Spring RestTemplate拦截器不执行请求

Question

When I configure RestTemplate use HttpClient then my interceptor only execute for first time, in second time it'll hang up when execute, in this block below. There is no exception, I don't know why! If I remove httpClient then no problem. (My interceptor intention is catch 401 unauthorized status to refresh access token)

if (url.contains("/auth") || url.contains("/custcare-common")) {
    return execution.execute(request, body);
}

Full code below:

public class RestTemplateHeaderInterceptor implements ClientHttpRequestInterceptor {

@Override
public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution)
        throws IOException {
    String url = request.getURI().getPath();
    if (url.contains("/auth") || url.contains("/custcare-common")) {
        return execution.execute(request, body);
    }

    HttpSession session = SessionBean.getSession();
    if (session != null) {
        // check header does not has token then add to header
        if (request.getHeaders().isEmpty() || !request.getHeaders().containsKey(HttpHeaders.AUTHORIZATION)) {
            // add jwt token to header
            Object accessToken = session.getAttribute(AppConstants.Token.ACCESS_TOKEN);
            if (accessToken != null) {
                request.getHeaders().add(HttpHeaders.AUTHORIZATION, SecurityConstants.TOKEN_PREFIX + accessToken);
            }
        }

        // refresh token when expire
        ClientHttpResponse response = execution.execute(request, body);
        if (response.getStatusCode() == HttpStatus.UNAUTHORIZED) {
            Object refreshToken = session.getAttribute(AppConstants.Token.REFRESH_TOKEN);
            if (refreshToken != null) {
                TokenData newTokenData = getNewToken(refreshToken.toString());
                if (newTokenData != null) {
                    session.setAttribute(AppConstants.Token.ACCESS_TOKEN, newTokenData.getAccessToken());
                    session.setAttribute(AppConstants.Token.REFRESH_TOKEN, newTokenData.getRefreshToken());

                    request.getHeaders().set(HttpHeaders.AUTHORIZATION, SecurityConstants.TOKEN_PREFIX + newTokenData.getAccessToken());

                    return execution.execute(request, body);
                }
            }
        }
    }

    return execution.execute(request, body);
}

private TokenData getNewToken(String refreshToken) {
    TokenData tokenData = null;

    RefreshTokenRequest request = new RefreshTokenRequest();
    request.setRefreshToken(refreshToken);

    MessagesResponse<TokenData> response = RestUtil.post(RestUtil.getCcApiUrl("cc-api.authen.refresh-token"), request, new ParameterizedTypeReference<MessagesResponse<TokenData>>() {});

    if (response != null) {
        tokenData = response.getData();
    }

    return tokenData;
}

}

My RestTemplate config:

@Configuration
public class RestTemplateConfig {

    @Bean
    public PoolingHttpClientConnectionManager poolingHttpClientConnectionManager() {
        PoolingHttpClientConnectionManager result = new PoolingHttpClientConnectionManager();
        result.setMaxTotal(20);
        return result;
    }

    @Bean
    public RequestConfig requestConfig() {
        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(60000).setConnectTimeout(60000)
                .setSocketTimeout(60000).build();

        return requestConfig;
    }

    @Bean
    public CloseableHttpClient httpClient() throws KeyManagementException, NoSuchAlgorithmException, KeyStoreException {
        TrustStrategy trustStrategy = new TrustStrategy() {
            @Override
            public boolean isTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
                return true;
            }
        };
        SSLContext sslContext = SSLContexts.custom().loadTrustMaterial(null, trustStrategy).build();
        SSLConnectionSocketFactory csf = new SSLConnectionSocketFactory(sslContext, new NoopHostnameVerifier());
        CloseableHttpClient result = HttpClientBuilder.create()
                .setConnectionManager(poolingHttpClientConnectionManager())
                .setDefaultRequestConfig(requestConfig())
                .setSSLSocketFactory(csf)
                .build();

        return result;
    }

    @Bean
    @Primary
    public RestTemplate restTemplate() throws KeyManagementException, NoSuchAlgorithmException, KeyStoreException {
        HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(httpClient());

        RestTemplate restTemplate = new RestTemplate(requestFactory);

        restTemplate.setErrorHandler(new RestResponseErrorHandler());

        List<ClientHttpRequestInterceptor> interceptors = restTemplate.getInterceptors();
        if (interceptors.isEmpty()) {
            interceptors = new ArrayList<>();
        }
        interceptors.add(new RestTemplateHeaderInterceptor());
        restTemplate.setInterceptors(interceptors);

        return restTemplate;
    }
}

Finally, I done deal with this issue by setting DefaultMaxPerRoute, but I still confuse about this. :D

@Bean
public PoolingHttpClientConnectionManager poolingHttpClientConnectionManager() {
    PoolingHttpClientConnectionManager result = new PoolingHttpClientConnectionManager();
    result.setMaxTotal(100);
    result.setDefaultMaxPerRoute(100);
    return result;
}

Answer 1

Can you try this

instead of below block of code ie

HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(httpClient());
RestTemplate restTemplate = new RestTemplate(requestFactory);

try

RestTemplate restTemplate = new RestTemplate();
restTemplate.setRequestFactory(new BufferingClientHttpRequestFactory(clientHttpRequestFactory()));

see if this works for you.

Answer 2

This is an old question, but as people still come here via their search engine of choice and there was confusion about why the change "worked", this might save someone some time:

The issue stems from the original http response not being consumed in your custom Interceptor class, if a 401 is the response code.

Upping the ConnectionPool capacity only hides the problem (and may "fix" the issue for the application run), but does not actually release the connection and fix the problem.

In your interceptor class, the 401 response that is never consumed down the stream you do a request, the 401 response needs to be manually consumed as its never handed down.

If a response has a 401 status, you execute a new request, and the original 401 response just blocks a connection forever. That's why there are no more connections available after a certain number of 401 requests (5 is default asfaik). As no more connections are available in the ConnectionPool after those 5 401 requests, the thread just hangs around and the execute call never finishes since it's waiting for a free connection to use.

The required change? One line of code to save us the headache and the workaround, close the response after the 401 check (or any time a response is not returned):

public class RestTemplateHeaderInterceptor implements ClientHttpRequestInterceptor {

@Override
public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution)
        throws IOException {
        // ... omitted ...

        // refresh token when expire
        // THIS RESPONSE IS NEVER HANDLED
        ClientHttpResponse response = execution.execute(request, body);
        if (response.getStatusCode() == HttpStatus.UNAUTHORIZED) {
            // Close response only needed for the status code and refresh
            response.close();
            // Continue on with your code.
            Object refreshToken = session.getAttribute(AppConstants.Token.REFRESH_TOKEN);
            if (refreshToken != null) {
                // ... omitted ...
                    return execution.execute(request, body);
                }
            }
        }
    }

    return execution.execute(request, body);
}

I'll not comment on the response not being used/returned if the code is not 401, it may make sense to just use that response and return it if there is nothing in this response that you want/need to handle in this interceptor.

Also note that a rerequest in an interceptor as done in this code for a 401 will not be passed through other interceptors added to the interceptorlist for the httpclient.