Faceting #

What are facets? #

Facets are related topics, e.g. if you have blog posts that are in categories, faceting allows you to show data about the categories of the blog posts returned in your search results.

For example, say you have 10 posts in “Rants” and 20 posts in “Recipes”. If you perform a search where there are 15 results, 8 of which are in the “Rants” category and 12 of which are in the “Recipes” category, you can show a list like so:

• Rants (8)
• Recipes (12)

This helps your visitors to narrow their search by filtering for a specific category.

AND facets #

Facets are by default applied as a combined AND query. For example, facet filtering by UserID 1,2 plus Parent 5 will result in:

UserID:1 AND UserID:2 AND Parent:5

OR facets #

Using OR facets, each facet is treated as a separate part of the query. In the above example, it would lead to the following query:

UserID:1 AND UserID:2 OR Parent:5

Difference between FacetFields and FacetFilters #

• Facet fields, are the fields that are expected to be returned by Solr and need to be configured.
• Facet filters, are the actual filters, that are applied at query time, to narrow down the results by the selected Facets.

Applying facets #

To configure Facets, have a look at the usage documentation.

Make sure your Facet Fields are set correctly, as per the documentation.

Any variable from your request that is not a valid Facet will be ignored.

AND facets #

To use AND facets, this example should get you started:

    $data = Controller::curr()->getRequest()->getVars();
    $index = Injector::inst()->get(MyIndex::class);
    $query = Injector::inst()->get(BaseQuery::class);
    $facetedFields = $index->getFacetFields();
    foreach ($facetedFields as $className => $field) {
        // Title of your field, as defined in the FacetFields
        if (!empty($data[$field['Title']])) {
            // Add a facet filter with its title and the value from the request data
            $query->addFacetFilter($field['Title'], $data[$field['Title']]);
        }
    }

Note, addFacetFilter and addAndFacetFilter are interchangeable.

OR facets #

To use OR facets, this example should get you started:

    $data = Controller::curr()->getRequest()->getVars();
    $index = Injector::inst()->get(MyIndex::class);
    $query = Injector::inst()->get(BaseQuery::class);
    $facetedFields = $index->getFacetFields();
    foreach ($facetedFields as $className => $field) {
        // Title of your field, as defined in the FacetFields
        if (!empty($data[$field['Title']])) {
            // Add a facet filter with its title and the value from the request data
            $query->addOrFacetFilter($field['Title'], $data[$field['Title']]);
        }
    }

Notice the subtle difference in $query->addOrFacetFilter() versus $query->addFacetFilter()

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