godot/doc/classes/JSON.xml
Rémi Verschelde 4c6bac15a3
Merge pull request #92656 from fire/vsk-json-to-native-4.3
Ability to convert native engine types to JSON and back.
2024-08-30 09:58:57 +02:00

153 lines
7.5 KiB
XML

<?xml version="1.0" encoding="UTF-8" ?>
<class name="JSON" inherits="Resource" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
<brief_description>
Helper class for creating and parsing JSON data.
</brief_description>
<description>
The [JSON] class enables all data types to be converted to and from a JSON string. This is useful for serializing data, e.g. to save to a file or send over the network.
[method stringify] is used to convert any data type into a JSON string.
[method parse] is used to convert any existing JSON data into a [Variant] that can be used within Godot. If successfully parsed, use [member data] to retrieve the [Variant], and use [method @GlobalScope.typeof] to check if the Variant's type is what you expect. JSON Objects are converted into a [Dictionary], but JSON data can be used to store [Array]s, numbers, [String]s and even just a boolean.
[codeblock]
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())
[/codeblock]
Alternatively, you can parse strings using the static [method parse_string] method, but it doesn't handle errors.
[codeblock]
var data = JSON.parse_string(json_string) # Returns null if parsing failed.
[/codeblock]
[b]Note:[/b] Both parse methods do not fully comply with the JSON specification:
- Trailing commas in arrays or objects are ignored, instead of causing a parser error.
- New line and tab characters are accepted in string literals, and are treated like their corresponding escape sequences [code]\n[/code] and [code]\t[/code].
- Numbers are parsed using [method String.to_float] which is generally more lax than the JSON specification.
- Certain errors, such as invalid Unicode sequences, do not cause a parser error. Instead, the string is cleaned up and an error is logged to the console.
</description>
<tutorials>
</tutorials>
<methods>
<method name="from_native" qualifiers="static">
<return type="Variant" />
<param index="0" name="variant" type="Variant" />
<param index="1" name="allow_classes" type="bool" default="false" />
<param index="2" name="allow_scripts" type="bool" default="false" />
<description>
Converts a native engine type to a JSON-compliant dictionary.
By default, classes and scripts are ignored for security reasons, unless [param allow_classes] or [param allow_scripts] are specified.
</description>
</method>
<method name="get_error_line" qualifiers="const">
<return type="int" />
<description>
Returns [code]0[/code] if the last call to [method parse] was successful, or the line number where the parse failed.
</description>
</method>
<method name="get_error_message" qualifiers="const">
<return type="String" />
<description>
Returns an empty string if the last call to [method parse] was successful, or the error message if it failed.
</description>
</method>
<method name="get_parsed_text" qualifiers="const">
<return type="String" />
<description>
Return the text parsed by [method parse] (requires passing [code]keep_text[/code] to [method parse]).
</description>
</method>
<method name="parse">
<return type="int" enum="Error" />
<param index="0" name="json_text" type="String" />
<param index="1" name="keep_text" type="bool" default="false" />
<description>
Attempts to parse the [param json_text] provided.
Returns an [enum Error]. If the parse was successful, it returns [constant OK] and the result can be retrieved using [member data]. If unsuccessful, use [method get_error_line] and [method get_error_message] to identify the source of the failure.
Non-static variant of [method parse_string], if you want custom error handling.
The optional [param keep_text] argument instructs the parser to keep a copy of the original text. This text can be obtained later by using the [method get_parsed_text] function and is used when saving the resource (instead of generating new text from [member data]).
</description>
</method>
<method name="parse_string" qualifiers="static">
<return type="Variant" />
<param index="0" name="json_string" type="String" />
<description>
Attempts to parse the [param json_string] provided and returns the parsed data. Returns [code]null[/code] if parse failed.
</description>
</method>
<method name="stringify" qualifiers="static">
<return type="String" />
<param index="0" name="data" type="Variant" />
<param index="1" name="indent" type="String" default="&quot;&quot;" />
<param index="2" name="sort_keys" type="bool" default="true" />
<param index="3" name="full_precision" type="bool" default="false" />
<description>
Converts a [Variant] var to JSON text and returns the result. Useful for serializing data to store or send over the network.
[b]Note:[/b] The JSON specification does not define integer or float types, but only a [i]number[/i] type. Therefore, converting a Variant to JSON text will convert all numerical values to [float] types.
[b]Note:[/b] If [param full_precision] is [code]true[/code], when stringifying floats, the unreliable digits are stringified in addition to the reliable digits to guarantee exact decoding.
The [param indent] parameter controls if and how something is indented; its contents will be used where there should be an indent in the output. Even spaces like [code]" "[/code] will work. [code]\t[/code] and [code]\n[/code] can also be used for a tab indent, or to make a newline for each indent respectively.
[b]Example output:[/b]
[codeblock]
## 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"
......}
...]
}
[/codeblock]
</description>
</method>
<method name="to_native" qualifiers="static">
<return type="Variant" />
<param index="0" name="json" type="Variant" />
<param index="1" name="allow_classes" type="bool" default="false" />
<param index="2" name="allow_scripts" type="bool" default="false" />
<description>
Converts a JSON-compliant dictionary that was created with [method from_native] back to native engine types.
By default, classes and scripts are ignored for security reasons, unless [param allow_classes] or [param allow_scripts] are specified.
</description>
</method>
</methods>
<members>
<member name="data" type="Variant" setter="set_data" getter="get_data" default="null">
Contains the parsed JSON data in [Variant] form.
</member>
</members>
</class>