Let socket = new WebSocket("wss:///article/websocket/chat/ws") ĭ. But for binary processing, to access individual data bytes, we can change it to "arraybuffer": That’s set by socket.binaryType property, it’s "blob" by default, so binary data comes as Blob objects.īlob is a high-level binary object, it directly integrates with, and other tags, so that’s a sane default. And for binary data, we can choose between Blob and ArrayBuffer formats. When we receive the data, text always comes as string. No settings required: just send it out in any format. send() method can send either text or binary data.Ī call nd(body) allows body in string or a binary format, including Blob, ArrayBuffer, etc. In the browser, we directly work only with text or binary frames. there’s also “connection close frame” and a few other service frames.“ping/pong frames” are used to check the connection, sent from the server, the browser responds to these automatically.“binary data frames” – contain binary data that parties send to each other.“text frames” – contain text data that parties send to each other.WebSocket communication consists of “frames” – data fragments, that can be sent from either side, and can be of several kinds: Here the server responds that it supports the extension “deflate-frame”, and only SOAP of the requested subprotocols. This optional header is set using the second parameter of new WebSocket. So, this header describes data formats that we’re going to use. WebSocket subprotocols are registered in the IANA catalogue. It is possible you are missing a dependency that is needed from npm install, but if it says it cannot find the main file you are trying to run. then you are most likely trying to run the wrong file. Sec-WebSocket-Protocol: soap, wamp means that we’d like to transfer not just any data, but the data in SOAP or WAMP (“The WebSocket Application Messaging Protocol”) protocols. If you are trying to run your Node.js application and you get something like this: Error: Cannot find module C:UsersMemyapp.js. The header Sec-WebSocket-Extensions is sent automatically by the browser, with the list of all extensions it supports. An extension is something related to transferring the data, functionality that extends WebSocket protocol. Sec-WebSocket-Extensions: deflate-frame means that the browser supports data compression. There may be additional headers Sec-WebSocket-Extensions and Sec-WebSocket-Protocol that describe extensions and subprotocols. The browser uses it to make sure that the response corresponds to the request.Īfterwards, the data is transfered using WebSocket protocol, we’ll see its structure (“frames”) soon. Here Sec-WebSocket-Accept is Sec-WebSocket-Key, recoded using a special algorithm. Sec-WebSocket-Accept: hsBlbuDTkk24srzEOTBUlZAlC2g= When new WebSocket(url) is created, it starts connecting immediately.ĭuring the connection the browser (using headers) asks the server: “Do you support Websocket?” And if the server replies “yes”, then the talk continues in WebSocket protocol, which is not HTTP at all. That’s actually it, we can talk WebSocket already. So you’ll see events open → message → close. It responds with “Hello from server, John”, then waits 5 seconds and closes the connection. de is usually 1006 in this caseįor demo purposes, there’s a small server server.js written in Node.js, for the example above, running. Let socket = new WebSocket("wss:///article/websocket/demo/hello") Īlert(` Data received from server: $`)
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