1 files changed, 55 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/protocol/JsonFrameDecoder.java b/src/main/java/org/traccar/protocol/JsonFrameDecoder.java
new file mode 100644
index 000000000..b2d7fbd53
--- /dev/null
+++ b/src/main/java/org/traccar/protocol/JsonFrameDecoder.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2021 Anton Tananaev (anton@traccar.org)
+ *
+ * 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 io.netty.buffer.ByteBuf;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+import org.traccar.BaseFrameDecoder;
+
+public class JsonFrameDecoder extends BaseFrameDecoder {
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
+
+        int startIndex = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '{');
+        if (startIndex >= 0) {
+
+            buf.readerIndex(startIndex);
+
+            int currentIndex = startIndex + 1;
+            int nesting = 1;
+            while (currentIndex < buf.writerIndex() && nesting > 0) {
+                byte currentByte = buf.getByte(currentIndex);
+                if (currentByte == '{') {
+                    nesting += 1;
+                } else if (currentByte == '}') {
+                    nesting -= 1;
+                }
+                currentIndex += 1;
+            }
+
+            if (nesting == 0) {
+                return buf.readRetainedSlice(currentIndex - startIndex);
+            }
+
+        }
+
+        return null;
+    }
+
+}