用键盘发送 "welcome message" 到 Viber 机器人

Send "welcome message" with keyboard to Viber bot

Viber API 允许在 conversation_started 事件类型上发送一些消息以允许用户订阅。从 documentation about "welcome message",我看到以下代码成功发送了文本和图像:

{
    "sender": {
        "name": "John McClane",
        "avatar": "http://avatar.example.com"
    },
    "tracking_data": "tracking data",
    "type": "text",
    "text": "Welcome to our bot!",
    "media": "http://www.images.com/img.jpg",
    "thumbnail": "http://www.images.com/thumb.jpg"
}

但是如何在那里添加一些按钮?
我希望我的用户能够按他们订阅并开始与我的机器人对话。

我尝试在消息中添加以下内容,但没有成功:

"keyboard": {
    "Type": "keyboard",
    "DefaultHeight": true,
    "Buttons": [{
        "ActionType": "reply",
        "ActionBody": "reply to me",
        "Text": "Key text",
        "TextSize": "regular"
    }]
}

经过一些尝试,我发现不能同时使用 media + thumbnailkeyboard 在同一个“欢迎消息”中。所以我删除了 mediathumbnail 键。现在以下代码有效:

{
    "sender": {
        "name": "John McClane",
        "avatar": "http://avatar.example.com"
    },
    "tracking_data": "tracking data",
    "type": "text",
    "text": "Welcome to our bot!",
    "keyboard": {
        "Type": "keyboard",
        "DefaultHeight": true,
        "Buttons": [{
            "ActionType": "reply",
            "ActionBody": "reply to me",
            "Text": "Key text",
            "TextSize": "regular"
        }]
    }
}