feat: handle archives without images

closes #56

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

@@ -1,6 +1,7 @@
 package org.gotson.komga.domain.model
 
 class MediaNotReadyException : Exception()
+class EmptyBookException(val mediaType: String) : Exception()
 class UnsupportedMediaTypeException(message: String, val mediaType: String) : Exception(message)
 class DirectoryNotFoundException(message: String) : Exception(message)
 class DuplicateNameException(message: String) : Exception(message)

komga/src/main/kotlin/org/gotson/komga/domain/service/BookAnalyzer.kt

@@ -4,6 +4,7 @@ import mu.KotlinLogging
 import net.coobird.thumbnailator.Thumbnails
 import net.greypanther.natsort.CaseInsensitiveSimpleNaturalComparator
 import org.gotson.komga.domain.model.Book
+import org.gotson.komga.domain.model.EmptyBookException
 import org.gotson.komga.domain.model.Media
 import org.gotson.komga.domain.model.MediaNotReadyException
 import org.gotson.komga.domain.model.UnsupportedMediaTypeException
@@ -19,16 +20,16 @@ private val logger = KotlinLogging.logger {}
 
 @Service
 class BookAnalyzer(
-    private val contentDetector: ContentDetector,
-    private val zipExtractor: ZipExtractor,
-    private val rarExtractor: RarExtractor,
-    private val pdfExtractor: PdfExtractor
+  private val contentDetector: ContentDetector,
+  private val zipExtractor: ZipExtractor,
+  private val rarExtractor: RarExtractor,
+  private val pdfExtractor: PdfExtractor
 ) {
 
   val supportedMediaTypes = mapOf(
-      "application/zip" to zipExtractor,
-      "application/x-rar-compressed" to rarExtractor,
-      "application/pdf" to pdfExtractor
+    "application/zip" to zipExtractor,
+    "application/x-rar-compressed" to rarExtractor,
+    "application/pdf" to pdfExtractor
   )
 
   private val natSortComparator: Comparator<String> = CaseInsensitiveSimpleNaturalComparator.getInstance()
@@ -36,7 +37,10 @@ class BookAnalyzer(
   private val thumbnailSize = 300
   private val thumbnailFormat = "jpeg"
 
-  @Throws(UnsupportedMediaTypeException::class)
+  @Throws(
+    UnsupportedMediaTypeException::class,
+    EmptyBookException::class
+  )
   fun analyze(book: Book): Media {
     logger.info { "Trying to analyze book: $book" }
 
@@ -46,7 +50,8 @@ class BookAnalyzer(
       throw UnsupportedMediaTypeException("Unsupported mime type: $mediaType. File: $book", mediaType)
 
     val pages = supportedMediaTypes.getValue(mediaType).getPagesList(book.path())
-        .sortedWith(compareBy(natSortComparator) { it.fileName })
+      .sortedWith(compareBy(natSortComparator) { it.fileName })
+    if (pages.isEmpty()) throw EmptyBookException(mediaType)
     logger.info { "Book has ${pages.size} pages" }
 
     logger.info { "Trying to generate cover for book: $book" }
@@ -67,32 +72,32 @@ class BookAnalyzer(
     val thumbnail = generateThumbnail(book, book.media.mediaType!!, book.media.pages.first().fileName)
 
     return Media(
-        mediaType = book.media.mediaType,
-        status = Media.Status.READY,
-        pages = book.media.pages,
-        thumbnail = thumbnail
+      mediaType = book.media.mediaType,
+      status = Media.Status.READY,
+      pages = book.media.pages,
+      thumbnail = thumbnail
     )
   }
 
   private fun generateThumbnail(book: Book, mediaType: String, entry: String): ByteArray? =
-      try {
-        ByteArrayOutputStream().use {
-          supportedMediaTypes.getValue(mediaType).getPageStream(book.path(), entry).let { cover ->
-            Thumbnails.of(cover.inputStream())
-                .size(thumbnailSize, thumbnailSize)
-                .outputFormat(thumbnailFormat)
-                .toOutputStream(it)
-            it.toByteArray()
-          }
+    try {
+      ByteArrayOutputStream().use {
+        supportedMediaTypes.getValue(mediaType).getPageStream(book.path(), entry).let { cover ->
+          Thumbnails.of(cover.inputStream())
+            .size(thumbnailSize, thumbnailSize)
+            .outputFormat(thumbnailFormat)
+            .toOutputStream(it)
+          it.toByteArray()
         }
-      } catch (ex: Exception) {
-        logger.warn(ex) { "Could not generate thumbnail for book: $book" }
-        null
       }
+    } catch (ex: Exception) {
+      logger.warn(ex) { "Could not generate thumbnail for book: $book" }
+      null
+    }
 
   @Throws(
-      MediaNotReadyException::class,
-      IndexOutOfBoundsException::class
+    MediaNotReadyException::class,
+    IndexOutOfBoundsException::class
   )
   fun getPageContent(book: Book, number: Int): ByteArray {
     logger.info { "Get page #$number for book: $book" }

komga/src/main/kotlin/org/gotson/komga/domain/service/BookLifecycle.kt

@@ -4,6 +4,7 @@ import mu.KotlinLogging
 import org.apache.commons.lang3.time.DurationFormatUtils
 import org.gotson.komga.domain.model.Book
 import org.gotson.komga.domain.model.BookPageContent
+import org.gotson.komga.domain.model.EmptyBookException
 import org.gotson.komga.domain.model.Media
 import org.gotson.komga.domain.model.MediaNotReadyException
 import org.gotson.komga.domain.model.UnsupportedMediaTypeException
@@ -34,8 +35,11 @@ class BookLifecycle(
       try {
         book.media = bookAnalyzer.analyze(book)
       } catch (ex: UnsupportedMediaTypeException) {
-        logger.info(ex) { "Unsupported media type: ${ex.mediaType}. Book: $book" }
+        logger.warn { "Unsupported media type: ${ex.mediaType}. Book: $book" }
         book.media = Media(status = Media.Status.UNSUPPORTED, mediaType = ex.mediaType)
+      } catch (ex: EmptyBookException) {
+        logger.warn { "Book does not contain any images: $book" }
+        book.media = Media(status = Media.Status.ERROR, mediaType = ex.mediaType)
       } catch (ex: Exception) {
         logger.error(ex) { "Error while parsing. Book: $book" }
         book.media = Media(status = Media.Status.ERROR)