Add connection callbacks

lib/xogmios/chain_sync.ex

@@ -8,6 +8,9 @@ defmodule Xogmios.ChainSync do
   @callback handle_block(map(), any()) ::
               {:ok, :next_block, map()} | {:ok, map()} | {:ok, :close, map()}
 
+  @callback handle_connect(map()) :: {:ok, map()}
+  @callback handle_disconnect(String.t(), map()) :: :ok
+
   # The keepalive option is used to maintain the connection active.
   # This is important because proxies might close idle connections after a few seconds.
   @keepalive_in_ms 5_000
@@ -29,6 +32,10 @@ defmodule Xogmios.ChainSync do
 
       require Logger
 
+      def handle_connect(state), do: {:ok, state}
+      def handle_disconnect(_reason, _state), do: :ok
+      defoverridable handle_connect: 1, handle_disconnect: 2
+
       def handle_message(%{"id" => "start"} = message, state) do
         %{
           "method" => "nextBlock",

lib/xogmios/chain_sync/connection.ex

@@ -40,14 +40,27 @@ defmodule Xogmios.ChainSync.Connection do
       def onconnect(_arg, state) do
         start_message = Messages.next_block_start()
         :websocket_client.cast(self(), {:text, start_message})
-        Logger.debug("onconnect")
-        {:ok, state}
+
+        case state.handler.handle_connect(state) do
+          {:ok, new_state} ->
+            {:ok, new_state}
+
+          _ ->
+            {:ok, state}
+        end
       end
 
       @impl true
       def ondisconnect(reason, state) do
         Logger.debug("ondisconnect #{inspect(reason)}")
-        {:reconnect, 5_000, state}
+
+        case state.handler.handle_disconnect(reason, state) do
+          :ok ->
+            {:reconnect, 5_000, state}
+
+          _ ->
+            {:reconnect, 5_000, state}
+        end
       end
 
       @impl true