Asynchronous messages in Hangouts Chat (The G Suite Dev Show)
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Asynchronous messages in Hangouts Chat (The G Suite Dev Show)


[MUSIC PLAYING] WESLEY CHUN: Hey there and
welcome to another episode of “The G Suite Dev Show.” I’m your host, Wesley Chun. As you can see,
we’re going to talk about sending alerts and
notifications in Hangouts Chat. But when would you want
to do this and why? You also have to
ask how to do this and where you can do it from. Well, the hint is
in the subtitle, but these answers
and more coming up. Chances are that,
if you’re here, you’ve probably already used
the Hangouts Chat bot framework and built bots, which
take user requests and respond synchronously. Well, if not, check
out the other video first, which introduces
the framework and how to write bots. OK, so we get bots generally
respond in a synchronous way, meaning that, when someone talks
to a bot, in a direct message or @mentions a bot
in a chat room, the Hangouts Chat service
forwards that message via HTTP posts to your bot. Your bot does what
it needs to do and sends its reply back
in the HTTP response, which is then rendered in the
chat room or direct message. By the way, we refer to rooms
and DMs more generically as spaces. These asynchronous replies
correspond to user requests. But what if you need to know
when a long-running background job has completed, or a
train or a bus running late is arriving soon? Or perhaps, you want an alert,
when a server has gone down or when a new customer is
added to the corporate CRM. Well, these are situations where
you need out-of-band messages, messages which are sent
asynchronously by your bot or other notification apps. The Hangouts Chat bot framework
supports asynchronous messages just for these
types of use cases. Asynchronous messages
can also be sent to specific threads of context. Well, more on this later. If you take a closer
look at the diagram, recognize that a bot
or some monitoring app is trying to send a
message to a space. So it needs to initiate a
connection to Hangouts Chat, meaning some level of
authorization is needed. Well, Hangouts Chat will
then send the notification to the requested space. There are two ways to
connect to Hangouts Chat. The first is for bots, and
those are service accounts. A service account is a special
type of Google account that is tied to your app–
in this case, a bot– instead of a user. The bot assumes the identity
of the service account to call the Hangouts Chat API. The second way is
for non-bot apps, and that is to use
incoming webhooks. This entails calling a specific
URL, with built-in credentials, to communicate to a space. Let’s tackle these
one at a time. Here is a short Python
script representing part of your overall
bot application. Beyond the imports, this script
starts with the OAuth scope for Hangouts Chat. This is the only
permission needed to send a message into a space. Merge that scope, along with
the service account client ID of the API project, to
generate the credentials needed to create an API endpoint. You can then use that endpoint
to send messages to a space. Now keep in mind that this
is just part of your bot. The code you don’t see here
is your custom workflow, like pulling information
from a database, calling external
APIs, or whatever processing you want
to do before you send that message into the space. Anytime you see
permission scopes in code, it’s a pretty strong indication
you’re calling an API. What makes Hangouts Chat
different from other Google APIs is that bots must have
a service account to call the API, because it’s
code that is never executed on behalf of a user. The Python script
we just saw was an example of creating
messages in a space. Now, more generally, the API
can do all CRUD operations on messages, as you see
from the API docs here. However, the API also
has additional features to give bots more context,
such as getting info on spaces or members in spaces. All right, well, that’s the
first asynchronous technique. Now along with the
API, Hangouts Chat also supports incoming
webhooks as a convenient way of sending asynchronous
messages into spaces that are not from a bot. They’re great for
one-off alerts, like the ones I
mentioned earlier– the server going down or a
new customer in the house. All right, but it doesn’t always
have to be something urgent. For example, it could be
used for standard or timed notifications. In other words,
incoming webhooks are a quick and easy
way to integrate any of your custom workflows. Now, the way you use
incoming webhooks is to go to the space for
which you want the webhook, pull down the selector
bar at the top, then choose Configure Webhooks. You’ll see the configuration
dialog pop up, like this one, featuring one webhook. Now you can have more than
one, because this room may get notified from
different sources, right? So you click Add Webhook to add
a new one, provide a webhook name, and an optional avatar– otherwise, you get the
generic webhook icon– then click Save. Then you click on the Copy
icon to copy that hook into your clipboard and then use
that link in your notification app. Now these URLs are
fairly long, since they have built-in authorization. Keep them safe,
because like API keys, anyone can use them to
post into that space if they’re somehow exposed. Incoming webhook messages can
come from a variety of sources, like this Python script, which
can do anything from network monitoring to CRM triggers. An incoming webhook doesn’t
even have to be code. You can even send an
alert into a space with just a cURL command,
like what you see here. Now here’s a snippet
of an incoming webhook I wrote for my team using
AppScript and a timed trigger, which is similar
to a UNIX cron job. This reminds them to send
out their weekly TPS reports, as well as submit
their timesheets, so they can get paid. Now one caveat is
that async messages can be numerous and disruptive
when every new message spawns a new thread. Well, Hangouts Chat has
an innovative feature using what are known
as thread keys, which direct all async messages
to the same threads, grouping related
notifications together, like what you see here,
and reducing the clutter. Thread keys are supported
by both the API and incoming webhooks. And here’s an example of its
use from our cURL example. All subsequent async messages
sent to the same thread key go to the same conversation. See the thread keys guide in
the docs for more information. Are you ready for
your next steps? Well, check out the
first link to read more about using the REST API. The next resource is all
about incoming webhooks. And finally, we’ve got the
Python incoming web Quickstart sample ready for you to try out. Now what should you do with
your newfound knowledge? Well, you’ve probably
already written a bot, so add the use of the API,
so your bot can send messages asynchronously into a space,
for any of the reasons we mentioned earlier, like
completion of a background job. For incoming webhooks,
start the Quickstart, and then build
something on top of that to send alerts or
other notifications into a relevant space, such
as the weekly reminder shown earlier. Well, with this new
tool under your belt, you’re now ready
to build bots that can send both synchronous
and asynchronous messages. Not all bots can
respond synchronously, and there will be
situations where async is the right tool for the job. All right, be sure to
subscribe to our channel and tune into
another episode soon. This is Wesley Chun from Google,
and we’ll see you upstairs in the G Suite. [MUSIC PLAYING]

7 thoughts on “Asynchronous messages in Hangouts Chat (The G Suite Dev Show)

  1. It's just we're putting new coversheets on all the TPS reports before they go out now. So if you could go ahead and try to remember to do that from now on, that'd be great. All right!

    Other than the reference, great video, it clarified a lot to me.

  2. Is it possible to implementing any kind of watcher on a space/room which makes POST call if anyone sends a message in it?

  3. Can someone please help me I get bots in my chat Hangout I read some things online will you can have fun with them where they can be helpful in the way if you know how to talk to them the how can I stop them it is it tool that you can get information

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