Fet/rest relation endpoints (fixes #790)

core/db_classes/EE_Base_Class.class.php

@@ -2329,8 +2329,8 @@ public function _add_relation_to(
      *                You can optionally include an array of key=>value pairs that allow you to further constrict the
      *                relation to being added. However, keep in mind that the columns (keys) given must match a column
      *                on the JOIN table and currently only the HABTM models accept these additional conditions. Also
-     *                remember that if an exact match isn't found for these extra cols/val pairs, then a NEW row is
-     *                created in the join table.
+     *                remember that if an exact match isn't found for these extra cols/val pairs, then no row is
+     *                deleted.
      * @return EE_Base_Class the relation was removed from
      * @throws ReflectionException
      * @throws InvalidArgumentException

core/db_models/relations/EE_HABTM_Relation.php

@@ -155,7 +155,7 @@ public function add_relation_to($this_obj_or_id, $other_obj_or_id, $extra_join_m
         $join_model_fk_to_this_model  = $this->get_join_model()->get_foreign_key_to($this->get_this_model()->get_this_model_name());
         $join_model_fk_to_other_model = $this->get_join_model()->get_foreign_key_to($this->get_other_model()->get_this_model_name());
 
-        $cols_n_values = array(
+        $foreign_keys = $all_fields = array(
             $join_model_fk_to_this_model->get_name()  => $this_model_obj->ID(),
             $join_model_fk_to_other_model->get_name() => $other_model_obj->ID(),
         );
@@ -173,18 +173,21 @@ public function add_relation_to($this_obj_or_id, $other_obj_or_id, $extra_join_m
                 );
                 $parsed_query[ $query_param ] = $val;
             }
-            $cols_n_values = array_merge($cols_n_values, $parsed_query);
+            $all_fields = array_merge($foreign_keys, $parsed_query);
         }
 
-        $query_params = array($cols_n_values);
-
-
-        $existing_entry_in_join_table = $this->get_join_model()->get_one($query_params);
-        // if there is already an entry in the join table, indicating a relationship, we're done
-        // again, if you want more sophisticated logic or insertions (handling more columns than just 2 foreign keys to
-        // the other tables, use the joining model directly!
+        $existing_entry_in_join_table = $this->get_join_model()->get_one(array($foreign_keys));
+        // If there is already an entry in the join table, indicating a relationship, update it instead of adding a
+        // new row.
+        // Again, if you want more sophisticated logic or insertions (handling more columns than just 2 foreign keys to
+        // the other tables) use the joining model directly!
         if (! $existing_entry_in_join_table) {
-            $this->get_join_model()->insert($cols_n_values);
+            $this->get_join_model()->insert($all_fields);
+        } else {
+            $this->get_join_model()->update(
+                $all_fields,
+                array($foreign_keys)
+            );
         }
         return $other_model_obj;
     }
@@ -232,4 +235,40 @@ public function remove_relation_to($this_obj_or_id, $other_obj_or_id, $where_que
         $this->get_join_model()->delete(array($cols_n_values));
         return $other_model_obj;
     }
+
+    /**
+     * Gets all the non-key fields (ie, not the primary key and not foreign keys) on the join model.
+     * @since $VID:$
+     * @return EE_Model_Field_Base[]
+     * @throws EE_Error
+     */
+    public function getNonKeyFields()
+    {
+        // all fields besides the primary key and two foreign keys should be parameters
+        $join_model = $this->get_join_model();
+        $standard_fields = array();
+        if ($join_model->has_primary_key_field()) {
+            $standard_fields[] = $join_model->primary_key_name();
+        }
+        if ($this->get_this_model()->has_primary_key_field()) {
+            $standard_fields[] = $this->get_this_model()->primary_key_name();
+        }
+        if ($this->get_other_model()->has_primary_key_field()) {
+            $standard_fields[] = $this->get_other_model()->primary_key_name();
+        }
+        return array_diff_key(
+            $join_model->field_settings(),
+            array_flip($standard_fields)
+        );
+    }
+
+    /**
+     * Returns true if the join model has non-key fields (ie, fields that aren't the primary key or foreign keys.)
+     * @since $VID:$
+     * @return boolean
+     */
+    public function hasNonKeyFields()
+    {
+        return count($this->get_join_model()->field_settings()) > 3;
+    }
 }

core/libraries/rest_api/controllers/model/Base.php

@@ -1,9 +1,11 @@
 <?php
 namespace EventEspresso\core\libraries\rest_api\controllers\model;
 
+use EEM_Base;
 use EventEspresso\core\libraries\rest_api\controllers\Base as Controller_Base;
 use EventEspresso\core\libraries\rest_api\ModelVersionInfo;
 use EE_Error;
+use EventEspresso\core\libraries\rest_api\RestException;
 
 /**
  * Base
@@ -80,5 +82,31 @@ public function isSubclassOfOne($object, $classnames)
         }
         return false;
     }
+
+    /**
+     * Verifies the model name provided was valid. If so, returns the model (as an object). Otherwise, throws an
+     * exception. Must be called after `setRequestedVersion()`.
+     * @since $VID:$
+     * @param $model_name
+     * @return EEM_Base
+     * @throws EE_Error
+     * @throws RestException
+     */
+    protected function validateModel($model_name)
+    {
+        if (! $this->getModelVersionInfo()->isModelNameInThisVersion($model_name)) {
+            throw new RestException(
+                'endpoint_parsing_error',
+                sprintf(
+                    __(
+                        'There is no model for endpoint %s. Please contact event espresso support',
+                        'event_espresso'
+                    ),
+                    $model_name
+                )
+            );
+        }
+        return $this->getModelVersionInfo()->loadModel($model_name);
+    }
 }
 // End of file Base.php

core/libraries/rest_api/controllers/model/Read.php

@@ -301,35 +301,8 @@ public static function handleRequestGetRelated(
         $controller = LoaderFactory::getLoader()->getNew('EventEspresso\core\libraries\rest_api\controllers\model\Read');
         try {
             $controller->setRequestedVersion($version);
-            if (! $controller->getModelVersionInfo()->isModelNameInThisVersion($model_name)) {
-                return $controller->sendResponse(
-                    new WP_Error(
-                        'endpoint_parsing_error',
-                        sprintf(
-                            __(
-                                'There is no model for endpoint %s. Please contact event espresso support',
-                                'event_espresso'
-                            ),
-                            $model_name
-                        )
-                    )
-                );
-            }
-            $main_model = $controller->getModelVersionInfo()->loadModel($model_name);
-            if (! $controller->getModelVersionInfo()->isModelNameInThisVersion($related_model_name)) {
-                return $controller->sendResponse(
-                    new WP_Error(
-                        'endpoint_parsing_error',
-                        sprintf(
-                            __(
-                                'There is no model for endpoint %s. Please contact event espresso support',
-                                'event_espresso'
-                            ),
-                            $related_model_name
-                        )
-                    )
-                );
-            }
+            $main_model = $controller->validateModel($model_name);
+            $controller->validateModel($related_model_name);
             return $controller->sendResponse(
                 $controller->getEntitiesFromRelation(
                     $request->get_param('id'),