Fix disconnect with keepalive

README.md

@@ -6,7 +6,15 @@ An Elixir client for [Ogmios](https://github.com/CardanoSolutions/ogmios).
 
 > Ogmios is a lightweight bridge interface for a Cardano node. It offers a WebSockets API that enables local clients to speak Ouroboros' mini-protocols via JSON/RPC. - https://ogmios.dev/
 
-It currently only partially supports the **Chain Synchronization** and **State Query** mini-protocols. See [Examples](#examples) section below for information on how to use it.
+Mini-Protocols supported by this library:
+
+- [x] Chain Synchronization
+- [ ] State Query (partially supported)
+- [ ] Mempool Monitoring
+- [ ] Tx Submission
+
+
+See [Examples](#examples) section below for information on how to use.
 
 ## Installing
 

lib/xogmios/chain_sync.ex

@@ -8,10 +8,14 @@ defmodule Xogmios.ChainSync do
   @callback handle_block(map(), any()) ::
               {:ok, :next_block, map()} | {:ok, map()} | {:ok, :close, map()}
 
+  # 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
+
   def start_link(client, opts) do
     {url, opts} = Keyword.pop(opts, :url)
     initial_state = Keyword.merge(opts, handler: client)
-    :websocket_client.start_link(url, client, initial_state)
+    :websocket_client.start_link(url, client, initial_state, keepalive: @keepalive_in_ms)
   end
 
   defmacro __using__(_opts) do