godot-docs/classes/class_json.rst

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.. _class_JSON:

JSON
====

**Inherits:** :ref:`RefCounted<class_RefCounted>` **<** :ref:`Object<class_Object>`

Helper class for creating and parsing JSON data.

Description
-----------

The ``JSON`` enables all data types to be converted to and from a JSON string. This useful for serializing data to save to a file or send over the network.

\ :ref:`stringify<class_JSON_method_stringify>` is used to convert any data type into a JSON string.

\ :ref:`parse<class_JSON_method_parse>` is used to convert any existing JSON data into a :ref:`Variant<class_Variant>` that can be used within Godot. If successfully parsed, use :ref:`get_data<class_JSON_method_get_data>` to retrieve the :ref:`Variant<class_Variant>`, and use ``typeof`` to check if the Variant's type is what you expect. JSON Objects are converted into a :ref:`Dictionary<class_Dictionary>`, but JSON data can be used to store :ref:`Array<class_Array>`\ s, numbers, :ref:`String<class_String>`\ s and even just a boolean.

\ **Example**\ 

::

    var data_to_send = ["a", "b", "c"]
    var json = JSON.new()
    var json_string = json.stringify(data_to_send)
    # Save data
    # ...
    # Retrieve data
    var error = json.parse(json_string)
    if error == OK:
        var data_received = json.get_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())

Methods
-------

+---------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`Variant<class_Variant>`         | :ref:`get_data<class_JSON_method_get_data>` **(** **)** |const|                                                                                                                                                           |
+---------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`int<class_int>`                 | :ref:`get_error_line<class_JSON_method_get_error_line>` **(** **)** |const|                                                                                                                                               |
+---------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`String<class_String>`           | :ref:`get_error_message<class_JSON_method_get_error_message>` **(** **)** |const|                                                                                                                                         |
+---------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`Error<enum_@GlobalScope_Error>` | :ref:`parse<class_JSON_method_parse>` **(** :ref:`String<class_String>` json_string **)**                                                                                                                                 |
+---------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`String<class_String>`           | :ref:`stringify<class_JSON_method_stringify>` **(** :ref:`Variant<class_Variant>` data, :ref:`String<class_String>` indent="", :ref:`bool<class_bool>` sort_keys=true, :ref:`bool<class_bool>` full_precision=false **)** |
+---------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Method Descriptions
-------------------

.. _class_JSON_method_get_data:

- :ref:`Variant<class_Variant>` **get_data** **(** **)** |const|

Returns the :ref:`Variant<class_Variant>` containing the data of a successful :ref:`parse<class_JSON_method_parse>`.

\ **Note:** It will return ``Null`` if the last call to parse was unsuccessful or :ref:`parse<class_JSON_method_parse>` has not yet been called.

----

.. _class_JSON_method_get_error_line:

- :ref:`int<class_int>` **get_error_line** **(** **)** |const|

Returns ``0`` if the last call to :ref:`parse<class_JSON_method_parse>` was successful, or the line number where the parse failed.

----

.. _class_JSON_method_get_error_message:

- :ref:`String<class_String>` **get_error_message** **(** **)** |const|

Returns an empty string if the last call to :ref:`parse<class_JSON_method_parse>` was successful, or the error message if it failed.

----

.. _class_JSON_method_parse:

- :ref:`Error<enum_@GlobalScope_Error>` **parse** **(** :ref:`String<class_String>` json_string **)**

Attempts to parse the ``json_string`` provided.

Returns an :ref:`Error<enum_@GlobalScope_Error>`. If the parse was successful, it returns ``OK`` and the result can be retrieved using :ref:`get_data<class_JSON_method_get_data>`. If unsuccessful, use :ref:`get_error_line<class_JSON_method_get_error_line>` and :ref:`get_error_message<class_JSON_method_get_error_message>` for identifying the source of the failure.

----

.. _class_JSON_method_stringify:

- :ref:`String<class_String>` **stringify** **(** :ref:`Variant<class_Variant>` data, :ref:`String<class_String>` indent="", :ref:`bool<class_bool>` sort_keys=true, :ref:`bool<class_bool>` full_precision=false **)**

Converts a :ref:`Variant<class_Variant>` var to JSON text and returns the result. Useful for serializing data to store or send over the network.

\ **Note:** The JSON specification does not define integer or float types, but only a *number* type. Therefore, converting a Variant to JSON text will convert all numerical values to :ref:`float<class_float>` types.

\ **Note:** If ``full_precision`` is true, when stringifying floats, the unreliable digits are stringified in addition to the reliable digits to guarantee exact decoding.

The ``indent`` parameter controls if and how something is indented, the string used for this parameter will be used where there should be an indent in the output, even spaces like ``"   "`` will work. ``\t`` and ``\n`` can also be used for a tab indent, or to make a newline for each indent respectively.

\ **Example output:**\ 

::

    ## JSON.stringify(my_dictionary)
    {"name":"my_dictionary","version":"1.0.0","entities":[{"name":"entity_0","value":"value_0"},{"name":"entity_1","value":"value_1"}]}
    
    ## JSON.stringify(my_dictionary, "\t")
    {
        "name": "my_dictionary",
        "version": "1.0.0",
        "entities": [
            {
                "name": "entity_0",
                "value": "value_0"
            },
            {
                "name": "entity_1",
                "value": "value_1"
            }
        ]
    }
    
    ## JSON.stringify(my_dictionary, "...")
    {
    ..."name": "my_dictionary",
    ..."version": "1.0.0",
    ..."entities": [
    ......{
    ........."name": "entity_0",
    ........."value": "value_0"
    ......},
    ......{
    ........."name": "entity_1",
    ........."value": "value_1"
    ......}
    ...]
    }

.. |virtual| replace:: :abbr:`virtual (This method should typically be overridden by the user to have any effect.)`
.. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`
.. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`
.. |constructor| replace:: :abbr:`constructor (This method is used to construct a type.)`
.. |static| replace:: :abbr:`static (This method doesn't need an instance to be called, so it can be called directly using the class name.)`
.. |operator| replace:: :abbr:`operator (This method describes a valid operator to use with this type as left-hand operand.)`