comet – Tarik Billa

Chrome’s loading indicator keeps spinning during XMLHttpRequest

January 8, 2024 by Tarik

I shamelessly stole Oleg’s test case and adjusted it a bit to simulate long-polling. load.html: <!DOCTYPE html> <head> <title>Demonstration of the jQery.load problem</title> <script src=”http://code.jquery.com/jquery-latest.js”></script> <script> jQuery(document).ready(function() { $(‘#main’).load(“test.php”); }); </script> </head> <body> <div id=’main’></div> </body> </html> test.php: <?php sleep(5); ?> <b>OK!</b> The result is interesting: in Firefox and Opera, no loading indicator is shown … Read more

HTML 5 Websockets will replace Comet?

December 27, 2023 by Tarik

There are 2 pieces to this puzzle: Q: Will the client-side portion of “comet” be necessary? A: Yes. Even in the next 2 years, you’re not going to see full support for WebSockets in the “major” browsers. IE8 for example doesn’t have support for it, nor does the current version of FireFox. Given that IE6 … Read more

Stop the browser “throbber of doom” while loading comet/server push iframe

December 17, 2023 by Tarik

After digging for a day and a night in the guts of the internets, here is what I came up with: server-sent events – Very cool, currently works only in Opera, but may be part of HTML5 and other browsers may support it sometime. Adds a new element tag with content-type of “application/x-dom-event-stream” which allows … Read more

Simple comet example using php and jquery

December 17, 2023 by Tarik

How does a WCF server inform a WCF client about changes? (Better solution then simple polling, e.g. Comet or long polling)

December 14, 2023 by Tarik

It sounds to me like you already know the answer: use long polling. 🙂 So I guess the only thing left to explain is how you might be able to accomplish this with WCF and in the most efficient manner possible. The basics: First, decide how long you want each “long poll” to be. For … Read more

Refused to set unsafe header “Origin” when using xmlHttpRequest of Google Chrome

December 5, 2023 by Tarik

This is just a guess, as I use jquery for ajax requests, including CORS. I think the browser is supposed to set the header, not you. If you were able to set the header, that would defeat the purpose of the security feature. Try the request without setting those headers and see if the browser … Read more

How do I use Comet with Spring MVC?

July 27, 2023 by Tarik

Atmosphere is really the best I’ve seen (I haven’t used any, but I’ve evaluated multiple solutions). The good thing with it is that it uses the best mechanism available. If running on servlet 3.0 – using the async support. If using jetty – using its support, and so on. It also has spring integration. So, … Read more

What specific use cases call for BOSH over WebSockets and long-polling? [closed]

June 11, 2023 by Tarik

First let me address WebSockets readiness: WebSockets implementation of the Hixie-76 protocol are shipped and enabled by default in Chrome, Safari and iOS (iPhone and iPad). The Hixie-76 protocol is also shipped but disabled by default in Firefox 4 and Opera 11. The web-socket-js project is a Flash shim/polyfill that adds WebSocket (Hixie-76) support to … Read more

Is there a server cost to using WebSockets?

May 11, 2023 by Tarik

There are lots of good overview sites to read about how websockets generally work like here and here. In a nutshell, they initiate a connection with a certain type of HTTP request and then after that, they are a direct TCP bi-directional connection between client and server. There is some server overhead to maintain an … Read more