Create a card message

This page explains how to create and send card-based messages as a Google Chat app. Cards support a defined layout, interactive UI elements like buttons, and rich media like images. To learn more about the ways you can use cards, see Design dynamic, interactive, and consistent UIs with cards. For more information about messages, see Google Chat messages overview.

Prerequisites

Node.js

Note: The Node.js code samples in this guide are written to run as a Google Cloud Function.

Python

Note: The Python code samples in this guide are written to run as a Google Cloud Function, using Python 3.9.

Apps Script

Create card messages

This section describes how to create card messages in two ways: by responding to a user interaction and calling the Google Chat API asynchronously.

Respond to a user

Chat apps can create card messages to respond to a user interaction, such as when a user sends the Chat app a message or adds the Chat app to a space. To learn more about responding to user interactions, see Receive and respond to Chat app interaction events.

In this example, a user sends a message to a Chat app and the Chat app responds by sending a card message that displays the user's name and avatar image:

A Chat app responding with a card featuring the sender's display name and avatar image.

Node.js

node/avatar-app/index.js
/**
 * Google Cloud Function that responds to messages sent from a
 * Google Chat room.
 *
 * @param {Object} req Request sent from Google Chat room
 * @param {Object} res Response to send back
 */
exports.helloChat = function helloChat(req, res) {
  if (req.method === 'GET' || !req.body.message) {
    res.send('Hello! This function is meant to be used in a Google Chat ' +
      'Room.');
  }

  const sender = req.body.message.sender.displayName;
  const image = req.body.message.sender.avatarUrl;

  const data = createMessage(sender, image);

  res.send(data);
};

/**
 * Creates a card with two widgets.
 * @param {string} displayName the sender's display name
 * @param {string} imageUrl the URL for the sender's avatar
 * @return {Object} a card with the user's avatar.
 */
function createMessage(displayName, imageUrl) {
  const cardHeader = {
    title: `Hello ${displayName}!`,
  };

  const avatarWidget = {
    textParagraph: {text: 'Your avatar picture: '},
  };

  const avatarImageWidget = {
    image: {imageUrl},
  };

  const avatarSection = {
    widgets: [
      avatarWidget,
      avatarImageWidget,
    ],
  };

  return {
    cardsV2: [{
      cardId: 'avatarCard',
      card: {
        name: 'Avatar Card',
        header: cardHeader,
        sections: [avatarSection],
      }
    }],
  };
}

Python

python/avatar-app/main.py
from typing import Any, Mapping

import flask
import functions_framework


# Google Cloud Function that responds to messages sent in
# Google Chat.
#
# @param {Object} req Request sent from Google Chat.
# @param {Object} res Response to send back.
@functions_framework.http
def hello_chat(req: flask.Request) -> Mapping[str, Any]:
  if req.method == "GET":
    return "Hello! This function must be called from Google Chat."

  request_json = req.get_json(silent=True)

  display_name = request_json["message"]["sender"]["displayName"]
  avatar = request_json["message"]["sender"]["avatarUrl"]

  response = create_message(name=display_name, image_url=avatar)

  return response


# Creates a card with two widgets.
# @param {string} name the sender's display name.
# @param {string} image_url the URL for the sender's avatar.
# @return {Object} a card with the user's avatar.
def create_message(name: str, image_url: str) -> Mapping[str, Any]:
  avatar_image_widget = {"image": {"imageUrl": image_url}}
  avatar_text_widget = {"textParagraph": {"text": "Your avatar picture:"}}
  avatar_section = {"widgets": [avatar_text_widget, avatar_image_widget]}

  header = {"title": f"Hello {name}!"}

  cards = {
      "cardsV2": [
          {
              "cardId": "avatarCard",
              "card": {
                  "name": "Avatar Card",
                  "header": header,
                  "sections": [avatar_section],
              },
          }
      ]
  }

  return cards

Apps Script

apps-script/avatar-app/hello-chat.gs
/**
 * Responds to a MESSAGE event in Google Chat.
 *
 * @param {Object} event the event object from Google Chat
 */
function onMessage(event) {
  const displayName = event.message.sender.displayName;
  const avatarUrl = event.message.sender.avatarUrl;

  return createMessage(displayName, avatarUrl);
}

/**
 * Creates a card with two widgets.
 * @param {string} displayName the sender's display name
 * @param {string} avatarUrl the URL for the sender's avatar
 * @return {Object} a card with the sender's avatar.
 */
function createMessage(displayName, avatarUrl) {
  const cardHeader = {
    title: `Hello ${displayName}!`
  };

  const avatarWidget = {
    textParagraph: {text: 'Your avatar picture: '}
  };

  const avatarImageWidget = {
    image: {imageUrl: avatarUrl}
  };

  const avatarSection = {
    widgets: [
      avatarWidget,
      avatarImageWidget
    ],
  };

  return {
    cardsV2: [{
      cardId: 'avatarCard',
      card: {
        name: 'Avatar Card',
        header: cardHeader,
        sections: [avatarSection],
      }
    }],
  };
}

Call the Google Chat API

The following explains how to create a card message by asynchronously calling the Google Chat API.

Calling the Chat API asynchronously requires authentication. Since only Chat apps can create card messages, a Chat app must use app authentication to create and send card messages (Chat apps can't use user authentication to send card messages on behalf of users). To learn more, see Google Chat authentication overview.

In this example, you create the following card message using app authentication:

A card message created with the Google Chat API.
Figure 1: A card message created with the Chat API.

To set up authentication and learn about creating messages asynchronously, see the Chat API guide.

Python

  1. In your working directory, create a file named chat_create_card_message.py.

  2. Include the following code in chat_create_card_message.py:

    from httplib2 import Http
from oauth2client.service_account import ServiceAccountCredentials
from apiclient.discovery import build

# Specify required scopes.
SCOPES = ['https://www.googleapis.com/auth/chat.bot']

# Specify service account details.
CREDENTIALS = ServiceAccountCredentials.from_json_keyfile_name(
    'credentials.json', SCOPES)

# Build the URI and authenticate with the service account.
chat = build('chat', 'v1', http=CREDENTIALS.authorize(Http()))

# Create a Chat message.
result = chat.spaces().messages().create(

    # The space to create the message in.
    #
    # Replace SPACE with a space name.
    # Obtain the space name from the spaces resource of Chat API,
    # or from a space's URL.
    parent='spaces/SPACE',

    # The message to create.
    body=
    {
      'cardsV2': [{
        'cardId': 'createCardMessage',
        'card': {
          'header': {
            'title': 'A Card Message!',
            'subtitle': 'Created with Chat REST API',
            'imageUrl': 'https://developers.google.com/chat/images/chat-product-icon.png',
            'imageType': 'CIRCLE'
          },
          'sections': [
            {
              'widgets': [
                {
                  'buttonList': {
                    'buttons': [
                      {
                        'text': 'Read the docs!',
                        'onClick': {
                          'openLink': {
                            'url': 'https://developers.google.com/chat'
                          }
                        }
                      }
                    ]
                  }
                }
              ]
            }
          ]
        }
      }]
    }

).execute()

print(result)

  3. In the code, replace SPACE with a space name, which you can obtain from the spaces.list() method in the Chat API, or from a space's URL.

  4. In your working directory, build and run the sample:

    python3 chat_create_card_message.py

To learn more about working with messages in the Chat API, see the following:

Troubleshoot

When a Google Chat app or card returns an error, the Chat interface surfaces a message saying "Something went wrong." or "Unable to process your request." Sometimes the Chat UI doesn't display any error message, but the Chat app or card produces an unexpected result; for example, a card message might not appear.

Although an error message might not display in the Chat UI, descriptive error messages and log data are available to help you fix errors when error logging for Chat apps is turned on. For help viewing, debugging, and fixing errors, see Troubleshoot and fix Google Chat errors.