Chat with C# and ASP.NET MVC

Ready to implement a chat application using Twilio Chat?

This application allow users to exchange messages through different channels, using the Twilio Chat API. With this example, we'll show you how to use this API to manage channels and their usages.

Properati built a web and mobile messaging app to help real estate buyers and sellers connect in real time. Learn more here.

For your convenience, we consolidated the source code for this tutorial in a single GitHub repository. Feel free to clone it and tweak as required.

Token Generation

In order to create a Twilio Chat client, you will need an access token. This token provides access for a client (such as a Javascript front end web application) to talk to the Twilio Chat API.

We generate this token by creating a new Token and providing it with an ChatGrant. With the Token at hand, we can use its method ToJwt() to return its string representation.

We can generate a token, now we need a way for the chat app to get it.

Token Generation Controller

On our controller we expose an endpoint that provides a valid token. Using the parameter:

• identity: identifies the user itself.

It uses tokenGenerator.Generate method to get hold of a new token and return it in a JSON format to be used for our client.

Now that we have a route that generates JWT tokens on demand, let's use this route to initialize our Twilio Chat Client.

Initialize the Chat Client

On our client, we fetch a new Token using a POST request to our endpoint.

And with the token we can instantiate a new Twilio.AccessManager that is used to initialize our Twilio.Chat.Client.

Now that we've initialized our Chat Client, lets see how we can get a list of channels.

Get the Channel List

After initializing the client, we can now call it's method getChannels to retrieve all visible channels. The method returns a promise as a result that we use to show the list of channels retrieved on the UI.

Next, we need a default channel.

Join the General Channel

This application will try to join a channel called "General Channel" when it starts. If the channel doesn't exist, we'll create one with that name. The scope of this example application will show you how to work only with public channels, but the Chat client allows you to create private channels and handle invitations.

Notice we set a unique name for the general channel as we don't want to create a new general channel every time we start the application.

Now let's listen for some channel events.

Listen to Channel Events

With access to the channel objects we can use them to listen to a series of events. In our case, we're setting listeners to the following events:

• messageAdded: When another member sends a message to the channel you are connected to.
• typingStarted: When another member is typing a message on the channel that you are connected to.
• typingEnded: When another member stops typing a message on the channel that you are connected to.
• memberJoined: When another member joins the channel that you are connected to.
• memberLeft: When another member leaves the channel that you are connected to.

Here, we just register a different function to handle each particular event.

The client emits events as well. Let's see how we can listen to those events as well.

Listen to Client Events

Just like with channels, we can register handlers for events on the Client:

• channelAdded: When a channel becomes visible to the Client.
• channelRemoved: When a channel is no longer visible to the Client.
• tokenExpired: When the supplied token expires.

We've actually got a real chat app going here, but let's make it more interesting with multiple channels.

Create a Channel

To create a new channel, the user clicks on the "+ Channel" link. That we'll show an input text field where it's possible to type the name of the new channel. The only restriction here, is that the user can't create a channel called "General Channel". Other than that, creating a channel is as simple as calling createChannel with an object that has the friendlyName key. You can create a channel with more options though, see a list of the options here.

Next, we will see how we can switch between channels.

Join Other Channels

When you tap on the name of a channel from the sidebar, that channel is set as the selectedChannel. The selectChannel method takes care of joining to the selected channel and setting up the selectedChannel.

At some point your users will want to delete a channel. Let's have a look at how that can be done.

Delete a Channel

Deleting a channel is even more simple than creating one. The application lets the user delete the channel they are currently joined to through the "delete current channel" link. The only thing you need to do to actually delete the channel from Twilio, is call the delete method on the channel you are trying to delete. As other methods on the `Channel' object, It'll return a promise where you can set function that is going to handle successes.

That's it! We've just implemented a simple chat application for C# using ASP.NET MVC.

Where to Next?

If you are a C# developer working with Twilio, you might want to check out these other tutorials:

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Masked Phone Numbers

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