jaguar_json

This package provides jaguar_serializer based interceptors, utitity methods and utility classes for Jaguar to make encoding and decoding JSON easier.

Interceptors

jaguar_json exposes interceptors to encode and decode Dart objects to and from JSON using two methods:

1. Using Serializer
2. Using JsonRepo

Using Serializer

Encode, Decode and Codec interceptors are provided to encode and decode json. Both these interceptors accept an instance of the Serializer<ModelType> class that it internally uses to serialize and deserialize.

Encode automatically serializes result returned from the route method. Care must be taken that the route returns an object of type ModelType.

Decode automatically de-serializes JSON body in the request to ModelType. The de-serialized dart object can be obtained in the route method using ctx.getInterceptorResult(Decode).

@Api(path: '/api/book')
class BookRoutes {
  static json.Decode decoder(_) => new json.Decode(bookSerializer);

  static json.Encode<Book> encoder(_) => new json.Encode<Book>(bookSerializer);

  @Post()
  @Wrap(const [decoder, encoder])
  Book one(Context ctx) {
    final Book book = ctx.getInterceptorResult(json.Decode);
    return book;
  }

  @Post(path: '/many')
  @Wrap(const [decoder, encoder])
  List<Book> list(Context ctx) => ctx.getInterceptorResult(json.Decode);
}

Using JsonRepo

Using JsonRepo simplifies the encoding and decoding. First task is to create a JsonRepo object and add all the required serializers to it.

EncodeRepo, DecodeRepo and CodecRepo interceptors are provided to encode and decode json using repo. Both these interceptors accept an instance of JsonRepo that it internally uses to find the appropriate serializer to serialize and deserialize. For the decoder to find the right serializer, the incoming JSON body must have a type field. The type field can be set in the DecodeRepo using typeKey argument.

final JsonRepo repo = new JsonRepo(
    serializers: [personSerializer, bookSerializer], withType: true);

json.CodecRepo codec(_) => new json.CodecRepo(repo);

@Api(path: '/api/book')
class BookRoutes {
  @Get()
  @WrapOne(codec)
  Book get(Context ctx) => new Book.fromNum(5);

  @Post()
  @WrapOne(codec)
  Book post(Context ctx) {
    final book = ctx.getInterceptorResult<Book>(json.CodecRepo);
    return book;
  }
}

JsonRoutes utility class

Apis can extend JsonRoutes class to get access to toJson and fromJson methods that using JsonRepo to make encoding and decoding JSON easier.

@Api(path: '/api/book')
class BookRoutes extends Object with json.JsonRoutes {
  JsonRepo get repo => models.repo;

  @Get()
  Response<String> get(Context ctx) => toJson(new Book.fromNum(5));

  @Post()
  Future<Response<String>> post(Context ctx) async =>
      toJson(await fromJson(ctx));
}

Utility functions

Global functions serialize and deserialize helps in encoding and decoding JSON using Serializer.

@Api(path: '/api/book')
class BookRoutes {
  @Get()
  Response<String> get(Context ctx) =>
      json.serialize(bookSerializer, new Book.fromNum(5));

  @Post()
  Future<Response<String>> post(Context ctx) async => json.serialize(
      bookSerializer, await json.deserialize(bookSerializer, ctx));
}