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support for nested items in @JsonKey(name:) #490

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support for nested items in @JsonKey(name:)#490
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P2 mediumState: help wantedType: enhancement
@KorbinianMossandl

Description

@KorbinianMossandl
KorbinianMossandl
opened on May 22, 2019 · edited by KorbinianMossandl

It would be great if we could directly access nested items in the name String of @JsonKey. Consider this Json:

"root_item": {
    "items": [
        {
            "name": "first nested item"
        },
        {
            "name": "second nested item"
        }
    ]
}

I would like to do:

@JsonKey(name: "root_item/items")
List<NestedItem> nestedItems;

Sorry if this is already possible, but i could not find anything.

Activity

kevmoo
added
Type: enhancement
P2 medium
on May 24, 2019
kevmoo

kevmoo commented on May 24, 2019

@kevmoo
kevmoo
on May 24, 2019
Collaborator

Interesting idea. It is currently not supported.

vanlooverenkoen

vanlooverenkoen commented on Jun 20, 2019

@vanlooverenkoen
vanlooverenkoen
on Jun 20, 2019
Contributor

This should really be added. Now we have to create extra objects because we had to use a crappy backend. Using a simple api to flatten your backend models

jayden320

jayden320 commented on Aug 12, 2019

@jayden320
jayden320
on Aug 12, 2019

I really need this feature. Is it supported now?

vanlooverenkoen

vanlooverenkoen commented on Oct 23, 2019

@vanlooverenkoen
vanlooverenkoen
on Oct 23, 2019
Contributor

Is there a roadmap for this feature? What timeframe could we expect for a P2?

k-paxian

k-paxian commented on Dec 21, 2019

@k-paxian
k-paxian
on Dec 21, 2019 · edited by k-paxian

If you guys are still waiting for that feature, this library already has it implemented
https://github.com/k-paxian/dart-json-mapper#nesting-configuration

@KorbinianMossandl thank you for a great idea! This thing is called rfc6901

vanlooverenkoen

vanlooverenkoen commented on Dec 23, 2019

@vanlooverenkoen
vanlooverenkoen
on Dec 23, 2019
Contributor

Thanks. but I need to use json_serializable. Because I am using retrofit.dart that uses toJson and fromJson.

kevmoo
added
State: help wanted
on Dec 23, 2019
kevmoo

kevmoo commented on Dec 23, 2019

@kevmoo
kevmoo
on Dec 23, 2019
Collaborator

PRs welcome here!

NicolaVerbeeck

NicolaVerbeeck commented on Dec 24, 2019

@NicolaVerbeeck
NicolaVerbeeck
on Dec 24, 2019

I am working on an implementation for this.
Rough draft can be found here: https://github.com/Chimerapps/json_serializable/tree/feature/json_path

WIP, not ready for production

mokai

mokai commented on Jan 3, 2020

@mokai
mokai
on Jan 3, 2020

Necessary function !

taoyimin

taoyimin commented on Jan 3, 2020

@taoyimin
taoyimin
on Jan 3, 2020

I really need this feature!

masewo

masewo commented on Mar 28, 2020

@masewo
masewo
on Mar 28, 2020

I forked @NicolaChimerapps fork and corrected two small errors:
https://github.com/masewo/json_serializable/tree/feature/json_path
For now it is working for me.

kevmoo

kevmoo commented on Mar 28, 2020

@kevmoo
kevmoo
on Mar 28, 2020
Collaborator

@masewo and @NicolaChimerapps – I'll happily take a solid PR with testing, etc

16 remaining items

kevmoo

kevmoo commented on Dec 28, 2021

@kevmoo
kevmoo
on Dec 28, 2021
Collaborator

There is NOT an open PR on this. That was a mistake.

The issue here: we need some other syntax for key that's not a String because any String can be a valid key in a JSON map. So we'd need to support List<String> for key – or add another value. Both of which are quite a bit of work!

ad-on-is

ad-on-is commented on Jan 29, 2022

@ad-on-is
ad-on-is
on Jan 29, 2022

There is NOT an open PR on this. That was a mistake.

The issue here: we need some other syntax for key that's not a String because any String can be a valid key in a JSON map. So we'd need to support List<String> for key – or add another value. Both of which are quite a bit of work!

How about something like

@JsonSerialiable(explicitJson: true, keySeparator: ">")


class Person {
@JsonKey(name: 'name>fist_name')
String name;
}
kevmoo
added a commit that references this issue on Feb 3, 2022

example: Add an example demonstrating how to do nested fields

ac08cc2
kevmoo
closed this as completedin 2dfffd0on Feb 3, 2022
kevmoo

kevmoo commented on Feb 3, 2022

@kevmoo
kevmoo
on Feb 3, 2022
Collaborator

After consideration, I've decided not to invest time here. It adds a LOT of complexity.

If you still want this feature, it's pretty easy to implement with a JsonConverter

See https://github.com/google/json_serializable.dart/blob/master/example/lib/nested_values_example.dart

qevka

qevka commented on Feb 7, 2022

@qevka
qevka
on Feb 7, 2022 · edited by qevka

After consideration, I've decided not to invest time here. It adds a LOT of complexity.

If you still want this feature, it's pretty easy to implement with a JsonConverter

See https://github.com/google/json_serializable.dart/blob/master/example/lib/nested_values_example.dart

That would be nice if JsonConvert was actually working. I am having the same problem that is mentioned here: #1066

I tried downgrading my build_runner and json_annotation packages and also tried just using your code directly neither worked.

Alameen688

Alameen688 commented on Mar 21, 2022

@Alameen688
Alameen688
on Mar 21, 2022

In my case I didn't need the toJson data to transform data back to the original structure I just needed to read the correct data and readValue worked perfectly fine in combination with deep_pick.

@JsonKey(readValue: readNestedItems)
List<NestedItem> nestedItems;
  static List<String, dynamic> readNestedItems(Map json, String key) {
    final fields = pick(json, key, 'items').asListOrEmpty(_yourFromPickFunction);
    return fields;
  }
Veeksi

Veeksi commented on Apr 14, 2022

@Veeksi
Veeksi
on Apr 14, 2022

After consideration, I've decided not to invest time here. It adds a LOT of complexity.
If you still want this feature, it's pretty easy to implement with a JsonConverter
See https://github.com/google/json_serializable.dart/blob/master/example/lib/nested_values_example.dart

That would be nice if JsonConvert was actually working. I am having the same problem that is mentioned here: #1066

I tried downgrading my build_runner and json_annotation packages and also tried just using your code directly neither worked.

I am also having this exact same problem with the explicit json converter

JPaulMora

JPaulMora commented on Dec 16, 2022

@JPaulMora
JPaulMora
on Dec 16, 2022

Chiming in to show support/need for this functionality.

rignaneseleo

rignaneseleo commented on Nov 15, 2023

@rignaneseleo
rignaneseleo
on Nov 15, 2023

Up

EvGeniyLell

EvGeniyLell commented on Dec 21, 2023

@EvGeniyLell
EvGeniyLell
on Dec 21, 2023 · edited by EvGeniyLell

I'm use next solution

@JsonKey(readValue: nestedReader, name: 'extras/apiKey') List<String>? extras,

where nestedReader is

Object? nestedReader(Map json, String key) {
  final keys = key.split('/');
  return _nestedReader(json, keys);
}

Object? _nestedReader(final Object? object, Iterable<String> keys) {
  if (keys.isEmpty || object == null) {
    return object;
  }
  if (object is Map) {
    final subObject = object[keys.first];
    final subKeys = keys.skip(1);
    return _nestedReader(subObject, subKeys);
  }
  if (object is List) {
    return object.fold<dynamic>([], (list, subObject) {
      return list..add(_nestedReader(subObject, keys));
    });
  }
  return object;
}

for this test

void main() {
  final Map map = {
    'extras': [
      {'apiKey': 1, 'name': 'a'},
      {'apiKey': 3, 'name': 'b'},
      {'apiKey': 5, 'name': 'c'},
      {'apiKey': 7, 'name': 'd'},
    ]
  };

  final result = nestedReader(map, 'extra/apiKey');
  print('result $result');
}

result will be

result (1, 3, 5, 7)

update:
also we can declare

class NestedJsonKey extends JsonKey {
  const NestedJsonKey({
    required super.name,
  }) : super(readValue: nestedReader);
}

and use it as

@NestedJsonKey(name: 'lastLocation/lng') double? test,
devnta

devnta commented on Mar 11, 2024

@devnta
devnta
on Mar 11, 2024

There is no solution to this problem in 2024

creativecreatorormaybenot

creativecreatorormaybenot commented on Mar 11, 2024

@creativecreatorormaybenot
creativecreatorormaybenot
on Mar 11, 2024

@phamquoctrongnta check 2dfffd0.

ho-doan-ominext
added 2 commits that reference this issue on Jul 11, 2024

Add JsonSerializabel.constructor

368a8c7

example: Add an example demonstrating how to do nested fields

2dfffd0
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          support for nested items in @JsonKey(name:) · Issue #490 · google/json_serializable.dart