Record all requests made to web service?

Question

I built a web service that takes requests from SITE1 and then plugs the values into SITE2. We're running into an issue where occasionally SITE1 will send the request twice within a very short timeframe (within 30 seconds - 5 minutes). If the initial request completes fast enough, I have safe guards that prevent against duplicate records being entered. However, if a second request comes in before the first has completed, the web service completes both requests concurrently.

I need to figure out if there is a way to store a global temporary list of requests so that I can compare against this list prior to inserting the values.

My web service operates on a pretty simple level, it is simple http://url.com/Tool?ID=123434. All I would need to do is store the incoming ID in a global list until the request has completed successfully.

What options are available to me?

Answer 1

Unbeknownst to me, Global Static variables are global across the entire web application, to all connections. It was as simple as do the following.

public static class GlobalVariables
{
    public static List<long> TicketsInQueue { get; set; }
}

On application start, the variable is initialized (application start, not URL request). Once a request comes in, a query goes out to see if the list contains the given ID, if it does not the value is then added to the list. If it does exists, the request is simply logged and thrown away.