I have a windows service for processing the MSMQ messages. It relies on the following logic
· There is a timer in the windows service. Every ten minute it will execute the method named “ProcessMessages”.
· Inside this method, it first creates a list of existing messageIds by calling GetAllMessages method of the queue.
· For each messageId, it receives the message (using ReceiveById) and stores it into a file
Is there a better way to achieve the message processing?
Reference: http://www.switchonthecode.com/tutorials/creating-a-simple-windows-service-in-csharp
Note: The following code does not give the desired result when I made it as a service; however there is no error in event viewer (I am not doing any explicit logging). It was working fine when it was a simple console app. How to correct it? [Now it is working when I changed the accoun to "User" as shwon in the comments below]
My actaul requirement is to process all messages at fixed time slots – say at 10 AM and 11 AM only (on each day). What is the best approach to do this?
namespace ConsoleSwitchApp
{
class Program : ServiceBase
{
private static Timer scheduleTimer = null;
static MessageQueue helpRequestQueue = null;
static System.Messaging.XmlMessageFormatter stringFormatter = null;
static void Main(string[] args)
{
ServiceBase.Run(new Program());
}
public Program()
{
this.ServiceName = "LijosService6";
//Queue initialize
helpRequestQueue = new MessageQueue(@".\Private$\MyPrivateQueue", false);
stringFormatter = new System.Messaging.XmlMessageFormatter(new string[] { "System.String" });
//Set Message Filters
MessagePropertyFilter filter = new MessagePropertyFilter();
filter.ClearAll();
filter.Body = true;
filter.Label = true;
filter.Priority = true;
filter.Id = true;
helpRequestQueue.MessageReadPropertyFilter = filter;
//Start a timer
scheduleTimer = new Timer();
scheduleTimer.Enabled = true;
scheduleTimer.Interval = 120000;//2 mins
scheduleTimer.AutoReset = true;
scheduleTimer.Start();
scheduleTimer.Elapsed += new ElapsedEventHandler(scheduleTimer_Elapsed);
}
protected static void scheduleTimer_Elapsed(object sender, ElapsedEventArgs e)
{
ProcessMessages();
}
private static void ProcessMessages()
{
string messageString = "1";
//Message Processing
List<string> messageIdList = GetAllMessageId();
foreach (string messageId in messageIdList)
{
System.Messaging.Message messages = helpRequestQueue.ReceiveById(messageId);
//Store the message into database
messages.Formatter = stringFormatter;
string messageBody = System.Convert.ToString(messages.Body);
if (String.IsNullOrEmpty(messageString))
{
messageString = messageBody;
}
else
{
messageString = messageString + "___________" + messageBody;
}
}
//Write File
string lines = DateTime.Now.ToString();
lines = lines.Replace("/", "-");
lines = lines.Replace(":", "_");
System.IO.StreamWriter file = new System.IO.StreamWriter("c:\\test" + lines + ".txt");
file.WriteLine(messageString);
file.Close();
}
private static List<string> GetAllMessageId()
{
List<string> messageIdList = new List<string>();
DataTable messageTable = new DataTable();
messageTable.Columns.Add("Label");
messageTable.Columns.Add("Body");
//Get All Messages
System.Messaging.Message[] messages = helpRequestQueue.GetAllMessages();
for (int index = 0; index < messages.Length; index++)
{
string messageId = (System.Convert.ToString(messages[index].Id));
messageIdList.Add(messageId);
messages[index].Formatter = stringFormatter;
messageTable.Rows.Add(new string[] { messages[index].Label, messages[index].Body.ToString() });
}
return messageIdList;
}
protected override void OnStart(string[] args)
{
base.OnStart(args);
}
protected override void OnStop()
{
base.OnStop();
}
}
}
namespace ConsoleSwitchApp
{
[RunInstaller(true)]
public class MyWindowsServiceInstaller : Installer
{
public MyWindowsServiceInstaller()
{
var processInstaller = new ServiceProcessInstaller();
var serviceInstaller = new ServiceInstaller();
//set the privileges
processInstaller.Account = ServiceAccount.LocalSystem;
serviceInstaller.DisplayName = "LijosService6";
serviceInstaller.StartType = ServiceStartMode.Manual;
//must be the same as what was set in Program's constructor
serviceInstaller.ServiceName = "LijosService6";
this.Installers.Add(processInstaller);
this.Installers.Add(serviceInstaller);
}
}
}
A nice alternative to using a timer is to use the MessageQueue.BeginReceive
method and do work in the ReceiveCompleted
event. This way your code will wait until there is a message in the queue and then immediately process the message, then check for the next message.
A short stub (a complete example in the linked MSDN article.)
private void Start()
{
MessageQueue myQueue = new MessageQueue(".\\myQueue");
myQueue.ReceiveCompleted +=
new ReceiveCompletedEventHandler(MyReceiveCompleted);
myQueue.BeginReceive();
}
private static void MyReceiveCompleted(Object source,
ReceiveCompletedEventArgs asyncResult)
{
try
{
MessageQueue mq = (MessageQueue)source;
Message m = mq.EndReceive(asyncResult.AsyncResult);
// TODO: Process the m message here
// Restart the asynchronous receive operation.
mq.BeginReceive();
}
catch(MessageQueueException)
{
// Handle sources of MessageQueueException.
}
return;
}