WS support

composer.json

@@ -4,7 +4,8 @@
     "type": "library",
     "require": {
       "php": ">=8.0",
-      "ext-curl": "*"
+      "ext-curl": "*",
+        "ratchet/pawl": "dev-master"
     },
     "license": "GPL-3.0",
     "autoload": {

src/KrakenAPIClient.php

@@ -9,6 +9,8 @@ class KrakenAPIClient
     public const DEFAULT_API_ROOT = 'https://api.kraken.com';
     public const DEFAULT_API_VERSION = '0';
     public const AUTHENTICATED_ENDPOINTS_URI_PATH = 'private/';
+    public const WEBSOCKET_PUBLIC_ENDPOINT = 'ws.kraken.com';
+    public const WEBSOCKET_PRIVATE_ENDPOINT = 'ws-auth.kraken.com';
 
     public function __construct(
         private ?string $key = null,
@@ -72,6 +74,18 @@ class KrakenAPIClient
         return $response['result'];
     }
 
+    public function stream(callable $callback, string $endpoint = self::WEBSOCKET_PUBLIC_ENDPOINT): void
+    {
+        \Ratchet\Client\connect(sprintf('wss://%s', $endpoint))->then(
+            $callback,
+            function ($e) {
+                throw new KrakenAPIException(
+                    sprintf('Error while connecting to Kraken API WebSocket: "%s".', $e->getMessage())
+                );
+            }
+        );
+    }
+
     private function loadClient(): void
     {
         if ($this->curl === false) {