How can I boost the search result in a way that the latest articles are more relevant?

I found this thread https://www.progress.com/documentation/sitefinity-cms/for-developers-customize-the-lucene-search-scoring that could be relevant for the scoring function, but I am not sure how to use it with Webnodes.

I tried to use IndexQuery.CustomQuery (together with BodySearch), but when I did, I did not get any results.

Hi Vidar

Boosting during indexing is not relevant here.

Here are my current status. Some article types already have som boosting and I have reduced their boosting by a huge amount. Search words are split up and fuzzy and boosting is applied to each word.

After that I want to apply the custom query boosting for newest articles. What is the correct way to do this?

Right now all the boosting logic is hidden in a class (MyCustomScoreQuery) derived from Lucene.Net.Search.Function.CustomScoreQuery, as described in the link from the first post. If I use the CustomQuery property I get no results. What happens if I use both BodySearch and CustomQuery.

To make it event more complex, the query is also used in an AdvancedIndexQuery<T>

// escape lucene characters and split into words
var terms = Regex.Replace(search, "([+\\-\\(\\)\\{\\}\\[\\]\"\\^\\~\\*\\?\\:\\\\]|\\&\\&|\\|\\|)", "\\$1")
.Split(' ')
.Where(a => !string.IsNullOrWhiteSpace(a));

search = "" + string.Join(" ", terms.Select(a => a + "~0.7^3.0")) + " " + string.Join(" ", terms.Select(a => a + "*^3.0"));

query.BodySearch = search;

// TODO: boost articles newer than X days ( with this active we get no results )
var q1 = new Lucene.Net.Search.BooleanQuery();
var myCustomSearch = new MyCustomScoreQuery(q1);
query.CustomQuery = myCustomSearch;


var advancedQuery = new AdvancedIndexQuery(query);
advancedQuery.SuggestDifferentSpelling = true;

if (!autoCompleteSearch)
{
	advancedQuery.EnableFacetedSearch      = true;
	advancedQuery.FacetFilterOption        = WAF.Engine.Search.Facets.FacetFilterOptions.ShowAllFacetValuesForActiveFacets;
	advancedQuery.CustomLuceneFieldsToFacetOn = new List() { "Class" };

	if (FacetFilters != null)
		advancedQuery.FacetFilters = FacetFilters;
}
SearchResultSet searchResultSet = WAFContext.Session.SearchAdvanced(advancedQuery);






		[Serializable]
		public class MyCustomScoreQuery : Lucene.Net.Search.Function.CustomScoreQuery
		{
			public MyCustomScoreQuery(Lucene.Net.Search.Query subQuery) : base(subQuery)
			{
			}

			/// 
			/// The custom score provider for 
			/// 
			protected class CustomizedScoreProvider : Lucene.Net.Search.Function.CustomScoreProvider
			{
				/// 
				/// Initializes a new instance of the  class.
				/// 
				///The index reader
				public CustomizedScoreProvider(Lucene.Net.Index.IndexReader reader) : base(reader)
				{
				}

				/// 
				public override float CustomScore(int doc, float subQueryScore, float[] valSrcScores)
				{
					var baseScore = base.CustomScore(doc, subQueryScore, valSrcScores);
					double boost = 1;
					var currentDocument = reader.Document(doc);
					var dateFieldValue = currentDocument.Get("LastModified");
					if (dateFieldValue != null)
					{
						var now = DateTime.UtcNow;
						var date = DateTime.Parse(dateFieldValue);// DateTools.StringToDate(dateFieldValue);
						var age = (int)(now - date).TotalDays;
						boost = CalculateBoost(age);
					}

					var adjustedScore = baseScore * boost;
					return (float)adjustedScore;
				}

				/// 
				/// Calculates the boost, based on the content's age
				/// 
				///Content's age in days
				/// The boost
				protected virtual double CalculateBoost(int days)
				{
					double boostFactor = 100;
					double maxRampFactor = 5;
					double curveAdjustmentFactor = 5;
					return Math.Pow(boostFactor / (maxRampFactor + days), 1 / curveAdjustmentFactor);
				}
			}
		}