Support Other Data Types

Problem/Motivation

Search API allows modules to provide backend-specific support for data types. SearchApiElasticsearchBackend does exactly this, defining a plugin to support the ObjectDataType. This module also provides a way to alter mappings.

In a recent project, I needed to add support for the Completion data type. I implemented the data type plugin and a processor plugin, and altered the mapping using hook_search_api_field_type_mapping_alter(). I also implemented an event subscriber to add my field mapping when the index is created.

This worked really well, except that Elasticsearch Connector marked the data type as unsupported. This is because SearchApiElasticsearchBackend has a method called supportsDataType() which checks to see if the provided type is in a hard-coded list of supported types. The only way around this I think is to patch SearchApiElasticsearchBackend.php to add in the other supported data types as needed.

Options

1. In SearchApiElasticsearchBackend::supportsDataType(), add an alter hook to allow sub-modules the chance to mark the data types that they provide as supported
2. Add direct support in elasticsearch_connector for the "completion" data type.
3. Don't hard the list of data types in the supportsDataType() method. Instead, add a method to the backend class that returns an array of supported data types, which calls the alter hook for sub-modules to extend that list. Then call this method in the supportsDataType() method.

Thoughts on direction?