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如何配置Netty管道以用作HTTP代理

javahttpnettyhttp-proxy
3

我使用Netty写了一个小的Http代理，它已经运行良好一段时间了。今天，在日志文件中出现了来自单个客户端的奇怪异常：

java.lang.UnsupportedOperationException: unsupported message type: DefaultFullHttpResponse (expected: ByteBuf, FileRegion)
    at io.netty.channel.nio.AbstractNioByteChannel.filterOutboundMessage(AbstractNioByteChannel.java:276) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannel$AbstractUnsafe.write(AbstractChannel.java:654) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.DefaultChannelPipeline$HeadContext.write(DefaultChannelPipeline.java:1054) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:658) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:716) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:651) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.handler.logging.LoggingHandler.write(LoggingHandler.java:289) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:658) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:716) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:706) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:741) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.handler.codec.http.HttpObjectAggregator.decode(HttpObjectAggregator.java:131) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.handler.codec.http.HttpObjectAggregator.decode(HttpObjectAggregator.java:54) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:89) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:163) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.handler.logging.LoggingHandler.channelRead(LoggingHandler.java:283) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:130) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:511) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:137) [netty-all-4.0.23.Final.jar:4.0.23.Final]
    at java.lang.Thread.run(Thread.java:745) [na:1.7.0_79]

查看源代码后，似乎发生了问题，当响应POST请求时发送100 Continue状态（HttpObjectAggregator 第130-139行）

if (is100ContinueExpected(m)) {
    ctx.writeAndFlush(CONTINUE).addListener(new ChannelFutureListener() {
        @Override
        public void operationComplete(ChannelFuture future) 
                throws Exception {
            if (!future.isSuccess()) {
                ctx.fireExceptionCaught(future.cause());
            }
        }
    });
}

事实上，导致问题的客户端似乎是唯一一个在请求中发送 Expect: 100-continue 标头。这使我认为我的处理程序管道可能设置不正确：

p.addLast(new LoggingHandler(LogLevel.DEBUG));
p.addLast(new HttpRequestDecoder());
p.addLast(new HttpObjectAggregator(MAX_CONTENT_LENGTH));
p.addLast(new HttpResponseEncoder());
p.addLast(new MyHandler(...));

API文档中关于HttpObjectAggregator的说明提到：

请注意，在ChannelPipeline中使用HttpObjectAggregator之前必须拥有HttpResponseEncoder或HttpRequestEncoder。

因此，我认为应该在管道中先使用HttpRequestDecoder和HttpResponseEncoder，然后再使用HttpObjectAggregator。这可能是我的问题所在。
你尝试过改变顺序吗（聚合器在你的MyHandler之前成为最后一个）？ - Frederic Brégier
1个回答
2

你试过更改顺序吗（将聚合器放在 MyHandler 之前的最后一个）？

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