Asynchronously Respond in new Hangout Chat using rest API, without using google app engine

Question

How can I post message as a bot(async) in new hangouts chat without using the Google App Engine. I have gone through the examples, but all of them use App Engine for authentication, but i need to authenticate it without using the same.

Answer 1

Here is a code sample that connects to a chat using an http request and a webhook from Google Hangout Chat with a Python script. Webhooks are the only alternative to using a service account. More info here: https://developers.google.com/hangouts/chat/how-tos/webhooks

`from httplib2 import Http
from json import dumps

#
# Hangouts Chat incoming webhook quickstart
#
def main():
    url = '<webhook url here>'
    bot_message = {
        'text' : 'text go here'}

    message_headers = { 'Content-Type': 'application/json; charset=UTF-8'}

    http_obj = Http()

    response = http_obj.request(
        uri=url,
        method='POST',
        headers=message_headers,
        body=dumps(bot_message),
    )

    print(response)

if __name__ == '__main__':
    main()
`

Answer 2

If your bot implementation is with google app script try to do it with google service account and as indicated here an example of async message

// Example bot for Hangouts Chat that demonstrates bot-initiated messages
// by spamming the user every minute.
//
// This bot makes use of the Apps Script OAuth2 library at:
//     https://github.com/googlesamples/apps-script-oauth2
//
// Follow the instructions there to add the library to your script.

// When added to a space, we store the space's ID in ScriptProperties.
function onAddToSpace(e) {
  PropertiesService.getScriptProperties()
      .setProperty(e.space.name, '');
  return {
    'text': 'Hi! I\'ll post a message here every minute. ' +
            'Please remove me after testing or I\'ll keep spamming you!'
  };
}

// When removed from a space, we remove the space's ID from ScriptProperties.
function onRemoveFromSpace(e) {
  PropertiesService.getScriptProperties()
      .deleteProperty(e.space.name);
}

// Add a trigger that invokes this function every minute via the
// "Edit > Current Project's Triggers" menu. When it runs, it will
// post in each space the bot was added to.
function onTrigger() {
  var spaceIds = PropertiesService.getScriptProperties()
      .getKeys();
  var message = { 'text': 'Hi! It\'s now ' + (new Date()) };
  for (var i = 0; i < spaceIds.length; ++i) {
    postMessage(spaceIds[i], message);
  }
}
var SCOPE = 'https://www.googleapis.com/auth/chat.bot';
// The values below are copied from the JSON file downloaded upon
// service account creation.
var SERVICE_ACCOUNT_PRIVATE_KEY = '-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n';
var SERVICE_ACCOUNT_EMAIL = 'service-account@project-id.iam.gserviceaccount.com';

// Posts a message into the given space ID via the API, using
// service account authentication.
function postMessage(spaceId, message) {
  var service = OAuth2.createService('chat')
      .setTokenUrl('https://accounts.google.com/o/oauth2/token')
      .setPrivateKey(SERVICE_ACCOUNT_PRIVATE_KEY)
      .setClientId(SERVICE_ACCOUNT_EMAIL)
      .setPropertyStore(PropertiesService.getUserProperties())
      .setScope(SCOPE);
  if (!service.hasAccess()) {
    Logger.log('Authentication error: %s', service.getLastError());
    return;
  }
  var url = 'https://chat.googleapis.com/v1/' + spaceId + '/messages';
  UrlFetchApp.fetch(url, {
    method: 'post',
    headers: { 'Authorization': 'Bearer ' + service.getAccessToken() },
    contentType: 'application/json',
    payload: JSON.stringify(message),
  });
}

Answer 3

You need to perform some below steps.

1. Create a service-account in console.developers.google.com and download the private key in JSON format

2. Use below modules if you code in python.

   from oauth2client.service_account import ServiceAccountCredentials from googleapiclient.discovery import build, build_from_document from httplib2 import Http

3. Below snippet will post the message to user via chat.google.

   scopes = ['https://www.googleapis.com/auth/chat.bot'] credentials = ServiceAccountCredentials.from_json_keyfile_name('/path/to/json', scopes) http = Http() credentials.authorize(http) chat = build('chat', 'v1', http=http) resp = chat.spaces().messages().create( parent=space, body={'text': 'HELLO WORLD'}).execute()

4. You would require a space name where you can post the code. You will get the same from hangout chat response.

Answer 4

It’s possible to do so using JavaScript, python, (possibly more). You can check out examples here: https://github.com/gsuitedevs/hangouts-chat-samples/tree/master/node/basic-cloud-functions-bot

If you’re using cards and JavaScript I would encourage you to checkout my library here: https://github.com/BaReinhard/hangouts-card-helper

I’m also in the process of creating another example for JavaScript that is more async focused that should provide and example that’s a bit easier to reason about the code. Will link when the PR is pushed.

Edit:

I realize that you mentioned REST api. The above answer is more useful for a specific bot that can be accessed @mentions. However, if you can provide us with a bit more information I can better fix my answer to answer your question.