I want to write a php site which uses the comet technology for real time update.
I have a few questions:
Is it better to use a comet server? Which comet server is good?
For comet server (e.g. orbited), I have to first install the python based orbited server and then write php file to create socket to connect to the comet server. Right? (Orbited.org does not have any tutorial about this.)
Yes it's better to use a dedicated server. StreamHub Comet Server seems to be the most popular these days.
For a tutorial on how to get started with comet read this: Getting Started with Comet and StreamHub.
If you get stuck there is a Google Group to seek help.
Depending on your needs, you could check WebSync OnDemand - it works well for PHP apps, and the hosting is offloaded. If you're only looking for a few users (<=10) it's free too.
Orbited PHP Client can be found at Download page.
Direct link: http://orbited.org/raw-attachment/wiki/Download/php-orbited.php
There are many solution in this moment for a comet Server: CometD contains an implementation of comet for the client (JavaScript library) and for the Server based on Jetty. Another good Option is to combine Atmosphere with Tomcat, Jetty, GlassFish, Weblogic, Grizzly, JBossWeb and JBoss, Resin, etc Another comet implementation come from APE: see ape-project.org If you want to implement yourself a solution (serverside and clientside) onyl using web server support you can choose between the web servers just named, but probably you must to invest a lot of effort.
来源：https://stackoverflow.com/questions/1250850/problem-of-choosing-comet-server