custom_node_field_preprocess_hooks.patch

diff --git a/modules/rdf/rdf.module b/modules/rdf/rdf.module
index e491c31..d68ce84 100644
--- a/modules/rdf/rdf.module
+++ b/modules/rdf/rdf.module
@@ -464,6 +464,12 @@ function rdf_process(&$variables, $hook) {
  * Implements MODULE_preprocess_HOOK().
  */
 function rdf_preprocess_node(&$variables) {
+  // If any module does not want to include rdf attibutes, exit.
+  foreach (module_implements('rdf_node_preprocess') as $module) {
+    if (!module_invoke($module, 'rdf_node_preprocess', $variables)) {
+      return;
+    }
+  }
   // Adds RDFa markup to the node container. The about attribute specifies the
   // URI of the resource described within the HTML element, while the @typeof
   // attribute indicates its RDF type (e.g., foaf:Document, sioc:Person, and so
@@ -548,6 +554,13 @@ function rdf_preprocess_node(&$variables) {
  */
 function rdf_preprocess_field(&$variables) {
   $element = $variables['element'];
+  // If any module does not want to include rdf attibutes, exit.
+  foreach (module_implements('rdf_field_preprocess') as $module) {
+    if (!module_invoke($module, 'rdf_field_preprocess', $element)) {
+      return;
+    }
+  }
+
   $mapping = rdf_mapping_load($element['#entity_type'], $element['#bundle']);
   $field_name = $element['#field_name'];