Dialogflow CX -- System Function in Custom Payload

[Raunix]

Hi there!

I am using Dialogflow CX to create a conversational agent.

I have connected to a DataStore (CSV with some columns), and the chatbot easily recognises the response for each question stored in the CSV.

I saw in a previous topic of this forum that you can use a system function to dynamically retrieve the URL associated to each question (another column in the CSV), and the link is provided to the user with the response. The function is  $sys.func.GET_FIELD($sys.func.GET($request.knowledge.sources[0], 0), "uri")

I would like to insert that dynamic link in a custom payload to give some format to the given URL, something like this:

{
"richContent": [
    [
        {
            "type": "button",
            "text": "Learn More",
            "link": "$sys.func.GET_FIELD($sys.func.GET($request.knowledge.sources[0], 0), 'uri')"
        }
    ]
                            ]
}

This is not working, the link is not recognised (retrieves null), and i would prefer not to develop a Webhook;

Do you guys know any workaround to achieve a system function recognizable in a Custom Payload or the Webhook is the only way to embellish a dynamic link in DialogFlow??