How to get started writing desktop application for OS X that manages a directory in the background?

I want to create a desktop application for OS X that does 3 things:

1. Creates a directory on the users computer with a custom icon
2. Downloads files to 开发者_开发百科that directory from my server
3. Monitors changes in that directory and subdirecties so that it may send commands to my server

I understand how to download a file into a directory and communicate with my server. Where I lack knowledge is really the steps to get started so that the app is essentially this "smart sync folder."

Can anyone recommend tutorials, sample code, or just some general direction of how to get started on an app like this? Think really stripped down version of DropBox

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Well, since you already know how to handle the web stuff, next step would be to get notifications when your folder changes.

Here's a good discussion of some good approaches (somewhat dated)

or

Download this demo to get started