Instance of 'Response<dynamic>' flutter Api Consumption

Question

I am trying to make a post request in flutter using chopper. I have made an ApiService.dart file as a generator file.

import 'package:bindle/Chopper/Models/LoginResponse.dart';
import 'package:chopper/chopper.dart';
part 'ApiService.chopper.dart';

@ChopperApi(baseUrl: 'http://192.168.1.20/bindal/api/v1/user/')
abstract class ApiService extends ChopperService {

  @Post(path: "login")
  Future<Response<LoginResponse>> doLogin([
  @Header('auth_key') String authType,
  @Query('email') String email,
  @Query('password') String password,
  @Query('userType') String userType,
  ]);

  static ApiService create() {
  final client = ChopperClient(
   // The first part of the URL is now here
   baseUrl: 'http://192.168.1.20/bindal/api/v1/user/',
   services: [
     // The generated implementation
     _$ApiService(),
   ],
   interceptors: [
    HttpLoggingInterceptor()
   ],
    // Converts data to & from JSON and adds the application/json header.
    converter: JsonConverter(),
  );

  // The generated class with the ChopperClient passed in
  return _$ApiService(client);
 }
}

And this is my generated file.

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'ApiService.dart';

// **************************************************************************
// ChopperGenerator
// **************************************************************************

class _$ApiService extends ApiService {
 _$ApiService([ChopperClient client]) {
 if (client == null) return;
 this.client = client;
}

final definitionType = ApiService;

Future<Response<LoginResponse>> doLogin(
   [String authType, String email, String password, String userType]) {
  final $url = 'http://192.168.1.20/bindal/api/v1/user/login';
  final Map<String, dynamic> $params = {
  'email': email,
  'password': password,
  'userType': userType
 };
 final $headers = {'auth_key': authType};
 final $request = Request('POST', $url, client.baseUrl,
    parameters: $params, headers: $headers);
return client.send<LoginResponse, LoginResponse>($request);
 }
}

Next what i Did is i generated a model class called as LoginResponse where I have to fetch the data.

abstract class LoginResponse implements Built<LoginResponse, LoginResponseBuilder> {

int get status;
String get message;

LoginResponse._();

factory LoginResponse([void Function(LoginResponseBuilder) updates]) = _$LoginResponse;
static LoginResponse fromJson(String jsonString){
return serializers.deserializeWith(LoginResponse.serializer, json.decode(jsonString));
}
 static Serializer<LoginResponse> get serializer => _$loginResponseSerializer; 
 }

this is the generated file for the above LoginResponse.dart file using built_value generator

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'LoginResponse.dart';

// **************************************************************************
// BuiltValueGenerator
// **************************************************************************

Serializer<LoginResponse> _$loginResponseSerializer =
 new _$LoginResponseSerializer();

class _$LoginResponseSerializer implements StructuredSerializer<LoginResponse> {
@override
final Iterable<Type> types = const [LoginResponse, _$LoginResponse];
@override
final String wireName = 'LoginResponse';

@override
Iterable<Object> serialize(Serializers serializers, LoginResponse object,
   {FullType specifiedType = FullType.unspecified}) {
   final result = <Object>[
   'status',
   serializers.serialize(object.status, specifiedType: const FullType(int)),
   'message',
   serializers.serialize(object.message,
       specifiedType: const FullType(String)),
  ];

 return result;
 }

 @override
 LoginResponse deserialize(
    Serializers serializers, Iterable<Object> serialized,
    {FullType specifiedType = FullType.unspecified}) {
    final result = new LoginResponseBuilder();

   final iterator = serialized.iterator;
   while (iterator.moveNext()) {
   final key = iterator.current as String;
   iterator.moveNext();
   final dynamic value = iterator.current;
   switch (key) {
     case 'status':
       result.status = serializers.deserialize(value,
           specifiedType: const FullType(int)) as int;
       break;

    case 'message':
       result.message = serializers.deserialize(value,
           specifiedType: const FullType(String)) as String;
       break;
   }
 }

 return result.build();
  }
 }

 class _$LoginResponse extends LoginResponse {
@override
final int status;
@override
final String message;

factory _$LoginResponse([void Function(LoginResponseBuilder) updates]) =>
   (new LoginResponseBuilder()..update(updates)).build();

_$LoginResponse._({this.status, this.message}) : super._() {
 if (status == null) {
   throw new BuiltValueNullFieldError('LoginResponse', 'status');
 }
 if (message == null) {
   throw new BuiltValueNullFieldError('LoginResponse', 'message');
   }
  }

 @override
 LoginResponse rebuild(void Function(LoginResponseBuilder) updates) =>
   (toBuilder()..update(updates)).build();

  @override
 LoginResponseBuilder toBuilder() => new LoginResponseBuilder()..replace(this);

@override
bool operator ==(Object other) {
if (identical(other, this)) return true;
return other is LoginResponse &&
    status == other.status &&
    message == other.message;

}

  @override
 int get hashCode {
  return $jf($jc($jc(0, status.hashCode), message.hashCode));
 }

  @override
  String toString() {
  return (newBuiltValueToStringHelper('LoginResponse')
      ..add('status', status)
      ..add('message', message))
    .toString();
   }
  }

  class LoginResponseBuilder
   implements Builder<LoginResponse, LoginResponseBuilder> {
   _$LoginResponse _$v;

  int _status;
  int get status => _$this._status;
  set status(int status) => _$this._status = status;

  String _message;
  String get message => _$this._message;
  set message(String message) => _$this._message = message;

 LoginResponseBuilder();

  LoginResponseBuilder get _$this {
 if (_$v != null) {
   _status = _$v.status;
   _message = _$v.message;
   _$v = null;
  }
  return this;
 }

  @override
  void replace(LoginResponse other) {
   if (other == null) {
    throw new ArgumentError.notNull('other');
   }
   _$v = other as _$LoginResponse;
 }

  @override
  void update(void Function(LoginResponseBuilder) updates) {
   if (updates != null) updates(this);
  }

  @override
  _$LoginResponse build() {
   final _$result =
      _$v ?? new _$LoginResponse._(status: status, message: message);
   replace(_$result);
   return _$result;
 }
 }

finally i called my api in the login page as

  void doLogin(String email, String pass, BuildContext context) async {
  try {
   final response = await Provider.of<ApiService>(context)
  .doLogin("d1d2fe0514f7d5c748c0e7e085b36f74","[email protected]",
  "e10adc3949ba59abbe56e057f20f883e","App");
   print(response.body);
  } catch (e) {
    print(e);
  }
 }

Which ultimately gives me Exception as => Instance of 'Response dynamic'

Please help me for what I am doing wrong.

Answer 1

The reason why the Response returns dyanmic is because the response wasn't serialized to the model you've defined. If LoginResponse is the model that should be used for the response, the LoginResponse class should have fromJson() that should serialize the json response. You can follow this guide to help you manage json serialization.