Generic search and dynamic query lists can be extended with custom filter queries, that are applied to the fq parameter of the Solr query.

Custom filter queries must be predefined in as an implementation of CustomFilterQuery and provided as a Spring bean, before they can be used. As CustomFilterQuery is an extension point also, custom filter queries may be provided as part of a plugin or directly, e.g. by CaasConfig.

Definition of custom filter queries

The definition of a custom filter query consists of a query identifier and a function, that maps the field values to a Solr query.

For example, a filter query definition could be defined with a query identifier EXCLUDE_IDS and a (here simplified) mapping function:

// Extension of input type FilterQueryArg in a graphql schema:
extend input FilterQueryArg {
  EXCLUDE_IDS: [String!]
}

// Bean factory in a configuration class
@Bean
public CustomFilterQuery excludeIdsQuery() {
  return new CustomFilterQuery() {

    /**
     * The query identifier.
     */
    @Override
    public String getName() {
      return "EXCLUDE_IDS";
    }

    /**
     * The mapping function.
     */
    @Override
    public String apply(List<String> values) {
      return SearchQueryHelper
        .negatedQuery(
          SearchQueryHelper
            .orQuery(SearchConstants.FIELDS.ID.toString(), values)
        );
    }
  };
}

In order to demonstrate the usage and possibilities, Headless Server comes with some out-of-the-box custom filter queries, namely:

There are some help utilities in SearchQueryHelper to generate the Solr query in Solr syntax. Alternatively, the Solr query can also be given in direct Solr syntax.

Apply custom filter queries

A custom filter query can be applied statically for all queries or dynamically for each graphql query.

Static custom filter queries

Static filter queries, that shall be applied to all Solr queries, can be passed to the corresponding *AdapterFactories, e.g. SearchServiceAdapterFactory or QueryListAdapterFactory. They are then added to all Solr queries automatically.

Dynamic custom filter queries

Dynamic filter queries, that are applied to a specific GraphQL query, can be added as query argument for generic search, faceted search, suggestions or dynamic query lists. The input format is defined via the built-in type FilterQueryArg

All custom filter queries are applied as fq (filter query) fragments to the Solr query.

This GraphQL query is an example for fetching a search result using the predefined custom filter queries EXCLUDE_IDS and TITLE_OR.

{
  {
    content {
      search(query: "*", docTypes: ["CMArticle"], customFilterQueries: [{EXCLUDE_IDS: ["1234", "5678"]}, {TITLE_OR: ["Make your dream come true", "Eveningwear Trends"]}]) {
        numFound
        result {
          id
          ... on CMArticle {
            title
          }
        }
      }
    }
  }
}
  

This GraphQL query is an example for fetching query list items using the predefined custom filter queries EXCLUDE_IDS.

{
  {
  content {
    queryList(id: "10") {
      ... on CMQueryList {
        id
        filteredItems(customFilterQueries: {EXCLUDE_IDS: ["1234", "5678"]}) {
            ... on CMLinkable {
              id
            }
          }
        }
      }
    }
  }
}