feat(api): add endpoints to get previous/next book of a book

komga-webui/src/services/komga-books.service.ts

@@ -45,6 +45,30 @@ export default class KomgaBooksService {
     }
   }
 
+  async getBookSiblingNext (bookId: number): Promise<BookDto> {
+    try {
+      return (await this.http.get(`${API_BOOKS}/${bookId}/next`)).data
+    } catch (e) {
+      let msg = 'An error occurred while trying to retrieve book'
+      if (e.response.data.message) {
+        msg += `: ${e.response.data.message}`
+      }
+      throw new Error(msg)
+    }
+  }
+
+  async getBookSiblingPrevious (bookId: number): Promise<BookDto> {
+    try {
+      return (await this.http.get(`${API_BOOKS}/${bookId}/previous`)).data
+    } catch (e) {
+      let msg = 'An error occurred while trying to retrieve book'
+      if (e.response.data.message) {
+        msg += `: ${e.response.data.message}`
+      }
+      throw new Error(msg)
+    }
+  }
+
   async getBookPages (bookId: number): Promise<PageDto[]> {
     try {
       return (await this.http.get(`${API_BOOKS}/${bookId}/pages`)).data

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

@@ -128,6 +128,37 @@ class BookController(
       it.toDto(includeFullUrl = principal.user.isAdmin())
     } ?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
 
+  @GetMapping("api/v1/books/{bookId}/previous")
+  fun getBookSiblingPrevious(
+    @AuthenticationPrincipal principal: KomgaPrincipal,
+    @PathVariable bookId: Long
+  ): BookDto =
+    bookRepository.findByIdOrNull(bookId)?.let { book ->
+      if (!principal.user.canAccessBook(book)) throw ResponseStatusException(HttpStatus.UNAUTHORIZED)
+
+      val previousBook = book.series.books
+        .sortedByDescending { it.number }
+        .find { it.number < book.number }
+
+      previousBook?.toDto(includeFullUrl = principal.user.isAdmin())
+        ?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
+    } ?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
+
+  @GetMapping("api/v1/books/{bookId}/next")
+  fun getBookSiblingNext(
+    @AuthenticationPrincipal principal: KomgaPrincipal,
+    @PathVariable bookId: Long
+  ): BookDto =
+    bookRepository.findByIdOrNull(bookId)?.let { book ->
+      if (!principal.user.canAccessBook(book)) throw ResponseStatusException(HttpStatus.UNAUTHORIZED)
+
+      val nextBook = book.series.books
+        .sortedBy { it.number }
+        .find { it.number > book.number }
+
+      nextBook?.toDto(includeFullUrl = principal.user.isAdmin()) ?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
+    } ?: throw ResponseStatusException(HttpStatus.NOT_FOUND)
+
 
   @GetMapping(value = [
     "api/v1/books/{bookId}/thumbnail",