module JSON::Serializable::Fake

Overview

JSON::Serializable::Fake allows method calls to generate JSON content.

Example

require "json/fakefield"

class Sum
  include JSON::Serializable
  include JSON::Serializable::Fake

  property a : UInt32
  property b : UInt32

  def initialize(@a, @b)
  end

  @[JSON::FakeField]
  def sum(json : ::JSON::Builder) : Nil
    json.number(a + b)
  end
end

s = Sum.new(10, 5)
puts s.to_json # => { "a": 10, "b": 5, "sum": 15 }

Usage

JSON::Serializable::Fake will create extend_to_json (which will actually call your methods) and will replace the on_to_json method generated by JSON::Serializable.

JSON::Serializable::Fake is compatible with JSON::Serializable::Unmapped and JSON::Serializable::Strict as long as JSON::Serializable::Fake is included last.

You can customize the behavior of each fake field via the JSON::FakeField annotation. Method calls MUST accept ::JSON::Builder as a parameter and return ::Nil. The construction of JSON elements is handled via ::JSON::Builder.

JSON::FakeField properties:

• key: an explicit name of the field added to the json string (by default it uses the method name)
• suppress_key: if true no json field will be implictly added. This allows the method call to create multiple json fields

WARNING At the moment it is not possible to deserialize fake fields into a method call. There is no technical limitation, just a lack of time. However, you can use JSON::Serializable::Unmapped to capture all the fake fields.

Defined in:

json-serializable-fake.cr:3
json-serializable-fake.cr:61

Constant Summary

VERSION = "0.0.1"

Instance Method Summary

• #to_json(json : JSON::Builder)

  heavily modelled after: https://github.com/crystal-lang/crystal/blob/fda656c71/src/json/serialization.cr#L181

Instance Method Detail