Add support for book front covers

CHANGELOG.md

@@ -16,7 +16,8 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We added the integrity check to the jabkit cli application. [#13848](https://github.com/JabRef/jabref/issues/13848)
 - We added support for Cygwin-file paths on a Windows Operating System. [#13274](https://github.com/JabRef/jabref/issues/13274)
 - We fixed an issue where "Print preview" would throw a `NullPointerException` if no printers were available. [#13708](https://github.com/JabRef/jabref/issues/13708)
-- We added "IEEE" as another option for parsing plain text citations. [#14233](github.com/JabRef/jabref/pull/14233)
+- We added cover images for books, which will display in entry previews if available, and can be automatically downloaded when adding an entry via ISBN. [#10120](https://github.com/JabRef/jabref/issues/10120)
+- We added "IEEE" as another option for parsing plain text citations. [#14233](https://github.com/JabRef/jabref/pull/14233)
 - We added automatic date-based groups that create year/month/day subgroups from an entry’s date fields. [#10822](https://github.com/JabRef/jabref/issues/10822)
 - We added `doi-to-bibtex` to `JabKit`. [#14244](https://github.com/JabRef/jabref/pull/14244)
 - We added `--provider=crossref` to `get-cited-works` at `JabKit`. [#14357](https://github.com/JabRef/jabref/pull/14357)

jabgui/src/main/java/org/jabref/gui/externalfiles/ImportHandler.java

@@ -414,7 +414,7 @@ public List<BibEntry> handleStringData(String data) throws FetcherException {
         LOGGER.trace("Checking if URL is a PDF: {}", data);
 
         if (URLUtil.isURL(data)) {
-            String fileName = data.substring(data.lastIndexOf('/') + 1);
+            String fileName = FileUtil.getFileNameFromUrl(data);
             if (FileUtil.isPDFFile(Path.of(fileName))) {
                 try {
                     return handlePdfUrl(data);
@@ -481,7 +481,10 @@ private List<BibEntry> handlePdfUrl(String pdfUrl) throws IOException {
             return List.of();
         }
         URLDownload urlDownload = new URLDownload(pdfUrl);
-        String filename = URLUtil.getFileNameFromUrl(pdfUrl);
+        String filename = FileUtil.getFileNameFromUrl(pdfUrl);
+        if (filename.isBlank()) {
+            filename = "downloaded.pdf";
+        }
         Path targetFile = targetDirectory.get().resolve(filename);
         try {
             urlDownload.toFile(targetFile);

jabgui/src/main/java/org/jabref/gui/importer/BookCoverFetcher.java

@@ -0,0 +1,127 @@
+package org.jabref.gui.importer;
+
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Optional;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.jabref.gui.externalfiletype.ExternalFileType;
+import org.jabref.gui.externalfiletype.ExternalFileTypes;
+import org.jabref.gui.frame.ExternalApplicationsPreferences;
+import org.jabref.logic.FilePreferences;
+import org.jabref.logic.importer.FetcherException;
+import org.jabref.logic.net.URLDownload;
+import org.jabref.logic.util.io.FileUtil;
+import org.jabref.model.database.BibDatabaseContext;
+import org.jabref.model.entry.BibEntry;
+import org.jabref.model.entry.LinkedFile;
+import org.jabref.model.entry.identifier.ISBN;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Provides functions for downloading and retrieving book covers for entries.
+ */
+public class BookCoverFetcher {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(BookCoverFetcher.class);
+
+    private static final Pattern URL_JSON_PATTERN = Pattern.compile("^\\s*\\{\\s*\"url\"\\s*:\\s*\"([^\"]*)\"\\s*\\}\\s*$");
+
+    private static final String URL_FETCHER_URL = "https://bookcover.longitood.com/bookcover/";
+    private static final String IMAGE_FALLBACK_URL = "https://covers.openlibrary.org/b/isbn/";
+    private static final String IMAGE_FALLBACK_SUFFIX = "-L.jpg";
+
+    private final ExternalApplicationsPreferences externalApplicationsPreferences;
+
+    public BookCoverFetcher(ExternalApplicationsPreferences externalApplicationsPreferences) {
+        this.externalApplicationsPreferences = externalApplicationsPreferences;
+    }
+
+    public Optional<Path> getDownloadedCoverForEntry(BibEntry entry, Path directory) {
+        Optional<ISBN> isbn = entry.getISBN();
+        if (isbn.isPresent()) {
+            final String name = "isbn-" + isbn.get().asString();
+            return findExistingImage(name, directory);
+        }
+        return Optional.empty();
+    }
+
+    public void downloadCoversForEntry(BibEntry entry, Path directory) {
+        Optional<ISBN> isbn = entry.getISBN();
+        if (isbn.isPresent()) {
+            final String name = "isbn-" + isbn.get().asString();
+            if (findExistingImage(name, directory).isEmpty()) {
+                final String url = getSourceForIsbn(isbn.get());
+                Optional<LinkedFile> file = downloadCoverImage(url, name, directory);
+            }
+        }
+    }
+
+    private Optional<Path> findExistingImage(String name, Path directory) {
+        for (ExternalFileType filetype : externalApplicationsPreferences.getExternalFileTypes()) {
+            if (filetype.getMimeType().startsWith("image/")) {
+                Path path = directory.resolve(FileUtil.getValidFileName(name + "." + t.getExtension()));
+                if (Files.exists(path)) {
+                    return Optional.of(path);
+                }
+            }
+        }
+        return Optional.empty();
+    }
+
+    private void downloadCoverImage(String url, String name, Path directory) {
+        Optional<String> extension = FileUtil.getFileExtension(FileUtil.getFileNameFromUrl(url));
+
+        try {
+            LOGGER.info("Downloading cover image file from {}", url);
+
+            URLDownload download = new URLDownload(url);
+            Optional<String> mime = download.getMimeType();
+
+            Optional<ExternalFileType> suggested = Optional.empty();
+            if (mime.isPresent()) {
+                suggested = ExternalFileTypes.getExternalFileTypeByMimeType(mime.get(), externalApplicationsPreferences);
+            }
+            if (suggested.isEmpty() && extension.isPresent()) {
+                suggested = ExternalFileTypes.getExternalFileTypeByExt(extension.get(), externalApplicationsPreferences);
+            }
+
+            if (suggested.isPresent()) {
+                if (suggested.get().getMimeType().startsWith("image/")) {
+                    download.toFile(directory.resolve(FileUtil.getValidFileName(name + "." + suggested.get().getExtension())));
+                }
+            }
+        } catch (FetcherException | MalformedURLException e) {
+            LOGGER.error("Error while downloading cover image file", e);
+        }
+    }
+
+    private static String getSourceForIsbn(ISBN isbn) {
+        if (isbn.isIsbn13()) {
+            String url = URL_FETCHER_URL + isbn.asString();
+            try {
+                LOGGER.info("Downloading book cover url from {}", url);
+
+                URLDownload download = new URLDownload(url);
+                String json = download.asString();
+                Matcher matches = URL_JSON_PATTERN.matcher(json);
+
+                if (matches.find()) {
+                    String coverUrlString = matches.group(1);
+                    if (coverUrlString != null) {
+                        return coverUrlString;
+                    }
+                }
+            } catch (FetcherException | MalformedURLException e) {
+                LOGGER.error("Error while querying cover url, using fallback", e);
+            }
+        }
+        return IMAGE_FALLBACK_URL + isbn.asString() + IMAGE_FALLBACK_SUFFIX;
+    }
+}

jabgui/src/main/java/org/jabref/gui/linkedfile/DownloadLinkedFileAction.java

@@ -246,7 +246,7 @@ private BackgroundTask<Path> prepareDownloadTask(Path targetDirectory, URLDownlo
                     if (this.suggestedName.isEmpty()) {
                         Optional<ExternalFileType> suggestedType = inferFileType(urlDownload);
                         ExternalFileType externalFileType = suggestedType.orElse(StandardExternalFileType.PDF);
-                        suggestedName = linkedFileHandler.getSuggestedFileName(externalFileType.getExtension());
+                        suggestedName = linkedFileHandler.getSuggestedFileName(Optional.of(externalFileType.getExtension()));
                     } else {
                         suggestedName = this.suggestedName;
                     }

jabgui/src/main/java/org/jabref/gui/newentry/NewEntryViewModel.java

@@ -22,6 +22,7 @@
 import org.jabref.gui.LibraryTab;
 import org.jabref.gui.StateManager;
 import org.jabref.gui.externalfiles.ImportHandler;
+import org.jabref.gui.importer.BookCoverFetcher;
 import org.jabref.gui.preferences.GuiPreferences;
 import org.jabref.gui.util.UiTaskExecutor;
 import org.jabref.logic.ai.AiService;
@@ -64,6 +65,8 @@ public class NewEntryViewModel {
     private final AiService aiService;
     private final FileUpdateMonitor fileUpdateMonitor;
 
+    private final BookCoverFetcher bookCoverFetcher;
+
     private final BooleanProperty executing;
     private final BooleanProperty executedSuccessfully;
 
@@ -102,6 +105,8 @@ public NewEntryViewModel(GuiPreferences preferences,
         this.aiService = aiService;
         this.fileUpdateMonitor = fileUpdateMonitor;
 
+        this.bookCoverFetcher = new BookCoverFetcher(preferences.getExternalApplicationsPreferences());
+
         executing = new SimpleBooleanProperty(false);
         executedSuccessfully = new SimpleBooleanProperty(false);
         doiCache = new HashMap<>();
@@ -232,6 +237,14 @@ public ReadOnlyBooleanProperty bibtexTextValidatorProperty() {
         return bibtexTextValidator.getValidationStatus().validProperty();
     }
 
+    private BibEntry withCoversDownloaded(BibEntry entry) {
+        if (preferences.getFilePreferences().shouldDownloadCovers()) {
+            Path directory = Path.of(preferences.getFilePreferences().coversDownloadLocation());
+            bookCoverFetcher.downloadCoversForEntry(entry, directory, preferences.getExternalApplicationsPreferences());
+        }
+        return entry;
+    }
+
     private class WorkerLookupId extends Task<Optional<BibEntry>> {
         @Override
         protected Optional<BibEntry> call() throws FetcherException {
@@ -242,7 +255,7 @@ protected Optional<BibEntry> call() throws FetcherException {
                 return Optional.empty();
             }
 
-            return fetcher.performSearchById(text);
+            return fetcher.performSearchById(text).map(this::withCoversDownloaded);
         }
     }
 
@@ -257,7 +270,7 @@ protected Optional<BibEntry> call() throws FetcherException {
                 return Optional.empty();
             }
 
-            return fetcher.performSearchById(text);
+            return fetcher.performSearchById(text).map(this::withCoversDownloaded);
         }
     }
 

jabgui/src/main/java/org/jabref/gui/preferences/linkedfiles/LinkedFilesTab.java

@@ -5,6 +5,7 @@
 import javafx.scene.control.Button;
 import javafx.scene.control.CheckBox;
 import javafx.scene.control.ComboBox;
+import javafx.scene.control.Label;
 import javafx.scene.control.RadioButton;
 import javafx.scene.control.TextField;
 
@@ -25,6 +26,11 @@ public class LinkedFilesTab extends AbstractPreferenceTabView<LinkedFilesTabView
 
     @FXML private TextField mainFileDirectory;
     @FXML private RadioButton useMainFileDirectory;
+
+    @FXML private CheckBox bookCoverDownload;
+    @FXML private Label bookCoverLabel;
+    @FXML private TextField bookCoverLocation;
+
     @FXML private RadioButton useBibLocationAsPrimary;
     @FXML private Button browseDirectory;
     @FXML private Button autolinkRegexHelp;
@@ -63,7 +69,11 @@ public void initialize() {
         mainFileDirectory.disableProperty().bind(viewModel.useBibLocationAsPrimaryProperty());
         browseDirectory.disableProperty().bind(viewModel.useBibLocationAsPrimaryProperty());
         useBibLocationAsPrimary.selectedProperty().bindBidirectional(viewModel.useBibLocationAsPrimaryProperty());
-        useMainFileDirectory.selectedProperty().bindBidirectional(viewModel.useMainFileDirectoryProperty());
+
+        bookCoverLocation.textProperty().bindBidirectional(viewModel.coversDownloadLocationProperty());
+        bookCoverLocation.disableProperty().bind(viewModel.shouldDownloadCoversProperty().not());
+        bookCoverLabel.disableProperty().bind(viewModel.shouldDownloadCoversProperty().not());
+        bookCoverDownload.selectedProperty().bindBidirectional(viewModel.shouldDownloadCoversProperty());
 
         moveToTrash.selectedProperty().bindBidirectional(viewModel.moveToTrashProperty());
         moveToTrash.setDisable(!NativeDesktop.get().moveToTrashSupported());

jabgui/src/main/java/org/jabref/gui/preferences/linkedfiles/LinkedFilesTabViewModel.java

@@ -44,6 +44,8 @@ public class LinkedFilesTabViewModel implements PreferenceTabViewModel {
     private final BooleanProperty moveToTrashProperty = new SimpleBooleanProperty();
     private final BooleanProperty openFileExplorerInFilesDirectory = new SimpleBooleanProperty();
     private final BooleanProperty openFileExplorerInLastDirectory = new SimpleBooleanProperty();
+    private final BooleanProperty shouldDownloadCovers = new SimpleBooleanProperty();
+    private final StringProperty coversDownloadLocation = new SimpleStringProperty("");
 
     private final Validator mainFileDirValidator;
 
@@ -90,6 +92,8 @@ public void setValues() {
         moveToTrashProperty.setValue(filePreferences.moveToTrash());
         openFileExplorerInFilesDirectory.setValue(filePreferences.shouldOpenFileExplorerInFileDirectory());
         openFileExplorerInLastDirectory.setValue(filePreferences.shouldOpenFileExplorerInLastUsedDirectory());
+        shouldDownloadCovers.setValue(filePreferences.shouldDownloadCovers());
+        coversDownloadLocation.setValue(filePreferences.coversDownloadLocation());
 
         // Autolink preferences
         switch (autoLinkPreferences.getCitationKeyDependency()) {
@@ -115,6 +119,8 @@ public void storeSettings() {
         filePreferences.setFulltextIndexLinkedFiles(fulltextIndex.getValue());
         filePreferences.setOpenFileExplorerInFileDirectory(openFileExplorerInFilesDirectory.getValue());
         filePreferences.setOpenFileExplorerInLastUsedDirectory(openFileExplorerInLastDirectory.getValue());
+        filePreferences.setShouldDownloadCovers(shouldDownloadCovers.getValue());
+        filePreferences.setOpenFileExplorerInLastUsedDirectory(coversDownloadLocation.getValue());
 
         // Autolink preferences
         if (autolinkFileStartsBibtexProperty.getValue()) {
@@ -216,5 +222,13 @@ public BooleanProperty openFileExplorerInFilesDirectoryProperty() {
     public BooleanProperty openFileExplorerInLastDirectoryProperty() {
         return openFileExplorerInLastDirectory;
     }
+
+    public BooleanProperty shouldDownloadCoversProperty() {
+        return shouldDownloadCovers;
+    }
+
+    public StringProperty coversDownloadLocationProperty() {
+        return coversDownloadLocation;
+    }
 }
 

jabgui/src/main/java/org/jabref/gui/preview/PreviewViewer.java

@@ -4,6 +4,7 @@
 import java.net.MalformedURLException;
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 
 import javafx.beans.InvalidationListener;
 import javafx.beans.Observable;
@@ -20,6 +21,9 @@
 import org.jabref.gui.StateManager;
 import org.jabref.gui.desktop.os.NativeDesktop;
 import org.jabref.gui.exporter.ExportToClipboardAction;
+import org.jabref.gui.externalfiletype.ExternalFileType;
+import org.jabref.gui.externalfiletype.ExternalFileTypes;
+import org.jabref.gui.importer.BookCoverFetcher;
 import org.jabref.gui.preferences.GuiPreferences;
 import org.jabref.gui.search.Highlighter;
 import org.jabref.gui.theme.ThemeManager;
@@ -30,9 +34,12 @@
 import org.jabref.logic.preview.PreviewLayout;
 import org.jabref.logic.util.BackgroundTask;
 import org.jabref.logic.util.TaskExecutor;
+import org.jabref.logic.util.io.FileUtil;
 import org.jabref.logic.util.strings.StringUtil;
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.BibEntry;
+import org.jabref.model.entry.LinkedFile;
+import org.jabref.model.entry.types.StandardEntryType;
 import org.jabref.model.search.query.SearchQuery;
 
 import com.airhacks.afterburner.injection.Injector;
@@ -81,6 +88,8 @@ function getSelectionHtml() {
     private final StringProperty searchQueryProperty;
     private final GuiPreferences preferences;
 
+    private final BookCoverFetcher bookCoverFetcher;
+
     private @Nullable BibDatabaseContext databaseContext;
     private @Nullable BibEntry entry;
     private PreviewLayout layout;
@@ -105,6 +114,8 @@ public PreviewViewer(DialogService dialogService,
         this.searchQueryProperty = searchQueryProperty;
         this.searchQueryProperty.addListener((_, _, _) -> highlightLayoutText());
 
+        this.bookCoverFetcher = new BookCoverFetcher(preferences.getExternalApplicationsPreferences());
+
         setFitToHeight(true);
         setFitToWidth(true);
         previewView = WebViewStore.get();
@@ -222,17 +233,31 @@ private String formatError(BibEntry entry, Throwable exception) {
     }
 
     private void setPreviewText(String text) {
+        String coverIfAny = "";
+        Optional<String> image = getCoverImageURL();
+        if (image.isPresent()) {
+            coverIfAny = "<img style=\"border-width:1px; border-style:solid; border-color:black; display:block; height:12rem;\" src=\"%s\"> <br>".formatted(image);
+        }
+
         layoutText = """
-                <html>
-                    <body id="previewBody">
-                        <div id="content"> %s </div>
-                    </body>
-                </html>
-                """.formatted(text);
+                    <html>
+                        <body id="previewBody">
+                            %s <div id="content"> %s </div>
+                        </body>
+                    </html>
+                """.formatted(coverIfAny, text);
         highlightLayoutText();
         setHvalue(0);
     }
 
+    private Optional<String> getCoverImageURL() {
+        if (entry != null) {
+            Path directory = Path.of(preferences.getFilePreferences().coversDownloadLocation());
+            return bookCoverFetcher.getDownloadedCoverForEntry(entry, location, preferences.getExternalApplicationsPreferences()).map(p -> p.toUri().toString());
+        }
+        return Optional.empty();
+    }
+
     private void highlightLayoutText() {
         if (layoutText == null) {
             return;