Netty，ProtoBuf，WebSocket;如何将BinaryWebSocketFrame转换为protobuf类型？

时间：2016-07-13 23:11:02

标签： javascript java netty protocol-buffers protobufjs

我有一台使用protobuf的服务器。处理程序定义为 - 

public class ServerHandler extends SimpleChannelInboundHandler<MyProtoBufType> {

管道如下 - 

pipeline.addLast(new ProtobufVarint32FrameDecoder());
pipeline.addLast(new ProtobufDecoder(MyProtoBufType.getDefaultInstance()));
pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
pipeline.addLast(new ProtobufEncoder());
pipeline.addLast("ServerHandler", new ServerHandler());

有了它和Java客户端一切正常。

现在，为了能够使用Javascript websocket进行连接，我修改了服务器管道，如下所示 - 

pipeline.addLast(new HttpServerCodec());
pipeline.addLast(new HttpObjectAggregator(65536));
pipeline.addLast(new WebSocketServerCompressionHandler());
pipeline.addLast(new WebSocketServerProtocolHandler(WEBSOCKET_PATH, null, true));
pipeline.addLast(new MessageToMessageDecoder<WebSocketFrame>() {
    @Override
    protected void decode(ChannelHandlerContext ctx, WebSocketFrame frame, List<Object> objs) throws Exception {
        ByteBuf buf = ((BinaryWebSocketFrame) frame).content();
        objs.add(buf);
        buf.retain();
    }
});
pipeline.addLast(new ProtobufVarint32FrameDecoder());
pipeline.addLast(new ProtobufDecoder(MyProtoBufType.getDefaultInstance()));
pipeline.addLast(new ProtobufVarint32LengthFieldPrepender());
pipeline.addLast(new ProtobufEncoder());
pipeline.addLast("ServerHandler", new ServerHandler());

以下是基于protobufjs库的Javascript客户端代码 - 

var ProtoBuf = dcodeIO.ProtoBuf,
    builder = ProtoBuf.loadProtoFile("./example.proto"),
    pkg = builder.build("com.example");
    socket = new WebSocket("ws://localhost:8484");

socket.binaryType = "arraybuffer"; 

socket.onopen = function() {
    var login = new pkg.Login({"userName": "hello", "password": "pass"});
    var wrapper = new pkg.MyProtoBufType();
    wrapper.set("login", login);
    socket.send(wrapper.toArrayBuffer());
};

运行上述代码时，服务器在protobuf解码器上失败。以下是stacktrace - 

WARN [nioEventLoopGroup-3-6] (DefaultChannelPipeline.java:1144) - An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
io.netty.handler.codec.DecoderException: com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field.  This could mean either than the input has been truncated or that an embedded message misreported its own length.
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:98)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:288)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:275)
    at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:391)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:243)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86)
    at io.netty.handler.codec.http.websocketx.Utf8FrameValidator.channelRead(Utf8FrameValidator.java:77)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler$1.channelRead(WebSocketServerProtocolHandler.java:159)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:288)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:262)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.handler.logging.LoggingHandler.channelRead(LoggingHandler.java:233)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:327)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1336)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:349)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:335)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:911)
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:123)
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:544)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:485)
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:399)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:371)
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:742)
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:145)
    at java.lang.Thread.run(Unknown Source)
Caused by: com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field.  This could mean either than the input has been truncated or that an embedded message misreported its own length.
    at com.google.protobuf.InvalidProtocolBufferException.truncatedMessage(InvalidProtocolBufferException.java:70)
    at com.google.protobuf.CodedInputStream.readRawBytesSlowPath(CodedInputStream.java:1187)
    at com.google.protobuf.CodedInputStream.readBytes(CodedInputStream.java:517)
    at com.google.protobuf.UnknownFieldSet$Builder.mergeFieldFrom(UnknownFieldSet.java:501)
    at com.google.protobuf.UnknownFieldSet$Builder.mergeFrom(UnknownFieldSet.java:478)
    at com.google.protobuf.UnknownFieldSet$Builder.mergeFrom(UnknownFieldSet.java:596)
    at com.google.protobuf.UnknownFieldSet$Builder.mergeFrom(UnknownFieldSet.java:281)
    at com.google.protobuf.CodedInputStream.readGroup(CodedInputStream.java:424)
    at com.google.protobuf.UnknownFieldSet$Builder.mergeFieldFrom(UnknownFieldSet.java:505)
    at com.google.protobuf.GeneratedMessage.parseUnknownField(GeneratedMessage.java:205)
    at com.exmaple.MyProtoBufType.<init>(CallBreakProtocol.java:15290)
    at com.exmaple.MyProtoBufType.<init>(CallBreakProtocol.java:15273)
    at com.exmaple.MyProtoBufType$1.parsePartialFrom(CallBreakProtocol.java:15638)
    at com.exmaple.MyProtoBufType$1.parsePartialFrom(CallBreakProtocol.java:1)
    at com.google.protobuf.AbstractParser.parsePartialFrom(AbstractParser.java:137)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:168)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:174)
    at com.google.protobuf.AbstractParser.parseFrom(AbstractParser.java:49)
    at io.netty.handler.codec.protobuf.ProtobufDecoder.decode(ProtobufDecoder.java:121)
    at io.netty.handler.codec.protobuf.ProtobufDecoder.decode(ProtobufDecoder.java:64)
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:88)
    ... 52 more

有没有人一起使用Netty，ProtoBuf和WebSocket？如何实现这一目标？

1 个答案:

答案 0 :(得分：0)

我只需删除以下内容 - 

pipeline.addLast(new ProtobufVarint32FrameDecoder());

现在工作正常。

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