- The WebSocket API (WebSockets)
- WebSockets for fun and profit
- The WebSocket API (WebSockets)
- PI Web API Channels (WebSocket connection) for multiple elements
WebSockets for fun and profit
Seamless communication is a must on the modern web. As internet speeds increase, we expect our data in real time. To address this need, WebSocket, a popular communication protocol finalized inenables websites to send and receive data without delay. With WebSockets, you can build multiplayer games, chat apps, and collaboration software that work on the open web. I built several projects with WebSockets before I started to wonder what exactly was happening under the hood. In this article, we will:. By the end of this piece, you should feel comfortable discussing how WebSockets work, and maybe even inspired to use it in your next project. The key word in that definition is two-way : with WebSocket, both the client and the server can trigger communication with one another, and both can send messages, at the same time. Why is this a big deal? In a traditional HTTP system, which is used by the majority of websites today, a web server is designed to receive and respond to requests from clients via HTTP messages. This traditional communication can only be initiated in one direction: from the client to the server. Server code defines what type of requests the server should expect and how to respond to each of them. A common metaphor for this type of communication is a restaurant kitchen. It goes something like this:. The important thing to note here is that the kitchen has no idea who the order is coming from. We do have ways around that—for example, clients can send along cookies that help the server identify the client, but the HTTP messages themselves are distinct and are read and fulfilled independently. The kitchen has no concept of you —only the orders that come in. In server-speak, the only way for clients to get updated information from the server is to send requests. You send a message to the server, as a request with some text as a payload. The server receives your request and stores the message. As it stands, you and your friend—both clients—need to constantly check the server for updates, introducing awkward delays between every message. Here it is! One dead simple solution to this problem is a technique called short polling. Just have the client ping the server repeatedly, say, every ms or over some fixed delay. That way, you get new data every ms. Another workaround to the delay in receiving data is a technique called long polling. Long polling is more efficient than pinging the server repeatedly since it saves the hassle of parsing request headers, querying for new data, and sending often-empty responses. However, the server must now keep track of multiple requests and their order. Also, requests can time out, and new requests need to be issued periodically. However, SSE is not supported by older browsers, and most browsers limit the number of SSE connections you can make at the same time. So, we need a way to send information to the server, and receive updates from the server when updates come in. Enter WebSocket! Supported by almost all modern browsersthe WebSocket API allows us to open exactly that kind of two-way connection with the server. Moreover, the server can keep track of each client and push messages to a subset of clients. With this capability we can invite all of our friends to our chat app and send messages to all of them, some of them, or only your best friend. So, how exactly does this magic work? In the last section, we mentioned HTTP several times. HTTP is a protocola set of rules for how computers communicate on the web. WebSocket is another protocol for sending and receiving messages.
The WebSocket API (WebSockets)
The WebSocket API is an advanced technology that makes it possible to open a two-way interactive communication session between the user's browser and a server. With this API, you can send messages to a server and receive event-driven responses without having to poll the server for a reply. Note: While a WebSocket connection is functionally somewhat similar to standard Unix-style sockets, they are not related. Get the latest and greatest from MDN delivered straight to your inbox. Sign in to enjoy the benefits of an MDN account. The compatibility table on this page is generated from structured data. Prefixed Notes. Last modified: Mar 1,by MDN contributors. Related Topics. Learn the best of web development Get the latest and greatest from MDN delivered straight to your inbox. The newsletter is offered in English only at the moment. Sign up now. Sign in with Github Sign in with Google. Chrome Full support 4. Edge Full support IE Full support Opera Full support Safari Full support 5. Chrome Android Full support Opera Android Full support Safari iOS Full support 4. Samsung Internet Android Full support 1. Chrome Full support Yes. Opera Full support Yes. WebView Android Full support Yes. Chrome Android Full support Yes. Firefox Android Full support 7. Opera Android? Safari iOS? Samsung Internet Android Full support Yes. Firefox Full support Yes. Safari Full support Yes.