Myoddweb.Directorywatcher

A fast and reliable File/Directory watcher for c#/c++ to replace the current .NET FileSystemWatcher class.

What it does

Reliable monitoring of
- Renamed files/directories
- Deleted files/directories
- Created files/directories
All exceptions are passed back to the caller.
Non-blocking delegates, if one function takes a long time ... we don't all have to suffer.
The interface does allow for porting to other platforms.
No buffer limitations, (well there is, but we play nicely).
Try and remove duplicates, (where possible).
Deleted, (then re-created), are re-monitored.
Watcher statistics

What it doesn't do

Bring me coffee.

Installing

Nuget

Package manager

Install-Package MyOddWeb.DirectoryWatcher

CLI

.NET

dotnet add package MyOddWeb.DirectoryWatcher

Packet

paket add MyOddWeb.DirectoryWatcher

Use case

My needs were to, reliably, monitor entire volumes for created/deleted/renamed files. I do really care for pattern matching.

The issue(s) with FileSystemWatcher

The current version of File Watcher is great, but it does have a couple of issues.

There is a buffer limitation, (in the API itself), and a badly written application can 'block' or 'miss' certain notification.
Duplicates are often sent, (when a file is updated 3 times between calls, we only need to know about the once).
Certain Exceptions cause the entire app to close.
UNC/Unix files are not supported, (in fact it causes FileSystemWatcher to take your system down).
Does not handle large volumes nicely.

Examples

Simple Watch

Add all the directories we want to 'observe'

    using( var watch = new Watcher() )
    {
      watch.Add(new Request("c:\\", true));
      watch.Add(new Request("d:\\foo\\bar\\", true));
      watch.Add(new Request("y:\\", true));

      // do something amazing with the data
      watch.OnAddedAsync += async (f, t) =>
      {
        // ..
      };

      // start watching
      watch.Start();

      // add some more
       watch.Add(new Request("z:\\", false));

      // optional stop in this case
      watch.Stop();
    }

You can start watching at any point

    // create Watcher
    var watcher = new Watcher();

    // Add a request.
    watch.Add(new Request("y:\\", true));

    // start watching
    watch.Start();

    // add some more
    watch.Add(new Request("z:\\", false));

Get notifications in case a file is created.

    watch.OnAddedAsync += async (f, t) =>
    {
      Console.ForegroundColor = ConsoleColor.Green;
      Console.WriteLine(
        $"[{f.DateTimeUtc.Hour}:{f.DateTimeUtc.Minute}:{f.DateTimeUtc.Second}]:{f.FileSystemInfo}");
      Console.ForegroundColor = foreground;
    };

we get given the file that was added as well as a cancellation token

And when we are done stop it ...

    watch.Stop();

Or Dispose of it

    watch.Dispose();

Your own 'Watcher' interface

You can create your own watcher interface

public class Watcher : IWatcher3
{
  // Implement IWatcher3
}

Watched Events

When a file event is raised we send a IFileSystemEvent event.

    /// <summary>
    /// The file system event.
    /// </summary>
    FileSystemInfo FileSystemInfo { get; }

    /// <summary>
    ///  Gets the full path of the directory or file.
    /// </summary>
    /// <returns>A string containing the full path.</returns>
    string FullName { get; }

    /// <summary>
    ///     For files, gets the name of the file. For directories, gets the name of the last
    ///     directory in the hierarchy if a hierarchy exists. Otherwise, the Name property
    ///     gets the name of the directory.
    /// </summary>
    /// <returns>A string that is the name of the parent directory, the name of the last directory
    ///     in the hierarchy, or the name of a file, including the file name extension.
    /// </returns>
    string Name { get; }

    /// <summary>
    /// The Action
    ///  Added
    ///  Removed
    ///  Touched
    ///  Renamed
    /// </summary>
    EventAction Action { get; }

    /// <summary>
    /// An error code related to the event, (if any)
    /// </summary>
    EventError Error { get; }

    /// <summary>
    /// The UTC date time of the event.
    /// </summary>
    DateTime DateTimeUtc { get; }

    /// <summary>
    /// Boolean if the update is a file or a directory.
    /// </summary>
    bool IsFile { get; }

    /// <summary>
    /// Return if the event is a certain action
    /// (same as Action == action)
    /// </summary>
    /// <param name="action"></param>
    /// <returns></returns>
    bool Is(EventAction action );

Statistics

You can get statistics at various intervals for the events being watched.

All you need to do is add Rates to your watchers

    using( var watch = new Watcher() )
    {
      // watch the folder with stats every 10000 ms
      // a value of 0, (default), turns it off.
      watch.Add(new Request("c:\\", true, new Rates(10000, 50 )));

      // do something amazing with the statistics
      // the values is `IStatistics` with a cancellation token
      watch.OnStatisticsAsync += async (s, t) =>
      {
        // ..
      };

      // start watching
      watch.Start();

      // ... do some clever stuff.

      // optional stop in this case
      watch.Stop();
    }

Logger

You can watch for certain events

Unknown = 0, Should never happen
Information = 1, nothing important, maybe something worth noting
Warning = 2, something happened, but we managed to recover from it
Error = 3, something broke, messages were probably lost.
Panic = 4, something really bad happened, the process probably died.
Debug = 100, Should not happen in release more, only for information

    using( var watch = new Watcher() )
    {
      // watch the folder with stats every 10000 ms
      // a value of 0, (default), turns it off.
      watch.Add(new Request("c:\\", true ));

      // do something amazing with the message
      // the values is `ILoggerEvent` with a cancellation token
      watch.OnLoggerAsync += async (e, t) =>
      {
        // ..
      };

      // start watching
      watch.Start();

      // ... do some clever stuff.

      // optional stop in this case
      watch.Stop();
    }

eyal7773 / myoddweb.directorywatcher