Connect PHP with Orbited

Question

After searching the web for a good Comet and also and asking you guys what my best option is, I've chose to go with Orbited. The problem is if you need a good documentation about Comet you won't find. I've installed Orbited and It seems It works just fine.

Basically, I want to constantly check a database and see if there is a new data. If there is, I want to push it to my clients and update their home page but I can't find any good and clear doc explaining how constantly check the database and push the new info to Orbited and then to the clients. Have you guys implemented that?

Also, how many users can Orbited handle?

Any ideas?

Answer 1

You could add a database trigger that sends messages to your message queue when the database got changed. This is also suggested here. Or, if it is only your app talking to the database, you could handle this from within the app via a Subject/Observer pattern, notifying the queue whenever someone called an action changing something in the DB.

I don't know how good or bad Orbited scales.

Answer 2

Have a reference table that keeps track of the last updated time of the source table. Create a update/delete/insert trigger for the source table that updates the time in the reference table.

Your comet script should keep checking the reference table for any change in the time. If the change is noticed, you can read the updated source table and push the data to your client's home page. Checking the reference table in a loop is faster because the MySQL will serve the results from its cache if nothing has changed.

And sorry, I don't know much about Orbited.

Answer 3

I would use the STOMP protocol with Orbited to communicate and push data to clients. Just find a good STOMP client with PHP and get started.

Here is an example of a use case with STOMP, although the server side is written in Ruby: http://fuglyatblogging.wordpress.com/2008/10/

I don't know if PHP with Apache (if that's what you are using) is the best suite for monitoring database changes. Read this article, under the section title "Orbited Server", for an explanation: http://thingsilearned.com/2009/06/09/starting-out-with-comet-orbited-part-1/

EDIT: If you want to go the route with PHP through a web server, you need to make one, and one only, request to a script that starts the monitoring and pushes out changes. And if that script times out or fails, you need to start a new one. A bit fugly :) A nicer, cleaner way would be, for example, to use twisted with python to start a monitoring process, completely separated from the web-server.