聊聊dubbo的ConsumerContextFilter

@Activate(group = CONSUMER, order = -10000)
public class ConsumerContextFilter extends ListenableFilter {
​
    public ConsumerContextFilter() {
        super.listener = new ConsumerContextListener();
    }
​
    @Override
    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
        RpcContext.getContext()
                .setInvoker(invoker)
                .setInvocation(invocation)
                .setLocalAddress(NetUtils.getLocalHost(), 0)
                .setRemoteAddress(invoker.getUrl().getHost(),
                        invoker.getUrl().getPort());
        if (invocation instanceof RpcInvocation) {
            ((RpcInvocation) invocation).setInvoker(invoker);
        }
        try {
            RpcContext.removeServerContext();
            return invoker.invoke(invocation);
        } finally {
            RpcContext.removeContext();
        }
    }
​
    static class ConsumerContextListener implements Listener {
        @Override
        public void onResponse(Result appResponse, Invoker<?> invoker, Invocation invocation) {
            RpcContext.getServerContext().setAttachments(appResponse.getAttachments());
        }
​
        @Override
        public void onError(Throwable t, Invoker<?> invoker, Invocation invocation) {
​
        }
    }
}

public class ConsumerContextFilterTest {
    Filter consumerContextFilter = new ConsumerContextFilter();
​
    @Test
    public void testSetContext() {
        URL url = URL.valueOf("test://test:11/test?group=dubbo&version=1.1");
        Invoker<DemoService> invoker = new MyInvoker<DemoService>(url);
        Invocation invocation = new MockInvocation();
        Result asyncResult = consumerContextFilter.invoke(invoker, invocation);
        asyncResult.thenApplyWithContext(result -> {
            assertEquals(invoker, RpcContext.getContext().getInvoker());
            assertEquals(invocation, RpcContext.getContext().getInvocation());
            assertEquals(NetUtils.getLocalHost() + ":0", RpcContext.getContext().getLocalAddressString());
            assertEquals("test:11", RpcContext.getContext().getRemoteAddressString());
            return result;
        });
    }
}