Add breadcrumbs to farm taxonomy term pages, and allow other modules to add breadcrumbs to them via a new hook_farm_taxonomy_breadcrumb().

farm_taxonomy.api.php

@@ -22,10 +22,30 @@
  * farm_taxonomy.
  */
 
+/**
+ * Add breadcrumbs to the taxonomy view page.
+ *
+ * @param object $term
+ *   The taxonomy term entity.
+ *
+ * @return array
+ *   Returns an array of links to add to the term's breadcrumb.
+ */
+function hook_farm_taxonomy_breadcrumb($term) {
+  $breadcrumb = array();
+
+  // If the asset is an animal, add a link to /farm/animals.
+  if ($farm_asset->type == 'animal') {
+    $breadcrumb[] = l(t('Animals'), 'farm/animals');
+  }
+
+  return $breadcrumb;
+}
+
 /**
  * Attach Views to taxonomy term pages.
  *
- * @param array $term
+ * @param object $term
  *   The taxonomy term entity.
  *
  * @return array
@@ -38,7 +58,7 @@
  *     'weight' - the weight of the View in the taxonomy page
  *       (this is useful for changing the order of Views)
  */
-function hook_taxonomy_term_view_views(array $term) {
+function hook_taxonomy_term_view_views($term) {
 
   // If the term is not a crop, bail.
   if ($term->vocabulary_machine_name != 'crop') {

farm_taxonomy.module

@@ -24,6 +24,9 @@ function farm_taxonomy_entity_view_alter(&$build, $type) {
   // Pull the term entity out of the build array.
   $term = $build['#term'];
 
+  // Set the term page breadcrumb.
+  _farm_taxonomy_term_set_breadcrumb($term);
+
   // Invoke hook_farm_taxonomy_term_view_views() to get a list of Views.
   $views = module_invoke_all('farm_taxonomy_term_view_views', $term);
 
@@ -100,3 +103,41 @@ function farm_taxonomy_entity_view_alter(&$build, $type) {
     );
   }
 }
+
+/**
+ * Helper function for setting farm taxonomy term page breadcrumbs.
+ *
+ * @param object $term
+ *   The taxonomy term.
+ */
+function _farm_taxonomy_term_set_breadcrumb($term) {
+
+  // Ask other modules for breadcrumbs for this term.
+  // We don't know if this term is part of a farm vocabulary yet, so we will
+  // only set the breadcrumb if this returns results.
+  $module_breadcrumbs = module_invoke_all('farm_taxonomy_breadcrumb', $term);
+
+  // If other modules provided breadcrumbs...
+  if (!empty($module_breadcrumbs)) {
+
+    // Get the default breadcrumb.
+    $default_breadcrumb = drupal_get_breadcrumb();
+
+    // Shift the first item off (home) and start a new breadcrumb array with it.
+    $home = array_shift($default_breadcrumb);
+    $breadcrumb = array($home);
+
+    // Add "Farm".
+    $farm = l(t('Farm'), 'farm');
+    $breadcrumb[] = $farm;
+
+    // Add the breadcrumbs provided by other modules.
+    $breadcrumb = array_merge($breadcrumb, $module_breadcrumbs);
+
+    // Finally, put the original breadcrumbs back onto the end.
+    $breadcrumb = array_merge($breadcrumb, $default_breadcrumb);
+
+    // Set the breadcrumb.
+    drupal_set_breadcrumb($breadcrumb);
+  }
+}