- implemented retained messages for OOCSI channels

iddi · Sep 20, 2021 · 95b07c1 · 95b07c1
1 parent 5f09ea0
commit 95b07c1
Show file tree

Hide file tree

Showing 3 changed files with 43 additions and 2 deletions.
diff --git a/server/dist/OOCSI_server.jar b/server/dist/OOCSI_server.jar
diff --git a/server/src/nl/tue/id/oocsi/server/model/Channel.java b/server/src/nl/tue/id/oocsi/server/model/Channel.java
@@ -16,11 +16,14 @@
  */
 public class Channel {
 
+	private static final String RETAIN_MESSAGE = "_RETAIN";
+
 	protected final Date created = new Date();
 	protected final ChangeListener presence;
 	protected final Map<String, Channel> subChannels = new ConcurrentHashMap<String, Channel>();
 
 	protected String token;
+	protected Message retainedMessage;
 
 	public Channel(String token, ChangeListener changeListener) {
 		this.token = token;
@@ -95,11 +98,25 @@ public void send(Message message) {
 			if (!subChannel.isPrivate()) {
 				if (!message.recipient.equals(subChannel.getName())) {
 					OOCSIServer.logEvent(message.sender, message.recipient, subChannel.getName(), message.data,
-							message.timestamp);
+					        message.timestamp);
 				}
 			}
 		}
 
+		// new message erases always retained message
+		retainedMessage = null;
+
+		// check for retained message flag and store message
+		if (message.data.containsKey(RETAIN_MESSAGE)) {
+			Object retainTimeoutRaw = message.data.getOrDefault(RETAIN_MESSAGE, "0");
+			try {
+				long timeout = Long.parseLong(retainTimeoutRaw.toString());
+				message.validUntil = new Date(System.currentTimeMillis() + timeout);
+				retainedMessage = message;
+			} catch (Exception e) {
+				// do nothing
+			}
+		}
 	}
 
 	/**
@@ -156,10 +173,21 @@ public String getChannelList() {
 	public void addChannel(Channel channel) {
 		if (!getName().equals(channel.getName()) && !subChannels.containsKey(channel.getName())) {
 			subChannels.put(channel.getName(), channel);
+
+			// update presence information
 			if (!channel.isPrivate()) {
 				presence.join(this, channel);
 				OOCSIServer.logConnection(getName(), channel.getName(), "added channel", new Date());
 			}
+
+			// send out the retained message to new client
+			final Message retainedMessageCopy = retainedMessage;
+			if (retainedMessageCopy != null && retainedMessageCopy.isValid()) {
+				channel.send(retainedMessageCopy);
+			} else {
+				// clear invalid or null message
+				retainedMessage = null;
+			}
 		}
 	}
 

diff --git a/server/src/nl/tue/id/oocsi/server/protocol/Message.java b/server/src/nl/tue/id/oocsi/server/protocol/Message.java
@@ -34,6 +34,10 @@ public class Message implements Serializable {
 	 * data payload of message
 	 */
 	public Map<String, Object> data;
+	/**
+	 * until when the message is valid (used for retained messages)
+	 */
+	public Date validUntil;
 
 	/**
 	 * create message from sender and recipient
@@ -86,14 +90,23 @@ public Message addData(String key, Object value) {
 		return this;
 	}
 
+	/**
+	 * check whether the message is still valid
+	 * 
+	 * @return
+	 */
+	public boolean isValid() {
+		return validUntil == null || validUntil.after(new Date());
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see java.lang.Object#toString()
 	 */
 	public String toString() {
 		return "{sender: " + sender + ", recipient: " + recipient + ", timestamp: " + timestamp + ", data: " + data
-				+ "}";
+		        + "}";
 	}
 
 }