JSON handling

Working with Json from Blueprints

Some of these features are only available in V27 onwards

To work with HTTP / WebSockets effectively, you'll often need to manipulate JSON data from Blueprint.

To facilitate this, we have enabled Epic's JsonBlueprintUtilities plugin which offers a collection of nodes for manipulating Json Objects. In addition, we have provided an extended set of nodes to augment the out of the box features that Epic provide.

Json Blueprint Utilities

Epic's JsonBlueprintUtilities plugin offers several useful features:

To / From String

Load Json From String

This can take a JSON string and convert it to a JSON Object

Get Json String

Converts a JSON Object to a JSON string

Convert Struct to Json String

Converts a UStruct directly to a JSON string

Get / Set Fields

The Get Field node allows you to retrieve a specific field from a JSON Object. The return value is a wildcard and so requires explicitly casting or connecting to an input pin.

The Set Field node allows you to set a specific field on a JSON Object with a wildcard typed field.

Internally this relies on Unreal's Json Serializer, so if a wildcard type is not explicitly serializable to/from Json you may end up with unexpected failures or results.

Field Inspection

Has Field

Allows you to inspect if a Json Object has a specific field.

Get Field Names

allows you to list all the field names on an object; which can then be used to enumerate them in a loop.

JSON Utilities

We have augmented Epic's nodes with some of our own to further facilitate working with JSON data.

To / From UStruct

Make Json Object from Struct

Converts any UStruct to a JSON object.

Make Struct from Json Object

Converts a JSON object into a struct of a specific, known type

Read Json Object into struct

Uses an existing struct (eg: in a variable) to read a JSON object

Nested Objects

Get Json Object at Location

Allows you to specifiy a dot.delimited.path to a field containing a JSON object.

For example; given this JSON object

{
    "person": {
        "forename": "alice",
        "surname": "smith"
    },
    "contact": {
        "address": {
            "street": "park avenue",
            "town": "exampleville"
        }
    }
}

The path of contact.address would return a Json Object containing:

{
    "street": "park avenue",
    "town": "exampleville"
}

To Map

This node allows you to read all fields into a specified (pre-made) map of either strings or integers.