Equivalent of FileSystemWatcher (.NET) in Cocoa

Question

I am developing an application in Cocoa. I want to constantly check whether the contents of a file in a particular location is changed or not (like FileSystemWatcher in .NET). Please anyone give me a solution

Answer 1

Please have a look at FSEvents.

Answer 2

As Diederik says, FSEvents is Apple's Carbon API for listening to file system events. Someone has created a Cocoa/Objective-C wrapper for FSEvents called SCEvents that is a little easier to use.

Answer 3

Another option would be to drink directly from the /dev/fsevents firehose. I work on an application that does exactly this and it works very well. You can be notified if a file changes, is deleted, is moved, has attributes changed, etc. Granted, this isn't a "Cocoa" option since it's mostly C code, but we're using this in a Cocoa app.

Answer 4

FSEvents are great, but they're used to monitor folders. To monitor a single file you'll want to check out kqueues. Try "man kqueue" in the terminal.

Answer 5

Look at the NSWorkspace class documentation.

Answer 6

Here's an example of how to do it with bookmarks and NSFileManager so that you can follow the file if it's moved.

https://github.com/ptrsghr/FileWatcher

Answer 7

A further resource on kqueues is http://developer.apple.com/documentation/Darwin/Conceptual/FSEvents_ProgGuide/KernelQueues/KernelQueues.html