Implement realtime API

src/main/php/com/openai/realtime/RealtimeApi.class.php

@@ -0,0 +1,83 @@
+<?php namespace com\openai\realtime;
+
+use text\json\Json;
+use util\URI;
+use util\data\Marshalling;
+use util\log\Traceable;
+use websocket\WebSocket;
+
+/** @see https://github.com/azure-samples/aoai-realtime-audio-sdk */
+class RealtimeApi implements Traceable {
+  private $ws, $headers;
+  private $cat= null;
+
+  /** @param string|util.URI $endpoint */
+  public function __construct($endpoint) {
+    $uri= $endpoint instanceof URI ? $endpoint : new URI($endpoint);
+    $this->ws= new WebSocket($uri);
+    $this->headers= ['api-key' => $uri->user()];
+    $this->marshalling= new Marshalling();
+  }
+
+  /** @param ?util.log.LogCategory $cat */
+  public function setTrace($cat) {
+    $this->cat= $cat;
+  }
+
+  /** Opens the underlying websocket, optionally passing headers */
+  public function connect(array $headers= []): self {
+    $headers+= $this->headers;
+    $this->cat && $this->cat->info($this->ws->socket(), $this->ws->path(), $headers);
+    $this->ws->connect($headers);
+    return $this;
+  }
+
+  /** Returns whether the underlying websocket is connected */
+  public function connected(): bool {
+    return $this->ws->connected();
+  }
+
+  /** Closes the underlying websocket */
+  public function close(): void {
+    $this->ws->close();
+  }
+
+  /**
+   * Sends a given payload. Doesn't wait for a response
+   *
+   * @param  var $payload
+   * @return void
+   */
+  public function send($payload): void {
+    $json= Json::of($this->marshalling->marshal($payload));
+    $this->cat && $this->cat->debug('>>>', $json);
+    $this->ws->send($json);
+  }
+
+  /**
+   * Receives an answer. Returns NULL if EOF is reached.
+   *
+   * @return var
+   */
+  public function receive() {
+    $json= $this->ws->receive();
+    $this->cat && $this->cat->debug('<<<', $json);
+    return null === $json ? null : $this->marshalling->unmarshal(Json::read($json));
+  }
+
+  /**
+   * Sends a given payload and returns the response to it.
+   *
+   * @param  var $payload
+   * @return var
+   */
+  public function transmit($payload) {
+    $this->send($payload);
+    return $this->receive();
+  }
+
+  /** Ensures socket is closed */
+  public function __destruct() {
+    $this->ws && $this->ws->close();
+  }
+}