store and expose entry categories (#727)

src/main/java/com/commafeed/backend/feed/FeedParser.java

@@ -86,6 +86,8 @@ public class FeedParser {
 
 				FeedEntryContent content = new FeedEntryContent();
 				content.setContent(getContent(item));
+				content.setCategories(FeedUtils.truncate(
+						item.getCategories().stream().map(c -> c.getName()).collect(Collectors.joining(", ")), 4096));
 				content.setTitle(getTitle(item));
 				content.setAuthor(StringUtils.trimToNull(item.getAuthor()));
 				SyndEnclosure enclosure = Iterables.getFirst(item.getEnclosures(), null);

src/main/java/com/commafeed/backend/model/FeedEntryContent.java

@@ -43,6 +43,9 @@ public class FeedEntryContent extends AbstractModel {
 	@Column(length = 255)
 	private String enclosureType;
 
+	@Column(length = 4096)
+	private String categories;
+
 	@OneToMany(mappedBy = "content")
 	private Set<FeedEntry> entries;
 

src/main/java/com/commafeed/backend/service/FeedEntryFilteringService.java

@@ -89,6 +89,7 @@ public class FeedEntryFilteringService {
 		context.set("content", entry.getContent().getContent() == null ? "" : Jsoup.parse(entry.getContent().getContent()).text()
 				.toLowerCase());
 		context.set("url", entry.getUrl() == null ? "" : entry.getUrl().toLowerCase());
+		context.set("categories", entry.getContent().getCategories() == null ? "" : entry.getContent().getCategories().toLowerCase());
 
 		Callable<Object> callable = script.callable(context);
 		Future<Object> future = executor.submit(callable);