Support intellitrac sync message (fix #227)

2 files changed, 59 insertions, 3 deletions

diff --git a/src/org/traccar/ServerManager.java b/src/org/traccar/ServerManager.java
index 914e818e3..ac97da4f2 100644
--- a/src/org/traccar/ServerManager.java
+++ b/src/org/traccar/ServerManager.java
@@ -791,9 +791,7 @@ public class ServerManager {
             serverList.add(new TrackerServer(this, new ServerBootstrap(), protocol) {
                 @Override
                 protected void addSpecificHandlers(ChannelPipeline pipeline) {
-                    byte delimiter[] = { (byte) '\r', (byte) '\n' };
-                    pipeline.addLast("frameDecoder",
-                            new DelimiterBasedFrameDecoder(1024, ChannelBuffers.wrappedBuffer(delimiter)));
+                    pipeline.addLast("frameDecoder", new IntellitracFrameDecoder(1024));
                     pipeline.addLast("stringDecoder", new StringDecoder());
                     pipeline.addLast("stringEncoder", new StringEncoder());
                     pipeline.addLast("objectDecoder", new IntellitracProtocolDecoder(ServerManager.this));
diff --git a/src/org/traccar/protocol/IntellitracFrameDecoder.java b/src/org/traccar/protocol/IntellitracFrameDecoder.java
new file mode 100644
index 000000000..461186310
--- /dev/null
+++ b/src/org/traccar/protocol/IntellitracFrameDecoder.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2013 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.protocol;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
+
+public class IntellitracFrameDecoder extends DelimiterBasedFrameDecoder {
+
+    private static final int MESSAGE_MINIMUM_LENGTH = 0;
+    
+    private static final byte delimiter[] = { (byte) '\r', (byte) '\n' };
+    
+    public IntellitracFrameDecoder(int maxFrameLength) {
+        super(maxFrameLength, ChannelBuffers.wrappedBuffer(delimiter));
+    }
+    
+    // example of sync header: 0xFA 0xF8 0x1B 0x01 0x81 0x60 0x33 0x3C
+    
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx,
+            Channel channel,
+            ChannelBuffer buf) throws Exception {
+        
+        // Check minimum length
+        if (buf.readableBytes() < MESSAGE_MINIMUM_LENGTH) {
+            return null;
+        }
+        
+        // Check for sync packet
+        if (buf.getUnsignedShort(buf.readerIndex()) == 0xFAF8) {
+            ChannelBuffer syncMessage = buf.readBytes(8);
+            if (channel != null) {
+                channel.write(syncMessage);
+            }
+        }
+
+        return super.decode(ctx, channel, buf);
+    }
+
+}