FileSystemWatcher and Queues with Parallel Execution

In this blog you will learn about FileSystemWatcher and Queues with Parallel Execution using C#.

Sometime we need a program to watch over particular Directory and then based on the Input,we need to perform some other task in parallel.

 

Here, I am providing a part of program(a window service)that uses FileSystemWacther to monitor a Directory and then based on Input perform some other task parallely.

 

Note: You should learn FileSystemWatcher before going through this Post.

OnStartis the Window Service method .You can use Console pgm or TaskScheduler also.

protected override void OnStart(string[] args)
{

    current_directory = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

    try
    {
        strDir = ConfigurationManager.AppSettings["Directory"];
        fileMask = ConfigurationManager.AppSettings["FileMask"];
        strBatfile = ConfigurationManager.AppSettings["Batch"];
        strlog = ConfigurationManager.AppSettings["Log"];

        Task.Factory.StartNew(QueueHandler);

        var fsw = new FileSystemWatcher();
        fsw.Created += (o, e) =>
        {
            // add a file to the queue
            filenames.Enqueue(e.FullPath);

        };

        fsw.Path = strDir + "\\";
        fsw.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
                         | NotifyFilters.FileName | NotifyFilters.DirectoryName;
        fsw.Filter = fileMask;

        fsw.EnableRaisingEvents = true;
        fsw.Deleted += new FileSystemEventHandler(OnDeleated);
        fsw.Renamed += new RenamedEventHandler(OnRenamed);


        fsw.EnableRaisingEvents = true;
    }
    catch (Exception exception)
    {
        CustomException.Write(CustomException.CreateExceptionString(exception.ToString()));
    }

}

And now we need to provide the function that runs in parallel (QueueHandler) using Queues. 

static void QueueHandler()
{
    bool run = true;
    AppDomain.CurrentDomain.DomainUnload += (s, e) =>
    {
        run = false;
        filenames.Enqueue("stop");
    };
    try
    {
        while (run)
        {
            string filename;
            if (filenames.TryDequeue(out filename) && run)
            {
                var proc = new Process();
                proc.StartInfo.FileName = Service1.strBatfile;   //here .exe can be added
                proc.Start();
               ;
                Log.getLogger("File Processed after executing batch\.exe:  Filename - :" + filename + " " + "Batch File Executed- > " + Service1.strBatfile + " at timestamp : " + DateTime.Now.ToString(), Service1.strlog);
                proc.WaitForExit(); // this blocks until the process ends....

            }
        }
    }
    catch (Exception exception)
    {
        CustomException.Write(CustomException.CreateExceptionString(exception.ToString()));
    }

Note: You can write your custom exception .How you want to Log depends on you.