Ditto.asByteBuffer(bytePayload) throws exception

Question

In the eclipse-ditto mappingcontext I placed following incomingScript:

function mapToDittoProtocolMsg(headers, textPayload, bytePayload, contentType) {
switch (contentType) {
    case "application/json":
        var jsonData = JSON.parse(textPayload);
        var temperature = jsonData.temp;
        var humidity = jsonData.hum;
        var path;
        var value;
        if (temperature != null && humidity != null) {
            path = "/features";
            value = {
                temperature: {
                    properties: {
                        value: temperature
                    }
                },
                humidity: {
                    properties: {
                        value: humidity
                    }
                }
            };
        } else if (temperature != null) {
            path = "/features/temperature/properties/value";
            value = temperature;
        } else if (humidity != null) {
            path = "/features/humidity/properties/value";
            value = humidity;
        }
        if (!path || !value) {
            return null;
        }
        return Ditto.buildDittoProtocolMsg("tenant_aloxy", headers["device_id"], "things", "twin", "commands", "modify", path, headers, value);
        break;
    case "application/octet-stream":
        let byteBuf = Ditto.asByteBuffer(bytePayload);
        var path = "/features/alp/properties/value";
        var value = 21;
        return Ditto.buildDittoProtocolMsg("tenant_aloxy", headers["device_id"], "things", "twin", "commands", "modify", path, headers, value);
    default:
        return null;
}

}

When I send in binary data, I'm hitting the second case of the switch as expected. However, when it tries to convert the incoming data as a bytebuffer (Ditto.asByteBuffer(bytePayload);) it throws following exception:

ReferenceError: "dcodeIO" is not defined.

Answer 1

That helper function in the "Ditto" scope requires the "ByteBuffer.js" library as described in the documentation: https://www.eclipse.org/ditto/connectivity-mapping.html#bytebufferjs (dcodeIO was used as scope for that library).

That means you have simply to enable that this library is loaded in the configuration of your mapping: https://www.eclipse.org/ditto/connectivity-mapping.html#configuration-options

{
  "incomingScript": "...",
  "outgoingScript": "...",
  "loadBytebufferJS": true,
  "loadLongJS": true
}

After that you should be able to use Ditto.asByteBuffer()