Realtime communication between the client and the server
The easiest way to send a realtime message from a client to a Sails app is by using the sails.io.js library. This library allows you to easily connect sockets to a running Sails app, and provides methods for making requests to Sails routes that are handled in the same manner as a "regular" HTTP request.
The sails.io.js library is automatically added to the default layout template of new Sails apps using a <script> tag. When a web page loads the sails.io.js script, it attempts to create a new client socket and connect it to the Sails app, exposing it as the global variable io.socket.
Examples
Include the sails.io.js library, and make a request to the /hello route of a Sails app using the automatically-connected socket:
<script type="text/javascript" src="/js/dependencies/sails.io.js"></script>
<script type="text/javascript">
io.socket.get('/hello', function responseFromServer (body, response) {
console.log("The server responded with status " + response.statusCode + " and said: ", body);
});
</script>
Now consider this more advanced (and less common) use case: let's disable the eager (auto-connecting) socket, and instead create a new client socket manually. When it successfully connects to the server, we'll make it log a message:
<script type="text/javascript" src="/js/dependencies/sails.io.js" autoConnect="false"></script>
<script type="text/javascript">
var mySocket = io.sails.connect();
mySocket.on('connect', function onConnect () {
console.log("Socket connected!");
});
</script>
Socket requests vs traditional AJAX requests
You may have noticed that a client socket .get() is very similar to making an AJAX request, for example by using jQuery's $.get() method. This is intentional—the goal is for you to be able to get the same response from Sails no matter where the request originated from. The benefit to making the request using a client socket is that the controller action in your Sails app will have access to the socket which made the request, allowing it to subscribe that socket to realtime notifications (see sending realtime messages from the server).
Reference
- View the full sails.io.js library reference.
- See the sails.sockets reference to learn how to send messages from the server to connected sockets
- See the resourceful pub-sub reference to learn how to use Sails blueprints to automatically send realtime messages about changes to your models.
- Visit the Socket.io website to learn more about the underlying library Sails uses for realtime communication
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