**feat(controller/cache): Add caching to VariantBrowserController for improved performance**

- Implemented caching for search results and detail panels with configurable durations.
- Added helper methods `getCachedSearchResults` and `getCachedDetailPanel` to fetch from cache or fallback to database queries.
- Updated variant views to utilize cached data, enhancing response times for public variant browsing.
- Adjusted `main.css` to modify code styling for better readability.

Author: JamesKane

app/controllers/VariantBrowserController.scala

@@ -1,36 +1,46 @@
 package controllers
 
 import jakarta.inject.{Inject, Singleton}
+import models.domain.genomics.VariantGroup
 import org.webjars.play.WebJarsUtil
+import play.api.cache.AsyncCacheApi
 import play.api.i18n.I18nSupport
 import play.api.mvc.*
 import repositories.{HaplogroupVariantRepository, VariantAliasRepository, VariantRepository}
 
+import scala.concurrent.duration.*
 import scala.concurrent.{ExecutionContext, Future}
 
 /**
  * Public controller for browsing variants (read-only).
  * Provides a searchable variant database for researchers.
+ * Results are cached to improve performance for the public view.
  */
 @Singleton
 class VariantBrowserController @Inject()(
                                           val controllerComponents: ControllerComponents,
                                           variantRepository: VariantRepository,
                                           variantAliasRepository: VariantAliasRepository,
-                                          haplogroupVariantRepository: HaplogroupVariantRepository
+                                          haplogroupVariantRepository: HaplogroupVariantRepository,
+                                          cache: AsyncCacheApi
                                         )(using webJarsUtil: WebJarsUtil, ec: ExecutionContext)
   extends BaseController with I18nSupport {
 
   private val DefaultPageSize = 25
 
+  // Cache durations - public view can be stale
+  private val SearchCacheDuration = 15.minutes
+  private val DetailCacheDuration = 1.hour
+  private val TotalCountCacheDuration = 30.minutes
+
   /**
    * Main variant browser page with search functionality.
    */
   def index(query: Option[String], page: Int, pageSize: Int): Action[AnyContent] = Action.async {
     implicit request: Request[AnyContent] =>
       val offset = (page - 1) * pageSize
       for {
-        (variantGroups, totalCount) <- variantRepository.searchGroupedPaginated(query.getOrElse(""), offset, pageSize)
+        (variantGroups, totalCount) <- getCachedSearchResults(query.getOrElse(""), offset, pageSize)
       } yield {
         val totalPages = Math.max(1, (totalCount + pageSize - 1) / pageSize)
         Ok(views.html.variants.browser(variantGroups, query, page, totalPages, pageSize, totalCount))
@@ -44,7 +54,7 @@ class VariantBrowserController @Inject()(
     implicit request: Request[AnyContent] =>
       val offset = (page - 1) * pageSize
       for {
-        (variantGroups, totalCount) <- variantRepository.searchGroupedPaginated(query.getOrElse(""), offset, pageSize)
+        (variantGroups, totalCount) <- getCachedSearchResults(query.getOrElse(""), offset, pageSize)
       } yield {
         val totalPages = Math.max(1, (totalCount + pageSize - 1) / pageSize)
         Ok(views.html.variants.listFragment(variantGroups, query, page, totalPages, pageSize, totalCount))
@@ -55,23 +65,46 @@ class VariantBrowserController @Inject()(
    * HTMX fragment for variant detail panel (read-only).
    */
   def detailPanel(id: Int): Action[AnyContent] = Action.async { implicit request: Request[AnyContent] =>
-    for {
-      variantOpt <- variantRepository.findByIdWithContig(id)
-      allVariantsInGroup <- variantOpt match {
-        case Some(vwc) =>
-          val groupKey = vwc.variant.commonName.orElse(vwc.variant.rsId).getOrElse(s"variant_${id}")
-          variantRepository.getVariantsByGroupKey(groupKey)
-        case None => Future.successful(Seq.empty)
-      }
-      aliases <- variantAliasRepository.findByVariantId(id)
-      haplogroups <- haplogroupVariantRepository.getHaplogroupsByVariant(id)
-    } yield {
-      variantOpt match {
-        case Some(variantWithContig) =>
-          val variantGroup = variantRepository.groupVariants(allVariantsInGroup).headOption
-          Ok(views.html.variants.detailPanel(variantWithContig, variantGroup, aliases, haplogroups))
-        case None =>
-          NotFound("Variant not found")
+    getCachedDetailPanel(id)
+  }
+
+  // === Caching helpers ===
+
+  /**
+   * Get cached search results or fetch from database.
+   * Cache key includes query, offset, and limit for proper pagination caching.
+   */
+  private def getCachedSearchResults(query: String, offset: Int, limit: Int): Future[(Seq[VariantGroup], Int)] = {
+    val cacheKey = s"variant-search:${query.toLowerCase.trim}:$offset:$limit"
+    cache.getOrElseUpdate(cacheKey, SearchCacheDuration) {
+      variantRepository.searchGroupedPaginated(query, offset, limit)
+    }
+  }
+
+  /**
+   * Get cached detail panel or fetch from database.
+   */
+  private def getCachedDetailPanel(id: Int)(implicit request: Request[AnyContent]): Future[Result] = {
+    val cacheKey = s"variant-detail:$id"
+    cache.getOrElseUpdate(cacheKey, DetailCacheDuration) {
+      for {
+        variantOpt <- variantRepository.findByIdWithContig(id)
+        allVariantsInGroup <- variantOpt match {
+          case Some(vwc) =>
+            val groupKey = vwc.variant.commonName.orElse(vwc.variant.rsId).getOrElse(s"variant_${id}")
+            variantRepository.getVariantsByGroupKey(groupKey)
+          case None => Future.successful(Seq.empty)
+        }
+        aliases <- variantAliasRepository.findByVariantId(id)
+        haplogroups <- haplogroupVariantRepository.getHaplogroupsByVariant(id)
+      } yield {
+        variantOpt match {
+          case Some(variantWithContig) =>
+            val variantGroup = variantRepository.groupVariants(allVariantsInGroup).headOption
+            Ok(views.html.variants.detailPanel(variantWithContig, variantGroup, aliases, haplogroups))
+          case None =>
+            NotFound("Variant not found")
+        }
       }
     }
   }

public/stylesheets/main.css

@@ -7,6 +7,12 @@ body {
     padding-bottom: 56px;
 }
 
+/* Override Bootstrap's default pink/cyan code styling to use gray */
+code {
+    color: #495057;
+    background-color: #f8f9fa;
+}
+
 .logo-placeholder {
     max-width: 900px; /* Increased for more horizontal span */
     display: block;