Fix subscriptions storage manager TTL (#1307)

The TTL argument on cache calls is in minutes in Laravel 5.5-5.7 and changed to seconds on Laravel 5.8+, passing a Carbon instance makes sure our TTL in seconds is always correct.

composer.json

@@ -25,6 +25,7 @@
     "require": {
         "php": ">= 7.1",
         "ext-json": "*",
+        "nesbot/carbon": "^1.26.0 || ^2.0",
         "illuminate/contracts": "5.5.* || 5.6.* || 5.7.* || 5.8.* || ^6.0 || ^7.0",
         "illuminate/http": "5.5.* || 5.6.* || 5.7.* || 5.8.* || ^6.0 || ^7.0",
         "illuminate/pagination": "5.5.* || 5.6.* || 5.7.* || 5.8.* || ^6.0 || ^7.0",

src/Subscriptions/StorageManager.php

@@ -2,6 +2,7 @@
 
 namespace Nuwave\Lighthouse\Subscriptions;
 
+use Carbon\Carbon;
 use Illuminate\Cache\CacheManager;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Collection;
@@ -78,7 +79,8 @@ public function storeSubscriber(Subscriber $subscriber, string $topic): void
         if ($this->ttl === null) {
             $this->cache->forever($channelKey, $subscriber);
         } else {
-            $this->cache->put($channelKey, $subscriber, $this->ttl);
+            // TODO: Change to just pass the ttl directly when support for Laravel <=5.7 is dropped
+            $this->cache->put($channelKey, $subscriber, Carbon::now()->addSeconds($this->ttl));
         }
     }
 
@@ -103,7 +105,8 @@ protected function storeTopic(string $key, Collection $topic): void
         if ($this->ttl === null) {
             $this->cache->forever($key, $topic);
         } else {
-            $this->cache->put($key, $topic, $this->ttl);
+            // TODO: Change to just pass the ttl directly when support for Laravel <=5.7 is dropped
+            $this->cache->put($key, $topic, Carbon::now()->addSeconds($this->ttl));
         }
     }