make BookMetadata.pages lazy

add caching for Bookmetadata, Bookmetadata.pages, Series.books
enhance books retrieval to reduce database load
rollback SeriesDto.booksCount to use books.size and leverage hibernate l2 cache and collection cache
fix Series thumbnail by getting the book by number instead of the first in the collection

komga/src/main/kotlin/org/gotson/komga/domain/model/BookMetadata.kt

@@ -1,7 +1,10 @@
 package org.gotson.komga.domain.model
 
 import net.greypanther.natsort.CaseInsensitiveSimpleNaturalComparator
+import org.hibernate.annotations.Cache
+import org.hibernate.annotations.CacheConcurrencyStrategy
 import java.util.*
+import javax.persistence.Cacheable
 import javax.persistence.CollectionTable
 import javax.persistence.Column
 import javax.persistence.ElementCollection
@@ -21,6 +24,8 @@ private val natSortComparator: Comparator<String> = CaseInsensitiveSimpleNatural
 
 @Entity
 @Table(name = "book_metadata")
+@Cacheable
+@Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region = "cache.bookmetadata")
 class BookMetadata(
     @Enumerated(EnumType.STRING)
     @Column(name = "status", nullable = false)
@@ -43,9 +48,10 @@ class BookMetadata(
   @OneToOne(optional = false, fetch = FetchType.LAZY, mappedBy = "metadata")
   lateinit var book: Book
 
-  @ElementCollection(fetch = FetchType.EAGER)
+  @ElementCollection(fetch = FetchType.LAZY)
   @CollectionTable(name = "book_metadata_page", joinColumns = [JoinColumn(name = "book_metadata_id")])
   @OrderColumn(name = "number")
+  @Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region = "cache.bookmetadata.collection.pages")
   private var _pages: MutableList<BookPage> = mutableListOf()
 
   var pages: List<BookPage>

komga/src/main/kotlin/org/gotson/komga/domain/model/Series.kt

@@ -51,6 +51,7 @@ class Series(
   lateinit var library: Library
 
   @OneToMany(cascade = [CascadeType.ALL], fetch = FetchType.LAZY, orphanRemoval = true, mappedBy = "series")
+  @Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region = "cache.series.collection.books")
   private var _books: MutableList<Book> = mutableListOf()
 
   var books: List<Book>

komga/src/main/kotlin/org/gotson/komga/domain/persistence/BookRepository.kt

@@ -3,7 +3,6 @@ package org.gotson.komga.domain.persistence
 import org.gotson.komga.domain.model.Book
 import org.gotson.komga.domain.model.BookMetadata
 import org.gotson.komga.domain.model.Library
-import org.gotson.komga.domain.model.Series
 import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
 import org.springframework.data.jpa.repository.JpaRepository
@@ -20,6 +19,4 @@ interface BookRepository : JpaRepository<Book, Long>, JpaSpecificationExecutor<B
   fun findAllByMetadataStatus(status: BookMetadata.Status): List<Book>
   fun findAllByMetadataThumbnailIsNull(): List<Book>
   fun findBySeriesLibraryIn(seriesLibrary: Collection<Library>, pageable: Pageable): Page<Book>
-
-  fun countBySeries(series: Series): Int
 }

komga/src/main/kotlin/org/gotson/komga/domain/persistence/SeriesRepository.kt

@@ -19,4 +19,5 @@ interface SeriesRepository : JpaRepository<Series, Long>, JpaSpecificationExecut
   fun findByLibraryIdAndUrlNotIn(libraryId: Long, urls: Collection<URL>): List<Series>
   fun findByLibraryIdAndUrl(libraryId: Long, url: URL): Series?
   fun deleteByLibraryId(libraryId: Long)
+  fun findByLibraryIdIn(libraryIDs: Collection<Long>): List<Series>
 }

komga/src/main/kotlin/org/gotson/komga/interfaces/web/rest/BookController.kt

@@ -62,19 +62,25 @@ class BookController(
     )
 
     return mutableListOf<Specification<Book>>().let { specs ->
-      if (!principal.user.sharedAllLibraries) {
-        specs.add(Book::series.`in`(seriesRepository.findByLibraryIn(principal.user.sharedLibraries)))
+      when {
+        !principal.user.sharedAllLibraries && !libraryIds.isNullOrEmpty() -> {
+          val authorizedLibraryIDs = libraryIds.intersect(principal.user.sharedLibraries.map { it.id })
+          if (authorizedLibraryIDs.isEmpty()) return@let Page.empty<Book>(pageRequest)
+          else specs.add(Book::series.`in`(seriesRepository.findByLibraryIdIn(authorizedLibraryIDs)))
+        }
+
+        !principal.user.sharedAllLibraries -> specs.add(Book::series.`in`(seriesRepository.findByLibraryIn(principal.user.sharedLibraries)))
+
+        !libraryIds.isNullOrEmpty() -> {
+          val libraries = libraryRepository.findAllById(libraryIds)
+          specs.add(Book::series.`in`(seriesRepository.findByLibraryIn(libraries)))
+        }
       }
 
       if (!searchTerm.isNullOrEmpty()) {
         specs.add(Book::name.likeLower("%$searchTerm%"))
       }
 
-      if (!libraryIds.isNullOrEmpty()) {
-        val libraries = libraryRepository.findAllById(libraryIds)
-        specs.add(Book::series.`in`(seriesRepository.findByLibraryIn(libraries)))
-      }
-
       if (specs.isNotEmpty()) {
         bookRepository.findAll(specs.reduce { acc, spec -> acc.and(spec)!! }, pageRequest)
       } else {

komga/src/main/kotlin/org/gotson/komga/interfaces/web/rest/Dto.kt

@@ -17,13 +17,13 @@ data class SeriesDto(
     val booksCount: Int
 )
 
-fun Series.toDto(booksCount: Int) = SeriesDto(
+fun Series.toDto() = SeriesDto(
     id = id,
     libraryId = library.id,
     name = name,
     url = url.toString(),
     lastModified = lastModifiedDate?.toUTC(),
-    booksCount = booksCount
+    booksCount = books.size
 )
 
 data class BookDto(

komga/src/main/kotlin/org/gotson/komga/interfaces/web/rest/SeriesController.kt

@@ -63,8 +63,8 @@ class SeriesController(
         !principal.user.sharedAllLibraries -> specs.add(Series::library.`in`(principal.user.sharedLibraries))
 
         !libraryIds.isNullOrEmpty() -> {
-          val values = libraryRepository.findAllById(libraryIds)
-          specs.add(Series::library.`in`(values))
+          val libraries = libraryRepository.findAllById(libraryIds)
+          specs.add(Series::library.`in`(libraries))
         }
       }
 
@@ -77,7 +77,7 @@ class SeriesController(
       } else {
         seriesRepository.findAll(pageRequest)
       }
-    }.map { it.toDto(bookRepository.countBySeries(it)) }
+    }.map { it.toDto() }
   }
 
   @GetMapping("/latest")
@@ -95,7 +95,7 @@ class SeriesController(
       seriesRepository.findAll(pageRequest)
     } else {
       seriesRepository.findByLibraryIn(principal.user.sharedLibraries, pageRequest)
-    }.map { it.toDto(bookRepository.countBySeries(it)) }
+    }.map { it.toDto() }
   }
 
   @GetMapping("{seriesId}")
@@ -105,7 +105,7 @@ class SeriesController(
   ): SeriesDto =
       seriesRepository.findByIdOrNull(id)?.let {
         if (!principal.user.canAccessSeries(it)) throw ResponseStatusException(HttpStatus.UNAUTHORIZED)
-        it.toDto(bookRepository.countBySeries(it))
+        it.toDto()
       } ?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
 
   @GetMapping(value = ["{seriesId}/thumbnail"], produces = [MediaType.IMAGE_JPEG_VALUE])
@@ -116,7 +116,7 @@ class SeriesController(
       seriesRepository.findByIdOrNull(id)?.let { series ->
         if (!principal.user.canAccessSeries(series)) throw ResponseStatusException(HttpStatus.UNAUTHORIZED)
 
-        val thumbnail = series.books.firstOrNull()?.metadata?.thumbnail
+        val thumbnail = series.books.minBy { it.number }?.metadata?.thumbnail
         if (thumbnail != null) {
           ResponseEntity.ok()
               .cacheControl(CacheControl

komga/src/main/resources/application.conf

@@ -21,6 +21,17 @@ caffeine.jcache {
     }
   }
 
+  cache.series.collection.books {
+    monitoring {
+      statistics = true
+    }
+    policy {
+      maximum {
+        size = 500
+      }
+    }
+  }
+
   cache.book {
       monitoring {
         statistics = true
@@ -31,4 +42,26 @@ caffeine.jcache {
         }
       }
     }
+
+  cache.bookmetadata {
+    monitoring {
+      statistics = true
+    }
+    policy {
+      maximum {
+        size = 500
+      }
+    }
+  }
+
+  cache.bookmetadata.collection.pages {
+    monitoring {
+      statistics = true
+    }
+    policy {
+      maximum {
+        size = 500
+      }
+    }
+  }
 }

komga/src/test/kotlin/org/gotson/komga/domain/service/LibraryScannerTest.kt

@@ -19,7 +19,9 @@ import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.test.context.junit.jupiter.SpringExtension
+import org.springframework.transaction.PlatformTransactionManager
 import org.springframework.transaction.annotation.Transactional
+import org.springframework.transaction.support.TransactionTemplate
 import java.nio.file.Paths
 
 @ExtendWith(SpringExtension::class)
@@ -30,7 +32,8 @@ class LibraryScannerTest(
     @Autowired private val libraryRepository: LibraryRepository,
     @Autowired private val bookRepository: BookRepository,
     @Autowired private val libraryScanner: LibraryScanner,
-    @Autowired private val bookLifecycle: BookLifecycle
+    @Autowired private val bookLifecycle: BookLifecycle,
+    @Autowired private val transactionManager: PlatformTransactionManager
 ) {
 
   @MockkBean
@@ -201,12 +204,14 @@ class LibraryScannerTest(
     verify(exactly = 2) { mockScanner.scanRootFolder(any()) }
     verify(exactly = 1) { mockParser.parse(any()) }
 
-    val book = bookRepository.findAll().first()
-    assertThat(book.metadata.status).isEqualTo(BookMetadata.Status.READY)
-    assertThat(book.metadata.mediaType).isEqualTo("application/zip")
-    assertThat(book.metadata.pages).hasSize(2)
-    assertThat(book.metadata.pages.map { it.fileName }).containsExactly("1.jpg", "2.jpg")
-    assertThat(book.lastModifiedDate).isNotEqualTo(book.createdDate)
+    TransactionTemplate(transactionManager).execute {
+      val book = bookRepository.findAll().first()
+      assertThat(book.metadata.status).isEqualTo(BookMetadata.Status.READY)
+      assertThat(book.metadata.mediaType).isEqualTo("application/zip")
+      assertThat(book.metadata.pages).hasSize(2)
+      assertThat(book.metadata.pages.map { it.fileName }).containsExactly("1.jpg", "2.jpg")
+      assertThat(book.lastModifiedDate).isNotEqualTo(book.createdDate)
+    }
   }
 
   @Test