Try to use preconfigured RestTemplate instance by default in HttpRequestExecutingMessageHandler [INT-4460]

[spring-operator]

Vyacheslav opened INT-4460 and commented

Currently HttpRequestExecutingMessageHandler creates new instance of RestTemplate if no one specified explicitly.

It may be more convenient to use preconfigured RestTemplate bean in current ApplicationContext. If there no RestTemplate beans then default to new instance.

Example:

@Configuration
public class RestTemplateConfig {

    @Bean
    public RestTemplate restTemplate() {
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setRequestFactory(...);
        return restTemplate;
    }

}

@Configuration
public class TestFlowConfig {

    @Bean
    public IntegrationFlow test() {
        return IntegrationFlows.from(Http.inboundGateway("/test"))
            .handle(Http.outboundGateway("http://127.0.0.1/test")); // implicitly uses RestTemplate declared in RestTemplateConfig
            .get();
    }

}

---

Affects: 5.0.4

[spring-operator]

Artem Bilan commented

How about this solution so far?

@Autowired
private RestTemplate restTemplate;
...
private HttpMessageHandlerSpec httOutboundGateway(String uri) {
	return Http.outboundGateway(uri, this.restTemplate);
}
...
@Bean
public IntegrationFlow test() {
     return IntegrationFlows.from(Http.inboundGateway("/test"))
           .handle(httOutboundGateway("http://127.0.0.1/test")); 
           .get();
}

The problem that make me reluctant to implement your request is that Spring Integration components don't do any auto-injection magic for user-defined beans. Plus this HttpRequestExecutingMessageHandler is a bit complex component to break it for potential auto-injection. Also pay attention how its restTemplate property is final. That's another argument do not implement auto-injection - for performance reason at runtime.

[spring-operator]

Artem Bilan commented

As we discussed we are not going to introduce any auto-injection complexity.