Improved scoring, added more documentation to LucenePackageSearcher, added explanations to results.

This commit is contained in:
Andrew Lalis 2023-10-10 13:51:54 -04:00
parent 79084dbb9e
commit db4774938a
3 changed files with 62 additions and 18 deletions

View File

@ -2,5 +2,6 @@ package com.andrewlalis.d_package_search;
public record PackageSearchResult(
String name,
String url
String url,
String explanation
) {}

View File

@ -20,6 +20,22 @@ import java.util.concurrent.Executors;
* search a Lucene index.
*/
public class LucenePackageSearcher implements PackageSearcher {
/**
* Factor by which we prefer results containing the entire search phrase
* instead of just a part of it.
*/
private static final float PHRASE_WEIGHT_MODIFIER = 2f;
/**
* A mapping of indexed fields, and the weight they contribute to a result's
* score, if the result contains a match for the field.
*/
private static final Map<String, Float> WEIGHTED_FIELDS = Map.of(
"name", 1f,
"description", 0.5f,
"readme", 0.25f
);
private final Path indexPath;
public LucenePackageSearcher(Path indexPath) {
@ -37,7 +53,11 @@ public class LucenePackageSearcher implements PackageSearcher {
List<PackageSearchResult> results = new ArrayList<>(25);
for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
Document doc = searcher.storedFields().document(scoreDoc.doc);
results.add(prepareResult(doc));
results.add(prepareResult(
doc,
"Search result scoring explanation:\n" +
searcher.explain(luceneQuery, scoreDoc.doc).toString()
));
}
return results;
} catch (IOException e) {
@ -55,35 +75,48 @@ public class LucenePackageSearcher implements PackageSearcher {
BooleanQuery.Builder queryBuilder = new BooleanQuery.Builder();
String[] searchTerms = queryText.toLowerCase().split("\\s+");
// We define a set of weighted fields that we will add prefix queries for.
Map<String, Float> weightedFields = Map.of(
"name", 1f,
"description", 0.5f,
"readme", 0.25f
);
// Only consider the first 5 search terms, and add a prefix query for each term for them.
for (int i = 0; i < Math.min(5, searchTerms.length); i++) {
for (var entry : weightedFields.entrySet()) {
for (var entry : WEIGHTED_FIELDS.entrySet()) {
String fieldName = entry.getKey();
float fieldWeight = entry.getValue();
Query termQuery = new BoostQuery(new PrefixQuery(new Term(fieldName, searchTerms[i])), fieldWeight);
queryBuilder.add(termQuery, BooleanClause.Occur.SHOULD);
}
}
/*
If there's more than one word in the search query, put an extra emphasis
on finding a match with the entire query together. We use the PhraseQuery
builder to build an ordered phrase query for each of the weighted fields.
*/
if (searchTerms.length > 1) {
for (var entry : WEIGHTED_FIELDS.entrySet()) {
String fieldName = entry.getKey();
float fieldWeight = entry.getValue();
PhraseQuery.Builder phraseQueryBuilder = new PhraseQuery.Builder();
for (int i = 0; i < searchTerms.length; i++) {
phraseQueryBuilder.add(new Term(fieldName, searchTerms[i]), i);
}
queryBuilder.add(new BoostQuery(phraseQueryBuilder.build(), fieldWeight * PHRASE_WEIGHT_MODIFIER), BooleanClause.Occur.SHOULD);
}
}
Query baseQuery = queryBuilder.build();
System.out.println("Query: " + baseQuery.toString());
Query boostedQuery = new BooleanQuery.Builder()
.add(baseQuery, BooleanClause.Occur.MUST)
.add(FeatureField.newSaturationQuery("features", "recency"), BooleanClause.Occur.SHOULD)
.add(FeatureField.newSaturationQuery("features", "downloads"), BooleanClause.Occur.SHOULD)
.add(FeatureField.newSaturationQuery("features", "recency", 0.25f, 1f/30f), BooleanClause.Occur.SHOULD)
.add(FeatureField.newSaturationQuery("features", "downloads", 0.5f, 500f), BooleanClause.Occur.SHOULD)
.build();
return boostedQuery;
}
private PackageSearchResult prepareResult(Document doc) {
private PackageSearchResult prepareResult(Document doc, String explanation) {
return new PackageSearchResult(
doc.get("name"),
doc.get("url")
doc.get("url"),
explanation
);
}
}

View File

@ -9,7 +9,7 @@
<h1>D Package Search</h1>
<p>
Use this site to search for D packages!
Use this site to search for D packages. It's currently a proof-of-concept for using Lucene to index and search for D packages, since it offers a lot of out-of-the-box features for things like full-text indexing, scoring based on numerical features, and explaining exactly how results were found.
</p>
<input id="search-input" type="text" placeholder="Search for a package..."/>
@ -27,26 +27,36 @@
container.innerHTML = "";
for (let i = 0; i < results.length; i++) {
const element = document.createElement("div");
element.style = "border: 1px solid black; margin: 5px; padding: 5px;";
const header = document.createElement("h3");
header.innerText = results[i].name;
element.appendChild(header);
const link = document.createElement("a");
link.href = results[i].url;
link.innerText = "Link to package";
link.innerText = results[i].url;
element.appendChild(link);
const explanation = document.createElement("pre");
explanation.innerText = results[i].explanation;
element.appendChild(explanation);
container.appendChild(element);
}
}
const searchInput = document.getElementById("search-input");
let searchTimeoutId = null;
searchInput.addEventListener("keyup", async () => {
const query = searchInput.value;
if (searchTimeoutId) {
window.clearTimeout(searchTimeoutId);
}
if (query.length < 1) {
showResults([]);
return;
}
const results = await fetchResults(query);
showResults(results);
searchTimeoutId = window.setTimeout(async () => {
const results = await fetchResults(query);
showResults(results);
}, 1000);
})
</script>
</body>