DataObjects can declare their own indexing behaviour

[unclecheese]

As a Silverstripe CMS developer, I want to leverage the power of the ORM to create a highly inclusive set of index fields on my dataobjects so that searches return more accurate results.

Acceptance Criteria

• Can whitelist both native and relationship fields for indexing
• Can list getters (computed fields) for indexing
• Include all fields on subclasses Note: Decided not to do this to avoid inferring field names
• Individual records can opt out of indexing (e.g. ShowInSearch)

[chillu]

Include all fields on subclasses

I think we should allow for selecting fields on subclasses, but not a * rule where it includes everything - because of #18.

Page:
  fields:
    Content
    MyCustomFieldOnSubclass

[dhensby]

It would be nice if you could index any object regardless of if it is from the ORM, for example by making them comply with an interface or trait.

The default behaviour could be supplied as a trait that is easily added to DataObjects.

Should be fairly simple by implementing a SearchServiceIndexable interface and a DataObjectIndexable trait (naming could be anything)

[unclecheese]

Yes, this is the intention: https://github.com/silverstripe/silverstripe-search-service/blob/master/src/Interfaces/DocumentInterface.php

And the DataObject implementation: https://github.com/silverstripe/silverstripe-search-service/blob/master/src/DataObject/DataObjectDocument.php

[unclecheese]

Removing "index all fields on subclasses" as Ingo and I have discussed the potential security hazards of implicit exposure of fields.

[chillu]

Can whitelist both native and relationship fields for indexing

This doesn't work with subclasses at the moment:

SilverStripe\SearchService\Service\IndexConfiguration:
  indexes:
    my_index:
      includeClasses:
        Page:
          fields:
            title:
              property: Title
            relation_only_on_subclass:
              property: MyRelation.Title

DataObject->relObject() throws when it can't find the relationship. I'm not keen to create subclass-specific index definitions, since we should use this layer to communicate the "flattening" which happens in App Search (doesn't know about subclasses). We could catch the LogicException but that's messy. As a workaround, we could check if the first segment of the dot notation name exists on the object?

diff --git a/src/DataObject/DataObjectDocument.php b/src/DataObject/DataObjectDocument.php
index 38090d8..e3dd790 100644
--- a/src/DataObject/DataObjectDocument.php
+++ b/src/DataObject/DataObjectDocument.php
@@ -343,8 +343,15 @@ class DataObjectDocument implements
      */
     public function toDBField(Field $field)
     {
+        $obj = $this->getDataObject();
         if ($field->getProperty()) {
-            return $this->getDataObject()->relObject($field->getProperty());
+            $firstField = explode('.', $field->getProperty())[0];
+            if ($obj->hasField($firstField) || $obj->hasMethod($firstField) || $obj->getRelationClass($firstField)) {
+                return $obj->relObject($field->getProperty());
+            } else {
+                // Guard against missing fields which only exist in some subclasses
+                return null;
+            }
         }
 
         return $this->resolveField($field->getSearchFieldName());