Add DataChannels (#157)

.github/workflows/ci.yml

@@ -14,8 +14,8 @@ jobs:
     name: CI on OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
     strategy:
       matrix:
-        otp: ['26']
-        elixir: ['1.16']
+        otp: ['27']
+        elixir: ['1.17']
     steps:
     - name: Set up Elixir
       uses: erlef/setup-beam@v1

examples/chat/.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

examples/chat/.gitignore

@@ -0,0 +1,26 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+chat-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

examples/chat/README.md

@@ -0,0 +1,11 @@
+# Chat
+
+Receive text chat messages using DataChannel and send them to other peers.
+
+While in `examples/chat` directory
+
+1. Run `mix deps.get`
+2. Run `mix run --no-halt`
+3. Visit `http://127.0.0.1:8829/index.html` in your browser.
+
+The IP and port of the app can be configured in `config/config.exs`.

examples/chat/config/config.exs

@@ -0,0 +1,8 @@
+import Config
+
+config :logger, level: :info
+
+# normally you take these from env variables in `config/runtime.exs`
+config :chat,
+  ip: {127, 0, 0, 1},
+  port: 8829

examples/chat/lib/chat.ex

@@ -0,0 +1,16 @@
+defmodule Chat do
+  use Application
+
+  @ip Application.compile_env!(:chat, :ip)
+  @port Application.compile_env!(:chat, :port)
+
+  @impl true
+  def start(_type, _args) do
+    children = [
+      {Bandit, plug: __MODULE__.Router, ip: @ip, port: @port},
+      {Registry, name: __MODULE__.PubSub, keys: :duplicate}
+    ]
+
+    Supervisor.start_link(children, strategy: :one_for_one)
+  end
+end

examples/chat/lib/chat/peer_handler.ex

@@ -0,0 +1,107 @@
+defmodule Chat.PeerHandler do
+  require Logger
+
+  alias ExWebRTC.{
+    DataChannel,
+    ICECandidate,
+    PeerConnection,
+    SessionDescription
+  }
+
+  @behaviour WebSock
+
+  @ice_servers [
+    %{urls: "stun:stun.l.google.com:19302"}
+  ]
+
+  @impl true
+  def init(_) do
+    {:ok, pc} = PeerConnection.start_link(ice_servers: @ice_servers)
+    {:ok, _} = Registry.register(Chat.PubSub, "chat", [])
+
+    state = %{
+      peer_connection: pc,
+      channel_ref: nil
+    }
+
+    {:ok, state}
+  end
+
+  @impl true
+  def handle_in({msg, [opcode: :text]}, state) do
+    msg
+    |> Jason.decode!()
+    |> handle_ws_msg(state)
+  end
+
+  @impl true
+  def handle_info({:ex_webrtc, _from, msg}, state) do
+    handle_webrtc_msg(msg, state)
+  end
+
+  @impl true
+  def handle_info({:chat_msg, msg}, state) do
+    :ok = PeerConnection.send_data(state.peer_connection, state.channel_ref, msg)
+    {:ok, state}
+  end
+
+  @impl true
+  def terminate(reason, _state) do
+    Logger.warning("WebSocket connection was terminated, reason: #{inspect(reason)}")
+  end
+
+  defp handle_ws_msg(%{"type" => "offer", "data" => data}, state) do
+    Logger.info("Received SDP offer:\n#{data["sdp"]}")
+
+    offer = SessionDescription.from_json(data)
+    :ok = PeerConnection.set_remote_description(state.peer_connection, offer)
+
+    {:ok, answer} = PeerConnection.create_answer(state.peer_connection)
+    :ok = PeerConnection.set_local_description(state.peer_connection, answer)
+
+    answer_json = SessionDescription.to_json(answer)
+
+    msg =
+      %{"type" => "answer", "data" => answer_json}
+      |> Jason.encode!()
+
+    Logger.info("Sent SDP answer:\n#{answer_json["sdp"]}")
+
+    {:push, {:text, msg}, state}
+  end
+
+  defp handle_ws_msg(%{"type" => "ice", "data" => data}, state) do
+    Logger.info("Received ICE candidate: #{data["candidate"]}")
+
+    candidate = ICECandidate.from_json(data)
+    :ok = PeerConnection.add_ice_candidate(state.peer_connection, candidate)
+    {:ok, state}
+  end
+
+  defp handle_webrtc_msg({:ice_candidate, candidate}, state) do
+    candidate_json = ICECandidate.to_json(candidate)
+
+    msg =
+      %{"type" => "ice", "data" => candidate_json}
+      |> Jason.encode!()
+
+    Logger.info("Sent ICE candidate: #{candidate_json["candidate"]}")
+
+    {:push, {:text, msg}, state}
+  end
+
+  defp handle_webrtc_msg({:data_channel, %DataChannel{ref: ref}}, state) do
+    state = %{state | channel_ref: ref}
+    {:ok, state}
+  end
+
+  defp handle_webrtc_msg({:data, ref, data}, %{channel_ref: ref} = state) do
+    Registry.dispatch(Chat.PubSub, "chat", fn entries ->
+      for {pid, _} <- entries, do: send(pid, {:chat_msg, data})
+    end)
+
+    {:ok, state}
+  end
+
+  defp handle_webrtc_msg(_msg, state), do: {:ok, state}
+end

examples/chat/lib/chat/router.ex

@@ -0,0 +1,15 @@
+defmodule Chat.Router do
+  use Plug.Router
+
+  plug(Plug.Static, at: "/", from: :chat)
+  plug(:match)
+  plug(:dispatch)
+
+  get "/ws" do
+    WebSockAdapter.upgrade(conn, Chat.PeerHandler, %{}, [])
+  end
+
+  match _ do
+    send_resp(conn, 404, "not found")
+  end
+end

examples/chat/mix.exs

@@ -0,0 +1,30 @@
+defmodule Chat.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :chat,
+      version: "0.1.0",
+      elixir: "~> 1.15",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  def application do
+    [
+      extra_applications: [:logger],
+      mod: {Chat, []}
+    ]
+  end
+
+  defp deps do
+    [
+      {:plug, "~> 1.15.0"},
+      {:bandit, "~> 1.2.0"},
+      {:websock_adapter, "~> 0.5.0"},
+      {:jason, "~> 1.4.0"},
+      {:ex_webrtc, path: "../../."}
+    ]
+  end
+end

examples/chat/mix.lock

@@ -0,0 +1,40 @@
+%{
+  "bandit": {:hex, :bandit, "1.2.3", "a98d664a96fec23b68e776062296d76a94b4459795b38209f4ae89cb4225709c", [:mix], [{:hpax, "~> 0.1.1", [hex: :hpax, repo: "hexpm", optional: false]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:thousand_island, "~> 1.0", [hex: :thousand_island, repo: "hexpm", optional: false]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "3e29150245a9b5f56944434e5240966e75c917dad248f689ab589b32187a81af"},
+  "bunch": {:hex, :bunch, "1.6.1", "5393d827a64d5f846092703441ea50e65bc09f37fd8e320878f13e63d410aec7", [:mix], [], "hexpm", "286cc3add551628b30605efbe2fca4e38cc1bea89bcd0a1a7226920b3364fe4a"},
+  "bunch_native": {:hex, :bunch_native, "0.5.0", "8ac1536789a597599c10b652e0b526d8833348c19e4739a0759a2bedfd924e63", [:mix], [{:bundlex, "~> 1.0", [hex: :bundlex, repo: "hexpm", optional: false]}], "hexpm", "24190c760e32b23b36edeb2dc4852515c7c5b3b8675b1a864e0715bdd1c8f80d"},
+  "bundlex": {:hex, :bundlex, "1.5.3", "35d01e5bc0679510dd9a327936ffb518f63f47175c26a35e708cc29eaec0890b", [:mix], [{:bunch, "~> 1.0", [hex: :bunch, repo: "hexpm", optional: false]}, {:elixir_uuid, "~> 1.2", [hex: :elixir_uuid, repo: "hexpm", optional: false]}, {:qex, "~> 0.5", [hex: :qex, repo: "hexpm", optional: false]}, {:req, ">= 0.4.0", [hex: :req, repo: "hexpm", optional: false]}, {:zarex, "~> 1.0", [hex: :zarex, repo: "hexpm", optional: false]}], "hexpm", "debd0eac151b404f6216fc60222761dff049bf26f7d24d066c365317650cd118"},
+  "castore": {:hex, :castore, "1.0.8", "dedcf20ea746694647f883590b82d9e96014057aff1d44d03ec90f36a5c0dc6e", [:mix], [], "hexpm", "0b2b66d2ee742cb1d9cb8c8be3b43c3a70ee8651f37b75a8b982e036752983f1"},
+  "crc": {:hex, :crc, "0.10.5", "ee12a7c056ac498ef2ea985ecdc9fa53c1bfb4e53a484d9f17ff94803707dfd8", [:mix, :rebar3], [{:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "3e673b6495a9525c5c641585af1accba59a1eb33de697bedf341e247012c2c7f"},
+  "elixir_make": {:hex, :elixir_make, "0.8.4", "4960a03ce79081dee8fe119d80ad372c4e7badb84c493cc75983f9d3bc8bde0f", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:certifi, "~> 2.0", [hex: :certifi, repo: "hexpm", optional: true]}], "hexpm", "6e7f1d619b5f61dfabd0a20aa268e575572b542ac31723293a4c1a567d5ef040"},
+  "elixir_uuid": {:hex, :elixir_uuid, "1.2.1", "dce506597acb7e6b0daeaff52ff6a9043f5919a4c3315abb4143f0b00378c097", [:mix], [], "hexpm", "f7eba2ea6c3555cea09706492716b0d87397b88946e6380898c2889d68585752"},
+  "ex_dtls": {:git, "https://github.com/elixir-webrtc/ex_dtls.git", "dff8ec1998dfb556b2d3dafbd30574d0da18b958", []},
+  "ex_ice": {:hex, :ex_ice, "0.8.0", "f9bd181e8fd2f8ac9a808587ee8a47bf667143069d75f6e4892a62156d798aa7", [:mix], [{:elixir_uuid, "~> 1.0", [hex: :elixir_uuid, repo: "hexpm", optional: false]}, {:ex_stun, "~> 0.2.0", [hex: :ex_stun, repo: "hexpm", optional: false]}, {:ex_turn, "~> 0.1.0", [hex: :ex_turn, repo: "hexpm", optional: false]}], "hexpm", "b0476f6b18986f6df48fda4cecb3be5022323572790d1bb49da10b177c936b4e"},
+  "ex_libsrtp": {:hex, :ex_libsrtp, "0.7.2", "211bd89c08026943ce71f3e2c0231795b99cee748808ed3ae7b97cd8d2450b6b", [:mix], [{:bunch, "~> 1.6", [hex: :bunch, repo: "hexpm", optional: false]}, {:bundlex, "~> 1.3", [hex: :bundlex, repo: "hexpm", optional: false]}, {:membrane_precompiled_dependency_provider, "~> 0.1.0", [hex: :membrane_precompiled_dependency_provider, repo: "hexpm", optional: false]}, {:unifex, "~> 1.1", [hex: :unifex, repo: "hexpm", optional: false]}], "hexpm", "2e20645d0d739a4ecdcf8d4810a0c198120c8a2f617f2b75b2e2e704d59f492a"},
+  "ex_rtcp": {:hex, :ex_rtcp, "0.4.0", "f9e515462a9581798ff6413583a25174cfd2101c94a2ebee871cca7639886f0a", [:mix], [], "hexpm", "28956602cf210d692fcdaf3f60ca49681634e1deb28ace41246aee61ee22dc3b"},
+  "ex_rtp": {:hex, :ex_rtp, "0.4.0", "1f1b5c1440a904706011e3afbb41741f5da309ce251cb986690ce9fd82636658", [:mix], [], "hexpm", "0f72d80d5953a62057270040f0f1ee6f955c08eeae82ac659c038001d7d5a790"},
+  "ex_sctp": {:git, "https://github.com/elixir-webrtc/ex_sctp.git", "1576207bda0eba3634a2b0075899042e9b309e60", []},
+  "ex_sdp": {:hex, :ex_sdp, "1.0.0", "c66cd66d60ad03ff1eecdc6db6a1b8a7b89fec260fcc22e8d6703fc5bbf430a3", [:mix], [{:bunch, "~> 1.3", [hex: :bunch, repo: "hexpm", optional: false]}, {:elixir_uuid, "~> 1.2", [hex: :elixir_uuid, repo: "hexpm", optional: false]}], "hexpm", "e165dff988b8ab9d93588636aa5f3f683e1f848fc63b78b12382c8fa3dd39216"},
+  "ex_stun": {:hex, :ex_stun, "0.2.0", "feb1fc7db0356406655b2a617805e6c712b93308c8ea2bf0ba1197b1f0866deb", [:mix], [], "hexpm", "1e01ba8290082ccbf37acaa5190d1f69b51edd6de2026a8d6d51368b29d115d0"},
+  "ex_turn": {:hex, :ex_turn, "0.1.0", "177405aadf3d754567d0d37cf881a83f9cacf8f45314d188633b04c4a9e7c1ec", [:mix], [{:ex_stun, "~> 0.2.0", [hex: :ex_stun, repo: "hexpm", optional: false]}], "hexpm", "d677737fb7d45274d5dac19fe3c26b9038b6effbc0a6b3e7417bccc76b6d1cd3"},
+  "finch": {:hex, :finch, "0.18.0", "944ac7d34d0bd2ac8998f79f7a811b21d87d911e77a786bc5810adb75632ada4", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:mint, "~> 1.3", [hex: :mint, repo: "hexpm", optional: false]}, {:nimble_options, "~> 0.4 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 0.2.6 or ~> 1.0", [hex: :nimble_pool, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "69f5045b042e531e53edc2574f15e25e735b522c37e2ddb766e15b979e03aa65"},
+  "hpax": {:hex, :hpax, "0.1.2", "09a75600d9d8bbd064cdd741f21fc06fc1f4cf3d0fcc335e5aa19be1a7235c84", [:mix], [], "hexpm", "2c87843d5a23f5f16748ebe77969880e29809580efdaccd615cd3bed628a8c13"},
+  "jason": {:hex, :jason, "1.4.4", "b9226785a9aa77b6857ca22832cffa5d5011a667207eb2a0ad56adb5db443b8a", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "c5eb0cab91f094599f94d55bc63409236a8ec69a21a67814529e8d5f6cc90b3b"},
+  "membrane_precompiled_dependency_provider": {:hex, :membrane_precompiled_dependency_provider, "0.1.2", "8af73b7dc15ba55c9f5fbfc0453d4a8edfb007ade54b56c37d626be0d1189aba", [:mix], [{:bundlex, "~> 1.4", [hex: :bundlex, repo: "hexpm", optional: false]}], "hexpm", "7fe3e07361510445a29bee95336adde667c4162b76b7f4c8af3aeb3415292023"},
+  "mime": {:hex, :mime, "2.0.6", "8f18486773d9b15f95f4f4f1e39b710045fa1de891fada4516559967276e4dc2", [:mix], [], "hexpm", "c9945363a6b26d747389aac3643f8e0e09d30499a138ad64fe8fd1d13d9b153e"},
+  "mint": {:hex, :mint, "1.6.2", "af6d97a4051eee4f05b5500671d47c3a67dac7386045d87a904126fd4bbcea2e", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1 or ~> 0.2.0 or ~> 1.0", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "5ee441dffc1892f1ae59127f74afe8fd82fda6587794278d924e4d90ea3d63f9"},
+  "nimble_options": {:hex, :nimble_options, "1.1.1", "e3a492d54d85fc3fd7c5baf411d9d2852922f66e69476317787a7b2bb000a61b", [:mix], [], "hexpm", "821b2470ca9442c4b6984882fe9bb0389371b8ddec4d45a9504f00a66f650b44"},
+  "nimble_pool": {:hex, :nimble_pool, "1.1.0", "bf9c29fbdcba3564a8b800d1eeb5a3c58f36e1e11d7b7fb2e084a643f645f06b", [:mix], [], "hexpm", "af2e4e6b34197db81f7aad230c1118eac993acc0dae6bc83bac0126d4ae0813a"},
+  "plug": {:hex, :plug, "1.15.3", "712976f504418f6dff0a3e554c40d705a9bcf89a7ccef92fc6a5ef8f16a30a97", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "cc4365a3c010a56af402e0809208873d113e9c38c401cabd88027ef4f5c01fd2"},
+  "plug_crypto": {:hex, :plug_crypto, "2.1.0", "f44309c2b06d249c27c8d3f65cfe08158ade08418cf540fd4f72d4d6863abb7b", [:mix], [], "hexpm", "131216a4b030b8f8ce0f26038bc4421ae60e4bb95c5cf5395e1421437824c4fa"},
+  "qex": {:hex, :qex, "0.5.1", "0d82c0f008551d24fffb99d97f8299afcb8ea9cf99582b770bd004ed5af63fd6", [:mix], [], "hexpm", "935a39fdaf2445834b95951456559e9dc2063d0a055742c558a99987b38d6bab"},
+  "req": {:hex, :req, "0.5.6", "8fe1eead4a085510fe3d51ad854ca8f20a622aae46e97b302f499dfb84f726ac", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.17", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "cfaa8e720945d46654853de39d368f40362c2641c4b2153c886418914b372185"},
+  "rustler": {:hex, :rustler, "0.34.0", "e9a73ee419fc296a10e49b415a2eb87a88c9217aa0275ec9f383d37eed290c1c", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:req, "~> 0.5", [hex: :req, repo: "hexpm", optional: false]}, {:toml, "~> 0.6", [hex: :toml, repo: "hexpm", optional: false]}], "hexpm", "1d0c7449482b459513003230c0e2422b0252245776fe6fd6e41cb2b11bd8e628"},
+  "shmex": {:hex, :shmex, "0.5.1", "81dd209093416bf6608e66882cb7e676089307448a1afd4fc906c1f7e5b94cf4", [:mix], [{:bunch_native, "~> 0.5.0", [hex: :bunch_native, repo: "hexpm", optional: false]}, {:bundlex, "~> 1.0", [hex: :bundlex, repo: "hexpm", optional: false]}], "hexpm", "c29f8286891252f64c4e1dac40b217d960f7d58def597c4e606ff8fbe71ceb80"},
+  "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
+  "thousand_island": {:hex, :thousand_island, "1.3.5", "6022b6338f1635b3d32406ff98d68b843ba73b3aa95cfc27154223244f3a6ca5", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "2be6954916fdfe4756af3239fb6b6d75d0b8063b5df03ba76fd8a4c87849e180"},
+  "toml": {:hex, :toml, "0.7.0", "fbcd773caa937d0c7a02c301a1feea25612720ac3fa1ccb8bfd9d30d822911de", [:mix], [], "hexpm", "0690246a2478c1defd100b0c9b89b4ea280a22be9a7b313a8a058a2408a2fa70"},
+  "unifex": {:hex, :unifex, "1.2.0", "90d1ec5e6d788350e07e474f7bd8b0ee866d6606beb9ca4e20dbb26328712a84", [:mix], [{:bunch, "~> 1.0", [hex: :bunch, repo: "hexpm", optional: false]}, {:bundlex, "~> 1.4", [hex: :bundlex, repo: "hexpm", optional: false]}, {:shmex, "~> 0.5.0", [hex: :shmex, repo: "hexpm", optional: false]}], "hexpm", "7a8395aabc3ba6cff04bbe5b995de7f899a38eb57f189e49927d6b8b6ccb6883"},
+  "websock": {:hex, :websock, "0.5.3", "2f69a6ebe810328555b6fe5c831a851f485e303a7c8ce6c5f675abeb20ebdadc", [:mix], [], "hexpm", "6105453d7fac22c712ad66fab1d45abdf049868f253cf719b625151460b8b453"},
+  "websock_adapter": {:hex, :websock_adapter, "0.5.6", "0437fe56e093fd4ac422de33bf8fc89f7bc1416a3f2d732d8b2c8fd54792fe60", [:mix], [{:bandit, ">= 0.6.0", [hex: :bandit, repo: "hexpm", optional: true]}, {:plug, "~> 1.14", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.6", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:websock, "~> 0.5", [hex: :websock, repo: "hexpm", optional: false]}], "hexpm", "e04378d26b0af627817ae84c92083b7e97aca3121196679b73c73b99d0d133ea"},
+  "zarex": {:hex, :zarex, "1.0.5", "58239e3ee5d75f343262bb4df5cf466555a1c689f920e5d3651a9333972f7c7e", [:mix], [], "hexpm", "9fb72ef0567c2b2742f5119a1ba8a24a2fabb21b8d09820aefbf3e592fa9a46a"},
+}

examples/chat/priv/static/index.html

@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta http-equiv="X-UA-Compatible" content="ie=edge">
+    <title>Elixir WebRTC Chat Example</title>
+  </head>
+  <body>
+    <h1>Elixir WebRTC Chat Example</h1>
+    <label for="chatInput">Chat:</label>
+    <input type="text" id="chatInput" name="chatInput">
+    <div id="chatMessages"></div>
+    <script src="script.js"></script>
+  </body>
+</html>

examples/chat/priv/static/script.js

@@ -0,0 +1,53 @@
+const pcConfig = { 'iceServers': [{ 'urls': 'stun:stun.l.google.com:19302' },] };
+const chatInput = document.getElementById("chatInput");
+const chatMessages = document.getElementById("chatMessages");
+
+const proto = window.location.protocol === "https:" ? "wss:" : "ws:"
+const ws = new WebSocket(`${proto}//${window.location.host}/ws`);
+ws.onopen = _ => start_connection(ws);
+ws.onclose = event => console.log("WebSocket connection was terminated:", event);
+
+const start_connection = async (ws) => {
+  const pc = new RTCPeerConnection(pcConfig);
+  pc.onicecandidate = event => {
+    if (event.candidate === null) return;
+
+    console.log("Sent ICE candidate:", event.candidate);
+    ws.send(JSON.stringify({ type: "ice", data: event.candidate }));
+  };
+
+  const dataChannel = pc.createDataChannel("chat");
+
+  dataChannel.onmessage = event => {
+    const msg = document.createElement("p");
+    msg.innerText = event.data;
+    chatMessages.appendChild(msg);
+  };
+
+  chatInput.onkeydown = event => {
+    if (event.code !== "Enter") return;
+    if (dataChannel.readyState !== "open") return;
+
+    dataChannel.send(chatInput.value);
+    chatInput.value = "";
+  };
+
+  ws.onmessage = async event => {
+    const {type, data} = JSON.parse(event.data);
+
+    switch (type) {
+      case "answer":
+        console.log("Received SDP answer:", data);
+        await pc.setRemoteDescription(data)
+        break;
+      case "ice":
+        console.log("Received ICE candidate:", data);
+        await pc.addIceCandidate(data);
+    }
+  };
+
+  const offer = await pc.createOffer();
+  await pc.setLocalDescription(offer);
+  console.log("Sent SDP offer:", offer)
+  ws.send(JSON.stringify({type: "offer", data: offer}));
+};