Boosting a computed index field in _content

Question

I have created a computed index field for our custom Lucene search index, and I have noticed that the contents do not get automatically added to the "_content" field in Lucene.

I would like to be able to search "_content" and find results that match any field including my computed index field.

I've read that I can add my computed field as part of "_content" just by naming it _content in the config:

<fields hint="raw:AddComputedIndexField">
    <field fieldName="_content">Project.Domain.Search.ComputedFields.PageTaxonomies, Project.Domain</field>
</fields>

I would like to boost any search results where the search terms are found in PageTaxonomies. But where can I apply the boost for this field if the field has the same name as _content?

Any help appreciated!

Answer 1

I would use a different field for your computed field, so it's easier to boost. if this is not possible, you'll have to use some tricks, as you can't distinguish the values coming from a different field.

The trick: Add a token to your value so you can identify and boost it

Assuming that for some reason you need the original value of your taxonomy, add a duplicated value to your value with a special token, then boost the search for that term: Let's say that your computer field now returns "taxonomy1"; modify your code to return "taxonomy1|mytokentaxonomy1" On your search, add an "or" with the "extra" value.

var queryPredicate = PredicateBuilder.True<SearchResult>();
queryPredicate = queryPredicate.And(i =>
                            i.YourField.Equals("taxonomy1") || i.YourField.Equals("mytokentaxonomy1").Boost(50));

This way, you are sure that the value you are generating with your computed field is boosted. If you don't need the original value, you can just use the special value.