Lazy Pirate client in C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;

using ZeroMQ;

namespace Examples
{
static partial class Program
{
//
// Lazy Pirate client
// Use zmq_poll (pollItem.PollIn) to do a safe request-reply
// To run, start lpserver and then randomly kill/restart it
//
// Author: metadings
//

static TimeSpan LPClient_RequestTimeout = TimeSpan.FromMilliseconds(2000);
static int LPClient_RequestRetries = 3;

static ZSocket LPClient_CreateZSocket(ZContext context, string name, out ZError error)
{
// Helper function that returns a new configured socket
// connected to the Lazy Pirate queue

var requester = new ZSocket(context, ZSocketType.REQ);
requester.IdentityString = name;
requester.Linger = TimeSpan.FromMilliseconds(1);

if (!requester.Connect("tcp://127.0.0.1:5555", out error))
{
return null;
}
return requester;
}

public static void LPClient(string[] args)
{
if (args == null || args.Length < 1)
{
Console.WriteLine();
Console.WriteLine("Usage: ./{0} LPClient [Name]", AppDomain.CurrentDomain.FriendlyName);
Console.WriteLine();
Console.WriteLine(" Name Your name. Default: People");
Console.WriteLine();
args = new string[] { "People" };
}

string name = args[0];

using (var context = new ZContext())
{
ZSocket requester = null;
try
{ // using (requester)

ZError error;

if (null == (requester = LPClient_CreateZSocket(context, name, out error)))
{
if (error == ZError.ETERM)
return; // Interrupted
throw new ZException(error);
}

int sequence = 0;
int retries_left = LPClient_RequestRetries;
var poll = ZPollItem.CreateReceiver();

while (retries_left > 0)
{
// We send a request, then we work to get a reply
using (var outgoing = ZFrame.Create(4))
{
outgoing.Write(++sequence);
if (!requester.Send(outgoing, out error))
{
if (error == ZError.ETERM)
return; // Interrupted
throw new ZException(error);
}
}

ZMessage incoming;
while (true)
{
// Here we process a server reply and exit our loop
// if the reply is valid.

// If we didn't a reply, we close the client socket
// and resend the request. We try a number of times
// before finally abandoning:

// Poll socket for a reply, with timeout
if (requester.PollIn(poll, out incoming, out error, LPClient_RequestTimeout))
{
using (incoming)
{
// We got a reply from the server
int incoming_sequence = incoming[0].ReadInt32();
if (sequence == incoming_sequence)
{
Console.WriteLine("I: server replied OK ({0})", incoming_sequence);
retries_left = LPClient_RequestRetries;
break;
}
else
{
Console_WriteZMessage("E: malformed reply from server", incoming);
}
}
}
else
{
if (error == ZError.EAGAIN)
{
if (--retries_left == 0)
{
Console.WriteLine("E: server seems to be offline, abandoning");
break;
}

Console.WriteLine("W: no response from server, retrying…");

// Old socket is confused; close it and open a new one
requester.Dispose();
if (null == (requester = LPClient_CreateZSocket(context, name, out error)))
{
if (error == ZError.ETERM)
return; // Interrupted
throw new ZException(error);
}

Console.WriteLine("I: reconnected");

// Send request again, on new socket
using (var outgoing = ZFrame.Create(4))
{
outgoing.Write(sequence);
if (!requester.Send(outgoing, out error))
{
if (error == ZError.ETERM)
return; // Interrupted
throw new ZException(error);
}
}

continue;
}

if (error == ZError.ETERM)
return; // Interrupted
throw new ZException(error);
}
}
}
}
finally
{
if (requester != null)
{
requester.Dispose();
requester = null;
}
}
}
}
}
}