From 208de1f5f5ecac70fd4dfbc3d5c46ae786fad8a5 Mon Sep 17 00:00:00 2001
From: Vitaly Takmazov
Date: Tue, 17 Jul 2018 16:53:43 +0300
Subject: XMPP: cache router stanzas until component connected

---
 .../main/java/com/juick/server/XMPPConnection.java |  1 +
 .../server/xmpp/router/StreamComponentServer.java  |  2 +-
 .../juick/server/xmpp/router/StreamHandler.java    |  2 +-
 .../com/juick/server/xmpp/router/XMPPRouter.java   | 36 ++++++++++++++++++++--
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/juick-server/src/main/java/com/juick/server/XMPPConnection.java b/juick-server/src/main/java/com/juick/server/XMPPConnection.java
index b63a4d47..344860fb 100644
--- a/juick-server/src/main/java/com/juick/server/XMPPConnection.java
+++ b/juick-server/src/main/java/com/juick/server/XMPPConnection.java
@@ -250,6 +250,7 @@ public class XMPPConnection implements StanzaListener, NotificationListener {
             }
         });
         router.addSessionStatusListener(event -> {
+            logger.info("event: " + event.getStatus(), event.getThrowable());
             if (event.getStatus().equals(XmppSession.Status.AUTHENTICATED)) {
                 logger.info("Authenticated, broadcasting...");
                 broadcastPresence(null);
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/router/StreamComponentServer.java b/juick-server/src/main/java/com/juick/server/xmpp/router/StreamComponentServer.java
index 5e2f6f82..a7759afa 100644
--- a/juick-server/src/main/java/com/juick/server/xmpp/router/StreamComponentServer.java
+++ b/juick-server/src/main/java/com/juick/server/xmpp/router/StreamComponentServer.java
@@ -53,6 +53,6 @@ public class StreamComponentServer extends Stream {
             return;
         }
         send(new Handshake().toString());
-        streamHandler.ready();
+        streamHandler.ready(this);
     }
 }
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/router/StreamHandler.java b/juick-server/src/main/java/com/juick/server/xmpp/router/StreamHandler.java
index 43836c2d..048c61ec 100644
--- a/juick-server/src/main/java/com/juick/server/xmpp/router/StreamHandler.java
+++ b/juick-server/src/main/java/com/juick/server/xmpp/router/StreamHandler.java
@@ -6,7 +6,7 @@ import rocks.xmpp.addr.Jid;
  * Created by vitalyster on 01.02.2017.
  */
 public interface StreamHandler {
-    void ready();
+    void ready(StreamComponentServer componentServer);
     void fail(final Exception ex);
     boolean filter(Jid from, Jid to);
     void stanzaReceived(String stanza);
diff --git a/juick-server/src/main/java/com/juick/server/xmpp/router/XMPPRouter.java b/juick-server/src/main/java/com/juick/server/xmpp/router/XMPPRouter.java
index 6edecf05..5a6ee055 100644
--- a/juick-server/src/main/java/com/juick/server/xmpp/router/XMPPRouter.java
+++ b/juick-server/src/main/java/com/juick/server/xmpp/router/XMPPRouter.java
@@ -2,6 +2,7 @@ package com.juick.server.xmpp.router;
 
 import com.juick.server.XMPPServer;
 import com.juick.server.xmpp.s2s.BasicXmppSession;
+import com.juick.server.xmpp.s2s.CacheEntry;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
@@ -30,10 +31,12 @@ import java.io.StringWriter;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.SocketException;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ExecutorService;
 
 @Component
@@ -44,6 +47,7 @@ public class XMPPRouter implements StreamHandler {
     private ExecutorService service;
 
     private final List<StreamComponentServer> connections = Collections.synchronizedList(new ArrayList<>());
+    private final List<CacheEntry> outCache = new CopyOnWriteArrayList<>();
 
     private ServerSocket listener;
 
@@ -135,6 +139,20 @@ public class XMPPRouter implements StreamHandler {
                     if (c.isLoggedIn()) {
                         connOut = c;
                         break;
+                    } else {
+                        logger.info("bouncing stanza to {} component until it will be ready", hostname);
+                        boolean haveCache = false;
+                        for (CacheEntry entry : outCache) {
+                            if (entry.hostname != null && entry.hostname.equals(hostname)) {
+                                entry.xml += xml;
+                                entry.updated = Instant.now();
+                                haveCache = true;
+                                break;
+                            }
+                        }
+                        if (!haveCache) {
+                            outCache.add(new CacheEntry(Jid.of(hostname), xml));
+                        }
                     }
                 }
             }
@@ -172,9 +190,23 @@ public class XMPPRouter implements StreamHandler {
         }
     }
 
-    @Override
-    public void ready() {
+    public String getFromCache(Jid to) {
+        final String[] cache = new String[1];
+        outCache.stream().filter(c -> c.hostname != null && c.hostname.equals(to)).findFirst().ifPresent(c -> {
+            cache[0] = c.xml;
+            outCache.remove(c);
+        });
+        return cache[0];
+    }
 
+    @Override
+    public void ready(StreamComponentServer componentServer) {
+        logger.info("component {} ready", componentServer.to);
+        String cache = getFromCache(componentServer.to);
+        if (cache != null) {
+            logger.debug("sending cache to {}", componentServer.to);
+            componentServer.send(cache);
+        }
     }
 
     @Override
-- 
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