Add support for preview detection; See: wpsharks/comet-cache#583

src/includes/closures/Ac/NcDebugConsts.php

@@ -166,6 +166,15 @@
  */
 const NC_DEBUG_GET_REQUEST_QUERIES = 'nc_debug_get_request_queries';
 
+/**
+* No-cache because it's a preview.
+*
+* @since 15xxxx Adding support for preview detection.
+*
+* @type string A unique string identifier in the set of `NC_DEBUG_` constants.
+*/
+const NC_DEBUG_PREVIEW = 'nc_debug_preview';
+
 /**
  * No-cache because the current request excluded by its URI.
  *

src/includes/closures/Ac/NcDebugUtils.php

@@ -140,6 +140,10 @@
                 $reason = __('because `$_GET` contains query string data. The current configuration says NOT to cache GET requests with a query string.', SLUG_TD);
                 break; // Break switch handler.
 
+            case NC_DEBUG_PREVIEW:
+                $reason = __('because `$_REQUEST` indicates this is simply a preview of something to come.', SLUG_TD);
+                break; // Break switch handler.    
+
             case NC_DEBUG_EXCLUDED_URIS:
                 $reason = __('because `$_SERVER[\'REQUEST_URI\']` matches a configured URI Exclusion Pattern on this installation.', SLUG_TD);
                 break; // Break switch handler.

src/includes/closures/Ac/ObUtils.php

@@ -150,6 +150,9 @@
     if (!ZENCACHE_GET_REQUESTS && $self->requestContainsUncacheableQueryVars()) {
         return $self->maybeSetDebugInfo(NC_DEBUG_GET_REQUEST_QUERIES);
     }
+    if (!empty($_REQUEST['preview'])) {
+        return $self->maybeSetDebugInfo(NC_DEBUG_PREVIEW);
+    }
     if (ZENCACHE_EXCLUDE_URIS && preg_match(ZENCACHE_EXCLUDE_URIS, $_SERVER['REQUEST_URI'])) {
         return $self->maybeSetDebugInfo(NC_DEBUG_EXCLUDED_URIS);
     }