Initial

lib/client.ex

@@ -0,0 +1,19 @@
+defmodule Broadcast.ClientHandler do
+  use Task
+
+  def start(sock) do
+    Task.start_link(__MODULE__, :handle, [sock])
+  end
+
+  def handle(sock) do
+    case :gen_tcp.recv(sock, 0) do
+      {:ok, line} ->
+        Broadcast.Server.broadcast("Someone said: " <> line)
+        handle(sock)
+
+      {:error, _} ->
+        :gen_tcp.close(sock)
+        Broadcast.Server.remove_client()
+    end
+  end
+end

lib/main.ex

@@ -0,0 +1,25 @@
+defmodule Broadcast do
+  @moduledoc """
+  A simple broadcast server
+  """
+  use Application
+
+  def console_loop() do
+    case IO.read(:stdio, :line) do
+      "mem\n" ->
+        IO.inspect :erlang.memory()
+      _ -> IO.puts "unknown command entered"
+    end
+    console_loop()
+  end
+
+  def main(_args \\ []) do
+    IO.puts "started"
+    {:ok, _} = Broadcast.Server.start(8080)
+    console_loop()
+  end
+
+  def start(_type, _args) do
+    main()
+  end
+end

lib/server.ex

@@ -0,0 +1,65 @@
+defmodule Broadcast.Server do
+  @moduledoc """
+    Implements the server. The server spawns a new process
+    for every client - the processes usually don't really talk to
+    each other, so this is trivial.
+  """
+  use GenServer
+  use Agent
+
+
+
+  def init(port) do
+    {:ok, sock} = :gen_tcp.listen(port, [:binary, packet: :line, active: false, reuseaddr: true])
+    spawn_link(fn -> accept_loop(sock) end)
+    {:ok, {sock, %{}}}
+  end
+
+  defp accept_loop(sock) do
+    case :gen_tcp.accept(sock) do
+      {:ok, client_socket} ->
+        {:ok, pid} = Broadcast.ClientHandler.start(client_socket)
+        GenServer.cast(__MODULE__, {:new_client, pid, client_socket})
+        accept_loop(sock)
+      {:error, _} ->
+        accept_loop(sock)
+    end
+  end
+
+  def handle_cast({:new_client, pid, client_sock}, {sock, clients}) do
+    {:noreply, {sock, clients |> Map.put(pid, client_sock)}}
+  end
+
+  def handle_cast({:remove, client}, {sock, clients}) do
+    new_clients = Map.delete(clients, client)
+    {:noreply, {sock, new_clients}}
+  end
+
+  def handle_cast({:broadcast, msg, sender}, {sock, clients}) do
+    clients |> Enum.map(fn {p, s} ->
+      if sender != p do
+        :gen_tcp.send(s, msg)
+      end
+    end)
+    {:noreply, {sock, clients}}
+  end
+
+  # Print out the memory usage for the client processes specifically
+
+  # From this point onwards is the actual API for this module,
+  # that should be called by ClientHandlers and main
+
+  @spec start(integer()) :: pid()
+  def start(port) when is_integer(port) do
+    GenServer.start_link(__MODULE__, port, name: __MODULE__)
+  end
+
+  def broadcast(msg) do
+    GenServer.cast(__MODULE__, {:broadcast, msg, self()})
+  end
+
+  def remove_client() do
+    GenServer.cast(__MODULE__, {:remove, self()})
+  end
+
+end