Deprecate+Remove ability to provide a custom ClientHttpRequestFactory instance in RestTemplateBuilder · Issue #11255 · spring-projects/spring-boot

tvahrst · 2017-12-04T19:49:14.000Z

# Problem When `ClientHttpRequestFactory` isn't explicitly set, `RestTemplateBuilder` invokes `detectRequestFactory()` internally for every new RestTemplate. So every RestTemplate gets it's own 'prototype' `ClientHttpRequestFactory`. On the other hand, when `ClientHttpRequestFactory` **is** explicitly set in RestTemplateBuilder, all subsequent build RestTemplates get the same 'singleton' `ClientHttpRequestFactory`. During `ResttemplateBuilder.build()` method, the current `ClientHttpRequestFactory` becomes customized with timout values (connection-timeout and read-timeout). This leads to problems when multiple RestTemplates with different timeout values are created. We have a Spring-Boot application that provides a `RestTemplateBuilder` bean which is already provided with a `HttpComponentsHttpRequestFactory`. Two service beans uses the `RestTemplateBuilder` to create a custom RestTemplate with different connection-timouts: ``` public class TestResttemplateBuilderTimeouts { private static Logger logger = LoggerFactory.getLogger(TestResttemplateBuilderTimeouts.class); @Test public void test1(){ // globally prepared ResttemplateBuilder: HttpComponentsClientHttpRequestFactory f = new HttpComponentsClientHttpRequestFactory(); RestTemplateBuilder builder = new RestTemplateBuilder().requestFactory(f); // in service bean 1: RestTemplate rt1 = builder.setConnectTimeout(10000).build(); // in service bean 2 RestTemplate rt2 = builder.setConnectTimeout(1000).build(); // service bean 1 uses RestTemplate expecting connectionTime 10 Secs. // but Connection-Timeout is only 1 Sec. try { logger.debug("start ..."); String s = rt1.getForObject("http://www.google.com:81", String.class); }finally { logger.debug("stop ..."); } } } ``` # Workaround Our current Workaround: we do not set `HttpComponentsHttpRequestFactory` explicitly but let `RestTemplateBuilder` detect this factory. For customizing (i.e. setting max-connections und max-connections-per-route) we use the systemproperties approach of the httpcomponents httpclient. # Possible Solution (breaking the api in *spring-web*) As far as I can see, all supported http implementations (httpcommons, netty, okhttp, okhttp3, SimpleClientHttpRequestFactory) allow a **per request** setting of connection- and read-timeouts. So a solution would be not to inject these timeouts into the `ClientHttpRequestFactory` but hold it as 'RequestSettings' in the `RestTemplateBuilder` and give them to every new created RestTemplate. The RestTemplate in turn has to provide these settings as additional method-parameter to `ClientHttpRequestFactory.createRequest()`. This will however break the api of ClientHttpRequestFactory... ``` public interface ClientHttpRequestFactory { /** * Create a new {@link ClientHttpRequest} for the specified URI and HTTP method. * The returned request can be written to, and then executed by calling * {@link ClientHttpRequest#execute()}. * @param uri the URI to create a request for * @param httpMethod the HTTP method to execute * @param requestSettings Request-Settings, containing for instance connection- and read-timeouts * @return the created request * @throws IOException in case of I/O errors */ ClientHttpRequest createRequest(URI uri, HttpMethod httpMethod, RequestSettings requestSettings) throws IOException; ```