feat(google-books): add optional API key configuration (#2629)

booklore-api/src/main/java/org/booklore/model/dto/settings/MetadataProviderSettings.java

@@ -27,6 +27,7 @@ public class MetadataProviderSettings {
     public static class Google {
         private boolean enabled;
         private String language;
+        private String apiKey;
     }
 
     @Data

booklore-api/src/main/java/org/booklore/service/metadata/parser/GoogleParser.java

@@ -4,6 +4,7 @@ import org.booklore.model.dto.Book;
 import org.booklore.model.dto.BookMetadata;
 import org.booklore.model.dto.request.FetchMetadataRequest;
 import org.booklore.model.dto.response.GoogleBooksApiResponse;
+import org.booklore.model.dto.settings.MetadataProviderSettings;
 import org.booklore.model.enums.MetadataProvider;
 import org.booklore.service.appsettings.AppSettingService;
 import org.booklore.util.BookUtils;
@@ -579,17 +580,23 @@ public class GoogleParser implements BookParser {
     }
 
     private String getApiUrl() {
-        String language = appSettingService.getAppSettings().getMetadataProviderSettings().getGoogle().getLanguage();
+        MetadataProviderSettings.Google googleSettings = appSettingService.getAppSettings()
+                .getMetadataProviderSettings().getGoogle();
 
-        if (language == null || language.isEmpty()) {
-            return GOOGLE_BOOKS_API_URL;
+        String language = googleSettings.getLanguage();
+        String apiKey = googleSettings.getApiKey();
+
+        UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(GOOGLE_BOOKS_API_URL);
+
+        if (language != null && !language.isEmpty()) {
+            builder.queryParam("langRestrict", language);
         }
 
-        return UriComponentsBuilder.fromUriString(GOOGLE_BOOKS_API_URL)
-            .queryParam("langRestrict", language)
-            .build()
-            .toUri()
-            .toString();
+        if (apiKey != null && !apiKey.isBlank()) {
+            builder.queryParam("key", apiKey);
+        }
+
+        return builder.build().toUri().toString();
     }
 
     private void waitForRateLimit() {

booklore-ui/src/app/features/settings/global-preferences/metadata-provider-settings/metadata-provider-settings.component.html

@@ -65,6 +65,16 @@
                     class="config-select">
                   </p-select>
                 </div>
+                <div class="config-field">
+                  <label class="config-label">API Key (Optional)</label>
+                  <p class="config-description">Providing a Google Books API key increases rate limits and improves reliability.</p>
+                  <input
+                    type="text"
+                    pInputText
+                    placeholder="Enter Google Books API key"
+                    [(ngModel)]="googleApiKey"
+                    class="config-input"/>
+                </div>
               </div>
             }
           </div>

booklore-ui/src/app/features/settings/global-preferences/metadata-provider-settings/metadata-provider-settings.component.ts

@@ -95,6 +95,7 @@ export class MetadataProviderSettingsComponent implements OnInit {
   doubanEnabled: boolean = false;
   lubimyCzytacEnabled: boolean = false;
   ranobedbEnabled: boolean = false;
+  googleApiKey: string = '';
 
   private appSettingsService = inject(AppSettingsService);
   private messageService = inject(MessageService);
@@ -116,6 +117,7 @@ export class MetadataProviderSettingsComponent implements OnInit {
         this.goodreadsEnabled = metadataProviderSettings?.goodReads?.enabled ?? false;
         this.googleEnabled = metadataProviderSettings?.google?.enabled ?? false;
         this.selectedGoogleLanguage = metadataProviderSettings?.google?.language ?? '';
+        this.googleApiKey = metadataProviderSettings?.google?.apiKey ?? '';
         this.hardcoverToken = metadataProviderSettings?.hardcover?.apiKey ?? '';
         this.hardcoverEnabled = metadataProviderSettings?.hardcover?.enabled ?? false;
         this.comicvineEnabled = metadataProviderSettings?.comicvine?.enabled ?? false;
@@ -157,6 +159,7 @@ export class MetadataProviderSettingsComponent implements OnInit {
           google: {
             enabled: this.googleEnabled,
             language: this.selectedGoogleLanguage,
+            apiKey: this.googleApiKey.trim()
           },
           hardcover: {
             enabled: this.hardcoverEnabled,

booklore-ui/src/app/shared/model/app-settings.model.ts

@@ -66,6 +66,7 @@ export interface Amazon {
 export interface Google {
   enabled: boolean;
   language: string;
+  apiKey: string;
 }
 
 export interface Goodreads {