Set Dialogflow response object based on user platform - chatbot

Question

I have a webhook server that responds to Dialogflow with rich message objects, which work on the Google Assistant.
However, in the case the user chatting with my bot from a different platform other than Google Assitant, such as the web or Amazon Alexa, I would like to send a basic text response.
After looking through the docs, I am not sure how I can send a response message object that will display a rich message object when the user uses Google Assistant, and a plain text response on other platforms as a fallback.
This is the format of my current rich message response object, taken from the docs: https://dialogflow.com/docs/reference/agent/message-objects#basic_card_response
{
"messages": [
{
"buttons": [
{
"openUrlAction": {
"url": "https://linkUrl.com"
},
"title": "AoG Card Link title"
}
],
"formattedText": "AoG Card Description",
"image": {
"url": "http://imageUrl.com"
},
"platform": "google",
"subtitle": "AoG Card Subtitle",
"title": "AoG Card Title",
"type": "basic_card"
}
]
}

Answer 1

To do this, you'll just include a regular text/speech response in the messages object.
In the /query doc, check out the POST response sample.
Your JSON should look something like this:
{
"messages": [
{
"buttons": [
{
"openUrlAction": {
"url": "https://linkUrl.com"
},
"title": "AoG Card Link title"
}
],
"formattedText": "AoG Card Description",
"image": {
"url": "http://imageUrl.com"
},
"platform": "google",
"subtitle": "AoG Card Subtitle",
"title": "AoG Card Title",
"type": "basic_card"
},
{
"speech": "text response",
"type": 0
}
]
}