fixing some errors

site/ops_api.php

@@ -56,13 +56,15 @@ function get_publication_details($document_reference) {
 
   if (strpos($response,"No results found") === false ) {
 
+    global $output;
+
     // Turn the API response into useful Json
     $json = json_decode($response);
 
     // For each invention title, check if it's in the original language
     foreach ($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'bibliographic-data'}->{'invention-title'} as $invention_title){
 
-      if ($invention_title->{'@lang'} === 'ol'){
+      if ((isset($invention_title->{'@lang'})) && ($invention_title->{'@lang'} === 'ol')){
 
         $output['original_title'] = $invention_title->{'$'};
 
@@ -73,7 +75,7 @@ function get_publication_details($document_reference) {
     // For each abstract, check if it's in the original language
     foreach ($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'abstract'} as $abstract){
 
-      if ($abstract->{'@lang'} === 'ol'){
+      if ((isset($abstract->{'@lang'})) && ($abstract->{'@lang'} === 'ol')){
 
         $output['original_abstract'] = $abstract->p->{'$'};