Use credentials array only if values passed via conf.php

lib/Data/S3Storage.php

@@ -82,31 +82,32 @@ class S3Storage extends AbstractData
      */
     public function __construct(array $options)
     {
-        $this->_options['credentials'] = array();
-
-        if (is_array($options) && array_key_exists('region', $options)) {
-            $this->_options['region'] = $options['region'];
-        }
-        if (is_array($options) && array_key_exists('version', $options)) {
-            $this->_options['version'] = $options['version'];
-        }
-        if (is_array($options) && array_key_exists('endpoint', $options)) {
-            $this->_options['endpoint'] = $options['endpoint'];
-        }
-        if (is_array($options) && array_key_exists('accesskey', $options)) {
-            $this->_options['credentials']['key'] = $options['accesskey'];
-        }
-        if (is_array($options) && array_key_exists('secretkey', $options)) {
-            $this->_options['credentials']['secret'] = $options['secretkey'];
-        }
-        if (is_array($options) && array_key_exists('use_path_style_endpoint', $options)) {
-            $this->_options['use_path_style_endpoint'] = filter_var($options['use_path_style_endpoint'], FILTER_VALIDATE_BOOLEAN);
-        }
-        if (is_array($options) && array_key_exists('bucket', $options)) {
-            $this->_bucket = $options['bucket'];
-        }
-        if (is_array($options) && array_key_exists('prefix', $options)) {
-            $this->_prefix = $options['prefix'];
+        if (is_array($options)) {
+            // AWS SDK will try to load credentials from environment if credentials are not passed via configuration 
+            // ref: https://docs.aws.amazon.com/sdk-for-php/v3/developer-guide/guide_credentials.html#default-credential-chain
+            if (isset($options['accesskey']) && isset($options['secretkey'])) {
+                $this->_options['credentials'] = array();
+                $this->_options['credentials']['key'] = $options['accesskey'];
+                $this->_options['credentials']['secret'] = $options['secretkey'];
+            }
+            if (array_key_exists('region', $options)) {
+                $this->_options['region'] = $options['region'];
+            }
+            if (array_key_exists('version', $options)) {
+                $this->_options['version'] = $options['version'];
+            }
+            if (array_key_exists('endpoint', $options)) {
+                $this->_options['endpoint'] = $options['endpoint'];
+            }
+            if (array_key_exists('use_path_style_endpoint', $options)) {
+                $this->_options['use_path_style_endpoint'] = filter_var($options['use_path_style_endpoint'], FILTER_VALIDATE_BOOLEAN);
+            }
+            if (array_key_exists('bucket', $options)) {
+                $this->_bucket = $options['bucket'];
+            }
+            if (array_key_exists('prefix', $options)) {
+                $this->_prefix = $options['prefix'];
+            }
         }
 
         $this->_client = new S3Client($this->_options);