WhoIs Sample Code


 

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
namespace whois
{
/// <summary>
/// This is my first real C# Project, it implements
/// a tool I find missing from the Windows XXXXX set
/// of operating systems, namely the 'whois' command
/// </summary>
/// <example>
/// The following will lookup microsoft.com using whois.internic.com
/// whois microsoft.com
///
/// The following will lookup 'ipluris.com' using whois.joker.com
/// (and no, that is not my real address)
/// whois whois.joker.com ipluris.com
/// </example>
public class Whois
{
private static int portNumber = 43; // whos is always on port 43
private string hostName;
/// <summary>
/// The only constructor, simply stores the host name given
/// </summary>
/// <param name="hostName">The hostname to contact for the search</param>
///
public Whois(string hostName)
{
this.hostName = hostName;
}
/// <summary>
/// Does the actual lookup against the given whois host using the
/// supplied search text. Note that I split the functionality of this methods
/// into three distinct parts each in their own try/catch block so that error
/// codes reported to the (l)user can be a bit more precise.
/// </summary>
/// <param name="searchText">The text to use for search criteria</param>
///
public void lookUp(string searchText)
{
// local member declaration block (yes, I am an old C developer
TcpClient theConnection = null;
NetworkStream networkStream =
null;
BufferedStream baseStream =
null;
StreamReader inputStream =
null;
StreamWriter outputStream =
null;
try
{
theConnection =
new TcpClient(hostName, portNumber);
// and create the base network stream
networkStream = theConnection.GetStream();
// and the baseStream
baseStream = new BufferedStream(networkStream);
}
catch(SocketException se)
{
// write something to inform the use and then go away
Console.WriteLine("Exception caught attempting to open connection to {0}.", hostName);
Console.WriteLine("\nException details : {0}", se.ToString());
return;
}
// now create the output stream and dump the string to search on
try
{
outputStream =
new StreamWriter(baseStream);
outputStream.WriteLine(searchText);
// off it goes
outputStream.Flush();
}
catch(Exception e)
{
// should be more specific here, but not sure what exception could be thrown
Console.WriteLine("Exception caught attempting to send data to host : {0}.",
hostName);
Console.WriteLine("\nException details : {0}", e.ToString());
// and close the connection
theConnection.Close();
return;
}
// and now read the dang response
try
{
inputStream =
new StreamReader(baseStream);
string intermediateOutput;
while(null != (intermediateOutput = inputStream.ReadLine()))
{
Console.WriteLine(intermediateOutput);
}
}
catch(Exception e)
{
// should be more specific here, but not sure what exception could be thrown
Console.WriteLine("Exception caught attempting to read data from host : {0}.", hostName);
Console.WriteLine("\nException details : {0}", e.ToString());
// and close the connection
theConnection.Close();
return;
}
theConnection.Close();
}
public static void Main(string[] args)
{
// very rudimentrary argument checking. Should be done much nicer
// and in more details.. some other time perhaps, not now
string host;
string search;
// this if/else is borderline candidate for a switch{} statement
if(0 == args.Length)
{
Console.WriteLine("usage : whois <lookup host> hostname");
return;
}
else if(2 == args.Length)
{
host = args[0];
search = args[1];
}
else
{
host = "whois.internic.net";
search = args[0];
}
// not encapsulating in try/catch block here
Whois whoisInstance = new Whois(host);
// and do the lookup
whoisInstance.lookUp(search);
}
}
}