C# 4 and .NET 4

672 ❘ ChaPTer 25 windOws services
ReadQuotes() is a helper method that reads all the quotes from a file that was specified in the constructor.
All the quotes are added to the List quotes. In addition, you are creating an instance of the
Random class that will be used to return random quotes:
protected void ReadQuotes()
{
quotes = File.ReadAllLines(filename).ToList();
random = new Random();
}
Another helper method is GetRandomQuoteOfTheDay(). This method returns a random quote from the
quotes collection:
protected string GetRandomQuoteOfTheDay()
{
int index = random.Next(0, quotes.Count);
return quotes[index];
}
In the Start() method, the complete file containing the quotes is read in the List quotes by
using the helper method ReadQuotes(). After this, a new thread is started, which immediately calls the
ListenerThread() method — similarly to the TcpReceive example in Chapter 24, “Networking.”
Here a thread is used because the Start() method cannot block and wait for a client; it must return
immediately to the caller (SCM). The SCM would assume that the start failed if the method didn’t return
to the caller in a timely fashion (30 seconds). The listener thread is set as a background thread so that the
application can exit without stopping this thread. The Name property of the thread is set because this helps
with debugging, as the name will show up in the debugger:
public void Start()
{
ReadQuotes();
listenerThread = new Thread(ListenerThread);
listenerThread.IsBackground = true;
listenerThread.Name = "Listener";
listenerThread.Start();
}
The thread function ListenerThread() creates a TcpListener instance. The AcceptSocket() method
waits for a client to connect. As soon as a client connects, AcceptSocket() returns with a socket associated
with the client. Next, GetRandomQuoteOfTheDay() is called to send the returned random quote to the client
using socket.Send():
protected void ListenerThread()
{
try
{
IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
listener = new TcpListener(ipAddress, port);
listener.Start();
while (true)
{
Socket clientSocket = listener.AcceptSocket();
string message = GetRandomQuoteOfTheDay();
UnicodeEncoding encoder = new UnicodeEncoding();
byte[] buffer = encoder.GetBytes(message);
clientSocket.Send(buffer, buffer.Length, 0);
clientSocket.Close();
}
}
catch (SocketException ex)
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