serialize

Source-generated serialization for Dart objects. This package uses package:source_gen to eliminate the time you spend writing boilerplate serialization code for your models. package:angel_serialize also powers package:angel_orm.

• Usage
  • Models
    • @Alias(...)
    • @exclude
  • Nesting

Usage

In your pubspec.yaml, you need to install the following dependencies:

dependencies:
  angel_serialize: ^1.0.0-alpha
dev_dependencies:
  angel_serialize_generator: ^1.0.0-alpha
  build_runner: ^0.5.0

You'll want to create a Dart script, usually named tool/phases.dart that invokes the JsonModelGenerator.

import 'package:build_runner/build_runner.dart';
import 'package:source_gen/source_gen.dart';
import 'package:angel_serialize_generator/angel_serialize_generator.dart';

final List<BuildAction> actions = [
  new BuildAction(new PartBuilder([const JsonModelGenerator()]),
      '<package-name>',
      inputs: const ['test/models/*.dart'])
];

And then, a tool/build.dart can build your serializers:

import 'package:build_runner/build_runner.dart';
import 'phases.dart';

main() => build(actions, deleteFilesByDefault: true);

If you want to watch for file changes and re-build when necessary, replace the build call with a call to watch. They take the same parameters.

Models

There are a few changes opposed to normal Model classes. You need to add a @serializable annotation to your model class to have it serialized, and a serializable model class's name should also start with a leading underscore. In addition, you may consider using an abstract class.

Rather you writing the public class, angel_serialize does it for you. This means that the main class can have its constructors automatically generated, in addition into serialization functions.

For example, say we have a Book model. Create a class named _Book:

library angel_serialize.test.models.book;

import 'package:angel_framework/common.dart';
import 'package:angel_serialize/angel_serialize.dart';
part 'book.g.dart';

@serializable
abstract class _Book extends Model {
  String author, title, description;
  int pageCount;
}

The following will be generated in book.g.dart:

// GENERATED CODE - DO NOT MODIFY BY HAND

part of angel_serialize.test.models.book;

// **************************************************************************
// Generator: JsonModelGenerator
// Target: abstract class _Book
// **************************************************************************

class Book extends _Book {
  @override
  String id;

  @override
  String author;

  @override
  String title;

  @override
  String description;

  @override
  int pageCount;

  @override
  DateTime createdAt;

  @override
  DateTime updatedAt;

  Book(
      {this.id,
      this.author,
      this.title,
      this.description,
      this.pageCount,
      this.createdAt,
      this.updatedAt});

  factory Book.fromJson(Map data) {
    return new Book(
        id: data['id'],
        author: data['author'],
        title: data['title'],
        description: data['description'],
        pageCount: data['page_count'],
        createdAt: data['created_at'] is DateTime
            ? data['created_at']
            : (data['created_at'] is String
                ? DateTime.parse(data['created_at'])
                : null),
        updatedAt: data['updated_at'] is DateTime
            ? data['updated_at']
            : (data['updated_at'] is String
                ? DateTime.parse(data['updated_at'])
                : null));
  }

  Map<String, dynamic> toJson() => {
        'id': id,
        'author': author,
        'title': title,
        'description': description,
        'page_count': pageCount,
        'created_at': createdAt == null ? null : createdAt.toIso8601String(),
        'updated_at': updatedAt == null ? null : updatedAt.toIso8601String()
      };

  static Book parse(Map map) => new Book.fromJson(map);
  
  Book clone() {
    return new Book.fromJson(toJson());
  }
}

Aliases

Whereas Dart fields conventionally are camelCased, most database columns tend to be snake_cased. This is not a problem, because we can define an alias for a field.

By default angel_serialize will transform keys into snake case. Use Alias to provide a custom name, or pass autoSnakeCaseNames: false to the builder;

@serializable
abstract class _Spy extends Model {
  /// Will show up as 'agency_id' in serialized JSON.
  /// 
  /// When deserializing JSON, instead of searching for an 'agencyId' key,
  /// it will use 'agency_id'.
  /// 
  /// Hooray!
  String agencyId;
  
  @Alias('foo')
  String someOtherField;
}

Excluding Keys

In pratice, there may keys that you want to exclude from JSON. To accomplish this, simply annotate them with @exclude:

@serializable
abstract class _Whisper extends Model {
  /// Will never be serialized to JSON
  @exclude
  String secret;
}

Nesting

angel_serialize also supports a few types of nesting of @serializable classes:

• As a class member
• As the type argument to a List
• As the second type argument to a Map

In other words, the following are all legal, and will be serialized/deserialized. Be sure to use the underscored name of a child class (ex. _Book):

@serializable
abstract class _Author extends Model {
  List<_Book> books;
  _Book newestBook;
  Map<String, _Book> booksByIsbn;
}

The caveat here is that nested classes must be written in the same file. source_gen otherwise will not be able to resolve the nested type.

ID and Dates

This package will automatically generate id, createdAt, and updatedAt fields for you, in the style of an Angel Model. To disable this, set autoIdAndDates to false in the builder constructor.