Fix some grammar. Fix ice_ip_filter default value

guides/deploying/fly.md

@@ -4,10 +4,10 @@ Elixir WebRTC-based apps can be easily deployed on [Fly.io](https://fly.io)!
 
 There are just two things you need to do:
 
-- configure a STUN server both on the client and server side
-- use custom Fly.io IP filter on the server side
+* configure a STUN server both on the client and server side
+* use a custom Fly.io IP filter on the server side
 
-In theory, configuring a STUN server just on a one side should be enough but we recommend to do it on both sides.
+In theory, configuring a STUN server just on one side should be enough but we recommend doing it on both sides.
 
 In JavaScript code:
 
@@ -17,7 +17,7 @@ pc = new RTCPeerConnection({
 });
 ```
 
-in Elixir code:
+In Elixir code:
 
 ```elixir
 ip_filter = Application.get_env(:your_app, :ice_ip_filter)
@@ -29,15 +29,15 @@ ip_filter = Application.get_env(:your_app, :ice_ip_filter)
   )
 ```
 
-in `runtime.exs`:
+In `runtime.exs`:
 
 ```elixir
 if System.get_env("FLY_IO") do
   config :your_app, ice_ip_filter: &ExWebRTC.ICE.FlyIpFilter.ip_filter/1
 end
 ```
 
-in fly.toml:
+In fly.toml:
 
 ```toml
 [env]
@@ -46,5 +46,5 @@ in fly.toml:
 ```
 
 That's it!
-No special UDP port exports or dedicated IP address needed.
+No special UDP port exports or dedicated IP address are needed.
 Just run `fly launch` and enjoy your deployment :)

lib/ex_webrtc/ice/fly_ip_filter.ex

@@ -2,8 +2,9 @@ defmodule ExWebRTC.ICE.FlyIpFilter do
   @moduledoc """
   ICE IP filter for Fly.io deployments.
 
-  This module defines a single function, which filters out IP addresses,
+  This module defines a single function, which filters IP addresses,
   which ICE Agent will use as its host candidates.
+  It accepts only the IPv4 address that `fly-global-services` resolves to.
   """
 
   @spec ip_filter(:inet.ip_address()) :: boolean()

lib/ex_webrtc/peer_connection/configuration.ex

@@ -163,7 +163,7 @@ defmodule ExWebRTC.PeerConnection.Configuration do
           controlling_process: Process.dest(),
           ice_servers: [ice_server()],
           ice_transport_policy: :relay | :all,
-          ice_ip_filter: (:inet.ip_address() -> boolean()),
+          ice_ip_filter: (:inet.ip_address() -> boolean()) | nil,
           ice_port_range: Enumerable.t(non_neg_integer()),
           audio_codecs: [RTPCodecParameters.t()],
           video_codecs: [RTPCodecParameters.t()],
@@ -240,7 +240,6 @@ defmodule ExWebRTC.PeerConnection.Configuration do
     feedbacks = Keyword.get(options, :rtcp_feedbacks, @default_rtcp_feedbacks)
 
     options
-    |> Keyword.put_new(:ice_ip_filter, fn _ -> true end)
     |> Keyword.put(:audio_extensions, Enum.map(audio_extensions, fn {_, ext} -> ext end))
     |> Keyword.put(:video_extensions, Enum.map(video_extensions, fn {_, ext} -> ext end))
     |> then(&struct(__MODULE__, &1))