# FileSystem
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An Elixir file change watcher wrapper based on
[FS](https://github.com/synrc/fs), the native file system listener.
## System Support
- MacOS - [fsevent](https://github.com/thibaudgg/rb-fsevent)
- GNU/Linux, FreeBSD and OpenBSD - [inotify](https://github.com/rvoicilas/inotify-tools/wiki)
- Windows - [inotify-win](https://github.com/thekid/inotify-win)
On MacOS 10.14, to compile `mac_listener`, run:
```console
open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg
```
## Usage
Add `file_system` to the `deps` of your mix.exs
``` elixir
defmodule MyApp.Mixfile do
use Mix.Project
def project do
...
end
defp deps do
[
{:file_system, "~> 1.0", only: :test},
]
end
...
end
```
### Subscription API
You can spawn a worker and subscribe to events from it:
```elixir
{:ok, pid} = FileSystem.start_link(dirs: ["/path/to/some/files"])
FileSystem.subscribe(pid)
```
or
```elixir
{:ok, pid} = FileSystem.start_link(dirs: ["/path/to/some/files"], name: :my_monitor_name)
FileSystem.subscribe(:my_monitor_name)
```
The `pid` you subscribed from will now receive messages like:
```
{:file_event, worker_pid, {file_path, events}}
```
and
```
{:file_event, worker_pid, :stop}
```
### Example Using GenServer
```elixir
defmodule Watcher do
use GenServer
def start_link(args) do
GenServer.start_link(__MODULE__, args)
end
def init(args) do
{:ok, watcher_pid} = FileSystem.start_link(args)
FileSystem.subscribe(watcher_pid)
{:ok, %{watcher_pid: watcher_pid}}
end
def handle_info({:file_event, watcher_pid, {path, events}}, %{watcher_pid: watcher_pid} = state) do
# Your own logic for path and events
{:noreply, state}
end
def handle_info({:file_event, watcher_pid, :stop}, %{watcher_pid: watcher_pid} = state) do
# Your own logic when monitor stop
{:noreply, state}
end
end
```
## Backend Options
For each platform, you can pass extra options to the underlying listener
process.
Each backend supports different extra options, check backend module
documentation for more details.
Here is an example to get instant notifications on file changes for MacOS:
```elixir
FileSystem.start_link(dirs: ["/path/to/some/files"], latency: 0, watch_root: true)
```