feat(ui): add Rescan button to Edit Metadata dialog

Adds a Rescan button to the MetadataEditorModal footer that POSTs to the
new per-book rescan endpoint, with rescanning state (disabled + spinner,
matching the existing Mark Read pattern), success/error toasts, and a
page reload to pick up the refreshed cover and metadata.

Dockerfile

@@ -43,7 +43,7 @@ RUN --mount=type=cache,target=/root/go/pkg/mod \
 # This stage is ONLY used for running tests, never deployed to production
 FROM golang:1.26-alpine AS test-runner
 
-RUN apk --no-cache add ca-certificates curl
+RUN apk --no-cache add ca-certificates curl poppler-utils
 
 WORKDIR /app
 
@@ -65,7 +65,7 @@ CMD ["go", "test", "./cmd/server/tests", "-v", "-timeout", "5m", "-parallel=1",
 # Final stage
 FROM alpine:latest
 
-RUN apk --no-cache add ca-certificates curl
+RUN apk --no-cache add ca-certificates curl poppler-utils
 
 # Install kepubify for EPUB→KEPUB conversion
 RUN wget -O /usr/bin/kepubify https://github.com/pgaskin/kepubify/releases/latest/download/kepubify-linux-64bit \

bruno/media-items/Rescan Media Item.yml

@@ -0,0 +1,35 @@
+info:
+  name: Rescan Media Item
+  type: http
+  seq: 9
+
+http:
+  method: POST
+  url: "{{base_url}}/api/media-items/{{media_item_id}}/rescan"
+  headers:
+    - name: ""
+      value: application/json
+  auth: inherit
+
+runtime:
+  scripts:
+    - type: tests
+      code: |-
+        test_rescan_media_item_success(status, headers, body) {
+            if (status !== 200) {
+              throw new Error("Expected status 200, got " + status);
+
+settings:
+  encodeUrl: true
+  timeout: 0
+  followRedirects: true
+  maxRedirects: 5
+
+docs: |-
+  ## Rescan Media Item
+
+    Re-extracts metadata and cover art for a single media item from the file on disk.
+
+    **Method:** POST
+
+    **Endpoint:** /api/media-items/{id}/rescan

internal/handlers/media.go

@@ -1309,6 +1309,42 @@ func (mh *MediaHandler) UpdateMediaItem(c *echo.Context) error {
 	return c.JSON(http.StatusOK, item)
 }
 
+// RescanMediaItem handles POST /api/media-items/:id/rescan (admin only)
+func (mh *MediaHandler) RescanMediaItem(c *echo.Context) error {
+	user := MustGetAuthenticatedUser(c)
+
+	if user.Role != "admin" {
+		return c.JSON(http.StatusForbidden, map[string]string{"error": "admin access required"})
+	}
+
+	mediaID := c.Param("id")
+	mediaUUID, err := uuid.Parse(mediaID)
+	if err != nil {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid media item id"})
+	}
+
+	if _, err := mh.db.GetMediaItem(c.Request().Context(), pgtype.UUID{Bytes: mediaUUID, Valid: true}); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return c.JSON(http.StatusNotFound, map[string]string{"error": "media item not found"})
+		}
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
+	}
+
+	scanner := services.NewMediaScanner(mh.db)
+	defer scanner.Close()
+
+	if err := scanner.RescanMediaItem(c.Request().Context(), pgtype.UUID{Bytes: mediaUUID, Valid: true}); err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
+	}
+
+	item, err := mh.db.GetMediaItem(c.Request().Context(), pgtype.UUID{Bytes: mediaUUID, Valid: true})
+	if err != nil {
+		return c.JSON(http.StatusInternalServerError, map[string]string{"error": err.Error()})
+	}
+
+	return c.JSON(http.StatusOK, item)
+}
+
 // DeleteMediaItem handles DELETE /api/media-items/:id (admin only)
 func (mh *MediaHandler) DeleteMediaItem(c *echo.Context) error {
 	user := MustGetAuthenticatedUser(c)

internal/router/media.go

@@ -60,6 +60,7 @@ func registerMediaRoutes(cfg *Config) {
 	// Admin-only media routes
 	admin.POST("/media-items", cfg.MediaHandler.CreateMediaItem)
 	admin.PUT("/media-items/:id", cfg.MediaHandler.UpdateMediaItem)
+	admin.POST("/media-items/:id/rescan", cfg.MediaHandler.RescanMediaItem)
 	admin.DELETE("/media-items/:id", cfg.MediaHandler.DeleteMediaItem)
 
 	// Shelf management (protected)

internal/services/media_scanner.go

@@ -23,6 +23,7 @@ import (
 	"io"
 	"io/fs"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"regexp"
 	"strconv"
@@ -2078,56 +2079,94 @@ func (s *MediaScanner) extractPDFCover(pdfPath string) (string, error) {
 	// Use pdfcpu API to extract images from first page
 	// ExtractImagesFile(inFile, outDir string, selectedPages []string, conf *model.Configuration) error
 	err = pdfcpuapi.ExtractImagesFile(pdfPath, tmpDir, []string{"1"}, nil)
+	if err == nil {
+		// Check for extracted images in the temp directory
+		entries, err := os.ReadDir(tmpDir)
+		if err == nil && len(entries) > 0 {
+			// Find the largest image (likely the cover)
+			var largestImage string
+			var largestSize int64
+
+			for _, entry := range entries {
+				if entry.IsDir() {
+					continue
+				}
+				info, err := entry.Info()
+				if err != nil {
+					continue
+				}
+				// Skip very small files (likely thumbnails or icons)
+				if info.Size() < 1000 {
+					continue
+				}
+				if info.Size() > largestSize {
+					largestImage = filepath.Join(tmpDir, entry.Name())
+					largestSize = info.Size()
+				}
+			}
+
+			if largestImage != "" {
+				// Read the image
+				imageData, err := os.ReadFile(largestImage)
+				if err == nil && len(imageData) > 0 {
+					// Save cover to disk (same pattern as comics: {pdf_path}.cover.jpg)
+					coverPath := pdfPath + ".cover.jpg"
+					if err := os.WriteFile(coverPath, imageData, 0644); err != nil {
+						return "", fmt.Errorf("failed to write cover file: %v", err)
+					}
+
+					return coverPath, nil
+				}
+			}
+		}
+	}
+
+	// No embedded raster cover found (e.g. vector/text first page) - fall back
+	// to rendering the first page with pdftoppm (poppler-utils).
+	return s.renderPDFCoverPage(pdfPath), nil
+}
+
+// renderPDFCoverPage renders the first page of a PDF file to a JPEG image
+// using pdftoppm. It saves the cover next to the PDF ({pdf_path}.cover.jpg).
+// Returns the path to the saved cover, or empty string if rendering failed.
+func (s *MediaScanner) renderPDFCoverPage(pdfPath string) string {
+	if _, err := exec.LookPath("pdftoppm"); err != nil {
+		fmt.Printf("Warning: pdftoppm not available, skipping PDF cover render for %s\n", pdfPath)
+		return ""
+	}
+
+	tmpDir, err := os.MkdirTemp("", "pdf-render-")
 	if err != nil {
-		// No images found or extraction failed - this is OK, just return empty
-		return "", nil
+		fmt.Printf("Warning: failed to create temp dir for PDF cover render %s: %v\n", pdfPath, err)
+		return ""
+	}
+	defer func() {
+		if err := os.RemoveAll(tmpDir); err != nil {
+			fmt.Printf("Warning: failed to remove temp directory %s: %v\n", tmpDir, err)
+		}
+	}()
+
+	outPrefix := filepath.Join(tmpDir, "cover")
+	cmd := exec.Command("pdftoppm", "-jpeg", "-f", "1", "-l", "1", "-singlefile", "-r", "150", pdfPath, outPrefix)
+	if output, err := cmd.CombinedOutput(); err != nil {
+		fmt.Printf("Warning: failed to render PDF cover from %s: %v, output: %s\n", pdfPath, err, string(output))
+		return ""
 	}
 
-	// Check for extracted images in the temp directory
-	entries, err := os.ReadDir(tmpDir)
-	if err != nil || len(entries) == 0 {
-		return "", nil
-	}
-
-	// Find the largest image (likely the cover)
-	var largestImage string
-	var largestSize int64
-
-	for _, entry := range entries {
-		if entry.IsDir() {
-			continue
-		}
-		info, err := entry.Info()
-		if err != nil {
-			continue
-		}
-		// Skip very small files (likely thumbnails or icons)
-		if info.Size() < 1000 {
-			continue
-		}
-		if info.Size() > largestSize {
-			largestImage = filepath.Join(tmpDir, entry.Name())
-			largestSize = info.Size()
-		}
-	}
-
-	if largestImage == "" {
-		return "", nil
-	}
-
-	// Read the image
-	imageData, err := os.ReadFile(largestImage)
-	if err != nil || len(imageData) == 0 {
-		return "", nil
+	imageData, err := os.ReadFile(outPrefix + ".jpg")
+	if err != nil || len(imageData) < 1000 {
+		fmt.Printf("Warning: PDF cover render produced no usable image for %s\n", pdfPath)
+		return ""
 	}
 
 	// Save cover to disk (same pattern as comics: {pdf_path}.cover.jpg)
 	coverPath := pdfPath + ".cover.jpg"
 	if err := os.WriteFile(coverPath, imageData, 0644); err != nil {
-		return "", fmt.Errorf("failed to write cover file: %v", err)
+		fmt.Printf("Warning: failed to write rendered PDF cover for %s: %v\n", pdfPath, err)
+		return ""
 	}
 
-	return coverPath, nil
+	return coverPath
 }
 
 // ComicInfo represents metadata from ComicInfo.xml
@@ -2618,6 +2657,51 @@ func (s *MediaScanner) updateMediaItem(ctx context.Context, mediaItemID pgtype.U
 	return err
 }
 
+// RescanMediaItem re-extracts metadata for a single media item and updates it.
+// It is the per-book rescan used by the Edit Metadata dialog and backfills
+// covers for items imported before the PDF render fallback existed.
+func (s *MediaScanner) RescanMediaItem(ctx context.Context, mediaItemID pgtype.UUID) error {
+	item, err := s.db.GetMediaItem(ctx, mediaItemID)
+	if err != nil {
+		return fmt.Errorf("media item not found: %w", err)
+	}
+
+	folders, err := s.db.GetLibraryFolders(ctx, item.LibraryID)
+	if err != nil || len(folders) == 0 {
+		return fmt.Errorf("no library folders found for library")
+	}
+
+	folderPaths := make([]string, 0, len(folders))
+	for _, folder := range folders {
+		folderPaths = append(folderPaths, folder.FolderPath)
+	}
+	s.folders = folderPaths
+
+	var fullPath string
+	for _, folder := range folders {
+		candidate := filepath.Join(folder.FolderPath, item.FilePath)
+		if _, err := os.Stat(candidate); err == nil {
+			fullPath = candidate
+			break
+		}
+	}
+	if fullPath == "" {
+		return fmt.Errorf("media file not found on disk: %s", item.FilePath)
+	}
+
+	info, err := os.Stat(fullPath)
+	if err != nil {
+		return fmt.Errorf("failed to stat media file: %w", err)
+	}
+
+	if err := s.updateMediaItem(ctx, mediaItemID, fullPath, info); err != nil {
+		return fmt.Errorf("failed to update media item: %w", err)
+	}
+	s.recomputeHashInfo(ctx, mediaItemID, item.LibraryID, fullPath)
+
+	return nil
+}
+
 func (s *MediaScanner) getMediaItemByFilePath(ctx context.Context, filePath string, libraryID pgtype.UUID) (database.MediaItems, error) {
 	return s.db.GetMediaItemByFilePath(ctx, database.GetMediaItemByFilePathParams{
 		FilePath:  s.getRelativePath(filePath),

templates/book_detail_modals.templ

@@ -609,7 +609,19 @@ templ MetadataEditorModal(book handlers.MediaDetail) {
 					</div>
 				</div>
 			</div>
-			<div class="flex justify-end space-x-3 p-6 border-t flex-shrink-0" style="border-color: var(--border);">
+		<div class="flex items-center justify-between p-6 border-t flex-shrink-0" style="border-color: var(--border);">
+			<button
+				@click="rescanBook()"
+				:disabled="rescanning"
+				class="btn btn-secondary"
+			>
+				<span x-show="!rescanning" class="inline-flex items-center gap-2">@Icon("sync", "h-4 w-4")<span>Rescan</span></span>
+				<svg x-show="rescanning" class="animate-spin inline-block h-5 w-5" viewBox="0 0 24 24" fill="none">
+					<circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
+					<path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z"></path>
+				</svg>
+			</button>
+			<div class="flex space-x-3">
 				<button
 					@click="hideMetadataEditor()"
 					class="btn btn-secondary"
@@ -625,5 +637,6 @@ templ MetadataEditorModal(book handlers.MediaDetail) {
 				</button>
 			</div>
 		</div>
+		</div>
 	</div>
 }

templates/book_detail_modals_templ.go

@@ -1336,7 +1336,15 @@ func MetadataEditorModal(book handlers.MediaDetail) templ.Component {
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 126, "\" readonly class=\"input opacity-60\"></div></div></div></div></div></div><div class=\"flex justify-end space-x-3 p-6 border-t flex-shrink-0\" style=\"border-color: var(--border);\"><button @click=\"hideMetadataEditor()\" class=\"btn btn-secondary\">Cancel</button> <button @click=\"saveMetadata()\" class=\"btn btn-primary\">")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 126, "\" readonly class=\"input opacity-60\"></div></div></div></div></div></div><div class=\"flex items-center justify-between p-6 border-t flex-shrink-0\" style=\"border-color: var(--border);\"><button @click=\"rescanBook()\" :disabled=\"rescanning\" class=\"btn btn-secondary\"><span x-show=\"!rescanning\" class=\"inline-flex items-center gap-2\">")
+		if templ_7745c5c3_Err != nil {
+			return templ_7745c5c3_Err
+		}
+		templ_7745c5c3_Err = Icon("sync", "h-4 w-4").Render(ctx, templ_7745c5c3_Buffer)
+		if templ_7745c5c3_Err != nil {
+			return templ_7745c5c3_Err
+		}
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 127, "<span>Rescan</span></span> <svg x-show=\"rescanning\" class=\"animate-spin inline-block h-5 w-5\" viewBox=\"0 0 24 24\" fill=\"none\"><circle class=\"opacity-25\" cx=\"12\" cy=\"12\" r=\"10\" stroke=\"currentColor\" stroke-width=\"4\"></circle> <path class=\"opacity-75\" fill=\"currentColor\" d=\"M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z\"></path></svg></button><div class=\"flex space-x-3\"><button @click=\"hideMetadataEditor()\" class=\"btn btn-secondary\">Cancel</button> <button @click=\"saveMetadata()\" class=\"btn btn-primary\">")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
@@ -1344,7 +1352,7 @@ func MetadataEditorModal(book handlers.MediaDetail) templ.Component {
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 127, "Save</button></div></div></div>")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 128, "Save</button></div></div></div></div>")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}

web/src/book-detail.ts

@@ -97,6 +97,7 @@ interface MetadataEditorState {
   coverFile: Blob | null;
   coverAction: string;
   saving: boolean;
+  rescanning: boolean;
   userRating: number;
   ratingHover: number;
   ratingSaving: boolean;
@@ -110,6 +111,7 @@ interface MetadataEditorState {
   generateCover(): Promise<void>;
   removeCover(): void;
   saveMetadata(): Promise<void>;
+  rescanBook(): Promise<void>;
   starFill(i: number): string;
   ratingText(): string;
   setRating(value: number): Promise<void>;
@@ -149,6 +151,7 @@ Alpine.data("bookDetail", () => {
     coverFile: null as Blob | null,
     coverAction: "keep",
     saving: false,
+    rescanning: false,
     userRating: 0,
     ratingHover: 0,
     ratingSaving: false,
@@ -559,6 +562,31 @@ Alpine.data("bookDetail", () => {
       }
     },
 
+    async rescanBook() {
+      if (this.rescanning) return;
+      this.rescanning = true;
+      const mediaId = getMediaId();
+      try {
+        const resp = await fetch(`/api/media-items/${mediaId}/rescan`, {
+          method: "POST",
+          headers: { Authorization: getAuthHeader() },
+        });
+        if (!resp.ok) {
+          const err = await resp.json().catch(() => ({}));
+          throw new Error(err.error || "Failed to rescan book");
+        }
+        showToast("Book rescanned successfully", "success");
+        setTimeout(() => window.location.reload(), 500);
+      } catch (e) {
+        showToast(
+          e instanceof Error ? e.message : "Failed to rescan book",
+          "error",
+        );
+      } finally {
+        this.rescanning = false;
+      }
+    },
+
     async searchEditorTags() {
       const libraryId = document.body.getAttribute("data-library-id") || "";
       if (!this.tagSearch || this.tagSearch.length < 2 || !libraryId) {