Respond to slash commands as a Google Chat app

This page explains how to set up and respond to slash commands for your Google Chat app.

A slash command is a common way that users invoke and interact with a Chat app. Slash commands also help users discover and use key features of a Chat app.

To use a slash command, users type a slash (/) and then a short text command, such as /about to get information about the Chat app. Users can discover available slash commands by typing a slash into Google Chat, which displays a window that lists the available commands for the Chat app:

Slash command window
Figure 1: The window that appears when users type a slash into Google Chat.

To decide whether you should set up slash commands, and to understand how to design user interactions, see the Google Chat design principles.

Pre-requisites

Node.js

Apps Script

Python

Set up a slash command

This section explains how to complete the following steps to set up a slash command:

  1. Create a name for your slash command.
  2. Configure the slash command in the Google Chat API.

Name your slash command

The name of a slash command is what users type in a Chat message to invoke the Chat app. A short description also appears below the name, to prompt users further about how to use the command:

Slash command name and description
Figure 2: The name and description for a slash command.

When choosing a name and description for your slash command, consider the following recommendations:

  • To name your slash command:

    • Use short, descriptive, and actionable words or phrases to make the commands clear and simple to the user. For example, instead of saying /createAReminder, use /remindMe.
    • If your command contains more than one word, help users read the command by using all lowercase for the first word and then capitalizing the first letter of additional words. For example, instead of /updatecontact, use /updateContact.
    • Consider whether to use a unique or common name for your command. If your command describes a typical interaction or feature, you can use a common name that users recognize and expect, such as /settingsor /feedback. Otherwise, try to use unique command names, because if your command name is the same for other Chat apps, the user must filter through similar commands to find and use yours.
  • To describe your slash command:

    • Keep the description short and clear so that users know what to expect when they invoke the command.
    • Let users know if there are any formatting requirements for the command. For example, if you create a /remindMe command that requires argument text, set the description to something like Remind me to do [something] at [time].
    • Let users know if the Chat app replies to everyone in the space, or privately to the user who invokes the command. For example, for the slash command /about, you could describe it as Learn about this app (Only visible to you). To respond privately to a slash command, see the section Respond with a private message.

Configure your slash command in the Google Chat API

To create a slash command, you need to specify information about the command in your Chat app's configuration for the Google Chat API.

To configure a slash command in the Google Chat API, complete the following steps:

  1. In the Google Cloud console, click Menu > APIs & Services > Enabled APIs & Services > Google Chat API

    Go to the Google Chat API page

  2. Click Configuration.

  3. Under Slash commands, click Add a slash command.

  4. Enter a name, command ID, and description for the command:

    1. Name: the display name for the command, and what users type to invoke your app. Must start with a slash, contain only text, and can be up to 50 characters.
    2. Description: the text that describes how to use and format the command. Descriptions can be up to 50 characters.
    3. Command ID: a number from 1 to 1000 that your Chat app uses to recognize the slash command and return a response.
  5. Optional: If you want your Chat app to respond to the command with a dialog, select the Open a dialog checkbox.

  6. Click Save.

The slash command is now configured for the Chat app.

Respond to a slash command

When users create a Chat message that contains a slash command, your Chat app receives a MESSAGE interaction event. The event payload contains information about the slash command, including the slashCommand and slashCommandMetadata fields. You use these fields to identify the command ID and return a custom response.

The following example shows the JSON payload for a MESSAGE interaction event that includes the slash command /vote:

    {
      ...
      "message": {
        ...
        "text": "/vote yes",
        "argumentText": " yes",
        "slashCommand": {
          "commandId": 2
        },
        "annotations": [
          {
            "length": 5,
            "startIndex": 0,
            "type": "SLASH_COMMAND",
            "slashCommand": {
              "commandName":"/vote",
              "commandId":1,
              "type": "INVOKE",
              "bot": {
                "avatarUrl": "https://www.example.com/images/vote-app-icon.png",
                "displayName": "Voter Chat App",
                "name": "users/1234567890987654321",
                "type": "BOT"
              }
            }
          }
        ]
      }
    }

To respond to a slash command, you can detect whether the slashCommand field is present in the event payload, and if so, return a response to the command. The following code sample shows how to respond to a MESSAGE interaction event that contains a slash command:

Node.js

/**
* Responds to a MESSAGE event in Google Chat.
*
* @param {Object} event the event object from Chat API.
*
* @return {object} function in response to a slash command.
*/

exports.onMessage = function onMessage(req, res) {

  // Stores the Google Chat event as a variable.
  var event = req.body;

  // Checks for the presence of event.message.slashCommand.
  if (event.message.slashCommand) {
    switch (event.message.slashCommand.commandId) {
      case ID: // The ID for your slash command
        res.runFunction; // The response to the slash command.
    }
  }

Apps Script

/**
* Responds to a MESSAGE event in Google Chat.
*
* @param {Object} event the event object from Chat API.
*
* @return {object} function in response to a slash command.
*/

function onMessage(event) {

  // Checks for the presence of event.message.slashCommand
  if (event.message.slashCommand) {
    switch (event.message.slashCommand.commandId) {
      case ID: // The ID for your slash command
        return runFunction; // The response to the slash command.
    }
  }
}

Python

from typing import Any, Mapping

import flask
import functions_framework

@functions_framework.http
def main(req: flask.Request) -> Mapping[str, Any]:
  """Responds to a MESSAGE event in Google Chat that includes a slash command.

  Args:
      req (flask.Request): the event object from Chat API.

  Returns:
      Mapping[str, Any]: function in response to a slash command.
  """
  if req.method == 'GET':
    return 'Sorry, this function must be called from a Google Chat.'

  request = req.get_json(silent=True)

  if slash_command := request.get('message', dict()).get('slashCommand'):
    command_id = slash_command['commandId']
    if command_id == ID:
      return runFunction

To use the code, replace the following:

Optional: Respond with a private message

In many cases, users don't want or expect the Chat app to respond to a slash command with a message that's visible to everyone in the space.

For example, if a team is using a Chat app that manages a customer support service, users could invoke a slash command such as /myCases to view support cases assigned to them. If the team adds the Chat app to a space, a user who uses this slash command in the space might want the Chat app to respond only to them. To avoid posting the user's support cases to everyone in the space, the Chat app can respond privately.

To respond to a slash command privately, see Send private messages to Google Chat users.

Complete example: Set up contacts using the Rolodex Chat app

The following example shows a Chat app that responds to the following slash commands:

  • The/help command returns a text message that explains how to get support with the Chat app. The command ID is set to 1.
  • The /createContact command opens a dialog where users can enter details about a contact. The command ID is set to 2.

Before you run this sample, follow the steps to configure the slash commands in the Google Chat API.

Node.js

/**
* Responds to messages that have links whose URLs
* match URL patterns configured for link previews.
*
* @param {Object} event The event object from Chat
* API.
*
* @return {Object} Response from the Chat app
* attached to the message with the previewed link.
*/
exports.onMessage = function onMessage(req, res) {

  // Store the Google Chat event as a variable.
  const event = req.body;

  if (req.method === "GET" || !event.message) {
    res.send("Hello! This function is meant to be used in a Google Chat " +
      "Space.");
  }

  // Checks for the presence of event.message.slashCommand.
  // If the slash command is "/help", responds with a text message.
  // If the slash command is "/createContact", opens a dialog.
  if (event.message.slashCommand) {
    switch (event.message.slashCommand.commandId) {
      case 1: // /help
        res.json({"text": "Contact bot helps you update your address book!"});
      case 2:  // /createContact
        res.openDialog(event);
    }
  }

  // If the Chat app doesn"t detect a slash command, it responds
  // with a card that prompts the user to add a contact
  else {
    res.json({
      "cardsV2": [{
        "cardId": "addContact",
        "card": {
          "header": {
            "title": "Rolodex",
            "subtitle": "Manage your contacts!",
            "imageUrl": "https://www.gstatic.com/images/branding/product/2x/contacts_48dp.png",
            "imageType": "CIRCLE"
          },
          "sections": [
            {
              "widgets": [
                {
                  "buttonList": {
                    "buttons": [
                      {
                        "text": "Add Contact",
                        "onClick": {
                          "action": {
                            "function": "openDialog",
                            "interaction": "OPEN_DIALOG"
                          }
                        }
                      }
                    ]
                  }
                }
              ]
            }
          ]
        }
      }]
    });
  }

  // Respond to button clicks on attached cards
  if (event.type === "CARD_CLICKED") {

    if (event.common.invokedFunction === "openDialog") {
      res.openDialog(event);
    }

    if (event.common.invokedFunction === "openSequentialDialog") {
      res.openSequentialDialog(event);
    }

    if (event.common.invokedFunction === "confirmDialogSuccess") {
      res.confirmDialogSuccess(event);
    }

  }
};

/**
* Opens and starts a dialog that lets users add details about a contact.
*
* @param {object} event the event object from Google Chat.
*
* @return {object} open a dialog.
*/
function openDialog(event) {
  res.json({
    "action_response": {
      "type": "DIALOG",
      "dialog_action": {
        "dialog": {
          "body": {
            "sections": [
              {
                "header": "Add new contact",
                "widgets": [
                  {
                    "textInput": {
                      "label": "Name",
                      "type": "SINGLE_LINE",
                      "name": "name"
                    }
                  },
                  {
                    "textInput": {
                      "label": "Address",
                      "type": "MULTIPLE_LINE",
                      "name": "address"
                    }
                  },
                  {
                    "decoratedText": {
                      "text": "Add to favorites",
                      "switchControl": {
                        "controlType": "SWITCH",
                        "name": "saveFavorite"
                      }
                    }
                  },
                  {
                    "decoratedText": {
                      "text": "Merge with existing contacts",
                      "switchControl": {
                        "controlType": "SWITCH",
                        "name": "mergeContact",
                        "selected": true
                      }
                    }
                  },
                  {
                    "buttonList": {
                      "buttons": [
                        {
                          "text": "Next",
                          "onClick": {
                            "action": {
                              "function": "openSequentialDialog"
                            }
                          }
                        }
                      ]
                    }
                  }
                ]
              }
            ]
          }
        }
      }
    }
  });
};

/**
* Opens a second dialog that lets users add more contact details.
*
* @param {object} event the event object from Google Chat.
*
* @return {object} open a dialog.
*/
function openSequentialDialog(event) {
  res.json({
    "action_response": {
      "type": "DIALOG",
      "dialog_action": {
        "dialog": {
          "body": {
            "sections": [
              {
                "header": "Add new contact",
                "widgets": [
                  {
                    "textInput": {
                      "label": "Notes",
                      "type": "MULTIPLE_LINE",
                      "name": "notes"
                    }
                  },
                  {
                    "selectionInput": {
                      "type": "RADIO_BUTTON",
                      "label": "Contact type",
                      "name": "contactType",
                      "items": [
                        {
                          "text": "Work",
                          "value": "Work",
                          "selected": false
                        },
                        {
                          "text": "Personal",
                          "value": "Personal",
                          "selected": false
                        }
                      ]
                    }
                  },
                  {
                    "buttonList": {
                      "buttons": [
                        {
                          "text": "Submit",
                          "onClick": {
                            "action": {
                              "function": "confirmDialogSuccess",
                              "parameters": [
                                {
                                  "key": "confirmDialogSuccess",
                                  "value": "confirmDialogSuccess"
                                }
                              ]
                            }
                          }
                        }
                      ]
                    },
                    "horizontalAlignment": "END"
                  }
                ]
              }
            ]
          }
        }
      }
    }
  });
}

/**
* Checks for a form input error, the absence of
* a "name" value, and returns an error if absent.
* Otherwise, confirms successful receipt of a dialog.
*
* Confirms successful receipt of a dialog.
*
* @param {Object} event the event object from Chat API.
*
* @return {object} open a Dialog in Google Chat.
*/
function receiveDialog(event) {

  // Checks to make sure the user entered a name
  // in a dialog. If no name value detected, returns
  // an error message.
  if (event.common.formInputs.contactName.stringInputs.value[0] === "") {
    return {
      "actionResponse": {
        "type": "DIALOG",
        "dialogAction": {
          "actionStatus": {
            "statusCode": "OK",
            "userFacingMessage": "Don't forget to name your new contact!"
          }
        }
      }
    };

    // Otherwise the app indicates that it received
    // form data from the dialog. Any value other than "OK"
    // gets returned as an error. "OK" is interpreted as
    // code 200, and the dialog closes.
  } else {
    res.json({
      "actionResponse": {
        "type": "DIALOG",
        "dialogAction": {
          "actionStatus": "OK"
        }
      }
    });
  }
}

Apps Script

apps-script/dialogs/rolodex.gs
/**
* Responds to a MESSAGE event in Google Chat.
*
* @param {Object} event the event object from Chat API.
*
* @return {Object} open a Dialog in response to a slash command
* or a card"s button click.
*/
function onMessage(event) {

  // Checks for the presence of event.message.slashCommand.
  // If the slash command is "/help", responds with a text message.
  // If the slash command is "/createContact", opens a dialog.
  if (event.message.slashCommand) {
    switch (event.message.slashCommand.commandId) {
      case 1: // /help
        return {"text": "Contact bot helps you update your address book!"}
      case 2:  // /createContact
        return openDialog(event);
    }
  }

  // If the Chat app doesn"t detect a slash command, it responds
  // with a card that prompts the user to add a contact
  else {
    return {
      "cardsV2": [{
        "cardId": "addContact",
        "card": {
          "header": {
            "title": "Rolodex",
            "subtitle": "Manage your contacts!",
            "imageUrl": "https://www.gstatic.com/images/branding/product/2x/contacts_48dp.png",
            "imageType": "CIRCLE"
          },
          "sections": [
            {
              "widgets": [
                {
                  "buttonList": {
                    "buttons": [
                      {
                        "text": "Add Contact",
                        "onClick": {
                          "action": {
                            "function": "openDialog",
                            "interaction": "OPEN_DIALOG"
                          }
                        }
                      }
                    ]
                  }
                }
              ]
            }
          ]
        }
      }]

    };
  }
}

/**
* Responds to a CARD_CLICKED event in Google Chat.
*
* @param {Object} event the event object from Google Chat
*/
function onCardClick(event) {

  if (event.common.invokedFunction === "openDialog") {
    return openDialog(event);
  }

  if (event.common.invokedFunction === "openSequentialDialog") {
    const contactName = fetchFormValue(event, "contactName");
    const address = fetchFormValue(event, "address");
    return openSequentialDialog(contactName, address);
  }

  if (event.common.invokedFunction === "receiveDialog") {
    const parameters = event.common.parameters;
    parameters["contactType"] = fetchFormValue(event, "contactType");
    parameters["notes"] = fetchFormValue(event, "notes");
    return receiveDialog(parameters);
  }
}

/**
 * Extracts form input value for a given widget
 * 
 * @param {Object} event the event object from Google Chat
 * @param {String} widgetName the widget name
 * @returns the form input value for the widget
 */
function fetchFormValue(event, widgetName) {
  const widget = event.common.formInputs[widgetName];
  if (widget) {
    return widget[""]["stringInputs"]["value"][0];
  }
}

/**
* Opens and starts a dialog that lets users add details about a contact.
*
*
* @return {Object} open a dialog.
*/
function openDialog(event) {
  return {
    "action_response": {
      "type": "DIALOG",
      "dialog_action": {
        "dialog": {
          "body": {
            "sections": [
              {
                "header": "Add new contact",
                "widgets": [
                  {
                    "textInput": {
                      "label": "Name",
                      "type": "SINGLE_LINE",
                      "name": "contactName"
                    }
                  },
                  {
                    "textInput": {
                      "label": "Address",
                      "type": "MULTIPLE_LINE",
                      "name": "address"
                    }
                  },
                  {
                    "decoratedText": {
                      "text": "Add to favorites",
                      "switchControl": {
                        "controlType": "SWITCH",
                        "name": "saveFavorite"
                      }
                    }
                  },
                  {
                    "decoratedText": {
                      "text": "Merge with existing contacts",
                      "switchControl": {
                        "controlType": "SWITCH",
                        "name": "mergeContact",
                        "selected": true
                      }
                    }
                  },
                  {
                    "buttonList": {
                      "buttons": [
                        {
                          "text": "Next",
                          "onClick": {
                            "action": {
                              "function": "openSequentialDialog"
                            }
                          }
                        }
                      ]
                    }
                  }
                ]
              }
            ]
          }
        }
      }
    }
  };
}

/**
* Opens a second dialog that lets users add more contact details.
*
* @param {String} contactName the contact name from the previous dialog.
* @param {String} address the address from the previous dialog.
*
* @return {Object} open a dialog.
*/
function openSequentialDialog(contactName, address) {
  return {
    "action_response": {
      "type": "DIALOG",
      "dialog_action": {
        "dialog": {
          "body": {
            "sections": [
              {
                "header": "Add new contact",
                "widgets": [
                  {
                    "textInput": {
                      "label": "Notes",
                      "type": "MULTIPLE_LINE",
                      "name": "notes"
                    }
                  },
                  {
                    "selectionInput": {
                      "type": "RADIO_BUTTON",
                      "label": "Contact type",
                      "name": "contactType",
                      "items": [
                        {
                          "text": "Work",
                          "value": "Work",
                          "selected": false
                        },
                        {
                          "text": "Personal",
                          "value": "Personal",
                          "selected": false
                        }
                      ]
                    }
                  },
                  {
                    "buttonList": {
                      "buttons": [
                        {
                          "text": "Submit",
                          "onClick": {
                            "action": {
                              "function": "receiveDialog",
                              "parameters": [
                                {
                                  "key": "contactName",
                                  "value": contactName
                                },
                                {
                                  "key": "address",
                                  "value": address
                                }
                              ]
                            }
                          }
                        }
                      ]
                    },
                    "horizontalAlignment": "END"
                  }
                ]
              }
            ]
          }
        }
      }
    }
  };
}

/**
* Checks for a form input error, the absence of
* a "name" value, and returns an error if absent.
* Otherwise, confirms successful receipt of a dialog.
*
* Confirms successful receipt of a dialog.
*
* @param {Object} parameters the form input values.
*
* @return {Object} open a Dialog in Google Chat.
*/
function receiveDialog(parameters) {

  // Checks to make sure the user entered a name
  // in a dialog. If no name value detected, returns
  // an error message.
  if (!parameters.contactName) {
    return {
      "actionResponse": {
        "type": "DIALOG",
        "dialogAction": {
          "actionStatus": {
            "statusCode": "INVALID_ARGUMENT",
            "userFacingMessage": "Don't forget to name your new contact!"
          }
        }
      }
    };

    // Otherwise the Chat app indicates that it received
    // form data from the dialog. Any value other than "OK"
    // gets returned as an error. "OK" is interpreted as
    // code 200, and the dialog closes.
  } else {
    return {
      "actionResponse": {
        "type": "DIALOG",
        "dialogAction": {
          "actionStatus": {
            "statusCode": "OK",
            "userFacingMessage": "Success " + JSON.stringify(parameters)
          }
        }
      }
    };
  }
}

Python

from typing import Any, Mapping

import flask
import functions_framework

@functions_framework.http
def main(req: flask.Request) -> Mapping[str, Any]:
  """Responds to a MESSAGE event in Google Chat that includes the /createContact
     slash command by opening a dialog.

  Args:
      req (flask.Request): the event object from Chat API.

  Returns:
      Mapping[str, Any]: open a Dialog in response to a card's button click.
  """

  if req.method == 'GET':
    return 'Sorry, this function must be called from a Google Chat.'

  request = req.get_json(silent=True)

  if request.get('type') == 'CARD_CLICKED':
    invoked_function = request.get('common', dict()).get('invokedFunction')
    if invoked_function == 'open_dialog':
      return open_dialog(request)

    elif invoked_function == 'open_sequential_dialog':
      return open_dialog(request)

    elif invoked_function == "receive_dialog":
      return receive_dialog(request)

  else:
    return {
      'cardsV2': [{
        'cardId': 'addContact',
        'card': {
          'header': {
            'title': 'Rolodex',
            'subtitle': 'Manage your contacts!',
            'imageUrl': 'https://www.gstatic.com/images/branding/product/2x/contacts_48dp.png',
            'imageType': 'CIRCLE'
          },
          'sections': [
            {
              'widgets': [
                {
                  'buttonList': {
                    'buttons': [
                      {
                        'text': 'Add Contact',
                        'onClick': {
                                'action': {
                                  'function': 'open_dialog',
                                  'interaction': 'OPEN_DIALOG'
                                }
                        }
                      }
                    ]
                  }
                }
              ]
            }
          ]
        }
      }]
    }

def open_dialog(request: Mapping[str, Any]) -> Mapping[str, Any]:
  """Opens a dialog in Google Chat.

  Args:
      request (Mapping[str, Any]): the event object from Chat API.

  Returns:
      Mapping[str, Any]: open a Dialog in response to a card's button click.
  """
  return {
    'action_response': {
      'type': 'DIALOG',
      'dialog_action': {
        'dialog': {
          'body': {
            'sections': [
              {
                'header': 'Add new contact',
                'widgets': [
                  {
                    'textInput': {
                      'label': 'Name',
                      'type': 'SINGLE_LINE',
                      'name': 'name'
                    }
                  },
                  {
                    'textInput': {
                      'label': 'Address',
                      'type': 'MULTIPLE_LINE',
                      'name': 'address'
                    }
                  },
                  {
                    'decoratedText': {
                      'text': 'Add to favorites',
                      'switchControl': {
                        'controlType': 'SWITCH',
                        'name': 'saveFavorite'
                      }
                    }
                  },
                  {
                    'decoratedText': {
                      'text': 'Merge with existing contacts',
                      'switchControl': {
                        'controlType': 'SWITCH',
                        'name': 'mergeContact',
                        'selected': True
                      }
                    }
                  },
                  {
                    'buttonList': {
                      'buttons': [
                        {
                          'text': 'Next',
                          'onClick': {
                            'action': {
                              'function': 'open_sequential_dialog'
                            }
                          }
                        }
                      ]
                    }
                  }
                ]
              }
            ]
          }
        }
      }
    }
  }

def open_sequential_dialog(request: Mapping[str, Any]) -> Mapping[str, Any]:
  """Opens a second dialog that lets users add more contact details.

  Args:
      request (Mapping[str, Any]): the event object from Chat API.

  Returns:
      Mapping[str, Any]: open a Dialog in response to a card's button click.
  """
  return {
    'action_response': {
      'type': 'DIALOG',
      'dialog_action': {
        'dialog': {
              'body': {
                'sections': [
                  {
                    'header': 'Add new contact',
                    'widgets': [
                      {
                        'textInput': {
                          'label': 'Notes',
                          'type': 'MULTIPLE_LINE',
                          'name': 'notes'
                        }
                      },
                      {
                        'selectionInput': {
                          'type': 'RADIO_BUTTON',
                          'label': 'Contact type',
                          'name': 'contactType',
                          'items': [
                            {
                              'text': 'Work',
                              'value': 'Work',
                              'selected': False
                            },
                            {
                              'text': 'Personal',
                              'value': 'Personal',
                              'selected': False
                            }
                          ]
                        }
                      },
                      {
                        'buttonList': {
                          'buttons': [
                            {
                              'text': 'Submit',
                              'onClick': {
                                'action': {
                                  'function': 'receive_dialog',
                                  'parameters': [
                                    {
                                      'key': 'receiveDialog',
                                      'value': 'receiveDialog'
                                    }
                                  ]
                                }
                              }
                            }
                          ]
                        },
                        'horizontalAlignment': 'END'
                      }
                    ]
                  }
                ]
              }
        }
      }
    }
  }

def receive_dialog(event: Mapping[str, Any]) -> Mapping[str, Any]:
  """Checks for a form input error, the absence of a "name" value, and returns
     an error if absent. Otherwise, confirms successful receipt of a dialog.

  Args:
      event (Mapping[str, Any]): the event object from Chat API.

  Returns:
      Mapping[str, Any]: the response.
  """

  if event.get('common', dict()) \
      .get('formInputs', dict()).get('contactName', dict()) \
          .get('stringInputs').get('value', list()):
    return {
      'actionResponse': {
        'type': 'DIALOG',
        'dialogAction': {
          'actionStatus': 'OK'
        }
      }
    }
  else:
    return {
      'actionResponse': {
        'type': 'DIALOG',
        'dialogAction': {
          'actionStatus': "Don't forget to name your new contact!"
        }
      }
    }