PHP警告：simplexml_load_file（）：I / O警告：无法加载外部实体Amazon AWS API

Question

我有一些返回PHP警告的PHP代码：

[30-Aug-2018 11:10:19 America/New_York] PHP Warning:  simplexml_load_file(): I/O warning : failed to load external entity "http://webservices.amazon.com/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=[HIDDEN]&AssociateTag=[HIDDEN]&Operation=ItemLookup&IdType=ASIN&ItemId=B003U4L36I&ResponseGroup=Images%2CMedium%2CLarge%2CSmall%2CItemAttributes%2CItemIds%2CSalesRank%2CReviews%2CBrowseNodes&Timestamp=2018-08-30T15:10:19.000Z&Signature=[HIDDEN]; in /functions.php on line 192

我将其格式化为更具可读性：

[30-Aug-2018 11:10:19 America/New_York] PHP Warning:  simplexml_load_file(): I/O warning : failed to load external entity 

"
http://webservices.amazon.com/onca/xml?
Service=AWSECommerceService&
AWSAccessKeyId=[HIDDEN]&
AssociateTag=[HIDDEN]&
Operation=ItemLookup&
IdType=ASIN&
ItemId=B003U4L36I&
ResponseGroup=Images%2CMedium%2CLarge%2CSmall%2CItemAttributes%2CItemIds%2CSalesRank%2CReviews%2CBrowseNodes&
Timestamp=2018-08-30T15:10:19.000Z&
Signature=[HIDDEN]; 
in /functions.php on line 192

functions.php中的192行是：

$xml_doc = simplexml_load_file($request);
    if($debugOutput == TRUE) echo time().' :: getXMLByASIN_V2 :: XML_DOC returned and loaded.</pre><BR>';
    return $xml_doc;

谢谢。