C# Cookbook

13.5. Handling Web Server Errors

Problem

You have obtained a response from a web server and you want to make sure that there were no errors in processing the initial request, such as failing to connect, being redirected, timing out, or failing to validate a certificate. You don’t want to have to catch all of the different response codes available.

Solution

Check the StatusCode property of the HttpWebResponse class to determine what category of status this StatusCode falls into, and return an enumeration value (ResponseCategories) representing the category. This technique will allow you to use a broader approach to dealing with response codes.

public static ResponseCategories VerifyResponse(HttpWebResponse httpResponse)
{
    // Just in case there are more success codes defined in the future
    // by HttpStatusCode, we will check here for the "success" ranges
    // instead of using the HttpStatusCode enum as it overloads some
    // values
    int statusCode = (int)httpResponse.StatusCode;
    if((statusCode >= 100)&& (statusCode <= 199))
    {
        return ResponseCategories.Informational;
    }
    else if((statusCode >= 200)&& (statusCode <= 299))
    {
        return ResponseCategories.Success;
    }
    else if((statusCode >= 300)&& (statusCode <= 399))
    {
        return ResponseCategories.Redirected;
    }
    else if((statusCode >= 400)&& (statusCode <= 499))
    {
        return ResponseCategories.ClientError;
    }
    else if((statusCode >= 500)&& (statusCode <= 599))
    {
        return ResponseCategories.ServerError;
    }
    return ResponseCategories.Unknown;
}

The ResponseCategories ...