Preview links

  • Google Chat link previewing allows Chat apps to display rich previews of shared links, enhancing context and enabling direct interaction within Chat spaces.

  • Chat apps can be configured to preview specific links by registering URL patterns in the Google Cloud Console.

  • When a matching link is shared, the Chat app receives a MESSAGE event and can respond with either a basic text message or a detailed card attachment containing interactive elements.

  • User interactions with card elements trigger CARD_CLICKED events, allowing the Chat app to update the card dynamically based on user actions.

  • This functionality streamlines workflows by reducing context switching and enabling users to take actions directly from within Chat, improving overall user experience and efficiency.

To prevent context switching when users share a link in Google Chat, your Chat app can preview the link by attaching a card to their message that gives more information and lets people take action right from Google Chat.

For example, imagine a Google Chat space that includes all of a company's customer service agents plus a Chat app named Case-y. Agents frequently share links to customer service cases in the Chat space, and each time they do their colleagues must open the case link to see details like assignee, status, and subject. Likewise, if someone wants to take ownership of a case or change the status, then they need to open the link.

Link previewing enables the space's resident Chat app, Case-y, to attach a card showing assignee, status, and subject whenever someone shares a case link. Buttons on the card let agents take ownership of the case and change the status directly from the chat stream.

When someone adds a link to their message, a chip appears which lets them know that a Chat app might preview the link.

Chip indicating that a Chat app might preview a link

After sending the message, the link is sent to the Chat app, which then generates and attaches the card to the user's message.

Chat app previewing a link by attaching a card to the message

Alongside the link, the card provides additional information about the link, including interactive elements like buttons. Your Chat app can update the attached card in response to user interactions, like button clicks.

If someone doesn't want the Chat app to preview their link by attaching a card to their message, they can prevent previewing by clicking on the preview chip. Users can remove the attached card at any time by clicking Remove preview.

Prerequisites

HTTP

A Google Chat app that receives and responds to user interactions. To build one, complete the HTTP quickstart.

Apps Script

A Google Chat app that receives and responds to user interactions. To build one, complete the Apps Script quickstart.

Register specific links - like example.com, support.example.com, and support.example.com/cases/ - as URL patterns on your Chat app's configuration page in Google Cloud console so your Chat app can preview them.

Link previews configuration menu

  1. Open the Google Cloud console.
  2. Next to "Google Cloud," click the Down arrow and open your Chat app's project.
  3. In the search field, type Google Chat API and click Google Chat API.
  4. Click Manage > Configuration.
  5. Under Link previews, add or edit a URL pattern.
    1. To configure link previews for a new URL pattern, click Add URL Pattern.
    2. To edit the configuration for an existing URL pattern, click the Down arrow .

  6. In the Host pattern field, enter the domain of the URL pattern. The Chat app will preview links to this domain.

    To have the Chat app preview links for a specific subdomain, like subdomain.example.com, include the subdomain.

    To have the Chat app preview links for the entire domain, specify a wildcard character with an asterisk (*) as the subdomain. For example, *.example.com matches subdomain.example.com and any.number.of.subdomains.example.com.

  7. In the Path prefix field, enter a path to append to the host pattern domain.

    To match all URLs in the host pattern domain, leave Path prefix empty.

    For example, if the Host pattern is support.example.com, to match URLs for cases hosted at support.example.com/cases/, enter cases/.

  8. Click Done.

  9. Click Save.

Now, whenever someone includes a link that matches a link preview URL pattern to a message in a Chat space that includes your Chat app, your app previews the link.

After you configure link previewing for a given link, your Chat app can recognize and preview the link by attaching more information to it.

Inside Chat spaces that include your Chat app, when someone's message contains a link that matches a link preview URL pattern, your Chat app receives an event object with a MessagePayload. In the payload, the message.matchedUrl (chat.messagePayload.message.matchedUrl.url) object contains the link that the user included in the message:

JSON

message: {
  matchedUrl: {
    url: "https://support.example.com/cases/case123"
  },
  ... // other message attributes redacted
}

By checking for the presence of the matchedUrl field in the MESSAGE event payload (chat.messagePayload.message.matchedUrl.url), your Chat app can add information to the message with the previewed link. Your Chat app can either reply with a basic text message or attach a card.

Reply with a text message

For basic responses, your Chat app can preview a link by replying with a simple text message to a link. This example attaches a message that repeats the link URL that matches a link preview URL pattern.

Node.js

node/chat/preview-link/index.js
// Reply with a text message for URLs of the subdomain "text"
if (chatMessage.matchedUrl.url.includes("text.example.com")) {
  return { hostAppDataAction: { chatDataAction: { createMessageAction: { message: {
    text: 'event.chat.messagePayload.message.matchedUrl.url: ' + chatMessage.matchedUrl.url
  }}}}};
}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Python

python/chat/preview-link/main.py
# Reply with a text message for URLs of the subdomain "text"
if "text.example.com" in chatMessage.get('matchedUrl').get('url'):
  return { 'hostAppDataAction': { 'chatDataAction': { 'createMessageAction': { 'message': {
    'text': 'event.chat.messagePayload.message.matchedUrl.url: ' + chatMessage.get('matchedUrl').get('url')
  }}}}}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Java

java/chat/preview-link/src/main/java/com/google/chat/previewLink/App.java
// Reply with a text message for URLs of the subdomain "text"
if (chatMessage.at("/matchedUrl/url").asText().contains("text.example.com")) {
  return new GenericJson() {{
    put("hostAppDataAction", new GenericJson() {{
      put("chatDataAction", new GenericJson() {{
        put("createMessageAction", new GenericJson() {{
          put("message", new Message()
            .setText("event.chat.messagePayload.message.matchedUrl.url: " + chatMessage.at("/matchedUrl/url").asText()));
        }});
      }});
    }});
  }};
}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Apps Script

apps-script/chat/preview-link/preview-link.gs
// Reply with a text message for URLs of the subdomain "text".
if (chatMessage.matchedUrl.url.includes("text.example.com")) {
  return { hostAppDataAction: { chatDataAction: { createMessageAction: { message: {
    text: 'event.chat.messagePayload.message.matchedUrl.url: ' + chatMessage.matchedUrl.url
  }}}}};
}

To attach a card to a previewed link, return the action DataActions with the ChatDataActionMarkup object of type UpdateInlinePreviewAction.

In the following example, a Chat app adds a preview card to messages that contain the URL pattern support.example.com.

Chat app previewing a link by attaching a card to the message

Node.js

node/chat/preview-link/index.js
// Attach a card to the message for URLs of the subdomain "support"
if (chatMessage.matchedUrl.url.includes("support.example.com")) {
  // A hard-coded card is used in this example. In a real-life scenario,
  // the case information would be fetched and used to build the card.
  return { hostAppDataAction: { chatDataAction: { updateInlinePreviewAction: { cardsV2: [{
    cardId: 'attachCard',
    card: {
      header: {
        title: 'Example Customer Service Case',
        subtitle: 'Case basics',
      },
      sections: [{ widgets: [
      { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
      { decoratedText: { topLabel: 'Assignee', text: 'Charlie'}},
      { decoratedText: { topLabel: 'Status', text: 'Open'}},
      { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
      { buttonList: { buttons: [{
        text: 'OPEN CASE',
        onClick: { openLink: {
          url: 'https://support.example.com/orders/case123'
        }},
      }, {
        text: 'RESOLVE CASE',
        onClick: { openLink: {
          url: 'https://support.example.com/orders/case123?resolved=y',
        }},
      }, {
        text: 'ASSIGN TO ME',
        onClick: { action: { function: FUNCTION_URL }}
      }]}}
      ]}]
    }
  }]}}}};
}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Python

python/chat/preview-link/main.py
# Attach a card to the message for URLs of the subdomain "support"
if "support.example.com" in chatMessage.get('matchedUrl').get('url'):
  # A hard-coded card is used in this example. In a real-life scenario,
  # the case information would be fetched and used to build the card.
  return { 'hostAppDataAction': { 'chatDataAction': { 'updateInlinePreviewAction': { 'cardsV2': [{
    'cardId': 'attachCard',
    'card': {
      'header': {
        'title': 'Example Customer Service Case',
        'subtitle': 'Case basics',
      },
      'sections': [{ 'widgets': [
      { 'decoratedText': { 'topLabel': 'Case ID', 'text': 'case123'}},
      { 'decoratedText': { 'topLabel': 'Assignee', 'text': 'Charlie'}},
      { 'decoratedText': { 'topLabel': 'Status', 'text': 'Open'}},
      { 'decoratedText': { 'topLabel': 'Subject', 'text': 'It won\'t turn on...' }},
      { 'buttonList': { 'buttons': [{
        'text': 'OPEN CASE',
        'onClick': { 'openLink': {
          'url': 'https://support.example.com/orders/case123'
        }},
      }, {
        'text': 'RESOLVE CASE',
        'onClick': { 'openLink': {
          'url': 'https://support.example.com/orders/case123?resolved=y',
        }},
      }, {
        'text': 'ASSIGN TO ME',
        'onClick': { 'action': { 'function': FUNCTION_URL }}
      }]}}
      ]}]
    }
  }]}}}}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Java

java/chat/preview-link/src/main/java/com/google/chat/previewLink/App.java
// Attach a card to the message for URLs of the subdomain "support"
if (chatMessage.at("/matchedUrl/url").asText().contains("support.example.com")) {
  // A hard-coded card is used in this example. In a real-life scenario,
  // the case information would be fetched and used to build the card.
  CardWithId cardV2 = new CardWithId()
    .setCardId("attachCard")
    .setCard(new GoogleAppsCardV1Card()
      .setHeader(new GoogleAppsCardV1CardHeader()
        .setTitle("Example Customer Service Case")
        .setSubtitle("Case basics"))
      .setSections(List.of(new GoogleAppsCardV1Section().setWidgets(List.of(
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Case ID")
          .setText("case123")),
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Assignee")
          .setText("Charlie")),
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Status")
          .setText("Open")),
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Subject")
          .setText("It won't turn on...")),
        new GoogleAppsCardV1Widget().setButtonList(new GoogleAppsCardV1ButtonList()
          .setButtons(List.of(
            new GoogleAppsCardV1Button()
              .setText("OPEN CASE")
            .setOnClick(new GoogleAppsCardV1OnClick()
                .setOpenLink(new GoogleAppsCardV1OpenLink()
                  .setUrl("https://support.example.com/orders/case123"))),
            new GoogleAppsCardV1Button()
              .setText("RESOLVE CASE")
            .setOnClick(new GoogleAppsCardV1OnClick()
                .setOpenLink(new GoogleAppsCardV1OpenLink()
                  .setUrl("https://support.example.com/orders/case123?resolved=y"))),
            new GoogleAppsCardV1Button()
              .setText("ASSIGN TO ME")
              .setOnClick(new GoogleAppsCardV1OnClick()
                .setAction(new GoogleAppsCardV1Action().setFunction(FUNCTION_URL)))
          ))
        )
      ))))
    );

  return new GenericJson() {{
    put("hostAppDataAction", new GenericJson() {{
      put("chatDataAction", new GenericJson() {{
        put("updateInlinePreviewAction", new GenericJson() {{
          put("cardsV2", List.of(cardV2));
        }});
      }});
    }});
  }};
}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Apps Script

apps-script/chat/preview-link/preview-link.gs
// Attach a card to the message for URLs of the subdomain "support".
if (chatMessage.matchedUrl.url.includes("support.example.com")) {
  // A hard-coded card is used in this example. In a real-life scenario,
  // the case information would be fetched and used to build the card.
  return { hostAppDataAction: { chatDataAction: { updateInlinePreviewAction: { cardsV2: [{
    cardId: 'attachCard',
    card: {
      header: {
        title: 'Example Customer Service Case',
        subtitle: 'Case summary',
      },
      sections: [{ widgets: [
      { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
      { decoratedText: { topLabel: 'Assignee', text: 'Charlie'}},
      { decoratedText: { topLabel: 'Status', text: 'Open'}},
      { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
      { buttonList: { buttons: [{
        text: 'OPEN CASE',
        onClick: { openLink: {
          url: 'https://support.example.com/orders/case123'
        }},
      }, {
        text: 'RESOLVE CASE',
        onClick: { openLink: {
          url: 'https://support.example.com/orders/case123?resolved=y',
        }},
      }, {
        text: 'ASSIGN TO ME',
        // Clicking this button triggers the execution of the function
        // "assign" from the Apps Script project.
        onClick: { action: { function: 'assign'}}
      }]}}
      ]}]
    }
  }]}}}};
}

Your Chat app can update a link preview card when users interact with it, such as clicking a button on the card.

To update the card, your Chat app must return the action DataActions with one of the following ChatDataActionMarkup objects:

To determine who sent the message, use the event payload (buttonClickedPayload) to check whether the sender (message.sender.type) is set to HUMAN (user) or BOT (Chat app).

The following example shows how a Chat app updates a link preview whenever a user clicks the Assign to Me button by updating the card's Assignee field and disabling the button.

Chat app previewing a link with an updated version of a card attached to the a message

Node.js

node/chat/preview-link/index.js
/**
 * Respond to clicks by assigning and updating the card that's attached to a
 * message previewed link of the pattern "support.example.com".
 *
 * @param {Object} chatMessage The chat message object from Google Workspace Add On event.
 * @return {Object} Action response depending on the message author.
 */
function handleCardClick(chatMessage) {
  // Creates the updated card that displays "You" for the assignee
  // and that disables the button.
  //
  // A hard-coded card is used in this example. In a real-life scenario,
  // an actual assign action would be performed before building the card.
  const message = { cardsV2: [{
    cardId: 'attachCard',
    card: {
      header: {
        title: 'Example Customer Service Case',
        subtitle: 'Case basics',
      },
      sections: [{ widgets: [
        { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
        // The assignee is now "You"
        { decoratedText: { topLabel: 'Assignee', text: 'You'}},
        { decoratedText: { topLabel: 'Status', text: 'Open'}},
        { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
        { buttonList: { buttons: [{
          text: 'OPEN CASE',
          onClick: { openLink: {
            url: 'https://support.example.com/orders/case123'
          }},
        }, {
          text: 'RESOLVE CASE',
          onClick: { openLink: {
            url: 'https://support.example.com/orders/case123?resolved=y',
          }},
        }, {
          text: 'ASSIGN TO ME',
          // The button is now disabled
          disabled: true,
          onClick: { action: { function: FUNCTION_URL }}
        }]}}
      ]}]
    }
  }]};

  // Use the adequate action response type. It depends on whether the message
  // the preview link card is attached to was created by a human or a Chat app.
  if(chatMessage.sender.type === 'HUMAN') {
    return { hostAppDataAction: { chatDataAction: { updateInlinePreviewAction: message }}};
  } else {
    return { hostAppDataAction: { chatDataAction: { updateMessageAction: message }}};
  }
}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Python

python/chat/preview-link/main.py
def handle_card_click(chatMessage: dict) -> dict:
  """Respond to clicks by assigning and updating the card that's attached to a
  message previewed link of the pattern "support.example.com".

  - Reply with text messages that echo "text.example.com" link URLs in messages.
  - Attach cards to messages with "support.example.com" link URLs.

  Args:
      chatMessage (Mapping[str, Any]): The chat message object from Google Workspace Add On event.

  Returns:
      Mapping[str, Any]: Action response depending on the message author.
  """
  # Creates the updated card that displays "You" for the assignee
  # and that disables the button.
  #
  # A hard-coded card is used in this example. In a real-life scenario,
  # an actual assign action would be performed before building the card.
  message = { 'cardsV2': [{
    'cardId': 'attachCard',
    'card': {
      'header': {
        'title': 'Example Customer Service Case',
        'subtitle': 'Case basics',
      },
      'sections': [{ 'widgets': [
      { 'decoratedText': { 'topLabel': 'Case ID', 'text': 'case123'}},
      # The assignee is now "You"
      { 'decoratedText': { 'topLabel': 'Assignee', 'text': 'You'}},
      { 'decoratedText': { 'topLabel': 'Status', 'text': 'Open'}},
      { 'decoratedText': { 'topLabel': 'Subject', 'text': 'It won\'t turn on...' }},
      { 'buttonList': { 'buttons': [{
        'text': 'OPEN CASE',
        'onClick': { 'openLink': {
          'url': 'https://support.example.com/orders/case123'
        }},
      }, {
        'text': 'RESOLVE CASE',
        'onClick': { 'openLink': {
          'url': 'https://support.example.com/orders/case123?resolved=y',
        }},
      }, {
        'text': 'ASSIGN TO ME',
        # The button is now disabled
        'disabled': True,
        'onClick': { 'action': { 'function': FUNCTION_URL }}
      }]}}
      ]}]
    }
  }]}

  # Use the adequate action response type. It depends on whether the message
  # the preview link card is attached to was created by a human or a Chat app.
  if chatMessage.get('sender').get('type') == 'HUMAN':
    return { 'hostAppDataAction': { 'chatDataAction': { 'updateInlinePreviewAction': message }}}
  else:
    return { 'hostAppDataAction': { 'chatDataAction': { 'updateMessageAction': message }}}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Java

java/chat/preview-link/src/main/java/com/google/chat/previewLink/App.java
/**
 * Respond to clicks by assigning and updating the card that's attached to a
 * message previewed link of the pattern "support.example.com".
 *
 * @param chatMessage The chat message object from Google Workspace Add On event.
 * @return Action response depending on the message author.
 */
GenericJson handleCardClick(JsonNode chatMessage) {
  // Creates the updated card that displays "You" for the assignee
  // and that disables the button.
  //
  // A hard-coded card is used in this example. In a real-life scenario,
  // an actual assign action would be performed before building the card.
  Message message = new Message().setCardsV2(List.of(new CardWithId()
    .setCardId("attachCard")
    .setCard(new GoogleAppsCardV1Card()
      .setHeader(new GoogleAppsCardV1CardHeader()
        .setTitle("Example Customer Service Case")
        .setSubtitle("Case basics"))
      .setSections(List.of(new GoogleAppsCardV1Section().setWidgets(List.of(
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Case ID")
          .setText("case123")),
        // The assignee is now "You"
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Assignee")
          .setText("You")),
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Status")
          .setText("Open")),
        new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
          .setTopLabel("Subject")
          .setText("It won't turn on...")),
        new GoogleAppsCardV1Widget().setButtonList(new GoogleAppsCardV1ButtonList()
          .setButtons(List.of(
            new GoogleAppsCardV1Button()
              .setText("OPEN CASE")
              .setOnClick(new GoogleAppsCardV1OnClick()
                .setOpenLink(new GoogleAppsCardV1OpenLink()
                  .setUrl("https://support.example.com/orders/case123"))),
            new GoogleAppsCardV1Button()
              .setText("RESOLVE CASE")
              .setOnClick(new GoogleAppsCardV1OnClick()
                .setOpenLink(new GoogleAppsCardV1OpenLink()
                  .setUrl("https://support.example.com/orders/case123?resolved=y"))),
            new GoogleAppsCardV1Button()
              .setText("ASSIGN TO ME")
              // The button is now disabled
              .setDisabled(true)
              .setOnClick(new GoogleAppsCardV1OnClick()
                .setAction(new GoogleAppsCardV1Action().setFunction(FUNCTION_URL)))
          ))
        )
      ))))
    )
  ));

  // Use the adequate action response type. It depends on whether the message
  // the preview link card is attached to was created by a human or a Chat app.
  if("HUMAN".equals(chatMessage.at("/sender/type").asText())) {
    return new GenericJson() {{
      put("hostAppDataAction", new GenericJson() {{
        put("chatDataAction", new GenericJson() {{
          put("updateInlinePreviewAction", message);
        }});
      }});
    }};
  } else {
    return new GenericJson() {{
      put("hostAppDataAction", new GenericJson() {{
        put("chatDataAction", new GenericJson() {{
          put("updateMessageAction", message);
        }});
      }});
    }};
  }
}

Replace FUNCTION_URL with the HTTP endpoint that handles button clicks.

Apps Script

apps-script/chat/preview-link/preview-link.gs
/**
 * Assigns and updates the card that's attached to a message with a
 * previewed link of the pattern "support.example.com".
 *
 * @param {Object} event The event object from the Google Workspace add-on.
 * @return {Object} Action response depending on the message author.
 */
function assign(event) {
  // Creates the updated card that displays "You" for the assignee
  // and that disables the button.
  //
  // A hard-coded card is used in this example. In a real-life scenario,
  // an actual assign action would be performed before building the card.
  const message = { cardsV2: [{
    cardId: 'attachCard',
    card: {
      header: {
        title: 'Example Customer Service Case',
        subtitle: 'Case summary',
      },
      sections: [{ widgets: [
        { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
        // The assignee is now "You"
        { decoratedText: { topLabel: 'Assignee', text: 'You'}},
        { decoratedText: { topLabel: 'Status', text: 'Open'}},
        { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
        { buttonList: { buttons: [{
          text: 'OPEN CASE',
          onClick: { openLink: {
            url: 'https://support.example.com/orders/case123'
          }},
        }, {
          text: 'RESOLVE CASE',
          onClick: { openLink: {
            url: 'https://support.example.com/orders/case123?resolved=y',
          }},
        }, {
          text: 'ASSIGN TO ME',
          // The button is now disabled
          disabled: true,
          onClick: { action: { function: 'assign'}}
        }]}}
      ]}]
    }
  }]};

  // Use the adequate action response type. It depends on whether the message
  // the preview link card is attached to was created by a human or a Chat app.
  if(event.chat.buttonClickedPayload.message.sender.type === 'HUMAN') {
    return { hostAppDataAction: { chatDataAction: { updateInlinePreviewAction: message }}};
  } else {
    return { hostAppDataAction: { chatDataAction: { updateMessageAction: message }}};
  }
}

Limits and considerations

As you configure link previews for your Chat app, take note of these limits and considerations:

  • Each Chat app supports link previews for up to 5 URL patterns.
  • Chat apps preview one link per message. If multiple previewable links are present in a single message, only the first previewable link previews.
  • Chat apps only preview links that begin with https://, so https://support.example.com/cases/ previews, but support.example.com/cases/ does not.
  • Unless the message includes other information that gets sent to the Chat app, such as a slash command, only the link URL is sent to the Chat app by link previews.
  • If a user posts the link, a Chat app can only update the link preview card if users interact with the card, such as with a button click. You can't call the Chat API's update() method on the Message resource to update a user's message asynchronously.
  • Chat apps must preview links for everyone in the space, so the message must omit the privateMessageViewer field.

As you implement link previews, you might need to debug your Chat app by reading the app's logs. To read the logs, visit the Logs Explorer on Google Cloud console.

The following documentation applies to Chat apps that aren't Google Workspace add-ons. To migrate a Chat app that isn't an add-on, see Convert a Google Chat app to a Google Workspace add-on.

Inside Chat spaces that include a Chat app that isn't an add-on, when someone's message contains a link that matches a link preview URL pattern, the Chat app receives a MESSAGE interaction event. The JSON payload for the interaction event contains the matchedUrl field:

JSON

message: {
  matchedUrl: {
    url: "https://support.example.com/cases/case123"
  },
  ... // other message attributes redacted
}

By checking for the presence of the matchedUrl field in the MESSAGE event payload, a Chat app that isn't an add-on can add information to the message with the previewed link.

Reply with a text message

For basic responses, a Chat app that isn't an add-on can preview a link by replying with a simple text message to a link. This example attaches a message that repeats the link URL that matches a link preview URL pattern:

Node.js

node/preview-link/index.js
// Reply with a text message for URLs of the subdomain "text"
if (event.message.matchedUrl.url.includes("text.example.com")) {
  return {
    text: 'event.message.matchedUrl.url: ' + event.message.matchedUrl.url
  };
}

Python

python/preview-link/main.py
# Reply with a text message for URLs of the subdomain "text"
if 'text.example.com' in event.get('message').get('matchedUrl').get('url'):
  return {
    'text': 'event.message.matchedUrl.url: ' +
            event.get('message').get('matchedUrl').get('url')
  }

Java

java/preview-link/src/main/java/com/google/chat/preview/App.java
// Reply with a text message for URLs of the subdomain "text"
if (event.at("/message/matchedUrl/url").asText().contains("text.example.com")) {
  return new Message().setText("event.message.matchedUrl.url: " +
    event.at("/message/matchedUrl/url").asText());
}

Apps Script

apps-script/preview-link/preview-link.gs
// Reply with a text message for URLs of the subdomain "text"
if (event.message.matchedUrl.url.includes("text.example.com")) {
  return {
    text: 'event.message.matchedUrl.url: ' + event.message.matchedUrl.url
  };
}

Attach a card that previews the link

To attach a card to a previewed link in a Chat app that isn't an add-on, return an ActionResponse of type UPDATE_USER_MESSAGE_CARDS. This example attaches a basic card:

Node.js

node/preview-link/index.js
// Attach a card to the message for URLs of the subdomain "support"
if (event.message.matchedUrl.url.includes("support.example.com")) {
  // A hard-coded card is used in this example. In a real-life scenario,
  // the case information would be fetched and used to build the card.
  return {
    actionResponse: { type: 'UPDATE_USER_MESSAGE_CARDS' },
    cardsV2: [{
      cardId: 'attachCard',
      card: {
        header: {
          title: 'Example Customer Service Case',
          subtitle: 'Case basics',
        },
        sections: [{ widgets: [
          { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
          { decoratedText: { topLabel: 'Assignee', text: 'Charlie'}},
          { decoratedText: { topLabel: 'Status', text: 'Open'}},
          { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
          { buttonList: { buttons: [{
            text: 'OPEN CASE',
            onClick: { openLink: {
              url: 'https://support.example.com/orders/case123'
            }},
          }, {
            text: 'RESOLVE CASE',
            onClick: { openLink: {
              url: 'https://support.example.com/orders/case123?resolved=y',
            }},
          }, {
            text: 'ASSIGN TO ME',
            onClick: { action: { function: 'assign'}}
          }]}}
        ]}]
      }
    }]
  };
}

Python

python/preview-link/main.py
# Attach a card to the message for URLs of the subdomain "support"
if 'support.example.com' in event.get('message').get('matchedUrl').get('url'):
  # A hard-coded card is used in this example. In a real-life scenario,
  # the case information would be fetched and used to build the card.
  return {
    'actionResponse': { 'type': 'UPDATE_USER_MESSAGE_CARDS' },
    'cardsV2': [{
      'cardId': 'attachCard',
      'card': {
        'header': {
          'title': 'Example Customer Service Case',
          'subtitle': 'Case basics',
        },
        'sections': [{ 'widgets': [
          { 'decoratedText': { 'topLabel': 'Case ID', 'text': 'case123'}},
          { 'decoratedText': { 'topLabel': 'Assignee', 'text': 'Charlie'}},
          { 'decoratedText': { 'topLabel': 'Status', 'text': 'Open'}},
          { 'decoratedText': { 'topLabel': 'Subject', 'text': 'It won\'t turn on...' }},
          { 'buttonList': { 'buttons': [{
            'text': 'OPEN CASE',
            'onClick': { 'openLink': {
              'url': 'https://support.example.com/orders/case123'
            }},
          }, {
            'text': 'RESOLVE CASE',
            'onClick': { 'openLink': {
              'url': 'https://support.example.com/orders/case123?resolved=y',
            }},
          }, {
            'text': 'ASSIGN TO ME',
            'onClick': { 'action': { 'function': 'assign'}}
          }]}}
        ]}]
      }
    }]
  }

Java

java/preview-link/src/main/java/com/google/chat/preview/App.java
// Attach a card to the message for URLs of the subdomain "support"
if (event.at("/message/matchedUrl/url").asText().contains("support.example.com")) {
  // A hard-coded card is used in this example. In a real-life scenario,
  // the case information would be fetched and used to build the card.
  return new Message()
    .setActionResponse(new ActionResponse()
      .setType("UPDATE_USER_MESSAGE_CARDS"))
    .setCardsV2(List.of(new CardWithId()
      .setCardId("attachCard")
      .setCard(new GoogleAppsCardV1Card()
        .setHeader(new GoogleAppsCardV1CardHeader()
          .setTitle("Example Customer Service Case")
          .setSubtitle("Case basics"))
        .setSections(List.of(new GoogleAppsCardV1Section().setWidgets(List.of(
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Case ID")
            .setText("case123")),
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Assignee")
            .setText("Charlie")),
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Status")
            .setText("Open")),
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Subject")
            .setText("It won't turn on...")),
          new GoogleAppsCardV1Widget()
            .setButtonList(new GoogleAppsCardV1ButtonList().setButtons(List.of(
              new GoogleAppsCardV1Button()
                .setText("OPEN CASE")
                .setOnClick(new GoogleAppsCardV1OnClick()
                  .setOpenLink(new GoogleAppsCardV1OpenLink()
                    .setUrl("https://support.example.com/orders/case123"))),
              new GoogleAppsCardV1Button()
                .setText("RESOLVE CASE")
                .setOnClick(new GoogleAppsCardV1OnClick()
                  .setOpenLink(new GoogleAppsCardV1OpenLink()
                    .setUrl("https://support.example.com/orders/case123?resolved=y"))),
              new GoogleAppsCardV1Button()
                .setText("ASSIGN TO ME")
                .setOnClick(new GoogleAppsCardV1OnClick()
                  .setAction(new GoogleAppsCardV1Action().setFunction("assign")))))))))))));
}

Apps Script

This example sends a card message by returning card JSON. You can also use the Apps Script card service.

apps-script/preview-link/preview-link.gs
// Attach a card to the message for URLs of the subdomain "support"
if (event.message.matchedUrl.url.includes("support.example.com")) {
  // A hard-coded card is used in this example. In a real-life scenario,
  // the case information would be fetched and used to build the card.
  return {
    actionResponse: { type: 'UPDATE_USER_MESSAGE_CARDS' },
    cardsV2: [{
      cardId: 'attachCard',
      card: {
        header: {
          title: 'Example Customer Service Case',
          subtitle: 'Case basics',
        },
        sections: [{ widgets: [
          { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
          { decoratedText: { topLabel: 'Assignee', text: 'Charlie'}},
          { decoratedText: { topLabel: 'Status', text: 'Open'}},
          { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
          { buttonList: { buttons: [{
            text: 'OPEN CASE',
            onClick: { openLink: {
              url: 'https://support.example.com/orders/case123'
            }},
          }, {
            text: 'RESOLVE CASE',
            onClick: { openLink: {
              url: 'https://support.example.com/orders/case123?resolved=y',
            }},
          }, {
            text: 'ASSIGN TO ME',
            onClick: { action: { function: 'assign'}}
          }]}}
        ]}]
      }
    }]
  };
}

Update a link preview card

To update a link preview card in a Chat app that isn't an add-on, handle the CARD_CLICKED interaction event and return an actionResponse based on who sent the message that contains the link preview:

  • If a user sent the message, set the actionResponse.type to UPDATE_USER_MESSAGE_CARDS.
  • If the Chat app sent the message, set the actionResponse.type to UPDATE_MESSAGE.

To determine who sent the message, you can use the message.sender.type field of the interaction event to see whether the sender was a HUMAN user or BOT.

The following example shows how a Chat app that isn't an add-on updates a link preview whenever a user clicks the Assign to Me button by updating the card's Assignee field and disabling the button:

Node.js

node/preview-link/index.js
/**
 * Updates a card that was attached to a message with a previewed link.
 *
 * @param {Object} event The event object from Chat.
 *
 * @return {Object} Response from the Chat app. Either a new card attached to
 * the message with the previewed link, or an update to an existing card.
 */
function onCardClick(event) {
  // To respond to the correct button, checks the button's actionMethodName.
  if (event.action.actionMethodName === 'assign') {
    // A hard-coded card is used in this example. In a real-life scenario,
    // an actual assign action would be performed before building the card.

    // Checks whether the message event originated from a human or a Chat app
    // and sets actionResponse.type to "UPDATE_USER_MESSAGE_CARDS if human or
    // "UPDATE_MESSAGE" if Chat app.
    const actionResponseType = event.message.sender.type === 'HUMAN' ?
      'UPDATE_USER_MESSAGE_CARDS' :
      'UPDATE_MESSAGE';

    // Returns the updated card that displays "You" for the assignee
    // and that disables the button.
    return {
      actionResponse: { type: actionResponseType },
      cardsV2: [{
        cardId: 'attachCard',
        card: {
          header: {
            title: 'Example Customer Service Case',
            subtitle: 'Case basics',
          },
          sections: [{ widgets: [
            { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
            // The assignee is now "You"
            { decoratedText: { topLabel: 'Assignee', text: 'You'}},
            { decoratedText: { topLabel: 'Status', text: 'Open'}},
            { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
            { buttonList: { buttons: [{
              text: 'OPEN CASE',
              onClick: { openLink: {
                url: 'https://support.example.com/orders/case123'
              }},
            }, {
              text: 'RESOLVE CASE',
              onClick: { openLink: {
                url: 'https://support.example.com/orders/case123?resolved=y',
              }},
            }, {
              text: 'ASSIGN TO ME',
              // The button is now disabled
              disabled: true,
              onClick: { action: { function: 'assign'}}
            }]}}
          ]}]
        }
      }]
    };
  }
}

Python

python/preview-link/main.py
def on_card_click(event: dict) -> dict:
  """Updates a card that was attached to a message with a previewed link."""
  # To respond to the correct button, checks the button's actionMethodName.
  if 'assign' == event.get('action').get('actionMethodName'):
    # A hard-coded card is used in this example. In a real-life scenario,
    # an actual assign action would be performed before building the card.

    # Checks whether the message event originated from a human or a Chat app
    # and sets actionResponse.type to "UPDATE_USER_MESSAGE_CARDS if human or
    # "UPDATE_MESSAGE" if Chat app.
    actionResponseType = 'UPDATE_USER_MESSAGE_CARDS' if \
      event.get('message').get('sender').get('type') == 'HUMAN' else \
      'UPDATE_MESSAGE'

    # Returns the updated card that displays "You" for the assignee
    # and that disables the button.
    return {
      'actionResponse': { 'type': actionResponseType },
      'cardsV2': [{
        'cardId': 'attachCard',
        'card': {
          'header': {
            'title': 'Example Customer Service Case',
            'subtitle': 'Case basics',
          },
          'sections': [{ 'widgets': [
            { 'decoratedText': { 'topLabel': 'Case ID', 'text': 'case123'}},
            # The assignee is now "You"
            { 'decoratedText': { 'topLabel': 'Assignee', 'text': 'You'}},
            { 'decoratedText': { 'topLabel': 'Status', 'text': 'Open'}},
            { 'decoratedText': { 'topLabel': 'Subject', 'text': 'It won\'t turn on...' }},
            { 'buttonList': { 'buttons': [{
              'text': 'OPEN CASE',
              'onClick': { 'openLink': {
                'url': 'https://support.example.com/orders/case123'
              }},
            }, {
              'text': 'RESOLVE CASE',
              'onClick': { 'openLink': {
                'url': 'https://support.example.com/orders/case123?resolved=y',
              }},
            }, {
              'text': 'ASSIGN TO ME',
              # The button is now disabled
              'disabled': True,
              'onClick': { 'action': { 'function': 'assign'}}
            }]}}
          ]}]
        }
      }]
    }

Java

java/preview-link/src/main/java/com/google/chat/preview/App.java
// Updates a card that was attached to a message with a previewed link.
Message onCardClick(JsonNode event) {
  // To respond to the correct button, checks the button's actionMethodName.
  if (event.at("/action/actionMethodName").asText().equals("assign")) {
    // A hard-coded card is used in this example. In a real-life scenario,
    // an actual assign action would be performed before building the card.

    // Checks whether the message event originated from a human or a Chat app
    // and sets actionResponse.type to "UPDATE_USER_MESSAGE_CARDS if human or
    // "UPDATE_MESSAGE" if Chat app.
    String actionResponseType =
      event.at("/message/sender/type").asText().equals("HUMAN")
      ? "UPDATE_USER_MESSAGE_CARDS" : "UPDATE_MESSAGE";

    // Returns the updated card that displays "You" for the assignee
    // and that disables the button.
    return new Message()
    .setActionResponse(new ActionResponse()
      .setType(actionResponseType))
    .setCardsV2(List.of(new CardWithId()
      .setCardId("attachCard")
      .setCard(new GoogleAppsCardV1Card()
        .setHeader(new GoogleAppsCardV1CardHeader()
          .setTitle("Example Customer Service Case")
          .setSubtitle("Case basics"))
        .setSections(List.of(new GoogleAppsCardV1Section().setWidgets(List.of(
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Case ID")
            .setText("case123")),
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Assignee")
            // The assignee is now "You"
            .setText("You")),
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Status")
            .setText("Open")),
          new GoogleAppsCardV1Widget().setDecoratedText(new GoogleAppsCardV1DecoratedText()
            .setTopLabel("Subject")
            .setText("It won't turn on...")),
          new GoogleAppsCardV1Widget()
            .setButtonList(new GoogleAppsCardV1ButtonList().setButtons(List.of(
              new GoogleAppsCardV1Button()
                .setText("OPEN CASE")
                .setOnClick(new GoogleAppsCardV1OnClick()
                  .setOpenLink(new GoogleAppsCardV1OpenLink()
                    .setUrl("https://support.example.com/orders/case123"))),
              new GoogleAppsCardV1Button()
                .setText("RESOLVE CASE")
                .setOnClick(new GoogleAppsCardV1OnClick()
                  .setOpenLink(new GoogleAppsCardV1OpenLink()
                    .setUrl("https://support.example.com/orders/case123?resolved=y"))),
              new GoogleAppsCardV1Button()
                .setText("ASSIGN TO ME")
                // The button is now disabled
                .setDisabled(true)
                .setOnClick(new GoogleAppsCardV1OnClick()
                  .setAction(new GoogleAppsCardV1Action().setFunction("assign")))))))))))));
  }
  return null;
}

Apps Script

This example sends a card message by returning card JSON. You can also use the Apps Script card service.

apps-script/preview-link/preview-link.gs
/**
 * Updates a card that was attached to a message with a previewed link.
 *
 * @param {Object} event The event object from Chat.
 *
 * @return {Object} Response from the Chat app. Either a new card attached to
 * the message with the previewed link, or an update to an existing card.
 */
function onCardClick(event) {
  // To respond to the correct button, checks the button's actionMethodName.
  if (event.action.actionMethodName === 'assign') {
    // A hard-coded card is used in this example. In a real-life scenario,
    // an actual assign action would be performed before building the card.

    // Checks whether the message event originated from a human or a Chat app
    // and sets actionResponse.type to "UPDATE_USER_MESSAGE_CARDS if human or
    // "UPDATE_MESSAGE" if Chat app.
    const actionResponseType = event.message.sender.type === 'HUMAN' ?
      'UPDATE_USER_MESSAGE_CARDS' :
      'UPDATE_MESSAGE';

    // Returns the updated card that displays "You" for the assignee
    // and that disables the button.
    return {
      actionResponse: { type: actionResponseType },
      cardsV2: [{
        cardId: 'attachCard',
        card: {
          header: {
            title: 'Example Customer Service Case',
            subtitle: 'Case basics',
          },
          sections: [{ widgets: [
            { decoratedText: { topLabel: 'Case ID', text: 'case123'}},
            // The assignee is now "You"
            { decoratedText: { topLabel: 'Assignee', text: 'You'}},
            { decoratedText: { topLabel: 'Status', text: 'Open'}},
            { decoratedText: { topLabel: 'Subject', text: 'It won\'t turn on...' }},
            { buttonList: { buttons: [{
              text: 'OPEN CASE',
              onClick: { openLink: {
                url: 'https://support.example.com/orders/case123'
              }},
            }, {
              text: 'RESOLVE CASE',
              onClick: { openLink: {
                url: 'https://support.example.com/orders/case123?resolved=y',
              }},
            }, {
              text: 'ASSIGN TO ME',
              // The button is now disabled
              disabled: true,
              onClick: { action: { function: 'assign'}}
            }]}}
          ]}]
        }
      }]
    };
  }
}