Nitrite/Flutter: Getting an error creating an ObjectRepository

[381outrageousDoors]

I'm new to Nitrite and Flutter, so I'm not sure if I'm missing something and could use some help. I'm trying to follow the docs to create an ObjectRepository for a Todo Object with an embedded Properties Object to understand how Nitrite works but hitting errors

I've tried both the code generator and doing it manually with an EntityDecorator.

The Todo Object has 1 field, the embedded final nonNull Properties object.
The Properties Object has 2 fields: a final nonNull String id and a final nonNull Map titled locations

Using the code generator, I annotated Todo with Entity and Convertable and Properties with Convertable. It looks like it breaks on getting the NitriteMapper.pluginManager. Also, the generated no2 files for Todo and Properties have errors saying "type dynamic can't be assigned to the parameter" when it tries to instantiate the objects.

Using EntityDecorator, it either says the errors above or when I try to cast the dynamic "document[fieldName]" to the specific type, it errors with the error at the bottom of this:

EntityDecorator for the Todo Object

class TodoDecorator extends EntityDecorator<Todo> {
  @override
  String get entityName => 'todos';

  @override
  EntityId? get idField => EntityId('properties', false, ['id']);

  @override
  List<EntityIndex> get indexFields => const [];
}

2 EntityConverters, 1 for Todo and the other for Properties and registered both using registerEntityConverter()

class TodoConverter extends EntityConverter<Todo> {
  @override
  Todo fromDocument(Document document, NitriteMapper nitriteMapper) {
    final propsDoc = document['properties'];
    var properties = nitriteMapper.tryConvert<Properties, Document>(propsDoc);
    return Todo(
     properties: properties,
    );
  }

class PropertiesConverter extends EntityConverter<Properties> {
  @override
  Properties fromDocument(Document document, NitriteMapper nitriteMapper) {
    final map = Map<String,String>();
    final locations = document['locations'] == null
        ? map
        : document['locations'];

    for (final entry in locations.entries) {
      final key = nitriteMapper.tryConvert<String, dynamic>(entry.key);
      final value = nitriteMapper.tryConvert<String, dynamic>(entry.value);
       map[key] = value ;
    }

    return Properties(
          id: document['id'],
          locations: map,
      );
  }

Then I try to create the TodoRepository using the TodoDecorator
final repository = await db.getRepository<Todo>(entityDecorator: TodoDecorator());

From there, it goes through some nitrite checks, confirms there is no TodosRepository and goes to create it. As part of the validation it goes into the fromDocument method for my TodoConverter. Then when it does tryConvert on the propsDoc, I get this error from nitrite's validation_utils:
type 'Null' is not a subtype of type 'Properties' in type cast

The debugger says the document passed into FromDocument is an empty map and the property it's trying to convert is null, which makes sense because the document and database are empty, but why is it trying to convert when it's supposed to be creating a repository? It feels like I missed a step but don't know what

Any help would be appreciated

[anidotnet]

Thanks for trying out Nitrite. Here is the code that would work in your case.

import 'dart:io';

import 'package:faker/faker.dart';
import 'package:nitrite/nitrite.dart';
import 'package:nitrite_hive_adapter/nitrite_hive_adapter.dart';

part 'github_test.no2.dart'; // <-- generated file

@Convertable()
@Entity()
class Todo with _$TodoEntityMixin {
  @Id()
  final String id;
  final Properties? properties;

  Todo({
    required this.id,
    this.properties,
  });

  @override
  String toString() {
    return 'Todo{id: $id, properties: $properties}';
  }
}

@Convertable()
class Properties {
  final String id;
  final Map<String, dynamic> locations;

  Properties({
    required this.id,
    required this.locations,
  });

  @override
  String toString() {
    return 'Properties{id: $id, locations: $locations}';
  }
}

void main() async {
  var faker = Faker();
  var dbPath = '${Directory.current.path}/db/${faker.guid.guid()}';

  var storeModule =
      HiveModule.withConfig().crashRecovery(true).path(dbPath).build();

  var db = await Nitrite.builder()
      .loadModule(storeModule)
      .registerEntityConverter(TodoConverter())                 // <-- generated converter
      .registerEntityConverter(PropertiesConverter())        // <-- generated converter
      .openOrCreate();

  var todoRepository = await db.getRepository<Todo>();

  var todo = Todo(
    id: faker.guid.guid(),
    properties: Properties(
      id: faker.guid.guid(),
      locations: {
        'location1': 'location1',
        'location2': 'location2',
      },
    ),
  );

  await todoRepository.insert(todo);

  var todoById = await todoRepository.getById(todo.id);
  print(todoById);
}

Notice the properties field is nullable in Todo object. The idea is, if you are using custom data type it has to be nullable for the entity validation to work. Probably, I'll have to clarify this more in the documentation.

[anidotnet]

Documentation has been updated here.

[381outrageousDoors]

Thank you that fixed me up!
Another question, do I need a converter for enums?

I have one in my Properties object and when I try to insert a todo, it breaks on converting the enum to a document.

[381outrageousDoors]

I ended up trying a customer converter for my enum:

class TodoTypeConverter extends EntityConverter<TodoType>{
  @override
  TodoTypefromDocument(Document document, NitriteMapper nitriteMapper) {
    if (document.isNotEmpty) {
      return TodoType.values.byName(document['type'] as String);
    } else {
      return TodoType.todo;
    }
  }

  @override
  Document toDocument(TodoTypeentity, NitriteMapper nitriteMapper) {
    return emptyDocument()
      ..put('type', entity.name);
  }
}

but I'm still getting this error

ObjectMappingException: Failed to map null to document
#0      new NitriteException (package:nitrite/src/exception/exceptions.dart:8:47)
#1      new ObjectMappingException (package:nitrite/src/exception/exceptions.dart)
#2      EntityId.createUniqueFilter (package:nitrite/src/repository/entity.dart:41:15)

[anidotnet]

Well it should be straight forward.

@Convertable()
@Entity()
class Todo with _$TodoEntityMixin {
  @Id()
  final String id;
  final Properties? properties;

  Todo({
    required this.id,
    this.properties,
  });

  @override
  String toString() {
    return 'Todo{id: $id, properties: $properties}';
  }
}

@Convertable()
class Properties {
  final String id;
  final TodoType type;
  final Map<String, dynamic> locations;

  Properties({
    required this.id,
    required this.type,
    required this.locations,
  });

  @override
  String toString() {
    return 'Properties{id: $id, locations: $locations}';
  }
}

enum TodoType { personal, work }

class TodoTypeConverter extends EntityConverter<TodoType> {
  @override
  TodoType fromDocument(Document document, NitriteMapper nitriteMapper) {
    return TodoType.values[document['type']];
  }

  @override
  Document toDocument(TodoType entity, NitriteMapper nitriteMapper) {
    var document = emptyDocument();
    document.put('type', entity.index);
    return document;
  }
}

[anidotnet]

You should register the TodoTypeConverter like other converters while opening the database, you should be good.

[anidotnet]

I have pushed a new version 1.1.0 just now, which supports code generation for enums. You don't need to manually write converters for enum anymore.

[381outrageousDoors]

Also, if I have my id in Properties, is this the correct implementation to have Nitrite use it for EntityId

  @Id(fieldName: 'id', embeddedFields: ['id'])
  final Properties? properties;

My error seems to be on line 154 in repository_operations.dart. It can't find the embedded id because it says idValue is null

[anidotnet]

You can declare the id this way:

@Entity()
@Convertable()
class Todo with _$TodoEntityMixin {
  @Id(fieldName: 'properties', embeddedFields: ['id'])
  final Properties? properties;

  Todo({
    this.properties,
  });

  @override
  String toString() {
    return 'Todo{properties: $properties}';
  }

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is Todo &&
          runtimeType == other.runtimeType &&
          properties == other.properties;

  @override
  int get hashCode => properties.hashCode;
}

@Convertable()
class Properties {
  final String id;
  final TodoType type;
  final Map<String, dynamic> locations;

  Properties({
    required this.id,
    required this.type,
    required this.locations,
  });

  @override
  String toString() {
    return 'Properties{id: $id, type: $type, locations: $locations}';
  }

  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is Properties &&
          runtimeType == other.runtimeType &&
          id == other.id &&
          type == other.type &&
          MapEquality().equals(locations, other.locations);

  @override
  int get hashCode => id.hashCode ^ type.hashCode ^ locations.hashCode;
}

@Convertable()
enum TodoType { personal, work }

And while retrieving by id, you can call this:

var byId = await todoRepository.getById('abcd-id-value');