Question

I am calling a web service via a httpwebrequest, and getting a response. The web service is meant to run 24/7.

What is the best way to structure this code, with checks that the service is “available”?

What I have:

if (NetworkIsAvailable())
{
  // Call web service
 // Handle exceptions within here.
}


else
{
 // to throw a relevant exception that there is no network
}

Is it wise to throw an exception, or just return false? The svc should never be down

Answer 1

Depending on the type of data you are receiving back, the frequency of checks, etc I would use a general purpose solution that tries the connection multiple times on a failure and then categorizes “exceptions” on failure (no two exceptions are ever the same in my experience).

For instance:

var failCount = 0;
var succeeded = false;

while ((failCount < 3) && (!succceeded)) {
   try {
      //call service....
      succeeded = true;
   } catch(WebException wex) {
      //handle wex, for instance look for timeout and retry
   } catch(...) {
     //Handle other exceptions differently...
     LogError("BOOOM: " + excep);
     throw;
   } catch(Exception ex) {
     //handle a general exception
     failCount++;
   }
}

if (failCount >= 4) {
   //Unspecified error multiple times, react appropriately...
}

Obviously you dont want to do this multiple tries if its expensive call, here I assume its a sort of “heartbeat” check thats not too expensive. The “failCount” can be adjusted depending on how “turbulent” you expect the connection to be.