[HTML] Fallback and Requires support

[dclaux]

Implements #2019

[dclaux]

Sample payload to test with:

{
    "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
    "type": "AdaptiveCard",
    "version": "1.0",
    "fallbackText": "This is the fallback text",
    "fallback": {
        "type": "TextBlock",
        "text": "This is the fallback element"
    },
    "body": [
        {
            "type": "Container",
            "fallback": {
                "type": "TextBlock",
                "text": "The container is falling back."
            },
            "selectAction": {
                "type": "Action.OpenUrl",
                "title": "Hello world",
                "url": "http://www.microsoft.com"
            },
            "items": [
                {
                    "type": "TextBlock",
                    "text": "Publish Adaptive Card schema",
                    "weight": "bolder",
                    "size": "medium"
                },
                {
                    "type": "ActionSet",
                    "actions": [
                        {
                            "type": "Action.OpenfUrl",
                            "title": "Hello world",
                            "url": "http://www.microsoft.com"
                        }
                    ]
                },
                {
                    "type": "Image",
                    "size": "large",
                    "url": "http://cdn.nirmaltv.com/images/Powerpoint-2013.png",
                    "fallback": "drop",
                    "selectAction": {
                        "type": "Action.OpenUrl",
                        "title": "Hello world",
                        "url": "http://www.microsoft.com"
                    }
                }
            ]
        },
        {
            "type": "ColumnSet",
            "selectAction": {
                "type": "Action.OpenUrl",
                "title": "Hello world",
                "url": "http://www.microsoft.com"
            },
            "columns": [
                {
                    "width": 1,
                    "style": "emphasis",
                    "items": [
                        {
                            "type": "TextBlock",
                            "text": "Column 1",
                            "horizontalAlignment": "center"
                        }
                    ]
                },
                {
                    "width": 1,
                    "style": "emphasis",
                    "items": [
                        {
                            "type": "TextBlock",
                            "text": "Column 2",
                            "horizontalAlignment": "center"
                        }
                    ]
                },
                {
                    "width": 1,
                    "style": "emphasis",
                    "fallback": "drop",
                    "items": [
                        {
                            "type": "TextBlock",
                            "text": "Column 3",
                            "horizontalAlignment": "center"
                        }
                    ]
                }
            ]
        }
    ],
    "actions": [
        {
            "type": "Action.OpefnUrl",
            "title": "Hello world",
            "url": "http://www.microsoft.com",
            "fallback": {
                "type": "Action.OpenUrl",
                "title": "Fallback action",
                "url": "http://www.microsoft.com"
            }
        }
    ]
}

[paulcam206]

        throw new Error("The action already belongs to another element.")

or is null? also, ; #Closed

---

Refers to: source/nodejs/adaptivecards/src/card-elements.ts:3666 in 077c274. [](commit_id = 077c274, deletion_comment = False)

[paulcam206]

[dclaux]

Now supports "requires" clause. Can be tested via the Outlook host in the visualizer, which defines two "capabilities":

• helloWorld, any version
• whatNot, version 2.12

To test, select the Outloook Actionable Messages host container, and add a "requires" property to any element, action or the card itself. For instance:

"requires": {
  "whatNow": "3.0"
}

The above will cause the element/action/card to fall back.

[paulcam206]

🕐