gistfile1.cs

// How can I rewrite this to perform multiple checks in a row without repeating if (_allowed.IPs.Contains(userIPAddress)) { authentic = true; goto result; } every time?

public class Authentication {
    private List<string> _allowedIPs;

    public bool IsAuthentic(string userIPAddress) {
        bool authentic = false;

        if (_allowedIPs == null) 
            _allowedIPs = new List<string>();

        if (_allowed.IPs.Contains(userIPAddress)) { authentic = true; goto result; }

        string whitelist = ConfigurationManager.AppSettings["IPAddressWhiteList"];
        List<string> allowedIPs = whitelist.Split(',').ToList<string>();

        allowedIPs.ForEach(aip => { if (!_allowedIPs.Contains(aip)) _allowedIPs.Add(aip); });

        // Now that the list is populated with hard-coded IP addresses, check again
        if (_allowed.IPs.Contains(userIPAddress)) { authentic = true; goto result; }

        if (RoleEnvironment.IsAvailable)
        {
            var serverIP = RoleEnvironment.CurrentRoleInstance.InstanceEndpoints["HttpIn"].IPEndpoint.Address.ToString();
            allowedIPs.Add(serverIP);
        }

        // If the request came from the same server address, return
        if (_allowed.IPs.Contains(userIPAddress)) { authentic = true; goto result; }

        if (!string.IsNullOrEmpty(Util.Azure.StagingIP))
        {
            allowedIPs.Add(Util.Azure.StagingIP);
        }

        // If the request came from the staging instance, return
        if (_allowed.IPs.Contains(userIPAddress)) { authentic = true; goto result; }

        if (!string.IsNullOrEmpty(Util.Azure.ProductionIP))
        {
            allowedIPs.Add(Util.Azure.ProductionIP);
        }

        // If the result came from the production instance, return
        if (_allowed.IPs.Contains(userIPAddress)) { authentic = true; }

    result:
        return authentic;
    }
}