如何使用Spring Cloud Stream应用启动器TCP处理消息

Question

I want to use the Spring Cloud Stream App Starter TCP Source project (maven artifact) in order to be able to receive TCP message through socket/port, process them and then push the result to a message broker (eg RabbitMQ).

This TCP source project seems to do exactly what I want, but it automatically sends the received message to the output channel. So, Is there a clean way to still use the TCP source project but intercept the TCP incoming message to transform them internally before to output them to my message broker?

Answer 1

See aggregation .

You create an aggregated app using the source and processor.

Spring Cloud Stream provides support for aggregating multiple applications together, connecting their input and output channels directly and avoiding the additional cost of exchanging messages via a broker. As of version 1.0 of Spring Cloud Stream, aggregation is supported only for the following types of applications:

sources, sinks, processors ...

They can be aggregated together by creating a sequence of interconnected applications, in which the output channel of an element in the sequence is connected to the input channel of the next element, if it exists. A sequence can start with either a source or a processor, it can contain an arbitrary number of processors and must end with either a processor or a sink.

EDIT

As a work around to the Source autowiring problem, you could try something like...

@EnableBinding(Source.class)
@EnableConfigurationProperties(TcpSourceProperties.class)
public class MyTcpSourceConfiguration {

    @Autowired
    private Source channels;

    @Autowired
    private TcpSourceProperties properties;

    @Bean
    public TcpReceivingChannelAdapter adapter(
            @Qualifier("tcpSourceConnectionFactory") AbstractConnectionFactory connectionFactory) {
        TcpReceivingChannelAdapter adapter = new TcpReceivingChannelAdapter();
        adapter.setConnectionFactory(connectionFactory);
        adapter.setOutputChannelName("toMyProcessor");
        return adapter;
    }

    @ServiceActivator(inputChannel = "toMyProcessor", outputChannel = Source.OUTPUT)
    public byte[] myProcessor(byte[] fromTcp) {
        ...
    }

    @Bean
    public TcpConnectionFactoryFactoryBean tcpSourceConnectionFactory(
            @Qualifier("tcpSourceDecoder") AbstractByteArraySerializer decoder) throws Exception {
        TcpConnectionFactoryFactoryBean factoryBean = new TcpConnectionFactoryFactoryBean();
        factoryBean.setType("server");
        factoryBean.setPort(this.properties.getPort());
        factoryBean.setUsingNio(this.properties.isNio());
        factoryBean.setUsingDirectBuffers(this.properties.isUseDirectBuffers());
        factoryBean.setLookupHost(this.properties.isReverseLookup());
        factoryBean.setDeserializer(decoder);
        factoryBean.setSoTimeout(this.properties.getSocketTimeout());
        return factoryBean;
    }

    @Bean
    public EncoderDecoderFactoryBean tcpSourceDecoder() {
        EncoderDecoderFactoryBean factoryBean = new EncoderDecoderFactoryBean(this.properties.getDecoder());
        factoryBean.setMaxMessageSize(this.properties.getBufferSize());
        return factoryBean;
    }

}