Durante este fin de semana tengo previsto cambiar de hosting (de Dreamhost a Silicontower) y de versión de WordPress, así que es posible que ocurran cosas extrañas durante un par de días.
Que la fuerza me acompañe.
Monday, 14 de June de 2010
Get MAC from IP address in .NET
After dealing with several options, most of them involving a call to a command line tool and parsing the output, which is not really elegant. Other solutions were based on obsolete VBScript client code and ActiveX, even worse.
Finally I found in the excellent pinvoke.net site a very nice and simple example using a simple call to iphlpapi.dll’s SendARP method. The trick was to use ARP to get the MAC from the IP.
Note that this has it’s limitations, as I will only work if the remote machine is in the same network and the packet does not need to go through a router. I was enough for our needs.
Here’s the code I adapted from the example:
public static string GetMAC(IPAddress ipAddr)
{
var mac = new byte[6];
var len = (uint)mac.Length;
var result = SendARP((int)ipAddr.Address, 0, mac, ref len);
if (result != 0)
{
return "MAC not found!";
}
var str = new string[(int)len];
for (var i = 0; i < len; i++)
{
str[i] = mac[i].ToString("x2");
}
return string.Join(":", str);
}
[DllImport("iphlpapi.dll", ExactSpelling = true)]
private static extern int SendARP(int destIP, int srcIP, byte[] pMacAddr, ref uint phyAddrLen);
Enjoy!
Thursday, 10 de June de 2010
NHibernate: Custom type is not serializable
Since I acquired a NHibernateProfiler license, an initialization warning message draw my attention, the text seemed quite easy to solve:
WARN: custom type is not Serializable: MyLibrary.MyCustomDataType
My first solution was adding
[Serializable] attribute to the custom type, but that didn’t make the trick. As it was only a warning, I did not investigate further at that moment.But the other day, debugging data access code I saw the warning again and the easiest solution was going to the source NHibernate code to find this:
TypeFactory.InjectParameters(userType, parameters);
if (!userType.ReturnedClass.IsSerializable)
{
LogManager.GetLogger(typeof(CustomType)).Warn("custom type is not Serializable: " + userTypeClass);
}
As seen in this code, the message is unclear, because the class that must be serializable is the ReturnedClass, not the custom UserType itself.
So, to solve the warning I just needed to add
[Serializable] to the class returned by my custom UserType instead than the type itself.