added endpoint to regenerate thumbnails

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

@@ -39,4 +39,18 @@ class BookManager(
     }.also { logger.info { "Parsing finished in ${DurationFormatUtils.formatDurationHMS(it)}" } })
   }
 
+  @Transactional
+  @Async("parseBookTaskExecutor")
+  fun regenerateThumbnailAndPersist(book: Book): Future<Long> {
+    logger.info { "Regenerate thumbnail and persist book: ${book.url}" }
+    return AsyncResult(measureTimeMillis {
+      try {
+        book.metadata = bookParser.regenerateThumbnail(book)
+      } catch (ex: Exception) {
+        logger.error(ex) { "Error while recreating thumbnail" }
+        book.metadata = BookMetadata(status = Status.ERROR)
+      }
+      bookRepository.save(book)
+    }.also { logger.info { "Thumbnail generated in ${DurationFormatUtils.formatDurationHMS(it)}" } })
+  }
 }

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

@@ -46,24 +46,45 @@ class BookParser(
     logger.info { "Book has ${pages.size} pages" }
 
     logger.info { "Trying to generate cover for book: ${book.url}" }
-    val thumbnail = try {
-      ByteArrayOutputStream().use {
-        supportedMediaTypes.getValue(mediaType).getPageStream(book.path(), pages.first().fileName).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.url}" }
-      null
-    }
+    val thumbnail = generateThumbnail(book, mediaType, pages.first().fileName)
 
     return BookMetadata(mediaType = mediaType, status = Status.READY, pages = pages, thumbnail = thumbnail)
   }
 
+  fun regenerateThumbnail(book: Book): BookMetadata {
+    logger.info { "Regenerate thumbnail for book: ${book.url}" }
+
+    if (book.metadata.status != Status.READY) {
+      logger.warn { "Book metadata is not ready, cannot generate thumbnail" }
+      throw MetadataNotReadyException()
+    }
+
+    val thumbnail = generateThumbnail(book, book.metadata.mediaType!!, book.metadata.pages.first().fileName)
+
+    return BookMetadata(
+        mediaType = book.metadata.mediaType,
+        status = Status.READY,
+        pages = book.metadata.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()
+          }
+        }
+      } catch (ex: Exception) {
+        logger.warn(ex) { "Could not generate thumbnail for book: ${book.url}" }
+        null
+      }
+
   fun getPageContent(book: Book, number: Int): ByteArray {
     logger.info { "Get page #$number for book: ${book.url}" }
 

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

@@ -94,4 +94,26 @@ class LibraryManager(
       logger.info { "Parsed ${booksToParse.size} books in ${DurationFormatUtils.formatDurationHMS(it)} (virtual: ${DurationFormatUtils.formatDurationHMS(sumOfTasksTime)})" }
     }
   }
+
+  @Synchronized
+  fun regenerateAllThumbnails() {
+    logger.info { "Regenerate thumbnail for all books" }
+    val booksToProcess = bookRepository.findAll()
+
+    var sumOfTasksTime = 0L
+    measureTimeMillis {
+      sumOfTasksTime = booksToProcess
+          .map { bookManager.regenerateThumbnailAndPersist(it) }
+          .map {
+            try {
+              it.get()
+            } catch (ex: Exception) {
+              0L
+            }
+          }
+          .sum()
+    }.also {
+      logger.info { "Generated ${booksToProcess.size} thumbnails in ${DurationFormatUtils.formatDurationHMS(it)} (virtual: ${DurationFormatUtils.formatDurationHMS(sumOfTasksTime)})" }
+    }
+  }
 }

komga/src/main/kotlin/org/gotson/komga/interfaces/web/AdminController.kt

@@ -0,0 +1,23 @@
+package org.gotson.komga.interfaces.web
+
+import org.gotson.komga.domain.service.LibraryManager
+import org.springframework.http.HttpStatus
+import org.springframework.security.access.prepost.PreAuthorize
+import org.springframework.web.bind.annotation.PostMapping
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.ResponseStatus
+import org.springframework.web.bind.annotation.RestController
+
+@RestController
+@RequestMapping("api/v1/admin")
+@PreAuthorize("hasRole('ROLE_ADMIN')")
+class AdminController(
+    private val libraryManager: LibraryManager
+) {
+
+  @PostMapping("rpc/thumbnails/regenerateall")
+  @ResponseStatus(HttpStatus.ACCEPTED)
+  fun regenerateAllThumbnails() {
+    libraryManager.regenerateAllThumbnails()
+  }
+}