feat(cbr-to-pdf,pdf-to-cbr): add PDF to/from CBR conversion with ebook optimization option (#4581)

# Description of Changes This pull request adds support for converting CBR (Comic Book RAR) files to PDF, optimizes CBZ/CBR-to-PDF conversion for e-readers using Ghostscript, and improves file type detection and image file handling. It introduces the `CbrUtils` and `PdfToCbrUtils` utility classes, refactors CBZ conversion logic, and integrates these features into the API controller. The most important changes are grouped below. ### CBR Support and Conversion: - Added the `com.github.junrar:junrar` dependency to support RAR/CBR archive extraction in `build.gradle`. (https://github.com/junrar/junrar and https://github.com/junrar/junrar?tab=License-1-ov-file#readme for repo and license) - Introduced the new utility class `CbrUtils` for converting CBR files to PDF, including image extraction, sorting, and error handling. - Added the `PdfToCbrUtils` utility class to convert PDF files into CBR archives by rendering each page as an image and packaging them. ### CBZ/CBR Conversion Optimization: - Refactored `CbzUtils.convertCbzToPdf` to support optional Ghostscript optimization for e-reader compatibility and added a new method for this. - Added `GeneralUtils.optimizePdfWithGhostscript`, which uses Ghostscript to optimize PDFs for e-readers, and integrated error handling. ### API Controller Integration: - Updated `ConvertImgPDFController` to support CBR conversion, CBZ/CBR optimization toggling, and Ghostscript availability checks. ### Endpoints <img width="1298" height="522" alt="image" src="https://github.com/user-attachments/assets/144d3e03-a637-451a-9c35-f784b2a66dc1" /> <img width="1279" height="472" alt="image" src="https://github.com/user-attachments/assets/879f221d-b775-4224-8edb-a23dbea6a0ca" /> ### UI <img width="384" height="105" alt="image" src="https://github.com/user-attachments/assets/5f861943-0706-4fad-8775-c40a9c1f3170" /> ### File Type and Image Detection Improvements: - Improved file extension detection for comic book files and image files in `CbzUtils` and added a shared regex pattern utility for image files. ### Additional notes: - Please keep in mind new the dependency, this is not dependency-free implementation (as opposed to CBZ converter) - RAR 5 currently not supported. (because JUNRAR does not support it) - Added the new ebook optimization func to GeneralUtils since we'll soon (hopefully) at least 3 book/ebook formats (EPUB, CBZ, CBR) all of which can use it. - Once again this has been thoroughly tested but can't share actual "real life" file due to copyright. Closes: #775  --- ## Checklist ### General - [x] I have read the [Contribution Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md) - [x] I have read the [Stirling-PDF Developer Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md) (if applicable) - [ ] I have read the [How to add new languages to Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md) (if applicable) - [x] I have performed a self-review of my own code - [x] My changes generate no new warnings ### Documentation - [x] I have updated relevant docs on [Stirling-PDF's doc repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/) (if functionality has heavily changed) - [ ] I have read the section [Add New Translation Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags) (for new translation tags only) ### UI Changes (if applicable) - [x] Screenshots or videos demonstrating the UI changes are attached (e.g., as comments or direct attachments in the PR) ### Testing (if applicable) - [x] I have tested my changes locally. Refer to the [Testing Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing) for more details. --------- Signed-off-by: Balázs Szücs <[email protected]>
2026-07-16 11:23:10 +02:00 · 2025-10-04 11:15:23 +01:00
parent fd95876d8f
commit ec1ac4cb2d
19 changed files with 856 additions and 18 deletions
@@ -8,6 +8,7 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 import java.util.zip.ZipEntry;
@@ -32,15 +33,20 @@ import io.swagger.v3.oas.annotations.tags.Tag;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;

+import stirling.software.SPDF.config.EndpointConfiguration;
+import stirling.software.SPDF.model.api.converters.ConvertCbrToPdfRequest;
 import stirling.software.SPDF.model.api.converters.ConvertCbzToPdfRequest;
+import stirling.software.SPDF.model.api.converters.ConvertPdfToCbrRequest;
 import stirling.software.SPDF.model.api.converters.ConvertPdfToCbzRequest;
 import stirling.software.SPDF.model.api.converters.ConvertToImageRequest;
 import stirling.software.SPDF.model.api.converters.ConvertToPdfRequest;
 import stirling.software.common.service.CustomPDFDocumentFactory;
+import stirling.software.common.util.CbrUtils;
 import stirling.software.common.util.CbzUtils;
 import stirling.software.common.util.CheckProgramInstall;
 import stirling.software.common.util.ExceptionUtils;
 import stirling.software.common.util.GeneralUtils;
+import stirling.software.common.util.PdfToCbrUtils;
 import stirling.software.common.util.PdfToCbzUtils;
 import stirling.software.common.util.PdfUtils;
 import stirling.software.common.util.ProcessExecutor;
@@ -58,10 +64,15 @@ public class ConvertImgPDFController {

    private final CustomPDFDocumentFactory pdfDocumentFactory;
    private final TempFileManager tempFileManager;
+    private final EndpointConfiguration endpointConfiguration;
    private static final Pattern EXTENSION_PATTERN =
            RegexPatternUtils.getInstance().getPattern(RegexPatternUtils.getExtensionRegex());
    private static final String DEFAULT_COMIC_NAME = "comic";

+    private boolean isGhostscriptEnabled() {
+        return endpointConfiguration.isGroupEnabled("Ghostscript");
+    }
+
    @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE, value = "/pdf/img")
    @Operation(
            summary = "Convert PDF to image(s)",
@@ -257,17 +268,29 @@ public class ConvertImgPDFController {
            description =
                    "This endpoint converts a CBZ (ZIP) comic book archive to a PDF file. "
                            + "Input:CBZ Output:PDF Type:SISO")
-    public ResponseEntity<byte[]> convertCbzToPdf(@ModelAttribute ConvertCbzToPdfRequest request)
+    public ResponseEntity<?> convertCbzToPdf(@ModelAttribute ConvertCbzToPdfRequest request)
            throws IOException {
        MultipartFile file = request.getFileInput();
+        boolean optimizeForEbook = request.isOptimizeForEbook();
+
+        // Disable optimization if Ghostscript is not available
+        if (optimizeForEbook && !isGhostscriptEnabled()) {
+            log.warn("Ghostscript optimization requested but Ghostscript is not enabled/available");
+            optimizeForEbook = false;
+        }
+
        byte[] pdfBytes;
        try {
-            pdfBytes = CbzUtils.convertCbzToPdf(file, pdfDocumentFactory, tempFileManager);
+            pdfBytes =
+                    CbzUtils.convertCbzToPdf(
+                            file, pdfDocumentFactory, tempFileManager, optimizeForEbook);
        } catch (IllegalArgumentException ex) {
            String message = ex.getMessage() == null ? "Invalid CBZ file" : ex.getMessage();
+            Map<String, Object> errorBody =
+                    Map.of("error", "Invalid CBZ file", "message", message, "trace", "");
            return ResponseEntity.status(HttpStatus.BAD_REQUEST)
-                    .contentType(MediaType.TEXT_PLAIN)
-                    .body(message.getBytes(java.nio.charset.StandardCharsets.UTF_8));
+                    .contentType(MediaType.APPLICATION_JSON)
+                    .body(errorBody);
        }

        String filename = createConvertedFilename(file.getOriginalFilename(), "_converted.pdf");
@@ -281,12 +304,12 @@ public class ConvertImgPDFController {
            description =
                    "This endpoint converts a PDF file to a CBZ (ZIP) comic book archive. "
                            + "Input:PDF Output:CBZ Type:SISO")
-    public ResponseEntity<byte[]> convertPdfToCbz(@ModelAttribute ConvertPdfToCbzRequest request)
+    public ResponseEntity<?> convertPdfToCbz(@ModelAttribute ConvertPdfToCbzRequest request)
            throws IOException {
        MultipartFile file = request.getFileInput();
-        Integer dpi = request.getDpi();
+        int dpi = request.getDpi();

-        if (dpi == null || dpi <= 0) {
+        if (dpi <= 0) {
            dpi = 300;
        }

@@ -295,9 +318,11 @@ public class ConvertImgPDFController {
            cbzBytes = PdfToCbzUtils.convertPdfToCbz(file, dpi, pdfDocumentFactory);
        } catch (IllegalArgumentException ex) {
            String message = ex.getMessage() == null ? "Invalid PDF file" : ex.getMessage();
+            Map<String, Object> errorBody =
+                    Map.of("error", "Invalid PDF file", "message", message, "trace", "");
            return ResponseEntity.status(HttpStatus.BAD_REQUEST)
-                    .contentType(MediaType.TEXT_PLAIN)
-                    .body(message.getBytes(java.nio.charset.StandardCharsets.UTF_8));
+                    .contentType(MediaType.APPLICATION_JSON)
+                    .body(errorBody);
        }

        String filename = createConvertedFilename(file.getOriginalFilename(), "_converted.cbz");
@@ -306,6 +331,75 @@ public class ConvertImgPDFController {
                cbzBytes, filename, MediaType.APPLICATION_OCTET_STREAM);
    }

+    @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE, value = "/cbr/pdf")
+    @Operation(
+            summary = "Convert CBR comic book archive to PDF",
+            description =
+                    "This endpoint converts a CBR (RAR) comic book archive to a PDF file. "
+                            + "Input:CBR Output:PDF Type:SISO")
+    public ResponseEntity<?> convertCbrToPdf(@ModelAttribute ConvertCbrToPdfRequest request)
+            throws IOException {
+        MultipartFile file = request.getFileInput();
+        boolean optimizeForEbook = request.isOptimizeForEbook();
+
+        // Disable optimization if Ghostscript is not available
+        if (optimizeForEbook && !isGhostscriptEnabled()) {
+            log.warn("Ghostscript optimization requested but Ghostscript is not enabled/available");
+            optimizeForEbook = false;
+        }
+
+        byte[] pdfBytes;
+        try {
+            pdfBytes =
+                    CbrUtils.convertCbrToPdf(
+                            file, pdfDocumentFactory, tempFileManager, optimizeForEbook);
+        } catch (IllegalArgumentException ex) {
+            String message = ex.getMessage() == null ? "Invalid CBR file" : ex.getMessage();
+            Map<String, Object> errorBody =
+                    Map.of("error", "Invalid CBR file", "message", message, "trace", "");
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST)
+                    .contentType(MediaType.APPLICATION_JSON)
+                    .body(errorBody);
+        }
+
+        String filename = createConvertedFilename(file.getOriginalFilename(), "_converted.pdf");
+
+        return WebResponseUtils.bytesToWebResponse(pdfBytes, filename);
+    }
+
+    @PostMapping(consumes = MediaType.MULTIPART_FORM_DATA_VALUE, value = "/pdf/cbr")
+    @Operation(
+            summary = "Convert PDF to CBR comic book archive",
+            description =
+                    "This endpoint converts a PDF file to a CBR-like (ZIP-based) comic book archive. "
+                            + "Note: Output is ZIP-based for compatibility. Input:PDF Output:CBR Type:SISO")
+    public ResponseEntity<?> convertPdfToCbr(@ModelAttribute ConvertPdfToCbrRequest request)
+            throws IOException {
+        MultipartFile file = request.getFileInput();
+        int dpi = request.getDpi();
+
+        if (dpi <= 0) {
+            dpi = 300;
+        }
+
+        byte[] cbrBytes;
+        try {
+            cbrBytes = PdfToCbrUtils.convertPdfToCbr(file, dpi, pdfDocumentFactory);
+        } catch (IllegalArgumentException ex) {
+            String message = ex.getMessage() == null ? "Invalid PDF file" : ex.getMessage();
+            Map<String, Object> errorBody =
+                    Map.of("error", "Invalid PDF file", "message", message, "trace", "");
+            return ResponseEntity.status(HttpStatus.BAD_REQUEST)
+                    .contentType(MediaType.APPLICATION_JSON)
+                    .body(errorBody);
+        }
+
+        String filename = createConvertedFilename(file.getOriginalFilename(), "_converted.cbr");
+
+        return WebResponseUtils.bytesToWebResponse(
+                cbrBytes, filename, MediaType.APPLICATION_OCTET_STREAM);
+    }
+
    private String createConvertedFilename(String originalFilename, String suffix) {
        if (originalFilename == null) {
            return GeneralUtils.generateFilename(DEFAULT_COMIC_NAME, suffix);
@@ -37,6 +37,20 @@ public class ConverterWebController {
        return "convert/pdf-to-cbz";
    }

+    @GetMapping("/cbr-to-pdf")
+    @Hidden
+    public String convertCbrToPdfForm(Model model) {
+        model.addAttribute("currentPage", "cbr-to-pdf");
+        return "convert/cbr-to-pdf";
+    }
+
+    @GetMapping("/pdf-to-cbr")
+    @Hidden
+    public String convertPdfToCbrForm(Model model) {
+        model.addAttribute("currentPage", "pdf-to-cbr");
+        return "convert/pdf-to-cbr";
+    }
+
    @GetMapping("/html-to-pdf")
    @Hidden
    public String convertHTMLToPdfForm(Model model) {
@@ -0,0 +1,23 @@
+package stirling.software.SPDF.model.api.converters;
+
+import org.springframework.web.multipart.MultipartFile;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+
+@Data
+@EqualsAndHashCode
+public class ConvertCbrToPdfRequest {
+
+    @Schema(
+            description = "The input CBR file to be converted to a PDF file",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private MultipartFile fileInput;
+
+    @Schema(
+            description = "Optimize the output PDF for ebook reading using Ghostscript",
+            defaultValue = "false")
+    private boolean optimizeForEbook;
+}
@@ -15,4 +15,9 @@ public class ConvertCbzToPdfRequest {
            description = "The input CBZ file to be converted to a PDF file",
            requiredMode = Schema.RequiredMode.REQUIRED)
    private MultipartFile fileInput;
+
+    @Schema(
+            description = "Optimize the output PDF for ebook reading using Ghostscript",
+            defaultValue = "false")
+    private boolean optimizeForEbook;
 }
@@ -0,0 +1,24 @@
+package stirling.software.SPDF.model.api.converters;
+
+import org.springframework.web.multipart.MultipartFile;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+
+@Data
+@EqualsAndHashCode
+public class ConvertPdfToCbrRequest {
+
+    @Schema(
+            description = "The input PDF file to be converted to a CBR file",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private MultipartFile fileInput;
+
+    @Schema(
+            description = "The DPI (Dots Per Inch) for rendering PDF pages as images",
+            example = "150",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private int dpi = 150;
+}
@@ -18,7 +18,7 @@ public class ConvertPdfToCbzRequest {

    @Schema(
            description = "The DPI (Dots Per Inch) for rendering PDF pages as images",
-            example = "300",
-            requiredMode = Schema.RequiredMode.NOT_REQUIRED)
-    private Integer dpi = 300;
+            example = "150",
+            requiredMode = Schema.RequiredMode.REQUIRED)
+    private int dpi = 150;
 }
@@ -610,10 +610,18 @@ home.cbzToPdf.title=CBZ to PDF
 home.cbzToPdf.desc=Convert CBZ comic book archives to PDF format.
 cbzToPdf.tags=conversion,comic,book,archive,cbz,zip

+home.cbrToPdf.title=CBR to PDF
+home.cbrToPdf.desc=Convert CBR comic book archives to PDF format.
+cbrToPdf.tags=conversion,comic,book,archive,cbr,rar
+
 home.pdfToCbz.title=PDF to CBZ
 home.pdfToCbz.desc=Convert PDF files to CBZ comic book archives.
 pdfToCbz.tags=conversion,comic,book,archive,cbz,pdf

+home.pdfToCbr.title=PDF to CBR
+home.pdfToCbr.desc=Convert PDF files to CBR comic book archives.
+pdfToCbr.tags=conversion,comic,book,archive,cbr,rar
+
 home.pdfToImage.title=PDF to Image
 home.pdfToImage.desc=Convert a PDF to a image. (PNG, JPEG, GIF, PSD)
 pdfToImage.tags=conversion,img,jpg,picture,photo,psd,photoshop
@@ -1445,6 +1453,7 @@ cbzToPDF.title=CBZ to PDF
 cbzToPDF.header=CBZ to PDF
 cbzToPDF.submit=Convert to PDF
 cbzToPDF.selectText=Select CBZ file
+cbzToPDF.optimizeForEbook=Optimize PDF for ebook readers (uses Ghostscript)

 #pdfToCBZ
 pdfToCBZ.title=PDF to CBZ
@@ -1453,6 +1462,21 @@ pdfToCBZ.submit=Convert to CBZ
 pdfToCBZ.selectText=Select PDF file
 pdfToCBZ.dpi=DPI (Dots Per Inch)

+#cbrToPDF
+cbrToPDF.title=CBR to PDF
+cbrToPDF.header=CBR to PDF
+cbrToPDF.submit=Convert to PDF
+cbrToPDF.selectText=Select CBR file
+cbrToPDF.optimizeForEbook=Optimize PDF for ebook readers (uses Ghostscript)
+
+#pdfToCBR
+pdfToCBR.title=PDF to CBR
+pdfToCBR.header=PDF to CBR
+pdfToCBR.submit=Convert to CBR
+pdfToCBR.selectText=Select PDF file
+pdfToCBR.dpi=DPI (Dots Per Inch)
+pdfToCBR.dpiHelp=Higher DPI results in better quality but larger file size.
+
 #pdfToImage
 pdfToImage.title=PDF to Image
 pdfToImage.header=PDF to Image
@@ -0,0 +1,44 @@
+<!DOCTYPE html>
+<html th:data-language="${#locale.toString()}" th:dir="#{language.direction}" th:lang="${#locale.language}"
+  xmlns:th="https://www.thymeleaf.org">
+
+<head>
+  <th:block th:insert="~{fragments/common :: head(title=#{cbrToPDF.title}, header=#{cbrToPDF.header})}"></th:block>
+</head>
+
+<body>
+  <th:block th:insert="~{fragments/common :: game}"></th:block>
+  <div id="page-container">
+    <div id="content-wrap">
+      <th:block th:insert="~{fragments/navbar.html :: navbar}"></th:block>
+      <br><br>
+      <div class="container">
+        <div class="row justify-content-center">
+          <div class="col-md-6 bg-card">
+            <div class="tool-header">
+              <span class="material-symbols-rounded tool-header-icon convertto">auto_stories</span>
+              <span class="tool-header-text" th:text="#{cbrToPDF.header}"></span>
+            </div>
+            <form enctype="multipart/form-data" id="cbrToPDFForm" method="post"
+              th:action="@{'/api/v1/convert/cbr/pdf'}">
+              <div
+                th:replace="~{fragments/common :: fileSelector(name='fileInput', multipleInputsForSingleRequest=false, accept='.cbr,.rar', inputText=#{cbrToPDF.selectText})}">
+              </div>
+              
+              <div class="form-check mb-3" th:if="${@endpointConfiguration.isGroupEnabled('Ghostscript')}">
+                <input id="optimizeForEbook" name="optimizeForEbook" type="checkbox" value="true">
+                <label for="optimizeForEbook" th:text="#{cbrToPDF.optimizeForEbook}">Optimize PDF for ebook readers (uses Ghostscript)</label>
+              </div>
+              
+              <br>
+              <button class="btn btn-primary" id="submitBtn" th:text="#{cbrToPDF.submit}" type="submit">Convert to PDF</button>
+            </form>
+          </div>
+        </div>
+      </div>
+    </div>
+    <th:block th:insert="~{fragments/footer.html :: footer}"></th:block>
+  </div>
+</body>
+
+</html>
@@ -25,6 +25,11 @@
                th:replace="~{fragments/common :: fileSelector(name='fileInput', multipleInputsForSingleRequest=false, accept='.cbz,.zip', inputText=#{cbzToPDF.selectText})}">
              </div>
              
+              <div class="form-check mb-3" th:if="${@endpointConfiguration.isGroupEnabled('Ghostscript')}">
+                <input id="optimizeForEbook" name="optimizeForEbook" type="checkbox" value="true">
+                <label for="optimizeForEbook" th:text="#{cbzToPDF.optimizeForEbook}">Optimize PDF for ebook readers (uses Ghostscript)</label>
+              </div>
+              
              <br>
              <button class="btn btn-primary" id="submitBtn" th:text="#{cbzToPDF.submit}" type="submit">Convert to PDF</button>
            </form>
@@ -0,0 +1,45 @@
+<!DOCTYPE html>
+<html th:data-language="${#locale.toString()}" th:dir="#{language.direction}" th:lang="${#locale.language}"
+  xmlns:th="https://www.thymeleaf.org">
+
+<head>
+  <th:block th:insert="~{fragments/common :: head(title=#{pdfToCBR.title}, header=#{pdfToCBR.header})}"></th:block>
+</head>
+
+<body>
+  <th:block th:insert="~{fragments/common :: game}"></th:block>
+  <div id="page-container">
+    <div id="content-wrap">
+      <th:block th:insert="~{fragments/navbar.html :: navbar}"></th:block>
+      <br><br>
+      <div class="container">
+        <div class="row justify-content-center">
+          <div class="col-md-6 bg-card">
+            <div class="tool-header">
+              <span class="material-symbols-rounded tool-header-icon convertto">auto_stories</span>
+              <span class="tool-header-text" th:text="#{pdfToCBR.header}"></span>
+            </div>
+            <form enctype="multipart/form-data" id="pdfToCBRForm" method="post"
+              th:action="@{'/api/v1/convert/pdf/cbr'}">
+              <div
+                th:replace="~{fragments/common :: fileSelector(name='fileInput', multipleInputsForSingleRequest=false, accept='.pdf', inputText=#{pdfToCBR.selectText})}">
+              </div>
+              
+              <div class="mb-3">
+                <label class="form-label" for="dpi" th:text="#{pdfToCBR.dpi}">DPI:</label>
+                <input class="form-control" id="dpi" max="600" min="50" name="dpi" type="number" value="300">
+                <div class="form-text" th:text="#{pdfToCBR.dpiHelp}">Higher DPI results in better quality but larger file size.</div>
+              </div>
+              
+              <br>
+              <button class="btn btn-primary" id="submitBtn" th:text="#{pdfToCBR.submit}" type="submit">Convert to CBR</button>
+            </form>
+          </div>
+        </div>
+      </div>
+    </div>
+    <th:block th:insert="~{fragments/footer.html :: footer}"></th:block>
+  </div>
+</body>
+
+</html>
@@ -50,6 +50,9 @@
      <div
        th:replace="~{fragments/navbarEntry :: navbarEntry('cbz-to-pdf', 'auto_stories', 'home.cbzToPdf.title', 'home.cbzToPdf.desc', 'cbzToPdf.tags', 'convertto')}">
      </div>
+      <div
+        th:replace="~{fragments/navbarEntry :: navbarEntry('cbr-to-pdf', 'auto_stories', 'home.cbrToPdf.title', 'home.cbrToPdf.desc', 'cbrToPdf.tags', 'convertto')}">
+      </div>
      <div
        th:replace="~{fragments/navbarEntry :: navbarEntry('file-to-pdf', 'draft', 'home.fileToPDF.title', 'home.fileToPDF.desc', 'fileToPDF.tags', 'convertto')}">
      </div>
@@ -77,6 +80,9 @@
      <div
        th:replace="~{fragments/navbarEntry :: navbarEntry('pdf-to-cbz', 'auto_stories', 'home.pdfToCbz.title', 'home.pdfToCbz.desc', 'pdfToCbz.tags', 'convert')}">
      </div>
+      <div
+        th:replace="~{fragments/navbarEntry :: navbarEntry('pdf-to-cbr', 'auto_stories', 'home.pdfToCbr.title', 'home.pdfToCbr.desc', 'pdfToCbr.tags', 'convert')}">
+      </div>
      <div
        th:replace="~{fragments/navbarEntry :: navbarEntry('pdf-to-pdfa', 'picture_as_pdf', 'home.pdfToPDFA.title', 'home.pdfToPDFA.desc', 'pdfToPDFA.tags', 'convert')}">
      </div>
@@ -114,6 +120,9 @@
      <div
        th:replace="~{fragments/navbarEntry :: navbarEntry('cbz-to-pdf', 'auto_stories', 'home.cbzToPdf.title', 'home.cbzToPdf.desc', 'cbzToPdf.tags', 'convertto')}">
      </div>
+      <div
+        th:replace="~{fragments/navbarEntry :: navbarEntry('cbr-to-pdf', 'auto_stories', 'home.cbrToPdf.title', 'home.cbrToPdf.desc', 'cbrToPdf.tags', 'convertto')}">
+      </div>
      <div
        th:replace="~{fragments/navbarEntry :: navbarEntry('file-to-pdf', 'draft', 'home.fileToPDF.title', 'home.fileToPDF.desc', 'fileToPDF.tags', 'convertto')}">
      </div>
@@ -0,0 +1,91 @@
+package stirling.software.SPDF.controller.api.converters;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.mock.web.MockMultipartFile;
+
+import stirling.software.common.util.CbrUtils;
+
+class CbrUtilsTest {
+
+    @Test
+    void testIsCbrFile_ValidCbrFile() {
+        MockMultipartFile cbrFile =
+                new MockMultipartFile(
+                        "file",
+                        "test.cbr",
+                        "application/x-rar-compressed",
+                        "test content".getBytes());
+
+        assertTrue(CbrUtils.isCbrFile(cbrFile));
+    }
+
+    @Test
+    void testIsCbrFile_ValidRarFile() {
+        MockMultipartFile rarFile =
+                new MockMultipartFile(
+                        "file",
+                        "test.rar",
+                        "application/x-rar-compressed",
+                        "test content".getBytes());
+
+        assertTrue(CbrUtils.isCbrFile(rarFile));
+    }
+
+    @Test
+    void testIsCbrFile_InvalidFile() {
+        MockMultipartFile textFile =
+                new MockMultipartFile("file", "test.txt", "text/plain", "test content".getBytes());
+
+        assertFalse(CbrUtils.isCbrFile(textFile));
+    }
+
+    @Test
+    void testIsCbrFile_NoFilename() {
+        MockMultipartFile noNameFile =
+                new MockMultipartFile(
+                        "file", null, "application/x-rar-compressed", "test content".getBytes());
+
+        assertFalse(CbrUtils.isCbrFile(noNameFile));
+    }
+
+    @Test
+    void testIsCbrFile_PdfFile() {
+        MockMultipartFile pdfFile =
+                new MockMultipartFile(
+                        "file", "document.pdf", "application/pdf", "pdf content".getBytes());
+
+        assertFalse(CbrUtils.isCbrFile(pdfFile));
+    }
+
+    @Test
+    void testIsCbrFile_JpegFile() {
+        MockMultipartFile jpegFile =
+                new MockMultipartFile("file", "image.jpg", "image/jpeg", "jpeg content".getBytes());
+
+        assertFalse(CbrUtils.isCbrFile(jpegFile));
+    }
+
+    @Test
+    void testIsCbrFile_ZipFile() {
+        MockMultipartFile zipFile =
+                new MockMultipartFile(
+                        "file", "archive.zip", "application/zip", "zip content".getBytes());
+
+        assertFalse(CbrUtils.isCbrFile(zipFile));
+    }
+
+    @Test
+    void testIsCbrFile_MixedCaseExtension() {
+        MockMultipartFile cbrFile =
+                new MockMultipartFile(
+                        "file",
+                        "test.CBR",
+                        "application/x-rar-compressed",
+                        "test content".getBytes());
+
+        assertTrue(CbrUtils.isCbrFile(cbrFile));
+    }
+}