Tim,
Sounds like a fun project! Some things to consider and investigate:
>>1) How often does the server receive a message for processing? (How many hits per minute or per second, etc)
>
>The server would be very often perhaps 20 per minute.
>The HTML help app whenever the user presses F1 so not so often.
>
>>2) How long does the server processing take?
>Probably about 5-10 seconds
At 20 requests per minute (1 every 5 seconds) and the server processing time at 5 to 10 seconds, you obviously will need more than one instance of your server code running to handle the load, or you will get progressively slower and slower on response time.
This means that a pooled COM server approach (MTS or COM+) looks like a good possibility, with your client code instantiating a COM server and calling a method on it.
>30 Seconds response is exceptable but real time (or near) would be nice.
With the pooled approach, your response time should be just slightly more than the server processing time.
>i'm thinking I should use Sockets and TCP\IP for the server and HTML help app.
>If it's the fastest. The messages shouldd be just a key and I don't want it polling with SQL frequently. I guess I'm looking for more info.
The issues to consider with Sockets is whether you can have two or more instances of a server app listening for messages and running off to do their stuff, or whether you have just one socket listener that somehow queues up requests for the server app by writing to a table or queue manager.
If you have one listener writing to a queue or table for another component to execute, you might as well just do that directly from your client side piece.
You could use MS Message Queueing and let the server-side component(s) pick the next message off the queue for processing or, if your client and server-side pieces are VFP, Rick Strahl's new wwAsyncWebRequest class (included in the latest version of Web Connection) can do the same thing with VFP tables as the message delivery mechanism.
http://www.west-wind.com/webconnection/docs/_0CI0PQWXQ.htm
