I have an idea for an application that notifies users of changes in certain markets (like PUSH technology) in real time.
I'd like to write a client that is capable of checking (or being told of) changes in real time. However, I do not want constant TCP/IP connections (any begining hacker could log in on up to 65000 connections, easily taking out a server with just a home machine - UNLESS I take out multiple logins from the same IP. Unfortunately this would take out anyone working behind a firewall - BAD!).
UDP would work for notification to the client, but I am wondering if there is another way.
I'd like the client to do the work of checking for news, but I don't want tremendous bandwidth usage from my server. Is there a way for a client to check for a condition to be true before proceding, that doesn't use bandwidth until the condition is true? I need a web-based condition to check, that only uses bandwidth if the condition is true.
For example, if I used an ASP page that returned NOTHING but a BLANK PAGE - that's 150 bytes for NOTHING! And, if I ask for a non-existant page from an IIS server, I get back the "404" page not found page. Again, wasted bandwidth.
The 150 doesn't sound like much, but it adds up when your client checks every 15 to 60 seconds over a few thousand users.
Any ideas?
