Document and refactor PeerConnection options (#11)

lib/ex_webrtc/ice_candidate.ex

@@ -1,5 +1,7 @@
 defmodule ExWebRTC.IceCandidate do
-  @moduledoc false
+  @moduledoc """
+  ICE candidate
+  """
 
   # not exacly the same as W3 IceCandidate
   @type t() :: %__MODULE__{

lib/ex_webrtc/peer_connection.ex

@@ -1,5 +1,7 @@
 defmodule ExWebRTC.PeerConnection do
-  @moduledoc false
+  @moduledoc """
+  PeerConnection
+  """
 
   use GenServer
 
@@ -46,12 +48,15 @@ defmodule ExWebRTC.PeerConnection do
               ]
 
   #### API ####
-
-  def start_link(configuration \\ []) do
+  @spec start_link(Configuration.options()) :: GenServer.on_start()
+  def start_link(options \\ []) do
+    configuration = Configuration.from_options!(options)
     GenServer.start_link(__MODULE__, {self(), configuration})
   end
 
-  def start(configuration \\ []) do
+  @spec start(Configuration.options()) :: GenServer.on_start()
+  def start(options \\ []) do
+    configuration = Configuration.from_options!(options)
     GenServer.start(__MODULE__, {self(), configuration})
   end
 
@@ -103,16 +108,7 @@ defmodule ExWebRTC.PeerConnection do
 
   @impl true
   def init({owner, config}) do
-    config = struct(Configuration, config)
-    :ok = Configuration.check_support(config)
-
-    # ATM, ExICE does not support relay via TURN
-    stun_servers =
-      config.ice_servers
-      |> Enum.flat_map(&if(is_list(&1.urls), do: &1.urls, else: [&1.urls]))
-      |> Enum.filter(&String.starts_with?(&1, "stun:"))
-
-    {:ok, ice_agent} = ICEAgent.start_link(:controlled, stun_servers: stun_servers)
+    {:ok, ice_agent} = ICEAgent.start_link(:controlled, stun_servers: config.ice_servers)
     dtls_transport = DTLSTransport.new(ice_agent)
 
     state = %__MODULE__{
@@ -425,8 +421,6 @@ defmodule ExWebRTC.PeerConnection do
         end
 
       {:ok, %{state | transceivers: new_transceivers, dtls_transport: dtls}}
-    else
-      error -> error
     end
   end
 

lib/ex_webrtc/peer_connection/configuration.ex

@@ -1,72 +1,43 @@
 defmodule ExWebRTC.PeerConnection.Configuration do
-  @moduledoc false
-
-  @type bundle_policy() ::
-          :balanced
-          | :max_compat
-          | :max_bundle
+  @moduledoc """
+  PeerConnection configuration
+  """
 
   @type ice_server() :: %{
           optional(:credential) => String.t(),
           optional(:username) => String.t(),
           :urls => [String.t()] | String.t()
         }
 
-  # TODO implement
-  @type certificate() :: :TODO
-
-  @type ice_transport_policy() ::
-          :all
-          | :relay
-
-  @type rtcp_mux_policy() ::
-          :negotiate
-          | :require
-
-  @type t() :: %__MODULE__{
-          bundle_policy: bundle_policy(),
-          certificates: [certificate()],
-          ice_candidate_pool_size: non_neg_integer(),
-          ice_servers: [ice_server()],
-          ice_transport_policy: ice_transport_policy(),
-          peer_identity: String.t(),
-          rtcp_mux_policy: rtcp_mux_policy()
-        }
-
-  defstruct bundle_policy: :max_bundle,
-            certificates: nil,
-            ice_candidate_pool_size: 0,
-            ice_servers: [],
-            ice_transport_policy: :all,
-            peer_identity: nil,
-            rtcp_mux_policy: :require
+  @typedoc """
+  Options that can be passed to `ExWebRTC.PeerConnection.start_link/1`.
 
-  @spec check_support(t()) :: :ok
-  def check_support(config) do
-    if config.ice_transport_policy != :all do
-      raise "#{inspect(config.ice_transport_policy)} ice transport policy is currently not supported"
-    end
+  Currently, ExWebRTC always uses the following config:
+  * bundle_policy - max_bundle
+  * ice_candidate_pool_size - 0
+  * ice_transport_policy - all
+  * rtcp_mux_policy - require
 
-    if config.ice_candidate_pool_size != 0 do
-      raise "Ice candidate pool size different than 0 (pre-gathering) is currently not supported"
-    end
+  This config cannot be changed.
+  """
+  @type options() :: [ice_servers: [ice_server()]]
 
-    if config.bundle_policy != :max_bundle do
-      raise "Bundle policy options different than :max_bundle are currently not supported"
-    end
+  @typedoc false
+  @type t() :: %__MODULE__{ice_servers: [ice_server()]}
 
-    if config.certificates != nil do
-      raise "Certificates configuration option is currently not supported"
-    end
+  defstruct ice_servers: []
 
-    if config.peer_identity != nil do
-      raise "Identify option is currently not supported"
-    end
+  @doc false
+  @spec from_options!(options()) :: t()
+  def from_options!(options) do
+    config = struct!(__MODULE__, options)
 
-    if config.rtcp_mux_policy != :require do
-      raise "RTCP mux policy option :negotiate is currently not supported"
-    end
+    # ATM, ExICE does not support relay via TURN
+    stun_servers =
+      config.ice_servers
+      |> Enum.flat_map(&List.wrap(&1.urls))
+      |> Enum.filter(&String.starts_with?(&1, "stun:"))
 
-    :ok
+    %__MODULE__{config | ice_servers: stun_servers}
   end
 end

lib/ex_webrtc/session_description.ex

@@ -1,5 +1,7 @@
 defmodule ExWebRTC.SessionDescription do
-  @moduledoc false
+  @moduledoc """
+  SessionDescription
+  """
 
   @type description_type() ::
           :answer