Custom boosting rule for scopes to boost by time passed since last update

Question

I am trying to implement a custom boosting rule (as described here) for the site search scope, where an item should be boosted by the time passed since last updated. For the record - we already implemented an index-time boosting rule for this which works, but a query-time boosting approach is more accurate since we don't plan a regular index rebuild.

So I use the resolveBoostingQuery (see here) pipeline to insert the custom rule:

where the update field is less than maximum days of [value,Integer,,number]

In code I use try to calculate the time passed with the update date field but I get the error:

Exception: System.NotSupportedException
Message: Invalid Method Call Argument Type: Field - FieldNode - Field: __smallupdateddate_tdt - System.DateTime. Only constant arguments is supported.

This is my code for now:

public override void ResolveBoostingQuery(ResolveBoostingQueryEventArgs args)
{
    var condition = args.RuleCondition as WhereRecentUpdate<RuleBoostingContext>;
    
    var expression = PredicateBuilder.True<ContentPage>();      
    var updatedExpression = PredicateBuilder.True<ContentPage>();
    updatedExpression = updatedExpression.And(page => DateTime.UtcNow.Subtract(page.Updated).TotalDays < condition.Value);
    
    args.Predicate = expression.And(updatedExpression).Boost(CalculateTimePassedBoost(args.Boost, condition.Value));
}

private float CalculateTimePassedBoost(float boost, int daysPassed) { ... }

It's not easy to find complex examples of how to use Sitecore Content Search predicates and I didn't find a good way to debug yet. Do you have an example to follow or an idea how to implement this feature?

Thanks

Answer 1

You are facing above issue due to Datetime comparison. Inside Solr, you can use between operator to perform datetime comparison with the below code:

var updatedExpression = PredicateBuilder.True<SearchResultItem>();
updatedExpression = updatedExpression.And(page => page.Updated.Between(DateTime.UtcNow.AddDays(-5), DateTime.UtcNow, Inclusion.Both));                   

This will solve the above issue you are encountering. You can find more details on the supported operator's in Solr here:

https://doc.sitecore.com/xp/en/developers/82/sitecore-experience-platform/linq-to-sitecore.html

Hope this helps!!!