ably-react-hooks

Use Ably in your React application using idiomatic, easy to use, React Hooks!

Using this package you can:

Interact with Ably channels using a react hook.
Send messages via Ably using the channel instances the hooks provide
Get notifications of user presence on channels
Send presence updates

The hooks provide a simplified syntax for interacting with Ably, and manage the lifecycle of the Ably SDK instances for you taking care to subscribe and unsubscribe to channels and events when your react componenets re-render.

Installation

The hooks ship as an ES6 module, so you can use the import syntax in your react code.

npm install --save @ably-labs/react-hooks

This works out of the box using create-react-app - and you can use the package immediately.

Ably channels and API keys

In order to use these hooks, you will need an Ably API key. If you are not already signed up, you can sign up now for a free Ably account. Once you have an Ably account:

Log into your app dashboard.
Under “Your apps”, click on “Manage app” for any app you wish to use for this tutorial, or create a new one with the “Create New App” button.
Click on the “API Keys” tab.
Copy the secret “API Key” value from your Root key, we will use this later when we build our app.

It is strongly recommended that you use Token Authentication, this will require server side code that is outside of the scope of this readme. In the examples below we use an API key directly in the markup, this is for *local development only and should not be used for production code and should not be committed to your repositories.

Usage

Once you've added the package using npm to your project, you can use the hooks in your react code.

Start by adding a reference to the hooks

import { configureAbly, useChannel } from "@ably-labs/react-hooks";

Then you need to use the configureAbly function to create an instance of the Ably JavaScript SDK.

configureAbly({ key: "your-ably-api-key", clientId: generateRandomId() });

configureAbly matches the method signature of the Ably SDK - and requires either a string or an AblyClientOptions. You can use this configuration object to setup your API keys, or tokenAuthentication as you normally would. If you want to use the usePresence hook, you'll need to explicitly provide a clientId.

Once you've done this, you can use the hooks in your code. The simplest example is as follows:

const [channel] = useChannel("your-channel-name", (message) => {
    console.log(message);
});

Every time a message is sent to your-channel-name it'll be logged to the console. You can do whatever you need to with those messages.

useChannel

The useChannel hook lets you subscribe to a channel and receive messages from it.

const [channel, ably] = useChannel("your-channel-name", (message) => {
    console.log(message);
});

Both the channel instance, and the Ably JavaScript SDK instance are returned from the useChannel call.

useChannel really shines when combined with a regular react useState hook - for example, you could keep a list of messages in your app state, and use the useChannel hook to subscribe to a channel, and update the state when new messages arrive.

const [messages, updateMessages] = useState([]);
const [channel] = useChannel("your-channel-name", (message) => {
    updateMessages((prev) => [...prev, message]);
});

// Convert the messages to list items to render in a react component
const messagePreviews = messages.map((msg, index) => <li key={index}>{msg.data.someProperty}</li>);

useChannel supports all of the parameter combinations of a regular call to channel.subscribe, so you can filter the messages you subscribe to by providing a message type to the useChannel function:

const [channel] = useChannel("your-channel-name", "test-message", (message) => {
    console.log(message); // Only logs messages sent using the `test-message` message type
});

The channel instance returned by useChannel can be used to send messages to the channel. It's just a regular Ably JavaScript SDK channel instance.

channel.publish("test-message", { text: "message text" });

usePresence

The usePresence hook lets you subscribe to presence events on a channel - this will allow you to get notified when a user joins or leaves the channel.

const [presenceData, updateStatus] = usePresence("your-channel-name");

// Convert presence data to list items to render    
const peers = presenceData.map((msg, index) => <li key={index}>{msg.clientId}: {msg.data}</li>);

usePresence returns an array of presence messages - again each message is a regular Ably JavaScript SDK presenceMessage instance.

You can optionally provide a string when you usePresence to set an initial presence data string.

const [presenceData, updateStatus] = usePresence("your-channel-name", "initial state");

The updateStatus function can be used to update the presence data for the current client:

updateStatus("new status");