Do not return content from cacheByHTTP if the request errors, otherwise callers can process bad content, like SC assets expecting RSS feeds and getting 404 error pages.

docs/changelog/7.x.x.txt

@@ -9,6 +9,7 @@
  - RFE: 9730 (actually missing documentation)
  - fixed: Crud updateFromFormPost
  - fixed: encryptLogin and sslEnabled both need to be true
+ - fixed: Cache's setByHTTP method returns content, even when it gets an error in the request.  This gives the SC asset fits.
 
 7.10.24
  - fixed #12318: asset error causes asset manager to fail

lib/WebGUI/Cache.pm

@@ -242,11 +242,11 @@ sub setByHTTP {
     my $response = $userAgent->request($request);
     if ($response->is_error) {
         $self->session->errorHandler->error($url." could not be retrieved.");
+        return undef;
     }
-    else {
-        $self->set($response->decoded_content,$ttl);
-    }
-    return $response->decoded_content;
+    my $value = $response->decoded_content;
+    $self->set($value ,$ttl);
+    return $value;
 }
 
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