improve spam automod and message cache, upgrade to JDK 25

Author: danthe1st

.github/workflows/build.yml

@@ -12,10 +12,10 @@ jobs:
       contents: read
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 17
+      - name: Set up JDK 25
         uses: actions/setup-java@v4
         with:
-          java-version: '17'
+          java-version: '25'
           distribution: 'temurin'
       - name: Grant execute permission for gradlew
         run: chmod +x gradlew
@@ -31,10 +31,10 @@ jobs:
     if: ${{ (github.event_name == 'push' && github.ref == 'refs/heads/main') || github.event_name == 'workflow_dispatch' }}
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: graalvm/setup-graalvm@v1
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'graalvm-community'
       - name: Build native-image
         run: ./gradlew nativeCompile -Pprod

build.gradle.kts

@@ -11,8 +11,8 @@ plugins {
 }
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_17
-    targetCompatibility = JavaVersion.VERSION_17
+    sourceCompatibility = JavaVersion.VERSION_25
+    targetCompatibility = JavaVersion.VERSION_25
 }
 
 group = "net.discordjug"
@@ -121,6 +121,7 @@ tasks.processTestAot {
 graalvmNative {
 	binaries {
 		named("main") {
+			buildArgs.add("-H:+ForeignAPISupport")//needed for AWT/plotting, see https://bugs.openjdk.org/browse/JDK-8337237
 			if (hasProperty("prod")) {
 				buildArgs.add("-O3")
 			} else {

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.2.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

src/main/java/net/discordjug/javabot/data/h2db/message_cache/MessageCache.java

@@ -27,9 +27,12 @@
 import java.net.http.HttpResponse.BodyHandlers;
 import java.nio.charset.StandardCharsets;
 import java.time.Instant;
+import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Deque;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.stream.Collectors;
@@ -46,7 +49,7 @@ public class MessageCache {
 	/**
 	 * A memory-cache (list) of sent Messages, wrapped to a {@link CachedMessage} object.
 	 */
-	public List<CachedMessage> cache = new ArrayList<>();
+	public Deque<CachedMessage> cache = new ArrayDeque<>();
 	/**
 	 * Amount of messages since the last synchronization.
 	 * <p>
@@ -71,12 +74,11 @@ public MessageCache(BotConfig botConfig, MessageCacheRepository cacheRepository,
 		this.botConfig = botConfig;
 		this.cacheRepository = cacheRepository;
 		try {
-			cache = cacheRepository.getAll();
+			cache = new ArrayDeque<>(cacheRepository.getAll());
 		} catch (DataAccessException e) {
 			ExceptionLogger.capture(e, getClass().getSimpleName());
 			log.error("Something went wrong during retrieval of stored messages.");
 		}
-
 	}
 
 	/**
@@ -85,7 +87,7 @@ public MessageCache(BotConfig botConfig, MessageCacheRepository cacheRepository,
 	public void synchronize() {
 		asyncPool.execute(()->{
 			cacheRepository.delete(cache.size());
-			cacheRepository.insertList(cache);
+			cacheRepository.insertList(new ArrayList<>(cache));
 			messageCount = 0;
 			log.info("Synchronized Database with local Cache.");
 		});
@@ -146,6 +148,22 @@ public void sendDeletedMessageToLog(Guild guild, MessageChannel channel, CachedM
 			requestMessageAttachments(message);
 		});
 	}
+	
+	/**
+	 * Retrieves all cached messages that were sent after a passed timestamp.
+	 * @param timestamp the timestamp since when messages should be received
+	 * @return the messages sent after the given timestamp as a {@link List}
+	 */
+	public List<CachedMessage> getMessagesAfter(OffsetDateTime timestamp) {
+		List<CachedMessage> cachedMessages = new ArrayList<>();
+		for (CachedMessage msg : this.cache.reversed()) {
+			if (UserSnowflake.fromId(msg.getMessageId()).getTimeCreated().isBefore(timestamp)) {
+				return cachedMessages.reversed();
+			}
+			cachedMessages.add(msg);
+		}
+		return cachedMessages.reversed();
+	}
 
 	/**
 	 * Requests each attachment from Discord's CDN.

src/main/java/net/discordjug/javabot/data/h2db/message_cache/MessageCacheListener.java

@@ -13,6 +13,7 @@
 
 import lombok.RequiredArgsConstructor;
 
+import java.util.Deque;
 import java.util.List;
 import java.util.Optional;
 
@@ -33,16 +34,15 @@ public void onMessageReceived(@NotNull MessageReceivedEvent event) {
 	@Override
 	public void onMessageUpdate(@NotNull MessageUpdateEvent event) {
 		if (this.ignoreMessageCache(event.getMessage())) return;
-		List<CachedMessage> cache = messageCache.cache;
+		Deque<CachedMessage> cache = messageCache.cache;
 		Optional<CachedMessage> optional = cache.stream().filter(m -> m.getMessageId() == event.getMessageIdLong()).findFirst();
 		CachedMessage before;
 		if (optional.isPresent()) {
-			before = optional.get();
-			cache.set(cache.indexOf(before), CachedMessage.of(event.getMessage()));
+			CachedMessage inCache= optional.get();
+			before = new CachedMessage(inCache.getMessageId(), inCache.getAuthorId(), inCache.getMessageContent(), inCache.getAttachments());
+			inCache.init(event.getMessage());
 		} else {
-			before = new CachedMessage();
-			before.setMessageId(event.getMessageIdLong());
-			before.setMessageContent("[unknown content]");
+			before = new CachedMessage(event.getMessageIdLong(), event.getAuthor().getIdLong(), "[unknown content]", List.of());
 			messageCache.cache(event.getMessage());
 		}
 		messageCache.sendUpdatedMessageToLog(event.getMessage(), before);

src/main/java/net/discordjug/javabot/data/h2db/message_cache/dao/MessageCacheRepository.java

@@ -110,14 +110,15 @@ public boolean delete(int amount) throws DataAccessException {
 	}
 
 	private CachedMessage read(ResultSet rs) throws SQLException {
-		CachedMessage cachedMessage = new CachedMessage();
-		cachedMessage.setMessageId(rs.getLong("message_cache.message_id"));
-		cachedMessage.setAuthorId(rs.getLong("author_id"));
-		cachedMessage.setMessageContent(rs.getString("message_content"));
+		List<String> attachments = new ArrayList<>();
 		String attachment = rs.getString("link");
-		if(attachment!=null) {
-			cachedMessage.getAttachments().add(attachment);
+		if(attachment != null) {
+			attachments.add(attachment);
 		}
-		return cachedMessage;
+		return new CachedMessage(
+				rs.getLong("message_cache.message_id"),
+				rs.getLong("author_id"),
+				rs.getString("message_content"),
+				attachments);
 	}
 }

src/main/java/net/discordjug/javabot/data/h2db/message_cache/model/CachedMessage.java

@@ -3,20 +3,44 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.ToString;
 import net.discordjug.javabot.util.MessageUtils;
 import net.dv8tion.jda.api.entities.Message;
 import net.dv8tion.jda.api.entities.Message.Attachment;
 
 /**
  * Represents a cached Message.
  */
-@Data
+@Getter
+@EqualsAndHashCode
+@ToString
 public class CachedMessage {
-	private long messageId;
-	private long authorId;
+	private final long messageId;
+	private final long authorId;
 	private String messageContent;
 	private List<String> attachments=new ArrayList<>();
+	
+	private CachedMessage(long messageId, long authorId) {
+		this.messageId = messageId;
+		this.authorId = authorId;
+	}
+	
+	/**
+	 * Creates a {@link CachedMessage} with the given information.
+	 * @param messageId The Discord ID of the message
+	 * @param authorId The Discord ID of the message author
+	 * @param messageContent the textual content of the message
+	 * @param attachments The attachment URLs
+	 */
+	public CachedMessage(long messageId, long authorId, String messageContent, List<String> attachments) {
+		super();
+		this.messageId = messageId;
+		this.authorId = authorId;
+		this.messageContent = messageContent;
+		this.attachments = List.copyOf(attachments);
+	}
 
 	/**
 	 * Converts a {@link Message} object to a {@link CachedMessage}.
@@ -25,15 +49,25 @@ public class CachedMessage {
 	 * @return The built {@link CachedMessage}.
 	 */
 	public static CachedMessage of(Message message) {
-		CachedMessage cachedMessage = new CachedMessage();
-		cachedMessage.setMessageId(message.getIdLong());
-		cachedMessage.setAuthorId(message.getAuthor().getIdLong());
-		cachedMessage.setMessageContent(MessageUtils.getMessageContent(message).trim());
-		cachedMessage.attachments = message
+		CachedMessage cachedMessage = new CachedMessage(message.getIdLong(), message.getAuthor().getIdLong());
+		cachedMessage.init(message);
+		return cachedMessage;
+	}
+	
+	/**
+	 * Resets the current {@link CachedMessage} to have the content of the passed {@link Message}.
+	 * @param message the {@link Message} this object is set to.
+	 */
+	public void init(Message message) {
+		messageContent = MessageUtils.getMessageContent(message).trim();
+		this.attachments = message
 				.getAttachments()
 				.stream()
 				.map(Attachment::getUrl)
 				.toList();
-		return cachedMessage;
+	}
+	
+	public void setMessageContent(String messageContent) {
+		this.messageContent = messageContent;
 	}
 }

src/main/java/net/discordjug/javabot/systems/moderation/AutoMod.java

@@ -2,6 +2,7 @@
 
 import lombok.extern.slf4j.Slf4j;
 import net.discordjug.javabot.data.config.BotConfig;
+import net.discordjug.javabot.data.h2db.message_cache.MessageCache;
 import net.discordjug.javabot.systems.moderation.warn.model.WarnSeverity;
 import net.discordjug.javabot.systems.notification.NotificationService;
 import net.discordjug.javabot.util.ExceptionLogger;
@@ -25,7 +26,6 @@
 import java.time.temporal.ChronoUnit;
 import java.util.Collections;
 import java.util.List;
-import java.util.Objects;
 import java.util.Scanner;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
@@ -35,7 +35,6 @@
  * This class checks all incoming messages for potential spam/advertising and warns or mutes the potential offender.
  */
 @Slf4j
-// TODO: Refactor this to be more efficient. Especially AutoMod#checkNewMessageAutomod
 public class AutoMod extends ListenerAdapter {
 
 	private static final Pattern INVITE_URL = Pattern.compile("discord(?:(\\.(?:me|io|gg)|sites\\.com)/.{0,4}|(?:app)?\\.com.{1,4}(?:invite|oauth2).{0,5}/)\\w+");
@@ -48,17 +47,20 @@ public class AutoMod extends ListenerAdapter {
 	private final BotConfig botConfig;
 	private List<String> spamUrls;
 	private final ModerationService moderationService;
+	private final MessageCache messageCache;
 
 	/**
 	 * Constructor of the class, that creates a list of strings with potential spam/scam urls.
 	 * @param notificationService The {@link QOTWPointsService}
 	 * @param botConfig The main configuration of the bot
 	 * @param moderationService Service object for moderating members
+	 * @param messageCache service for retrieving cached messages
 	 */
-	public AutoMod(NotificationService notificationService, BotConfig botConfig, ModerationService moderationService) {
+	public AutoMod(NotificationService notificationService, BotConfig botConfig, ModerationService moderationService, MessageCache messageCache) {
 		this.notificationService = notificationService;
 		this.botConfig = botConfig;
 		this.moderationService = moderationService;
+		this.messageCache = messageCache;
 		try(Scanner scan = new Scanner(new URL("https://raw.githubusercontent.com/DevSpen/scam-links/master/src/links.txt").openStream()).useDelimiter("\\A")) {
 			String response = scan.next();
 			spamUrls = List.of(response.split("\n"));
@@ -102,15 +104,20 @@ private boolean canBypassAutomod(Member member) {
 	 */
 	private void checkNewMessageAutomod(@Nonnull Message message) {
 		// spam
-		message.getChannel().getHistory().retrievePast(10).queue(messages -> {
-			int spamCount = (int) messages.stream().filter(msg -> !msg.equals(message))
-					// filter for spam
-					.filter(msg -> msg.getAuthor().equals(message.getAuthor()) && !msg.getAuthor().isBot())
-					.filter(msg -> (message.getTimeCreated().toEpochSecond() - msg.getTimeCreated().toEpochSecond()) < 6).count();
-			if (spamCount > 5) {
-				handleSpam(message, message.getMember());
-			}
-		});
+		long spamCount = messageCache.getMessagesAfter(message.getTimeCreated().minusSeconds(6))
+			.stream()
+			.filter(cached -> cached.getMessageId() != message.getIdLong()) // exclude new/current message
+			.filter(cached -> cached.getAuthorId() == message.getAuthor().getIdLong())
+			.filter(cached -> 
+				// only java files -> not spam
+				cached.getAttachments().isEmpty() || 
+				cached.getAttachments().stream()
+					.anyMatch(attachment -> !attachment.contains(".java?")))
+			.count() + 1; // include new message
+			
+		if (spamCount >= 5) {
+			handleSpam(message, message.getMember());
+		}
 
 		checkContentAutomod(message);
 	}
@@ -149,16 +156,12 @@ private void doAutomodActions(Message message, String reason) {
 	}
 
 	/**
-	 * Handles potential spam messages.
+	 * Handles detected spam messages.
 	 *
-	 * @param msg    the message
+	 * @param msg    the (last) spam message
 	 * @param member the member to be potentially warned
 	 */
 	private void handleSpam(@Nonnull Message msg, Member member) {
-		// java files -> not spam
-		if (!msg.getAttachments().isEmpty() && msg.getAttachments().stream().allMatch(a -> Objects.equals(a.getFileExtension(), "java"))) {
-			return;
-		}
 		moderationService
 				.timeout(
 						member.getUser(),
@@ -168,6 +171,7 @@ private void handleSpam(@Nonnull Message msg, Member member) {
 						msg.getChannel(),
 						false
 				);
+		msg.delete().queue();
 	}
 
 	/**