deanmike / minifswatcher

A file system watcher alternative for C#

MiniFSWatcher

MiniFSWatcher is a file system event watcher for C# based on the minispy driver example from Microsoft. Compared to the default FileSystemWatcher class, MiniFSWatcher provides the following benefits:

Capturing file moved events

The default FileSystemWatcher has no notion of moved files, it'll only generate "created" and "deleted" events instead. MiniFSWatcher will let you track file movement within one partition.

Reducing the amount of changed events

With the AggregateEvents option, you'll only receive one file event when the respective file handle is closed and thus no more consecutive changes will occure. If multiple write operations were performed, only one "changed" event is triggered. If a file is created and changed (i.e. due to a copy operation), you'll only receive one "created" event.

Getting information about the process causing the change

Sometimes it is useful to know who caused the change, for example to ignore changes performed by a certain application. MiniFSWatcher provides the ID of the causing process with every event and further allows to directly filter out all events caused by its own process ID.

Usage

The following example shows how to use MiniFSWatcher to watch a directory and all subdirectories.

var eventWatcher = new EventWatcher();

eventWatcher.OnRenameOrMove += (filename, oldFilename, process) =>
{
  Console.WriteLine("File " + oldFilename + " has been moved to " + filename + " by process " + process );
};

eventWatcher.Connect();
eventWatcher.WatchPath("C:\\Users\\MyUser\\*");

Installation

MiniFSWatcher consists of a user mode C# library and a minifilter driver running in kernel mode. Both components need to be installed to observe file system events.

Installing the user mode library

You can install the user mode library from nuget or simply add the MiniFSWatcher project to your project references.

Installing the kernel mode driver

The kernel driver needs to be compiled and installed manually. Therefore, make sure you have the Windows Driver Kit (WDK) 10 installed. After compiling the driver with VS, you can install the driver with the following command

 RUNDLL32.EXE SETUPAPI.DLL,InstallHinfSection DefaultInstall 132 ./minifswatcher.inf

The driver will be loaded automatically after reboot. To load it manually without reboot, run

 fltmc.exe load minifswatcher

If you don't have a valid code signing certificate and try to install the driver on 64bit Windows, you need to enable test signed drivers as described here.

Please make sure to always compile and install the correct driver version (32/64bit) depending on your operating system!

To uninstall the driver, run

RUNDLL32.EXE SETUPAPI.DLL,InstallHinfSection DefaultUninstall 132 ./minifswatcher.inf