JSON NESTED CLASSES PROBLEM

[meladam20]

I want to use complex nested classes so i have this two classes

@JsonSerializable(explicitToJson: true)
@DataRepository([JsonServerAdapter])
class User extends DataModel {
final String? id;
final String firstName;
final String lastName;
final List role;
}

AND

class Role extends DataModel {
final String? id;
final String libelleRole;
}

All things work well, i can save data in local but when i use hot reload, i get this error :

flutter: [flutter_data] Box failed to open:
type '_Map<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>'
#0 _$UserFromJson. user.g.dart:62

AND

this is the line 62 of user.g.dart file

User _$UserFromJson(Map<String, dynamic> json) => User(
id: json['_id'] as String?,
firstName: json['firstName'] as String,
lastName: json['lastName'] as String,
email: json['email'] as String,
password: json['password'] as String,
(Line62)role: (json['role'] as List)
.map((e) => Role.fromJson(e as Map<String, dynamic>))
.toList(),
);

Please can you help me ?

[meladam20]

Hello @frank06 , please help me. I need an anwser.

[meladam20]

When i use HasMany or either Belong, i can't receive data in my mongo database with my nodejs server. I try it during long time but any issue so i used "List" to progress.

[frank06]

Look around https://github.com/flutterdata there is enough sample code, you should be able to make it work

[meladam20]

I think that the problem is in my nodejs server

i change List in HasMany like that :

@JsonSerializable(explicitToJson: true)
@DataRepository([JsonServerAdapter])
class User extends DataModel {
final String? id;
final String firstName;
final String lastName;
final HasMany role;

User({
this.id,
required this.firstName,
required this.lastName,
required this.email,
required this.password,
required this.role,
});
}

And the user that i want to save in mongo database :

final developerRole = Role(libelleRole: 'developpeur');

final user = User(
    firstName: firstName.text,
    lastName: lastName.text,
    email: email.text,
    password: password.text,
    role: HasMany({developerRole}));

user.save();

Look at my mongoose model

const UserSchema = new mongoose.Schema({
firstName: {
type: String,
required: true
},
lastName: {
type: String,
required: true
},
email: {
type: String,
required: true
},
password: {
type: String,
required: true
},
role: [{
type: 'ObjectId',
ref: 'Role',
}]
},
{versionKey: false}
);

But in my user.controller.js of the nodejs, i can't get the value of the field "Role" in req.body

const addUser = async (req, res) => {
console.log(req.body);
const newUser = new User({...req.body});
let userSave = await newUser.save();
res.json(userSave);
};

In the console, the value of req.body is :

{
role: [],
_id: 648caa6429ad10965a0c455b,
firstName: 'zer',
lastName: 'zef',
email: '[email protected]',
password: '$2a$10$QOIiUv3ExqhB6RdjjBWCj.JGNUeayFraXdjTdkgluPQTCqFDTkM42'
}

Please why the value of array role is always empty despite all my tests ?

[meladam20]

Please @frank06, this is a right way to save model witth hasMany relationship ?

final developerRole = Role(libelleRole: 'developpeur');

final user = User(
firstName: firstName.text,
lastName: lastName.text,
email: email.text,
password: password.text,
role: HasMany({developerRole}));
user.save();

I just want to be sure that is right way to remote this kind of data.

[frank06]

I don't have time to go through you code, I'm sorry

If you want to save relationship data you definitely need to override the serializers. Please search the issues https://github.com/flutterdata/flutter_data/issues , I'm sure I explained that a few times. I might have explained it to you in one of yours.

Here's a good example of custom serializers (just for the structure): https://github.com/flutterdata/flutter_data_json_api_adapter

If not just set up your debugger and step through FD code, it's not hard to understand the whole process