Begin WebSocket support for Broadcast and Player control

modules/React/Dns/Query/CachedExecutor.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace React\Dns\Query;
+
+use React\Dns\Model\Message;
+use React\Dns\Model\Record;
+
+class CachedExecutor implements ExecutorInterface
+{
+    private $executor;
+    private $cache;
+
+    public function __construct(ExecutorInterface $executor, RecordCache $cache)
+    {
+        $this->executor = $executor;
+        $this->cache = $cache;
+    }
+
+    public function query($nameserver, Query $query)
+    {
+        $executor = $this->executor;
+        $cache = $this->cache;
+
+        return $this->cache
+            ->lookup($query)
+            ->then(
+                function ($cachedRecords) use ($query) {
+                    return $this->buildResponse($query, $cachedRecords);
+                },
+                function () use ($executor, $cache, $nameserver, $query) {
+                    return $executor
+                        ->query($nameserver, $query)
+                        ->then(function ($response) use ($cache, $query) {
+                            $cache->storeResponseMessage($query->currentTime, $response);
+                            return $response;
+                        });
+                }
+            );
+    }
+
+    public function buildResponse(Query $query, array $cachedRecords)
+    {
+        $response = new Message();
+
+        $response->header->set('id', $this->generateId());
+        $response->header->set('qr', 1);
+        $response->header->set('opcode', Message::OPCODE_QUERY);
+        $response->header->set('rd', 1);
+        $response->header->set('rcode', Message::RCODE_OK);
+
+        $response->questions[] = new Record($query->name, $query->type, $query->class);
+
+        foreach ($cachedRecords as $record) {
+            $response->answers[] = $record;
+        }
+
+        $response->prepare();
+
+        return $response;
+    }
+
+    protected function generateId()
+    {
+        return mt_rand(0, 0xffff);
+    }
+}