Crystalizer

[De]serialize any Crystal object - out of the box. Supports JSON, YAML and Byte format.

Features

[De]serialize anything, "out-of-the-box"
Advanced serialization with annotations, but not required
Shared annotations for all formats (JSON, YAML...)

Implementation bonus: no monkey patching involved :) (no method pollution on objects)

Installation

Add the dependency to your shard.yml:

dependencies:
  crystalizer:
    github: j8r/crystalizer

Documentation

https://j8r.github.io/crystalizer

Usage

Basic

require "crystalizer/json"
require "crystalizer/yaml"

struct Point
  getter x : Int32
  @[Crystalizer::Field(key: "Y")]
  getter y : String

  def initialize(@x, @y)
  end
end

point = Point.new 1, "a"

{Crystalizer::YAML, Crystalizer::JSON}.each do |format|
  puts format
  string = format.serialize point
  puts string
  puts format.deserialize string, to: Point
end

Result:

Crystalizer::YAML
---
x: 1
Y: a
Point(@x=1, @y="a")
Crystalizer::JSON
{
  "x": 1,
  "Y": "a"
}
Point(@x=1, @y="a")

Any

Parsing any type, and converting to JSON/YAML.

require "crystalizer/json"
require "crystalizer/yaml"

yaml_string = <<-E
one: 1
two: 2
sub:
  ary:
  - one
  - 2
E

yaml_any = Crystalizer::YAML.parse yaml_string
puts yaml_any

json_string = Crystalizer::JSON.serialize yaml_any
puts json_string

json_any = Crystalizer::JSON.parse json_string
puts Crystalizer::YAML.serialize json_any

Result:

{"one" => 1, "two" => 2, "sub" => {"ary" => ["one", 2]}}
{
  "one": 1,
  "two": 2,
  "sub": {
    "ary": [
      "one",
      2
    ]
  }
}
---
one: 1
two: 2
sub:
  ary:
  - one
  - 2

User-defined serialization

Allows to define custom serialization and deserialization for a given type.

struct MyType
  include Crystalizer::Type

  def initialize(@i : Int32)
  end

  def self.deserialize(deserializer : Crystalizer::Deserializer)
    new deserializer.deserialize to: Int32
  end

  def serialize(serializer : Crystalizer::Serializer) : Nil
    serializer.serialize @i
  end
end

Note

Annotations are similar to the stdlib's Serializable, but all features are not yet fully implemented.

crystalizer