Adaptive card in teams not workig - REST API - node.js

Question

I created a bot (nodejs server) for teams - through bot framework.
I'm trying to send adaptive card that I created through: adaptive cards designer
and I get error :
{"code":"BadArgument","message":"ContentType of an attachment is not set"}
The request body :
{
"type": "message",
"from": {
"id": "xxxxxx"
},
"conversation": {
"id": "xxxxxx"
},
"recipient": {
"id": "xxxxx"
},
"replyToId": "xxxxx",
"text": "some text",
"attachments": [
{
"type": "AdaptiveCard",
"$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
"version": "1.2",
"body": [
{
"type": "TextBlock",
"text": "some text"
},
{
"type": "Input.Date",
"separator": true
}
]
}
]
}
I would appreciate help

Answer 1

When adding attachments you'll want to set the contentType and content properties of the attachment object.
https://learn.microsoft.com/en-us/azure/bot-service/rest-api/bot-framework-rest-connector-api-reference?view=azure-bot-service-4.0#attachment-object
{
"type": "message",
"from": {
"id": "xxxxxx"
},
"conversation": {
"id": "xxxxxx"
},
"recipient": {
"id": "xxxxx"
},
"replyToId": "xxxxx",
"text": "some text",
"attachments": [
{
"contentType": "application/vnd.microsoft.card.adaptive",
"content": {
"type": "AdaptiveCard",
"$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
"version": "1.2",
"body": [
{
"type": "TextBlock",
"text": "some text"
},
{
"type": "Input.Date",
"separator": true
}
]
}
}
]
}

Answer 2

As per the comments above, this is a pro-active message, but using the Bot Framework libraries are a much better approach than trying to call the bot endpoints directly (I wondered if, by "REST", you meant the Bot Framework endpoint or the Graph Api, but in either case the Bot Framework is easier to work with for proactive messages).
Please see specifically this sample for how to do this in Node.