classes/class_json

[giscus[bot]]

classes/class_json

Inherits: Resource< RefCounted< Object Helper class for creating and parsing JSON data. Description: The JSON class enables all data types to be converted to and from a JSON string. This is useful ...

https://docs.godotengine.org/en/stable/classes/class_json.html

[8-bit-pixel]

Will it ever have built-in support for YAML or JSON5?
Regular JSON and XML aren’t so human friendly, and having to write out large chunks of NPC dialogue in one of those would be quite labour-intensive. Also, the comments provided by JSON5 and YAML are really useful for readability.

[tetrapod00]

YAML was proposed and rejected in godotengine/godot-proposals#941 (see also godotengine/godot-proposals#5108).
As for JSON5, I don't even see a proposal for it: https://github.com/godotengine/godot-proposals/issues?q=is%3Aissue+json5+.

[Calinou]

You can manually write files in the ConfigFile format, which provides usability similar to JSON5 and can store comments.

[schaefchenaufderweide]

I am sorry, but this help is such a complete mess.

var data_to_send = ["a", "b", "c"]
var json_string = JSON.stringify(data_to_send)
# Save data
# ...
# Retrieve data
var json = JSON.new()
var error = json.parse(json_string)
if error == OK:
	var data_received = json.data
	if typeof(data_received) == TYPE_ARRAY:
		print(data_received) # Prints array
	else:
		print("Unexpected data")
else:
	print("JSON Parse Error: ", json.get_error_message(), " in ", json_string, " at line ", json.get_error_line())

Why would you first save data and then load it again? This doesnt make sense. Examples should state both loading and saving.

[ducviet321]

It's an example to save to a persistent storage, and then read it again when you reopen your app. Maybe the comment should be changed to # Save data to persistent storage

[schaefchenaufderweide]

Also this line doesnt make any sense:

if error == OK:
	var data_received = json.data
	if typeof(data_received) == TYPE_ARRAY:
		print(data_received) # Prints array
	else:
		print("Unexpected data")

Why would you ask if the data is an array, if you want a json-file?

[ducviet321]

Because in the example, it is an array. It was deserialized back into program object of type array

[PrimisSolutions]

A common use case here is to read JSON from a file, which the documentation here does not address.

Suppose you have a file containing a list of names, split into first and last names at res://Data/names.json:

{
    "file_name": "names.json"
    "first_names" : ["Arthur", "James",  "Annie", "Jane"]
    "last_names" : ["Smith", "Edwards", "Thomas"]
}

# get_names.gd
    # Get name data in the form of a dictionary
	var json = JSON.new()
	var names_string= FileAccess.get_file_as_string("res://Data/names.json")
	var names_as_dict= JSON.parse_string(names_string)

    var example_name = names_as_dict["first_names"].pick_random() + " " + names_as_dict["last_names"].pick_random()

[Calinou]

Pull request opened:

• Document saving and loading JSON from/to the filesystem in JSON class example godot#104132

[OtherRealms]

thank you, I could not have figure that out

[cannotuser]

How can I do this from Godot/CSharp?

[RedpingDev]

var data_to_send = ["a", "b", "c"]
var json_string = JSON.stringify(data_to_send)
# Save data
# ...
# Retrieve data
var json = JSON.new()
var error = json.parse(json_string)
if error == OK:
	var data_received = json.data
	if typeof(data_received) == TYPE_ARRAY:
		print(data_received) # Prints array
	else:
		print("Unexpected data")
else:
	print("JSON Parse Error: ", json.get_error_message(), " in ", json_string, " at line ", json.get_error_line())

Now, shouldn't we be doing JSON.new() here?
like this?

var data_to_send = ["a", "b", "c"]
var json_string = JSON.stringify(data_to_send)
# Save data
# ...
# Retrieve data
var parse_result = JSON.parse_string(json_string)
if parse_result.error == OK:
    var data_received = parse_result.result
    if typeof(data_received) == TYPE_ARRAY:
        print(data_received) # Prints array
    else:
        print("Unexpected data")
else:
    print("JSON Parse Error: ", parse_result.error_string)

[hsw2201]

So I don't see it anywhere in the docs but it seems
var my_data = preload("res://my_json.json").data
is easy way to get data from json file in disk I guess

[Calinou]

Note that this only works for JSON files that are imported as Resources in the project. This won't work for arbitrary JSON files on the filesystem (e.g. in user://).

[CreativeHouseDotOrg]

Warning

The docs say stringify() will convert any data type which is not true. Stringify only accepts Variants to be converted to a json formatted string.

stringify() is used to convert any data type into a JSON string.

public static string Stringify(Variant data, string indent = "", bool sortKeys = true, bool fullPrecision = false)
{
  return NativeCalls.godot_icall_4_708(MethodBind0, data, indent, sortKeys.ToGodotBool(), fullPrecision.ToGodotBool());
}

[Calinou]

A Variant is technically "any data type", since even null is considered a Variant (one that is of Nil type).

[CreativeHouseDotOrg]

Yeah but good luck trying that with class objects other than Variants like dtos.

To be able to serialize custom objects I started using System.Text.Json.JsonSerializer.Serialize and System.Text.Json.JsonSerializer.Deserialize<T>.

And imo "any data type" is to ambigious since variants are variants and "any" should really be referred to "any" including variants AND custom objects.

[EiTaNBaRiBoA]

Yeah but good luck trying that with class objects other than Variants like dtos.

To be able to serialize custom objects I started using System.Text.Json.JsonSerializer.Serialize and System.Text.Json.JsonSerializer.Deserialize<T>.

And imo "any data type" is to ambigious since variants are variants and "any" should really be referred to "any" including variants AND custom objects.

I’ve developed JsonClassConverter, a Godot plugin designed serializing and deserializing Godot classes to and from JSON, and it has features for JSON comparison, diffing, and manipulation.
ForgeJSONGD Repo
ForgeJSONGD in Godot Asset Library

[CreativeHouseDotOrg]

Yeah but good luck trying that with class objects other than Variants like dtos.
To be able to serialize custom objects I started using System.Text.Json.JsonSerializer.Serialize and System.Text.Json.JsonSerializer.Deserialize<T>.
And imo "any data type" is to ambigious since variants are variants and "any" should really be referred to "any" including variants AND custom objects.

I’ve developed JsonClassConverter, a Godot plugin designed serializing and deserializing Godot classes to and from JSON, and it has features for JSON comparison, diffing, and manipulation. JsonClassConverter Repo JsonClassConverter in Godot Asset Library

Is there a C# Wrapper as well?

[EiTaNBaRiBoA]

Yeah but good luck trying that with class objects other than Variants like dtos.
To be able to serialize custom objects I started using System.Text.Json.JsonSerializer.Serialize and System.Text.Json.JsonSerializer.Deserialize<T>.
And imo "any data type" is to ambigious since variants are variants and "any" should really be referred to "any" including variants AND custom objects.

I’ve developed JsonClassConverter, a Godot plugin designed serializing and deserializing Godot classes to and from JSON, and it has features for JSON comparison, diffing, and manipulation. JsonClassConverter Repo JsonClassConverter in Godot Asset Library

Is there a C# Wrapper as well?

Yes

using Godot;

[GlobalClass]
public partial class PlayerData : GodotObject
{
    [Export]
    public string Name { get; set; }

    [Export]
    public int Score { get; set; }
}

public partial class GameManager : Node
{
    private const string SavePath = "user://player_data.json";
    private const string ForgeJSONGDPath = "res://addons/ForgeJSONGD/ForgeJSONGD.gd";

    public override void _Ready()
    {
        // Load the ForgeJSONGD singleton script
        var forgeJsonScript = ResourceLoader.Load<Script>(ForgeJSONGDPath);

        // --- SAVE DATA ---
        var player = new PlayerData { Name = "C-Sharp Hero", Score = 1500 };
        var jsonDict = forgeJsonScript.Call("class_to_json", player);
        forgeJsonScript.Call("store_json_file", SavePath, jsonDict);
        GD.Print("Player data saved from C#!");

        // --- LOAD DATA ---
        var loadedPlayer = forgeJsonScript.Call("json_file_to_class", new PlayerData(), SavePath).As<PlayerData>();
        if (loadedPlayer != null)
        {
            GD.Print($"Loaded Player: {loadedPlayer.Name}, Score: {loadedPlayer.Score}");
            // Output: Loaded Player: C-Sharp Hero, Score: 1500
        }
    }
}