best practice to fetch data from api in flutter - flutter

Question

i am working on news application (full-stack) and i am using strapi for back-end and flutter as front-end and i wondering if there is some standard or pattern to fetch data from api in flutter (or any front-end )
cuz there are many methods can be used but i am asking for best approach ,
for example i can fetch list of data with it's related entities to the front end ( with http://localhost:1337/api/news-items?populate=*
but the problem with this approach is
if any related entity is null an exception occurred [thank for
null-safety ]
the model or dto become very complex that leads to get god class
class NewsItemList {
NewsItemList({
required this.data,
required this.meta,
});
List<NewsItemListDatum> data;
Meta meta;
factory NewsItemList.fromJson(Map<String, dynamic> json) => NewsItemList(
data: List<NewsItemListDatum>.from(json["data"].map((x) => NewsItemListDatum.fromJson(x))),
meta: Meta.fromJson(json["meta"]),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
"meta": meta.toJson(),
};
}
class NewsItemListDatum {
NewsItemListDatum({
required this.id,
required this.attributes,
});
int id;
PurpleAttributes attributes;
factory NewsItemListDatum.fromJson(Map<String, dynamic> json) => NewsItemListDatum(
id: json["id"],
attributes: PurpleAttributes.fromJson(json["attributes"]),
);
Map<String, dynamic> toJson() => {
"id": id,
"attributes": attributes.toJson(),
};
}
class PurpleAttributes {
PurpleAttributes({
required this.title,
required this.description,
required this.pubDate,
required this.author,
required this.createdAt,
required this.updatedAt,
required this.content,
required this.link,
required this.source,
required this.thumbnail,
required this.newsCats,
required this.comments,
required this.governorate,
required this.likes,
});
String title;
String description;
String pubDate;
String author;
DateTime createdAt;
DateTime updatedAt;
String content;
String link;
String source;
String thumbnail;
NewsCats newsCats;
Comments comments;
Governorate governorate;
Likes likes;
factory PurpleAttributes.fromJson(Map<String, dynamic> json) => PurpleAttributes(
title: json["title"],
description: json["description"],
pubDate: json["pubDate"],
author: json["author"],
createdAt: DateTime.parse(json["createdAt"]),
updatedAt: DateTime.parse(json["updatedAt"]),
content: json["content"],
link: json["link"],
source: json["source"],
thumbnail: json["thumbnail"],
newsCats: NewsCats.fromJson(json["news_cats"]),
comments: Comments.fromJson(json["comments"]),
governorate: Governorate.fromJson(json["governorate"]),
likes: Likes.fromJson(json["likes"]),
);
Map<String, dynamic> toJson() => {
"title": title,
"description": description,
"pubDate": pubDate,
"author": author,
"createdAt": createdAt.toIso8601String(),
"updatedAt": updatedAt.toIso8601String(),
"content": content,
"link": link,
"source": source,
"thumbnail": thumbnail,
"news_cats": newsCats.toJson(),
"comments": comments.toJson(),
"governorate": governorate.toJson(),
"likes": likes.toJson(),
};
}
class Comments {
Comments({
required this.data,
});
List<CommentsDatum> data;
factory Comments.fromJson(Map<String, dynamic> json) => Comments(
data: List<CommentsDatum>.from(json["data"].map((x) => CommentsDatum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class CommentsDatum {
CommentsDatum({
required this.id,
required this.attributes,
});
int id;
FluffyAttributes attributes;
factory CommentsDatum.fromJson(Map<String, dynamic> json) => CommentsDatum(
id: json["id"],
attributes: FluffyAttributes.fromJson(json["attributes"]),
);
Map<String, dynamic> toJson() => {
"id": id,
"attributes": attributes.toJson(),
};
}
class FluffyAttributes {
FluffyAttributes({
required this.content,
required this.createdAt,
required this.updatedAt,
});
String content;
DateTime createdAt;
DateTime updatedAt;
factory FluffyAttributes.fromJson(Map<String, dynamic> json) => FluffyAttributes(
content: json["content"],
createdAt: DateTime.parse(json["createdAt"]),
updatedAt: DateTime.parse(json["updatedAt"]),
);
Map<String, dynamic> toJson() => {
"content": content,
"createdAt": createdAt.toIso8601String(),
"updatedAt": updatedAt.toIso8601String(),
};
}
class Governorate {
Governorate({
required this.data,
});
Dat data;
factory Governorate.fromJson(Map<String, dynamic> json) => Governorate(
data: Dat.fromJson(json["data"]),
);
Map<String, dynamic> toJson() => {
"data": data.toJson(),
};
}
class Dat {
Dat({
required this.id,
required this.attributes,
});
int id;
DataAttributes attributes;
factory Dat.fromJson(Map<String, dynamic> json) => Dat(
id: json["id"],
attributes: DataAttributes.fromJson(json["attributes"]),
);
Map<String, dynamic> toJson() => {
"id": id,
"attributes": attributes.toJson(),
};
}
class DataAttributes {
DataAttributes({
required this.name,
required this.createdAt,
required this.updatedAt,
});
String name;
DateTime createdAt;
DateTime updatedAt;
factory DataAttributes.fromJson(Map<String, dynamic> json) => DataAttributes(
name: json["name"],
createdAt: DateTime.parse(json["createdAt"]),
updatedAt: DateTime.parse(json["updatedAt"]),
);
Map<String, dynamic> toJson() => {
"name": name,
"createdAt": createdAt.toIso8601String(),
"updatedAt": updatedAt.toIso8601String(),
};
}
class Likes {
Likes({
required this.data,
});
List<LikesDatum> data;
factory Likes.fromJson(Map<String, dynamic> json) => Likes(
data: List<LikesDatum>.from(json["data"].map((x) => LikesDatum.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class LikesDatum {
LikesDatum({
required this.id,
required this.attributes,
});
int id;
TentacledAttributes attributes;
factory LikesDatum.fromJson(Map<String, dynamic> json) => LikesDatum(
id: json["id"],
attributes: TentacledAttributes.fromJson(json["attributes"]),
);
Map<String, dynamic> toJson() => {
"id": id,
"attributes": attributes.toJson(),
};
}
class TentacledAttributes {
TentacledAttributes({
required this.likeit,
required this.createdAt,
required this.updatedAt,
required this.publishedAt,
});
bool likeit;
DateTime createdAt;
DateTime updatedAt;
DateTime publishedAt;
factory TentacledAttributes.fromJson(Map<String, dynamic> json) => TentacledAttributes(
likeit: json["likeit"],
createdAt: DateTime.parse(json["createdAt"]),
updatedAt: DateTime.parse(json["updatedAt"]),
publishedAt: DateTime.parse(json["publishedAt"]),
);
Map<String, dynamic> toJson() => {
"likeit": likeit,
"createdAt": createdAt.toIso8601String(),
"updatedAt": updatedAt.toIso8601String(),
"publishedAt": publishedAt.toIso8601String(),
};
}
class NewsCats {
NewsCats({
required this.data,
});
List<Dat> data;
factory NewsCats.fromJson(Map<String, dynamic> json) => NewsCats(
data: List<Dat>.from(json["data"].map((x) => Dat.fromJson(x))),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
};
}
class Meta {
Meta({
required this.pagination,
});
Pagination pagination;
factory Meta.fromJson(Map<String, dynamic> json) => Meta(
pagination: Pagination.fromJson(json["pagination"]),
);
Map<String, dynamic> toJson() => {
"pagination": pagination.toJson(),
};
}
class Pagination {
Pagination({
required this.page,
required this.pageSize,
required this.pageCount,
required this.total,
});
int page;
int pageSize;
int pageCount;
int total;
factory Pagination.fromJson(Map<String, dynamic> json) => Pagination(
page: json["page"],
pageSize: json["pageSize"],
pageCount: json["pageCount"],
total: json["total"],
);
Map<String, dynamic> toJson() => {
"page": page,
"pageSize": pageSize,
"pageCount": pageCount,
"total": total,
};
}
the code generated using https://app.quicktype.io/
3- delay occurred cuz of transection in the backend and amount of data handled in application
4- although it is hard coded but it is useful cuz i don't need to make a lot of api calls [ like get comments where item id is 5 ]
or i can fetch a list of data without it's related entities
in this case i will get list of items and every time i need get related entity i make another api call
class NewsItemsListApiData {
NewsItemsListApiData({
required this.data,
required this.meta,
});
List<NewsItem> data;
Meta meta;
factory NewsItemsListApiData.fromJson(Map<String, dynamic> json) =>
NewsItemsListApiData(
data:
List<NewsItem>.from(json["data"].map((x) => NewsItem.fromJson(x))),
meta: Meta.fromJson(json["meta"]),
);
Map<String, dynamic> toJson() => {
"data": List<dynamic>.from(data.map((x) => x.toJson())),
"meta": meta.toJson(),
};
}
class NewsItem {
NewsItem({
required this.id,
required this.attributes,
});
int id;
Attributes attributes;
factory NewsItem.fromJson(Map<String, dynamic> json) => NewsItem(
id: json["id"],
attributes: Attributes.fromJson(json["attributes"]),
);
Map<String, dynamic> toJson() => {
"id": id,
"attributes": attributes.toJson(),
};
}
class Attributes {
Attributes({
required this.title,
required this.description,
required this.pubDate,
required this.author,
required this.createdAt,
required this.updatedAt,
required this.content,
required this.link,
required this.source,
required this.thumbnail,
});
String title;
String description;
String pubDate;
String author;
DateTime createdAt;
DateTime updatedAt;
String content;
String link;
String source;
String thumbnail;
factory Attributes.fromJson(Map<String, dynamic> json) => Attributes(
title: json["title"],
description: json["description"],
pubDate: json["pubDate"],
author: json["author"],
createdAt: DateTime.parse(json["createdAt"]),
updatedAt: DateTime.parse(json["updatedAt"]),
content: json["content"],
link: json["link"],
source: json["source"],
thumbnail: json["thumbnail"],
);
Map<String, dynamic> toJson() => {
"title": title,
"description": description,
"pubDate": pubDate,
"author": author,
"createdAt": createdAt.toIso8601String(),
"updatedAt": updatedAt.toIso8601String(),
"content": content,
"link": link,
"source": source,
"thumbnail": thumbnail,
};
}
class Meta {
Meta({
required this.pagination,
});
Pagination pagination;
factory Meta.fromJson(Map<String, dynamic> json) => Meta(
pagination: Pagination.fromJson(json["pagination"]),
);
Map<String, dynamic> toJson() => {
"pagination": pagination.toJson(),
};
}
class Pagination {
Pagination({
required this.page,
required this.pageSize,
required this.pageCount,
required this.total,
});
int page;
int pageSize;
int pageCount;
int total;
factory Pagination.fromJson(Map<String, dynamic> json) => Pagination(
page: json["page"],
pageSize: json["pageSize"],
pageCount: json["pageCount"],
total: json["total"],
);
Map<String, dynamic> toJson() => {
"page": page,
"pageSize": pageSize,
"pageCount": pageCount,
"total": total,
};
}
so any ideas about best practice and clean code or any other methods makes the code less error prone and more clean ?