more error-handling and fixing some PHP errors

site/ops_api.php

     $json = json_decode($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 $invention_title){
+    if (isset($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'bibliographic-data'}->{'invention-title'})){
 
-      if ((isset($invention_title->{'@lang'})) && ($invention_title->{'@lang'} === 'ol')){
+      foreach ($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'bibliographic-data'}->{'invention-title'} as $invention_title){
 
-        $output['original_title'] = $invention_title->{'$'};
+        if ((isset($invention_title->{'@lang'})) && ($invention_title->{'@lang'} === 'ol')){
+
+          $output['original_title'] = $invention_title->{'$'};
+
+        }
 
       }
 
     }
 
     // For each abstract, check if it's in the original language
-    foreach ($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'abstract'} as $abstract){
+    if (isset($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'abstract'})){
+
+      foreach ($json->{'ops:world-patent-data'}->{'exchange-documents'}->{'exchange-document'}->{'abstract'} as $abstract){
+
+        if ((isset($abstract->{'@lang'})) && ($abstract->{'@lang'} === 'ol')){
 
-      if ((isset($abstract->{'@lang'})) && ($abstract->{'@lang'} === 'ol')){
+          $output['original_abstract'] = $abstract->p->{'$'};
 
-        $output['original_abstract'] = $abstract->p->{'$'};
+        }
 
       }
 

site/public/random.php

 
   <br><br>
 
+  <?php
+    if (isset($random_record['title'])):
+  ?>
+
   Title:
 
   <?php
   <br><br>
 
   <?php
+    endif;
+  ?>
 
+  <?php
     if (isset($publication_details['original_title'])):
   ?>
 
   ?>
 
   <?php
-  if ($random_record['abstract']):
+  if (isset($random_record['abstract'])):
   ?>
 
   Abstract: