CODEWITHSUNDEEP
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forthrin
forthrin

Reputation: 2777

Long Polling or WebSockets

I am writing Web chat where you have several one-on-one conversations with people on the screen at the same time. (Basically, like a personal messenger, without group chats).

My technology options seem to be Long Polling and WebSockets, and I'm trying to choose.

The upside with Long Polling is that's it's very easy to implement, and I can return whatever data i want (a customized JSON-object with the data required to update the page).

What I'm afraid of with WebSockets is that there's no native library for it in PHP, so you have to shop between different 3rd party ones, and the concepts seem more complicated, what with channels and subscriptions and what have you.

Browser compatibility is not an issue for me.

  1. Is the performance of Long Polling much poorer than with Websockets? If no, then my decision is easy!

  2. Is there a really simple Websocket server for PHP? Or is the concept so simple I could write my own? (Mozilla has a really simple tutorial on writing a client, but not on a server).

Upvotes: 1

Views: 2878

Answers (1)

mattexx
mattexx

Reputation: 6606

Assuming that your long-polling scheme involves an endpoint hosted by the same web server as your frontend, this will mean two active connections for every user of the application, so you will basically cut the number of users you can support in half. Your websocket server would run on a different port and can bypass your web server, so the connections are a lot of saved overhead with websockets.

Another place websockets save on overhead is that once your connection is established, there is no need for constant requests and responses. Zombie websocket connections are essentially free in terms of both bandwidth and CPU.

Finally, I would not think that long polling would be simpler to implement. Since websockets are designed to do exactly what you want, I think that leveraging an existing websocket package will actually save you some lines of code. I would look at Ratchet (feature-rich) or phpwebsocket (lite), if you want to use PHP.

Upvotes: 2

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