: "me", foo: "bar", fuzzy: "1000"})
# => {"id"=>42, "name"=>"me", "fuzzy"=>"1000"}
# "42" -> 42! type coerced!
serializer.serialize({id: "42", name: "me", fuzzy: 42})
# => {"id"=>42, "name"=>"me", "fuzzy"=>42}
serializer.serialize({id: "42", name: "me"})
# => {"id"=>42, "name"=>"me", "fuzzy"=>nil}
# multiple type auto select!
serializer.serialize({})
# => {"id"=>0, "name"=>nil, "fuzzy"=>nil}
# nil -> 0! required property's type coerced!
serializer.serialize({id: 10, name: "I don't need null keys!"}).compact
# => {"id"=>10, "name"=>"I don't need null keys!"}
# compact it!
class A
def id
42
end
end
serializer.serialize(A.new)
# => {"id"=>42, "name"=>nil, "fuzzy"=>nil}
# method also allowed
class Schema
def type
:string
end
end
serializer2 = JSON::Schema::Serializer.new(Schema.new)
serializer2.serialize(32)
# => "32"
# non-hash schema allowed
#
# object injector allowed!
#
class FooSerializer
def initialize(model)
@model = model
end
def first
@model.first
end
def count
@model.size
end
end
serializer_injected = JSON::Schema::Serializer.new(
{
type: :object,
inject: :Foo,
properties: {
first: { type: :integer },
count: { type: :integer },
},
},
{
inject_key: :inject,
injectors: {
Foo: FooSerializer,
},
},
)
serializer_injected.serialize([1, 2, 3])
# => {"first"=>1, "count"=>3}
#
# object injector with context
#
class BarSerializer
def initialize(model, context = nil)
@model = model
@context = context
end
def id
@model[:id]
end
def score
@context[@model[:id]]
end
end
inject_context = {
1 => 100,
2 => 200,
}
serializer_injected_with_context = JSON::Schema::Serializer.new(
{
type: :object,
inject: :Bar,
properties: {
id: { type: :integer },
score: { type: :integer },
},
},
{
inject_key: :inject,
injectors: {
Bar: BarSerializer,
},
inject_context: inject_context,
},
)
serializer_injected_with_context.serialize({ id: 1 })
# => { "id" => 1, "score" => 100 }
#
# inject in serializer
#
class ParentSerializer
include JSON::Schema::Serializer::WithContext
def initialize(model, context = nil)
@model = model
@context = context
end
def id
@model[:id]
end
def score
@context[:parent_scores][@model[:id]]
end
def child
# it can be
# with_context(context) { data }
# with_context(data, context)
# with_context(data: data, context: context)
with_context(@context.merge(child_scores: { 1 => 100, 2 => 200 })) do
@model[:child]
end
end
end
class ChildSerializer
def initialize(model, context = nil)
@model = model
@context = context
end
def id
@model[:id]
end
def score
@context[:child_scores][@model[:id]]
end
end
serializer_injected_with_context_in_serializer = JSON::Schema::Serializer.new(
{
type: :object,
inject: :Parent,
properties: {
id: { type: :integer },
score: { type: :integer },
child: {
type: :object,
inject: :Child,
properties: {
id: { type: :integer },
score: { type: :integer },
},
},
},
},
{
inject_key: :inject,
injectors: {
Parent: ParentSerializer,
Child: ChildSerializer,
},
inject_context: { 1 => 10, 2 => 20 },
},
)
serializer_injected_with_context_in_serializer.serialize({ id: 1, child: { id: 2 } })
# => { "id" => 1, "score" => 10, "child" => { "id" => 2, "score" => 200 } }
#
# also you can inject context with arraylike data
#
class ItemsSerializer
include JSON::Schema::Serializer::WithContext
def initialize(models, context = nil)
@models = models
@context = context
end
def map(&block)
context = (@context || {}).merge(scores: {...})
@models.map { |model| block.call(with_context(model, context)) }
# CAUTION!
# not like below!
# with_context(@models.map(&block), context)
# with_context(context) { @models.map(&block) }
end
end
#
# inject model can initialize by keywords
#
class KeywordSerializer
def initialize(data:, context: nil)
@data = data
@context = context
end
...
end
serializer_with_keyword_init_inject = JSON::Schema::Serializer.new(
{
type: :object,
inject: :Keyword,
properties: { ... },
},
{
inject_key: :inject,
injectors: {
Keyword: KeywordSerializer,
Child: ChildSerializer,
},
inject_by_keyword: true, # <- keyword_init!
},
)"additionalProperties" is allowed but must be a schema object or false. (not true)
If "additionalProperties" does not exists, this serializer works as { additionalProperties": false }.
JSON::Schema::Serializer does not resolve $ref so use external resolver.
with hana and json_refs gem example:
require "hana"
require "json_refs"
require "json/schema/serializer"
schema = {
"type" => "object",
"properties" => {
"foo" => { "type" => "integer" },
"bar" => { "$ref" => "#/properties/foo" },
},
}
serializer = JSON::Schema::Serializer.new(JsonRefs.(schema))
serializer.serialize({foo: 0, bar: "42"})
# => {"foo"=>0, "bar"=>42}
# resolver option also available
def walk(all, part)
if part.is_a?(Array)
part.map { |item| walk(all, item) }
elsif part.is_a?(Hash)
ref = part["$ref"] || part[:"$ref"]
if ref
Hana::Pointer.new(ref[1..-1]).eval(all)
else
part.map { |k, v| [k, walk(all, v)] }.to_h
end
else
part
end
end
serializer2 = JSON::Schema::Serializer.new(schema["properties"]["bar"], {
resolver: ->(part_schema) do
walk(JsonRefs.(schema), part_schema))
end
})The initializer.
JSON schema object. The serializer tries schema["type"], schema[:type] and schema.type!
options
schema object $ref resolver
input key transform
new({
type: :object,
properties: {
userCount: { type: :integer },
},
}, { schema_key_transform_for_input: ->(name) { name.underscore } }).serialize({ user_count: 1 }) == { "userCount" => 1 }output key transform
new({
type: :object,
properties: {
userCount: { type: :integer },
},
}, { schema_key_transform_for_output: ->(name) { name.underscore } }).serialize({ userCount: 1 }) == { "user_count" => 1 }options[:injectors] [Hashlike<String, Class>, Class], options[:inject_key] [String, Symbol], options[:inject_context] [any], options[:inject_by_keyword] [Boolean]
If schema has inject key, the serializer treats data by injectors[inject_key].new(data) (or injectors.send(inject_key).new(data)).
And if inject_context is present, injectors[inject_key].new(data, inject_context) (or injectors.send(inject_key).new(data, inject_context)).
And if inject_by_keyword is true, new(data, inject_context) will be new(data: data, context: inject_context).
See examples in Usage.
CAUTION: In many case you should define the nil? method in the injector class because Injector always initialized by Injector.new(obj) even if obj == nil.
If data is null, always serialize null.
new({ type: :string }, { null_through: true }).serialize(nil) == nilIf data == "" in integer or number schema, returns nil.
new({ type: :integer }, { empty_string_number_coerce_null: true }).serialize("") == nilIf data == "" in boolean schema, returns nil.
new({ type: :boolean }, { empty_string_boolean_coerce_null: true }).serialize("") == nilIf specified, boolean schema treats !false_values.include?(data).
new({ type: :boolean }, { false_values: Set.new([false]) }).serialize(nil) == trueIf true, boolean schema treats only true to be true.
new({ type: :boolean }, { no_boolean_coerce: true }).serialize(1) == falseIf true, array or object schema does not accept primitive data and returns empty value.
new({ type: :object }, { guard_primitive_in_structure: true }).serialize(1) == {}
new({ type: :object }, { guard_primitive_in_structure: true, null_through: true }).serialize(1) == nilSerialize the object data by the schema.
Serialize target object. The serializer tries data["foo"], data[:foo] and data.foo!
#with_context!(data, context), #with_context!(data: data, context: context), #with_context!(context) { data }
If you use with_context!(data, context) as the return value of the serializer, then "child" serializer can use that context.
See examples in Usage.
Zlib License
After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/Narazaka/json-schema-serializer.