Feature - Versionable serialization

[e1himself]

The idea is to have different serializers (and unserializers) that can handle JSONs of different versions.

$prev_version_json = $serializer->serialize($value, '0.44');
$current_version_json = $serializer->serialize($value);

---

Changelog

• Model classes are not JsonSerializable anymore (BC break)

• Add (optional) version property to all serialized Value objects (BC break)

• Unserializer class has been dropped in favour of Serializer (BC break)
  Also the namespace has changed:
  Prezly\Slate\Unserializer → Prezly\Slate\Serialization\Serializer.

• Serializer class changed interface (BC break)

  class Serializer implements ValueSerializer 
  {
      /**
       * Serialize value to JSON
       *
       * Optionally you can provide desired serialization version.
       *
       * If no version argument provided, default serialization version
       * will be used (which is set to LATEST by default).
       *
       * @param \Prezly\Slate\Model\Value $value
       * @param string|null $version
       * @return string
       */
      public function toJson(Value $value, ?string $version = null): string
  
      /**
       * Unserialize value from JSON
       *
       * Optional you can provide serialization version to use
       * in case if value JSON does not have "version" property.
       *
       * If no version argument is given, default serialization
       * version will be implied (which is set to LATEST by default).
       *
       * @param string $value
       * @param string|null $default_version
       * @return \Prezly\Slate\Model\Value
       */
      public function fromJson(string $value, ?string $default_version = null): Value;
  }

  • Implement VersionSerializer for v0.40 ... v0.45
  • Implement VersionSerializer for v0.46+