Informing users when data changes

staggman

I wonder if anyone can help, I am building a contact management system using LAMP.

I have contact details coming in via XML.

When new data arrives, it gets assigned to a particular agents by a trigger that reads rules about what sort of contact details goes to which sort of agent.

Everything works fine but I have one small problem that I am struggling to overcome;

I need to inform each agent in real time that a new contact has been made and assigned to them; I need to inform the browser that there is new data available on the server.

Does anyone know of a working method that will be resilient enough to survive machines going to sleep etc?

Thanks in advance

etully

You would need to have some technique that would be cross vendor compliant. That is, Apple might put their computers to sleep with one technique, Dell, might use another, Asus motherboards could use another, and some computers will completely shut themselves off. If there is a way for a web browser to "wake" a sleeping machine (and I don't think there is one), but even if there was... I doubt that it would work for every vendor... especially the ones who have the computer shut themselves off.

So I think your best solution is to either require that Agents not be allowed to use computers that go into sleep mode or look into an API that dials phone numbers and relays messages in voice. I think those can be had for around $.30 per call. So you update the screen, wait 30 seconds for the user to click "Ok, I got the message". If no click, then dial the Agent's phone number.

Yes, I admit that this is a silly answer. But given the nature of sleep mode on different computers, I can't think of a more safe solution.

staggman

What I'm looking for is any suggestions anyone can make about a simple but reliable reverse ajax/comet method that can be used to notify an agent through the browser that there is new data available to him after the arrival of said data has caused a trigger to fire in the database.

That is, I want to notify a logged in user's browser that a change has occured on the server that he can then choose to react to.

I had tried a simple comet example that I found but had run into problems with being unable to dynamically create the data file to be shared and also with one end of the connection being lost (in this case by a machine going to sleep)

paulnaj

You could do something like this ...

Add a iframe to the agents 'view'. The page in the iframe refreshes itself every couple of minutes (or whatever). On refeshing it looks up the 'data' and checks if there is something new ...

Might be the sort of thing you're looking for.

etully

That doesn't address the sleep mode problem. Logically, once you lose one end of the communications channel, your only option is to rely on a different channel. Once the computer falls asleep, the entire computer is unreliable. Since sleep mode operates differently on different platforms, the only reliable solution is to pick a channel that is always open. Email is no good because it requires people to check their email - and even automated email checkers could be silenced by the sleep mode. Radio is no good because it's a one : many broadcast (and people don't use radios as much as they used to) (and not everyone is within your broadcast range) (and they could be on the wrong channel). Telephones serve as a perfect backup for a sleeping computer because everyone has one, they are always is listen mode (even if you're on a call), the alert is audible, and they are a one : one connection.

staggman is asking for something simple and reliable.

You can have a simple, web based solution as long as you don't care if it's reliable.