Class: ElasticGraph::GraphQL::QueryAdapter::RequestedFields

Inherits:
Object
  • Object
show all
Defined in:
lib/elastic_graph/graphql/query_adapter/requested_fields.rb

Overview

Query adapter that populates the ‘requested_fields` attribute of an `DatastoreQuery` in order to limit what fields we fetch from the datastore to only those that we actually need to satisfy the GraphQL query. This results in more efficient datastore queries, similar to doing `SELECT f1, f2, …` instead of `SELECT *` for a SQL query.

Defined Under Namespace

Classes: WithoutSchema

Instance Method Summary collapse

Constructor Details

#initialize(schema) ⇒ RequestedFields

Returns a new instance of RequestedFields.



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# File 'lib/elastic_graph/graphql/query_adapter/requested_fields.rb', line 34

def initialize(schema)
  @schema = schema
end

Instance Method Details

#call(field:, query:, lookahead:, args:, context:) ⇒ Object 



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# File 'lib/elastic_graph/graphql/query_adapter/requested_fields.rb', line 38

def call(field:, query:, lookahead:, args:, context:)
  attributes = query_attributes_for(field: field, lookahead: lookahead)
  query.merge_with(**attributes)
end

#query_attributes_for(field:, lookahead:) ⇒ Object 



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# File 'lib/elastic_graph/graphql/query_adapter/requested_fields.rb', line 43

def query_attributes_for(field:, lookahead:)
  index_field_paths =
    field.type
      .unwrap_fully
      .search_index_definitions
      .flat_map { |index_def| index_def.fields_by_path.keys }
      .to_set

  attributes =
    if field.type.relay_connection?
      highlights = lookahead
        .selection(@schema.element_names.edges)
        .selection(@schema.element_names.highlights)

      {
        individual_docs_needed: pagination_fields_need_individual_docs?(lookahead) || relay_connection_node_from(lookahead).selected?,
        requested_fields: requested_fields_under(relay_connection_node_from(lookahead), index_field_paths),
        request_all_highlights: requesting_all_highlights?(lookahead),
        requested_highlights: requested_fields_under(highlights, index_field_paths)
      }
    else
      {
        requested_fields: requested_fields_under(lookahead, index_field_paths)
      }
    end

  attributes.merge(total_document_count_needed: query_needs_total_document_count?(lookahead))
end