Merge pull request #10639 from 4Science/task/main/DURACOM-109

Proxy Configuration and Connection Leak using HTTP Clients

checkstyle-suppressions.xml

@@ -7,4 +7,5 @@
     <!-- TODO: We should have these turned on. But, currently there's a known bug with indentation checks
          on JMockIt Expectations blocks and similar. See https://github.com/checkstyle/checkstyle/issues/3739 -->
     <suppress checks="Indentation" files="src[/\\]test[/\\]java"/>
+    <suppress checks="Regexp" files="DSpaceHttpClientFactory\.java"/>
 </suppressions>

checkstyle.xml

@@ -136,5 +136,22 @@ For more information on CheckStyle configurations below, see: http://checkstyle.
         <module name="OneStatementPerLine"/>
         <!-- Require that "catch" statements are not empty (must at least contain a comment) -->
         <module name="EmptyCatchBlock"/>
+
+        <!-- Require to use DSpaceHttpClientFactory.getClient() statement instead of creating directly the client -->
+        <module name="Regexp">
+            <property name="format" value="HttpClientBuilder\.create\s*\(\s*\)" />
+            <property name="message" value="Use DSpaceHttpClientFactory.getClient() instead of HttpClientBuilder.create()" />
+            <property name="illegalPattern" value="true"/>
+            <property name="ignoreComments" value="true"/>
+        </module>
+        <!-- Require to use DSpaceHttpClientFactory.getClient() statement instead of creating directly the client -->
+        <module name="Regexp">
+            <property name="format" value="HttpClients\.createDefault\s*\(\s*\)" />
+            <property name="message" value="Use DSpaceHttpClientFactory.getClient() instead of HttpClients.createDefault()" />
+            <property name="illegalPattern" value="true"/>
+            <property name="ignoreComments" value="true"/>
+        </module>
+
+
     </module>
 </module>

dspace-api/pom.xml

@@ -774,6 +774,7 @@
             <version>1.19.0</version>
             <scope>test</scope>
         </dependency>
+
         <!-- Used for Solr core export/import -->
         <dependency>
             <groupId>com.opencsv</groupId>
@@ -942,5 +943,10 @@
             </exclusions>
         </dependency>
 
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>mockwebserver</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

dspace-api/src/main/java/org/dspace/app/client/DSpaceHttpClientFactory.java

@@ -0,0 +1,152 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.app.client;
+
+import static org.apache.commons.collections4.ListUtils.emptyIfNull;
+
+import java.util.List;
+
+import org.apache.http.HttpRequestInterceptor;
+import org.apache.http.HttpResponseInterceptor;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+import org.dspace.services.ConfigurationService;
+import org.dspace.utils.DSpace;
+import org.springframework.beans.factory.annotation.Autowired;
+
+/**
+ * Factory of {@link HttpClient} with common configurations.
+ *
+ * @author Luca Giamminonni (luca.giamminonni at 4science.it)
+ *
+ */
+public class DSpaceHttpClientFactory {
+
+    @Autowired
+    private ConfigurationService configurationService;
+
+    @Autowired
+    private DSpaceProxyRoutePlanner proxyRoutePlanner;
+
+    @Autowired(required = false)
+    private List<HttpRequestInterceptor> requestInterceptors;
+
+    @Autowired(required = false)
+    private List<HttpResponseInterceptor> responseInterceptors;
+
+    /**
+     * Get an instance of {@link DSpaceHttpClientFactory} from the Spring context.
+     * @return the bean instance
+     */
+    public static DSpaceHttpClientFactory getInstance() {
+        return new DSpace().getSingletonService(DSpaceHttpClientFactory.class);
+    }
+
+    /**
+     * Build an instance of {@link HttpClient} setting the proxy if configured.
+     *
+     * @return the client
+     */
+    public CloseableHttpClient build() {
+        return build(HttpClientBuilder.create(), true);
+    }
+
+    /**
+     * return a Builder if an instance of {@link HttpClient} pre-setting the proxy if configured.
+     *
+     * @return the client
+     */
+    public HttpClientBuilder builder(boolean setProxy) {
+        HttpClientBuilder clientBuilder = HttpClientBuilder.create();
+        if (setProxy) {
+            clientBuilder.setRoutePlanner(proxyRoutePlanner);
+        }
+        getRequestInterceptors().forEach(clientBuilder::addInterceptorLast);
+        getResponseInterceptors().forEach(clientBuilder::addInterceptorLast);
+        return clientBuilder;
+    }
+
+    /**
+     * Build an instance of {@link HttpClient} without setting the proxy, even if
+     * configured.
+     *
+     * @return the client
+     */
+    public CloseableHttpClient buildWithoutProxy() {
+        return build(HttpClientBuilder.create(), false);
+    }
+
+    /**
+     * Build an instance of {@link HttpClient} setting the proxy if configured,
+     * disabling automatic retries and setting the maximum total connection.
+     *
+     * @param  maxConnTotal the maximum total connection value
+     * @return              the client
+     */
+    public CloseableHttpClient buildWithoutAutomaticRetries(int maxConnTotal) {
+        HttpClientBuilder clientBuilder = HttpClientBuilder.create()
+                .disableAutomaticRetries()
+                .setMaxConnTotal(maxConnTotal);
+        return build(clientBuilder, true);
+    }
+
+    /**
+     * Build an instance of {@link HttpClient} setting the proxy if configured with
+     * the given request configuration.
+     * @param  requestConfig the request configuration
+     * @return               the client
+     */
+    public CloseableHttpClient buildWithRequestConfig(RequestConfig requestConfig) {
+        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create()
+                .setDefaultRequestConfig(requestConfig);
+        return build(httpClientBuilder, true);
+    }
+
+    private CloseableHttpClient build(HttpClientBuilder clientBuilder, boolean setProxy) {
+        if (setProxy) {
+            clientBuilder.setRoutePlanner(proxyRoutePlanner);
+        }
+        getRequestInterceptors().forEach(clientBuilder::addInterceptorLast);
+        getResponseInterceptors().forEach(clientBuilder::addInterceptorLast);
+        return clientBuilder.build();
+    }
+
+    public ConfigurationService getConfigurationService() {
+        return configurationService;
+    }
+
+    public void setConfigurationService(ConfigurationService configurationService) {
+        this.configurationService = configurationService;
+    }
+
+    public List<HttpRequestInterceptor> getRequestInterceptors() {
+        return emptyIfNull(requestInterceptors);
+    }
+
+    public void setRequestInterceptors(List<HttpRequestInterceptor> requestInterceptors) {
+        this.requestInterceptors = requestInterceptors;
+    }
+
+    public List<HttpResponseInterceptor> getResponseInterceptors() {
+        return emptyIfNull(responseInterceptors);
+    }
+
+    public void setResponseInterceptors(List<HttpResponseInterceptor> responseInterceptors) {
+        this.responseInterceptors = responseInterceptors;
+    }
+
+    public DSpaceProxyRoutePlanner getProxyRoutePlanner() {
+        return proxyRoutePlanner;
+    }
+
+    public void setProxyRoutePlanner(DSpaceProxyRoutePlanner proxyRoutePlanner) {
+        this.proxyRoutePlanner = proxyRoutePlanner;
+    }
+}

dspace-api/src/main/java/org/dspace/app/client/DSpaceProxyRoutePlanner.java

@@ -0,0 +1,73 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.app.client;
+
+import java.util.Arrays;
+
+import org.apache.commons.lang3.ArrayUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.http.HttpException;
+import org.apache.http.HttpHost;
+import org.apache.http.HttpRequest;
+import org.apache.http.impl.conn.DefaultRoutePlanner;
+import org.apache.http.protocol.HttpContext;
+import org.dspace.services.ConfigurationService;
+
+/**
+ * Extension of {@link DefaultRoutePlanner} that determine the proxy based on
+ * the configuration service, ignoring configured hosts.
+ *
+ * @author Luca Giamminonni (luca.giamminonni at 4science.it)
+ *
+ */
+public class DSpaceProxyRoutePlanner extends DefaultRoutePlanner {
+
+    private ConfigurationService configurationService;
+
+    public DSpaceProxyRoutePlanner(ConfigurationService configurationService) {
+        super(null);
+        this.configurationService = configurationService;
+    }
+
+    @Override
+    protected HttpHost determineProxy(HttpHost target, HttpRequest request, HttpContext context) throws HttpException {
+        if (isTargetHostConfiguredToBeIgnored(target)) {
+            return null;
+        }
+        String proxyHost = configurationService.getProperty("http.proxy.host");
+        String proxyPort = configurationService.getProperty("http.proxy.port");
+        if (StringUtils.isAnyBlank(proxyHost, proxyPort)) {
+            return null;
+        }
+        try {
+            return new HttpHost(proxyHost, Integer.parseInt(proxyPort), "http");
+        } catch (NumberFormatException e) {
+            throw new RuntimeException("Invalid proxy port configuration: " + proxyPort);
+        }
+    }
+
+    private boolean isTargetHostConfiguredToBeIgnored(HttpHost target) {
+        String[] hostsToIgnore = configurationService.getArrayProperty("http.proxy.hosts-to-ignore");
+        if (ArrayUtils.isEmpty(hostsToIgnore)) {
+            return false;
+        }
+        return Arrays.stream(hostsToIgnore)
+                .anyMatch(host -> matchesHost(host, target.getHostName()));
+    }
+
+    private boolean matchesHost(String hostPattern, String hostName) {
+        if (hostName.equals(hostPattern)) {
+            return true;
+        } else if (hostPattern.startsWith("*")) {
+            return hostName.endsWith(StringUtils.removeStart(hostPattern, "*"));
+        } else if (hostPattern.endsWith("*")) {
+            return hostName.startsWith(StringUtils.removeEnd(hostPattern, "*"));
+        }
+        return false;
+    }
+}

dspace-api/src/main/java/org/dspace/app/ldn/action/SendLDNMessageAction.java

@@ -18,9 +18,9 @@ import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.app.ldn.model.Notification;
 import org.dspace.content.Item;
 import org.dspace.core.Context;
@@ -34,22 +34,14 @@ public class SendLDNMessageAction implements LDNAction {
 
     private static final Logger log = LogManager.getLogger(SendLDNMessageAction.class);
 
-    private CloseableHttpClient client = null;
+    private CloseableHttpClient client;
 
     public SendLDNMessageAction() {
-        HttpClientBuilder builder = HttpClientBuilder.create();
-        client = builder
-            .disableAutomaticRetries()
-            .setMaxConnTotal(5)
-            .build();
     }
 
     public SendLDNMessageAction(CloseableHttpClient client) {
-        this();
-        if (client != null) {
         this.client = client;
     }
-    }
 
     @Override
     public LDNActionStatus execute(Context context, Notification notification, Item item) throws Exception {
@@ -66,9 +58,10 @@ public class SendLDNMessageAction implements LDNAction {
         // NOTE: Github believes there is a "Potential server-side request forgery due to a user-provided value"
         // This is a false positive because the LDN Service URL is configured by the user from DSpace.
         // See the frontend configuration at [dspace.ui.url]/admin/ldn/services
-        try (
+        if (client == null) {
-            CloseableHttpResponse response = client.execute(httpPost);
+            client = DSpaceHttpClientFactory.getInstance().buildWithoutAutomaticRetries(5);
-            ) {
+        }
+        try (CloseableHttpResponse response = client.execute(httpPost)) {
             if (isSuccessful(response.getStatusLine().getStatusCode())) {
                 result = LDNActionStatus.CONTINUE;
             } else if (isRedirect(response.getStatusLine().getStatusCode())) {
@@ -77,6 +70,7 @@ public class SendLDNMessageAction implements LDNAction {
         } catch (Exception e) {
             log.error(e);
         }
+        client.close();
         return result;
     }
 
@@ -91,9 +85,9 @@ public class SendLDNMessageAction implements LDNAction {
             statusCode == HttpStatus.SC_TEMPORARY_REDIRECT;
     }
 
-    private LDNActionStatus handleRedirect(CloseableHttpResponse oldresponse,
+    private LDNActionStatus handleRedirect(CloseableHttpResponse oldResponse,
                                         HttpPost request) throws HttpException {
-        Header[] urls = oldresponse.getHeaders(HttpHeaders.LOCATION);
+        Header[] urls = oldResponse.getHeaders(HttpHeaders.LOCATION);
         String url = urls.length > 0 && urls[0] != null ? urls[0].getValue() : null;
         if (url == null) {
             throw new HttpException("Error following redirect, unable to reach"
@@ -102,17 +96,14 @@ public class SendLDNMessageAction implements LDNAction {
         LDNActionStatus result = LDNActionStatus.ABORT;
         try {
             request.setURI(new URI(url));
-            try (
+            try (CloseableHttpResponse response = client.execute(request)) {
-                CloseableHttpResponse response = client.execute(request);
-                ) {
                 if (isSuccessful(response.getStatusLine().getStatusCode())) {
-                    return LDNActionStatus.CONTINUE;
+                    result = LDNActionStatus.CONTINUE;
                 }
             }
         } catch (Exception e) {
             log.error("Error following redirect:", e);
         }
-
+        return result;
-        return LDNActionStatus.ABORT;
     }
 }

dspace-api/src/main/java/org/dspace/app/sherpa/SHERPAService.java

@@ -17,15 +17,15 @@ import jakarta.annotation.PostConstruct;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.http.HttpEntity;
-import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
 import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.app.sherpa.v2.SHERPAPublisherResponse;
 import org.dspace.app.sherpa.v2.SHERPAResponse;
 import org.dspace.app.sherpa.v2.SHERPAUtils;
@@ -45,8 +45,6 @@ import org.springframework.cache.annotation.Cacheable;
  */
 public class SHERPAService {
 
-    private CloseableHttpClient client = null;
-
     private int maxNumberOfTries;
     private long sleepBetweenTimeouts;
     private int timeout = 5000;
@@ -59,19 +57,6 @@ public class SHERPAService {
     @Autowired
     ConfigurationService configurationService;
 
-    /**
-     * Create a new HTTP builder with sensible defaults in constructor
-     */
-    public SHERPAService() {
-        HttpClientBuilder builder = HttpClientBuilder.create();
-        // httpclient 4.3+ doesn't appear to have any sensible defaults any more. Setting conservative defaults as
-        // not to hammer the SHERPA service too much.
-        client = builder
-            .disableAutomaticRetries()
-            .setMaxConnTotal(5)
-            .build();
-    }
-
     /**
      * Complete initialization of the Bean.
      */
@@ -132,14 +117,14 @@ public class SHERPAService {
                 timeout,
                 sleepBetweenTimeouts));
 
-            try {
+            try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().buildWithoutAutomaticRetries(5)) {
                 Thread.sleep(sleepBetweenTimeouts);
 
                 // Construct a default HTTP method (first result)
                 method = constructHttpGet(type, field, predicate, value, start, limit);
 
                 // Execute the method
-                HttpResponse response = client.execute(method);
+                try (CloseableHttpResponse response = client.execute(method)) {
                     int statusCode = response.getStatusLine().getStatusCode();
 
                     log.debug(response.getStatusLine().getStatusCode() + ": "
@@ -173,6 +158,7 @@ public class SHERPAService {
                         log.debug("Empty SHERPA response body for query on " + value);
                         sherpaResponse = new SHERPAPublisherResponse("SHERPA/RoMEO returned no response");
                     }
+                }
             } catch (URISyntaxException e) {
                 String errorMessage = "Error building SHERPA v2 API URI: " + e.getMessage();
                 log.error(errorMessage, e);
@@ -235,14 +221,14 @@ public class SHERPAService {
                 timeout,
                 sleepBetweenTimeouts));
 
-            try {
+            try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().buildWithoutAutomaticRetries(5)) {
                 Thread.sleep(sleepBetweenTimeouts);
 
                 // Construct a default HTTP method (first result)
                 method = constructHttpGet(type, field, predicate, value, start, limit);
 
                 // Execute the method
-                HttpResponse response = client.execute(method);
+                try (CloseableHttpResponse response = client.execute(method)) {
                     int statusCode = response.getStatusLine().getStatusCode();
 
                     log.debug(response.getStatusLine().getStatusCode() + ": "
@@ -275,6 +261,7 @@ public class SHERPAService {
                         log.debug("Empty SHERPA response body for query on " + value);
                         sherpaResponse = new SHERPAResponse("SHERPA/RoMEO returned no response");
                     }
+                }
             } catch (URISyntaxException e) {
                 String errorMessage = "Error building SHERPA v2 API URI: " + e.getMessage();
                 log.error(errorMessage, e);

dspace-api/src/main/java/org/dspace/app/util/WebAppServiceImpl.java

@@ -13,12 +13,12 @@ import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpHead;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.app.util.dao.WebAppDAO;
 import org.dspace.app.util.service.WebAppService;
 import org.dspace.core.Context;
@@ -77,8 +77,8 @@ public class WebAppServiceImpl implements WebAppService {
             for (WebApp app : webApps) {
                 method = new HttpHead(app.getUrl());
                 int status;
-                try (CloseableHttpClient client = HttpClientBuilder.create().build()) {
+                try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
-                    HttpResponse response = client.execute(method);
+                    CloseableHttpResponse response = client.execute(method);
                     status = response.getStatusLine().getStatusCode();
                 }
                 if (status != HttpStatus.SC_OK) {

dspace-api/src/main/java/org/dspace/authenticate/oidc/impl/OidcClientImpl.java

@@ -22,12 +22,13 @@ import org.apache.commons.io.IOUtils;
 import org.apache.http.HttpEntity;
 import org.apache.http.HttpResponse;
 import org.apache.http.NameValuePair;
-import org.apache.http.client.HttpClient;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpUriRequest;
 import org.apache.http.client.methods.RequestBuilder;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.message.BasicNameValuePair;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.authenticate.oidc.OidcClient;
 import org.dspace.authenticate.oidc.OidcClientException;
 import org.dspace.authenticate.oidc.model.OidcTokenResponseDTO;
@@ -83,21 +84,17 @@ public class OidcClientImpl implements OidcClient {
     }
 
     private <T> T executeAndParseJson(HttpUriRequest httpUriRequest, Class<T> clazz) {
-
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
-        HttpClient client = HttpClientBuilder.create().build();
-
             return executeAndReturns(() -> {
-
+                CloseableHttpResponse response = client.execute(httpUriRequest);
-            HttpResponse response = client.execute(httpUriRequest);
-
                 if (isNotSuccessfull(response)) {
                     throw new OidcClientException(getStatusCode(response), formatErrorMessage(response));
                 }
-
                 return objectMapper.readValue(getContent(response), clazz);
-
             });
-
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     private <T> T executeAndReturns(ThrowingSupplier<T, Exception> supplier) {

dspace-api/src/main/java/org/dspace/content/packager/AbstractMETSIngester.java

@@ -11,8 +11,6 @@ import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
-import java.net.URL;
-import java.net.URLConnection;
 import java.sql.SQLException;
 import java.util.Iterator;
 import java.util.List;
@@ -21,7 +19,11 @@ import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
 import org.apache.commons.collections4.CollectionUtils;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.authorize.AuthorizeException;
 import org.dspace.content.Bitstream;
 import org.dspace.content.BitstreamFormat;
@@ -1310,13 +1312,12 @@ public abstract class AbstractMETSIngester extends AbstractPackageIngester {
         if (params.getBooleanProperty("manifestOnly", false)) {
             // NOTE: since we are only dealing with a METS manifest,
             // we will assume all external files are available via URLs.
-            try {
+            try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
                 // attempt to open a connection to given URL
-                URL fileURL = new URL(path);
+                try (CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(path))) {
-                URLConnection connection = fileURL.openConnection();
-
                     // open stream to access file contents
-                return connection.getInputStream();
+                    return httpResponse.getEntity().getContent();
+                }
             } catch (IOException io) {
                 log
                     .error("Unable to retrieve external file from URL '"

dspace-api/src/main/java/org/dspace/ctask/general/BasicLinkChecker.java

@@ -9,11 +9,15 @@ package org.dspace.ctask.general;
 
 import java.io.IOException;
 import java.net.HttpURLConnection;
-import java.net.URL;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.content.DSpaceObject;
 import org.dspace.content.Item;
 import org.dspace.content.MetadataValue;
@@ -135,24 +139,20 @@ public class BasicLinkChecker extends AbstractCurationTask {
      * @return The HTTP response code (e.g. 200 / 301 / 404 / 500)
      */
     protected int getResponseStatus(String url, int redirects) {
-        try {
+        RequestConfig config = RequestConfig.custom().setRedirectsEnabled(true).build();
-            URL theURL = new URL(url);
+        try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().buildWithRequestConfig(config)) {
-            HttpURLConnection connection = (HttpURLConnection) theURL.openConnection();
+            CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(url));
-            connection.setInstanceFollowRedirects(true);
+            int statusCode = httpResponse.getStatusLine().getStatusCode();
-            int statusCode = connection.getResponseCode();
             int maxRedirect = configurationService.getIntProperty("curate.checklinks.max-redirect", 0);
             if ((statusCode == HttpURLConnection.HTTP_MOVED_TEMP || statusCode == HttpURLConnection.HTTP_MOVED_PERM ||
                     statusCode == HttpURLConnection.HTTP_SEE_OTHER)) {
-                connection.disconnect();
+                String newUrl = httpResponse.getFirstHeader("Location").getValue();
-                String newUrl = connection.getHeaderField("Location");
                 if (newUrl != null && (maxRedirect >= redirects || maxRedirect == -1)) {
                     redirects++;
                     return getResponseStatus(newUrl, redirects);
                 }
-
             }
             return statusCode;
-
         } catch (IOException ioe) {
             // Must be a bad URL
             log.debug("Bad link: " + ioe.getMessage());

dspace-api/src/main/java/org/dspace/ctask/general/MetadataWebService.java

@@ -30,13 +30,13 @@ import javax.xml.xpath.XPathExpressionException;
 import javax.xml.xpath.XPathFactory;
 
 import org.apache.http.HttpEntity;
-import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.authorize.AuthorizeException;
 import org.dspace.content.DSpaceObject;
 import org.dspace.content.Item;
@@ -255,14 +255,13 @@ public class MetadataWebService extends AbstractCurationTask implements Namespac
     }
 
     protected int callService(String value, Item item, StringBuilder resultSb) throws IOException {
-
         String callUrl = urlTemplate.replaceAll("\\{" + templateParam + "\\}", value);
-        CloseableHttpClient client = HttpClientBuilder.create().build();
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
             HttpGet req = new HttpGet(callUrl);
             for (Map.Entry<String, String> entry : headers.entrySet()) {
                 req.addHeader(entry.getKey(), entry.getValue());
             }
-        HttpResponse resp = client.execute(req);
+            try (CloseableHttpResponse resp = client.execute(req)) {
                 int status = Curator.CURATE_ERROR;
                 int statusCode = resp.getStatusLine().getStatusCode();
                 if (statusCode == HttpStatus.SC_OK) {
@@ -271,8 +270,8 @@ public class MetadataWebService extends AbstractCurationTask implements Namespac
                         // boiler-plate handling taken from Apache 4.1 javadoc
                         InputStream instream = entity.getContent();
                         try {
-                    // This next line triggers a false-positive XXE warning from LGTM, even though we disallow DTD
+                            // This next line triggers a false-positive XXE warning from LGTM, even though
-                    // parsing during initialization of docBuilder in init()
+                            // we disallow DTD parsing during initialization of docBuilder in init()
                             Document doc = docBuilder.parse(instream);  // lgtm [java/xxe]
                             status = processResponse(doc, item, resultSb);
                         } catch (SAXException saxE) {
@@ -289,10 +288,6 @@ public class MetadataWebService extends AbstractCurationTask implements Namespac
                             // Closing the input stream will trigger connection release
                             instream.close();
                         }
-                // When HttpClient instance is no longer needed,
-                // shut down the connection manager to ensure
-                // immediate deallocation of all system resources
-                client.close();
                     } else {
                         log.error(" obtained no valid service response");
                         resultSb.append("no service response");
@@ -303,6 +298,8 @@ public class MetadataWebService extends AbstractCurationTask implements Namespac
                 }
                 return status;
             }
+        }
+    }
 
     protected int processResponse(Document doc, Item item, StringBuilder resultSb) throws IOException {
         boolean update = false;

dspace-api/src/main/java/org/dspace/ctask/general/MicrosoftTranslator.java

@@ -12,12 +12,12 @@ import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 
 import org.apache.commons.io.IOUtils;
-import org.apache.http.HttpResponse;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.services.ConfigurationService;
 import org.dspace.services.factory.DSpaceServicesFactory;
 
@@ -60,11 +60,10 @@ public class MicrosoftTranslator extends AbstractTranslator {
         String url = baseUrl + "?appId=" + apiKey;
         url += "&to=" + to + "&from=" + from + "&text=" + text;
 
-        try (CloseableHttpClient client = HttpClientBuilder.create().build()) {
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
             HttpGet hm = new HttpGet(url);
-            HttpResponse httpResponse = client.execute(hm);
+            try (CloseableHttpResponse httpResponse = client.execute(hm)) {
                 log.debug("Response code from API call is " + httpResponse);
-
                 if (httpResponse.getStatusLine().getStatusCode() == 200) {
                     String response = IOUtils.toString(httpResponse.getEntity().getContent(),
                             StandardCharsets.ISO_8859_1);
@@ -74,8 +73,7 @@ public class MicrosoftTranslator extends AbstractTranslator {
                     translatedText = response;
                 }
             }
-
+        }
         return translatedText;
     }
 }
-

dspace-api/src/main/java/org/dspace/eperson/CaptchaServiceImpl.java

@@ -17,15 +17,15 @@ import java.util.regex.Pattern;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import jakarta.annotation.PostConstruct;
-import org.apache.http.HttpResponse;
 import org.apache.http.NameValuePair;
-import org.apache.http.client.HttpClient;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpPost;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.message.BasicNameValuePair;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.eperson.service.CaptchaService;
 import org.dspace.services.ConfigurationService;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -82,18 +82,17 @@ public class CaptchaServiceImpl implements CaptchaService {
             throw new RuntimeException(e.getMessage(), e);
         }
 
-        HttpClient httpClient = HttpClientBuilder.create().build();
+        try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
-        HttpResponse httpResponse;
-        GoogleCaptchaResponse googleResponse;
             final ObjectMapper objectMapper = new ObjectMapper();
-        try {
+            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPost)) {
-            httpResponse = httpClient.execute(httpPost);
+                GoogleCaptchaResponse googleResponse = objectMapper.readValue(httpResponse.getEntity().getContent(),
-            googleResponse = objectMapper.readValue(httpResponse.getEntity().getContent(), GoogleCaptchaResponse.class);
+                        GoogleCaptchaResponse.class);
+                validateGoogleResponse(googleResponse, action);
+            }
         } catch (IOException e) {
             log.error(e.getMessage(), e);
             throw new RuntimeException("Error during verify google recaptcha site", e);
         }
-        validateGoogleResponse(googleResponse, action);
     }
 
     private boolean responseSanityCheck(String response) {

dspace-api/src/main/java/org/dspace/external/OpenaireRestConnector.java

@@ -27,13 +27,13 @@ import org.apache.http.HttpStatus;
 import org.apache.http.NameValuePair;
 import org.apache.http.NoHttpResponseException;
 import org.apache.http.StatusLine;
-import org.apache.http.client.HttpClient;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.message.BasicNameValuePair;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.app.util.Util;
 import org.json.JSONObject;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -120,7 +120,7 @@ public class OpenaireRestConnector {
         params.add(new BasicNameValuePair("grant_type", "client_credentials"));
         httpPost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
 
-        HttpClient httpClient = HttpClientBuilder.create().build();
+        try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
             HttpResponse getResponse = httpClient.execute(httpPost);
 
             JSONObject responseObject = null;
@@ -141,12 +141,13 @@ public class OpenaireRestConnector {
                 }
             }
             if (responseObject == null || !responseObject.has("access_token") || !responseObject.has("expires_in")) {
-            throw new IOException("Unable to grab the access token using provided service url, client id and secret");
+                throw new IOException("Unable to grab the access token using provided service url, " +
+                        "client id and secret");
             }
 
             return new OpenaireRestToken(responseObject.get("access_token").toString(),
                     Long.valueOf(responseObject.get("expires_in").toString()));
-
+        }
     }
 
     /**
@@ -171,7 +172,7 @@ public class OpenaireRestConnector {
                 httpGet.addHeader("Authorization", "Bearer " + accessToken);
             }
 
-            HttpClient httpClient = HttpClientBuilder.create().build();
+            try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
                 getResponse = httpClient.execute(httpGet);
 
                 StatusLine status = getResponse.getStatusLine();
@@ -192,8 +193,8 @@ public class OpenaireRestConnector {
                             if (limitMax.length > 0) {
                                 limitMsg = limitMsg.concat(" of " + limitMax[0].getValue());
                             }
-                        getGotError(
+                            getGotError(new NoHttpResponseException(status.getReasonPhrase() + " with usage limit "
-                                new NoHttpResponseException(status.getReasonPhrase() + " with usage limit " + limitMsg),
+                                            + limitMsg),
                                     url + '/' + file);
                         } else {
                             // 429 - Rate limit abuse
@@ -207,6 +208,7 @@ public class OpenaireRestConnector {
 
                 // do not close this httpClient
                 result = getResponse.getEntity().getContent();
+            }
         } catch (MalformedURLException e1) {
             getGotError(e1, url + '/' + file);
         } catch (Exception e) {

dspace-api/src/main/java/org/dspace/external/OrcidRestConnector.java

@@ -7,17 +7,18 @@
  */
 package org.dspace.external;
 
+import java.io.ByteArrayInputStream;
 import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.Scanner;
 
 import org.apache.commons.lang3.StringUtils;
-import org.apache.http.HttpResponse;
+import org.apache.http.client.methods.CloseableHttpResponse;
-import org.apache.http.client.HttpClient;
 import org.apache.http.client.methods.HttpGet;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 
 /**
  * @author Antoine Snyers (antoine at atmire.com)
@@ -39,7 +40,7 @@ public class OrcidRestConnector {
     }
 
     public InputStream get(String path, String accessToken) {
-        HttpResponse getResponse = null;
+        CloseableHttpResponse getResponse = null;
         InputStream result = null;
         path = trimSlashes(path);
 
@@ -49,11 +50,13 @@ public class OrcidRestConnector {
             httpGet.addHeader("Content-Type", "application/vnd.orcid+xml");
             httpGet.addHeader("Authorization","Bearer " + accessToken);
         }
-        try {
+        try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
-            HttpClient httpClient = HttpClientBuilder.create().build();
             getResponse = httpClient.execute(httpGet);
-            //do not close this httpClient
+            try (InputStream responseStream = getResponse.getEntity().getContent()) {
-            result = getResponse.getEntity().getContent();
+                // Read all the content of the response stream into a byte array to prevent TruncatedChunkException
+                byte[] content = responseStream.readAllBytes();
+                result = new ByteArrayInputStream(content);
+            }
         } catch (Exception e) {
             getGotError(e, fullPath);
         }

dspace-api/src/main/java/org/dspace/external/provider/impl/OrcidV3AuthorDataProvider.java

@@ -169,13 +169,7 @@ public class OrcidV3AuthorDataProvider extends AbstractExternalDataProvider {
         }
         initializeAccessToken();
         InputStream bioDocument = orcidRestConnector.get(id + ((id.endsWith("/person")) ? "" : "/person"), accessToken);
-        Person person = converter.convertSinglePerson(bioDocument);
+        return converter.convertSinglePerson(bioDocument);
-        try {
-            bioDocument.close();
-        } catch (IOException e) {
-            log.error(e.getMessage(), e);
-        }
-        return person;
     }
 
     /**
@@ -220,11 +214,6 @@ public class OrcidV3AuthorDataProvider extends AbstractExternalDataProvider {
                 }
             }
         }
-        try {
-            bioDocument.close();
-        } catch (IOException e) {
-            log.error(e.getMessage(), e);
-        }
         return bios.stream().map(bio -> convertToExternalDataObject(bio)).collect(Collectors.toList());
     }
 

dspace-api/src/main/java/org/dspace/google/client/GoogleAnalyticsClientImpl.java

@@ -18,9 +18,9 @@ import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.google.GoogleAnalyticsEvent;
 
 /**
@@ -42,7 +42,7 @@ public class GoogleAnalyticsClientImpl implements GoogleAnalyticsClient {
     public GoogleAnalyticsClientImpl(String keyPrefix, GoogleAnalyticsClientRequestBuilder requestBuilder) {
         this.keyPrefix = keyPrefix;
         this.requestBuilder = requestBuilder;
-        this.httpclient = HttpClients.createDefault();
+        this.httpclient = DSpaceHttpClientFactory.getInstance().build();
     }
 
     @Override

dspace-api/src/main/java/org/dspace/identifier/doi/DataCiteConnector.java

@@ -36,10 +36,10 @@ import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.util.EntityUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.authorize.AuthorizeException;
 import org.dspace.content.DSpaceObject;
 import org.dspace.content.crosswalk.CrosswalkException;
@@ -719,7 +719,7 @@ public class DataCiteConnector
         httpContext.setCredentialsProvider(credentialsProvider);
 
         HttpEntity entity = null;
-        try ( CloseableHttpClient httpclient = HttpClientBuilder.create().build(); ) {
+        try (CloseableHttpClient httpclient = DSpaceHttpClientFactory.getInstance().build()) {
             HttpResponse response = httpclient.execute(req, httpContext);
 
             StatusLine status = response.getStatusLine();

dspace-api/src/main/java/org/dspace/identifier/ezid/EZIDRequest.java

@@ -26,9 +26,9 @@ import org.apache.http.client.protocol.HttpClientContext;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.identifier.DOI;
 import org.dspace.identifier.IdentifierException;
 
@@ -87,7 +87,7 @@ public class EZIDRequest {
             this.authority = authority;
         }
 
-        client = HttpClientBuilder.create().build();
+        client = DSpaceHttpClientFactory.getInstance().build();
         httpContext = HttpClientContext.create();
         if (null != username) {
             URI uri = new URI(scheme, host, path, null);
@@ -124,7 +124,7 @@ public class EZIDRequest {
             this.authority = authority;
         }
 
-        client = HttpClientBuilder.create().build();
+        client = DSpaceHttpClientFactory.getInstance().build();
         httpContext = HttpClientContext.create();
         if (null != username) {
             CredentialsProvider credentialsProvider = new BasicCredentialsProvider();

dspace-api/src/main/java/org/dspace/iiif/IIIFApiQueryServiceImpl.java

@@ -12,12 +12,14 @@ import static org.dspace.iiif.canvasdimension.Util.checkDimensions;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
-import java.net.HttpURLConnection;
-import java.net.URL;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.content.Bitstream;
 import org.dspace.iiif.util.IIIFSharedUtils;
 
@@ -35,14 +37,10 @@ public class IIIFApiQueryServiceImpl implements IIIFApiQueryService {
     public int[] getImageDimensions(Bitstream bitstream) {
         int[] arr = new int[2];
         String path = IIIFSharedUtils.getInfoJsonPath(bitstream);
-        URL url;
         BufferedReader in = null;
-        try {
+        try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
-            url = new URL(path);
+            CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(path));
-            HttpURLConnection con = (HttpURLConnection) url.openConnection();
+            in = new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent()));
-            con.setRequestMethod("GET");
-            in = new BufferedReader(
-                new InputStreamReader(con.getInputStream()));
             String inputLine;
             StringBuilder response = new StringBuilder();
             while ((inputLine = in.readLine()) != null) {

dspace-api/src/main/java/org/dspace/importer/external/liveimportclient/service/LiveImportClientImpl.java

@@ -17,19 +17,16 @@ import java.util.Optional;
 import org.apache.commons.collections.MapUtils;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.StringUtils;
-import org.apache.http.HttpHost;
 import org.apache.http.HttpResponse;
 import org.apache.http.client.config.RequestConfig;
-import org.apache.http.client.config.RequestConfig.Builder;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
-import org.apache.http.client.methods.HttpRequestBase;
 import org.apache.http.client.utils.URIBuilder;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.services.ConfigurationService;
 import org.springframework.beans.factory.annotation.Autowired;
 
@@ -53,16 +50,11 @@ public class LiveImportClientImpl implements LiveImportClient {
     @Override
     public String executeHttpGetRequest(int timeout, String URL, Map<String, Map<String, String>> params) {
         HttpGet method = null;
+        RequestConfig config = RequestConfig.custom().setConnectionRequestTimeout(timeout).build();
         try (CloseableHttpClient httpClient = Optional.ofNullable(this.httpClient)
-                                                      .orElseGet(HttpClients::createDefault)) {
+                                        .orElse(DSpaceHttpClientFactory.getInstance().buildWithRequestConfig(config))) {
-
-            Builder requestConfigBuilder = RequestConfig.custom();
-            requestConfigBuilder.setConnectionRequestTimeout(timeout);
-            RequestConfig defaultRequestConfig = requestConfigBuilder.build();
-
             String uri = buildUrl(URL, params.get(URI_PARAMETERS));
             method = new HttpGet(uri);
-            method.setConfig(defaultRequestConfig);
 
             Map<String, String> headerParams = params.get(HEADER_PARAMETERS);
             if (MapUtils.isNotEmpty(headerParams)) {
@@ -71,7 +63,6 @@ public class LiveImportClientImpl implements LiveImportClient {
                 }
             }
 
-            configureProxy(method, defaultRequestConfig);
             if (log.isDebugEnabled()) {
                 log.debug("Performing GET request to \"" + uri + "\"...");
             }
@@ -95,21 +86,17 @@ public class LiveImportClientImpl implements LiveImportClient {
     @Override
     public String executeHttpPostRequest(String URL, Map<String, Map<String, String>> params, String entry) {
         HttpPost method = null;
+        RequestConfig config = RequestConfig.custom().build();
         try (CloseableHttpClient httpClient = Optional.ofNullable(this.httpClient)
-                                                      .orElseGet(HttpClients::createDefault)) {
+                .orElse(DSpaceHttpClientFactory.getInstance().buildWithRequestConfig(config))) {
-
-            Builder requestConfigBuilder = RequestConfig.custom();
-            RequestConfig defaultRequestConfig = requestConfigBuilder.build();
 
             String uri = buildUrl(URL, params.get(URI_PARAMETERS));
             method = new HttpPost(uri);
-            method.setConfig(defaultRequestConfig);
             if (StringUtils.isNotBlank(entry)) {
                 method.setEntity(new StringEntity(entry));
             }
             setHeaderParams(method, params);
 
-            configureProxy(method, defaultRequestConfig);
             if (log.isDebugEnabled()) {
                 log.debug("Performing POST request to \"" + uri + "\"..." );
             }
@@ -129,17 +116,6 @@ public class LiveImportClientImpl implements LiveImportClient {
         return StringUtils.EMPTY;
     }
 
-    private void configureProxy(HttpRequestBase method, RequestConfig defaultRequestConfig) {
-        String proxyHost = configurationService.getProperty("http.proxy.host");
-        String proxyPort = configurationService.getProperty("http.proxy.port");
-        if (StringUtils.isNotBlank(proxyHost) && StringUtils.isNotBlank(proxyPort)) {
-            RequestConfig requestConfig = RequestConfig.copy(defaultRequestConfig)
-                    .setProxy(new HttpHost(proxyHost, Integer.parseInt(proxyPort), "http"))
-                    .build();
-            method.setConfig(requestConfig);
-        }
-    }
-
     /**
      * Allows to set the header parameters to the HTTP Post method
      * 

dspace-api/src/main/java/org/dspace/license/CCLicenseConnectorServiceImpl.java

@@ -10,9 +10,6 @@ package org.dspace.license;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.StringReader;
-import java.net.MalformedURLException;
-import java.net.URL;
-import java.net.URLConnection;
 import java.text.MessageFormat;
 import java.util.Collections;
 import java.util.HashMap;
@@ -28,9 +25,9 @@ import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.mime.MultipartEntityBuilder;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.util.EntityUtils;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.services.ConfigurationService;
 import org.jdom2.Attribute;
 import org.jdom2.Document;
@@ -70,12 +67,7 @@ public class CCLicenseConnectorServiceImpl implements CCLicenseConnectorService,
 
     @Override
     public void afterPropertiesSet() throws Exception {
-        HttpClientBuilder builder = HttpClientBuilder.create();
+        client = DSpaceHttpClientFactory.getInstance().buildWithoutAutomaticRetries(5);
-
-        client = builder
-                .disableAutomaticRetries()
-                .setMaxConnTotal(5)
-                .build();
 
         // disallow DTD parsing to ensure no XXE attacks can occur.
         // See https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html
@@ -333,23 +325,13 @@ public class CCLicenseConnectorServiceImpl implements CCLicenseConnectorService,
     @Override
     public Document retrieveLicenseRDFDoc(String licenseURI) throws IOException {
         String ccLicenseUrl = configurationService.getProperty("cc.api.rooturl");
-
         String issueUrl = ccLicenseUrl + "/details?license-uri=" + licenseURI;
-
+        try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
-        URL request_url;
+            CloseableHttpResponse httpResponse = httpClient.execute(new HttpPost(issueUrl));
-        try {
-            request_url = new URL(issueUrl);
-        } catch (MalformedURLException e) {
-            return null;
-        }
-        URLConnection connection = request_url.openConnection();
-        connection.setDoOutput(true);
-        try {
             // parsing document from input stream
-            InputStream stream = connection.getInputStream();
+            InputStream stream = httpResponse.getEntity().getContent();
             Document doc = parser.build(stream);
             return doc;
-
         } catch (Exception e) {
             log.error("Error while retrieving the license document for URI: " + licenseURI, e);
         }

dspace-api/src/main/java/org/dspace/orcid/client/OrcidClientImpl.java

@@ -35,13 +35,14 @@ import org.apache.http.HttpEntity;
 import org.apache.http.HttpResponse;
 import org.apache.http.HttpStatus;
 import org.apache.http.NameValuePair;
-import org.apache.http.client.HttpClient;
 import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpUriRequest;
 import org.apache.http.client.methods.RequestBuilder;
 import org.apache.http.entity.StringEntity;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.message.BasicNameValuePair;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.orcid.OrcidToken;
 import org.dspace.orcid.exception.OrcidClientException;
 import org.dspace.orcid.model.OrcidEntityType;
@@ -254,10 +255,8 @@ public class OrcidClientImpl implements OrcidClient {
     }
 
     private void executeSuccessful(HttpUriRequest httpUriRequest) {
-        try {
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
-            HttpClient client = HttpClientBuilder.create().build();
+            CloseableHttpResponse response = client.execute(httpUriRequest);
-            HttpResponse response = client.execute(httpUriRequest);
-
             if (isNotSuccessfull(response)) {
                 throw new OrcidClientException(
                     getStatusCode(response),
@@ -272,21 +271,17 @@ public class OrcidClientImpl implements OrcidClient {
     }
 
     private <T> T executeAndParseJson(HttpUriRequest httpUriRequest, Class<T> clazz) {
-
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
-        HttpClient client = HttpClientBuilder.create().build();
-
             return executeAndReturns(() -> {
-
+                CloseableHttpResponse response = client.execute(httpUriRequest);
-            HttpResponse response = client.execute(httpUriRequest);
-
                 if (isNotSuccessfull(response)) {
                     throw new OrcidClientException(getStatusCode(response), formatErrorMessage(response));
                 }
-
                 return objectMapper.readValue(response.getEntity().getContent(), clazz);
-
             });
-
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     /**
@@ -301,44 +296,37 @@ public class OrcidClientImpl implements OrcidClient {
      * @throws OrcidClientException if the incoming response is not successful
      */
     private <T> T executeAndUnmarshall(HttpUriRequest httpUriRequest, boolean handleNotFoundAsNull, Class<T> clazz) {
-
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
-        HttpClient client = HttpClientBuilder.create().build();
-
             return executeAndReturns(() -> {
-
+                CloseableHttpResponse response = client.execute(httpUriRequest);
-            HttpResponse response = client.execute(httpUriRequest);
-
                 if (handleNotFoundAsNull && isNotFound(response)) {
                     return null;
                 }
-
                 if (isNotSuccessfull(response)) {
                     throw new OrcidClientException(getStatusCode(response), formatErrorMessage(response));
                 }
-
                 return unmarshall(response.getEntity(), clazz);
-
             });
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     private OrcidResponse execute(HttpUriRequest httpUriRequest, boolean handleNotFoundAsNull) {
-        HttpClient client = HttpClientBuilder.create().build();
+        try (CloseableHttpClient client = DSpaceHttpClientFactory.getInstance().build()) {
-
             return executeAndReturns(() -> {
-
+                CloseableHttpResponse response = client.execute(httpUriRequest);
-            HttpResponse response = client.execute(httpUriRequest);
-
                 if (handleNotFoundAsNull && isNotFound(response)) {
                     return new OrcidResponse(getStatusCode(response), null, getContent(response));
                 }
-
                 if (isNotSuccessfull(response)) {
                     throw new OrcidClientException(getStatusCode(response), formatErrorMessage(response));
                 }
-
                 return new OrcidResponse(getStatusCode(response), getPutCode(response), getContent(response));
-
             });
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     private <T> T executeAndReturns(ThrowingSupplier<T, Exception> supplier) {

dspace-api/src/main/java/org/dspace/orcid/model/factory/OrcidFactoryUtils.java

@@ -20,7 +20,7 @@ import org.apache.commons.lang3.StringUtils;
 import org.apache.http.HttpResponse;
 import org.apache.http.client.methods.HttpPost;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.json.JSONObject;
 
 /**
@@ -97,7 +97,7 @@ public final class OrcidFactoryUtils {
             httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
 
             HttpResponse response;
-            try (CloseableHttpClient httpClient = HttpClientBuilder.create().build()) {
+            try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().build()) {
                 response = httpClient.execute(httpPost);
             }
             JSONObject responseObject = null;

dspace-api/src/main/java/org/dspace/qaevent/service/impl/QAEventActionServiceImpl.java

@@ -22,9 +22,9 @@ import org.apache.http.client.methods.HttpPost;
 import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClients;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.content.Item;
 import org.dspace.content.QAEvent;
 import org.dspace.content.service.ItemService;
@@ -114,20 +114,19 @@ public class QAEventActionServiceImpl implements QAEventActionService {
      * Make acknowledgement to the configured urls for the event status.
      */
     private void makeAcknowledgement(String eventId, String source, String status) {
-        String[] ackwnoledgeCallbacks = configurationService
+        String[] acknowledgeCallbacks = configurationService
             .getArrayProperty("qaevents." + source + ".acknowledge-url");
-        if (ackwnoledgeCallbacks != null) {
+        if (acknowledgeCallbacks != null) {
-            for (String ackwnoledgeCallback : ackwnoledgeCallbacks) {
+            for (String acknowledgeCallback : acknowledgeCallbacks) {
-                if (StringUtils.isNotBlank(ackwnoledgeCallback)) {
+                if (StringUtils.isNotBlank(acknowledgeCallback)) {
                     ObjectNode node = jsonMapper.createObjectNode();
                     node.put("eventId", eventId);
                     node.put("status", status);
                     StringEntity requestEntity = new StringEntity(node.toString(), ContentType.APPLICATION_JSON);
-                    CloseableHttpClient httpclient = HttpClients.createDefault();
+                    try (CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().buildWithoutProxy()) {
-                    HttpPost postMethod = new HttpPost(ackwnoledgeCallback);
+                        HttpPost postMethod = new HttpPost(acknowledgeCallback);
                         postMethod.setEntity(requestEntity);
-                    try {
+                        httpClient.execute(postMethod);
-                        httpclient.execute(postMethod);
                     } catch (IOException e) {
                         log.error(e.getMessage(), e);
                     }

dspace-api/src/main/java/org/dspace/service/impl/HttpConnectionPoolService.java

@@ -19,11 +19,11 @@ import org.apache.http.HttpResponse;
 import org.apache.http.conn.ConnectionKeepAliveStrategy;
 import org.apache.http.conn.HttpClientConnectionManager;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
 import org.apache.http.message.BasicHeaderElementIterator;
 import org.apache.http.protocol.HTTP;
 import org.apache.http.protocol.HttpContext;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.services.ConfigurationService;
 
 /**
@@ -112,7 +112,7 @@ public class HttpConnectionPoolService {
      * @return the client.
      */
     public CloseableHttpClient getClient() {
-        CloseableHttpClient httpClient = HttpClientBuilder.create()
+        CloseableHttpClient httpClient = DSpaceHttpClientFactory.getInstance().builder(true).create()
                 .setKeepAliveStrategy(keepAliveStrategy)
                 .setConnectionManager(connManager)
                 .build();

dspace-api/src/main/java/org/dspace/statistics/SolrLoggerServiceImpl.java

@@ -54,7 +54,6 @@ import org.apache.commons.lang3.StringUtils;
 import org.apache.http.HttpResponse;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.impl.client.CloseableHttpClient;
-import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.solr.client.solrj.SolrClient;
@@ -84,6 +83,7 @@ import org.apache.solr.common.params.MapSolrParams;
 import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.common.params.ShardParams;
 import org.apache.solr.common.util.NamedList;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.authorize.service.AuthorizeService;
 import org.dspace.content.Bitstream;
 import org.dspace.content.Bundle;
@@ -1208,7 +1208,7 @@ public class SolrLoggerServiceImpl implements SolrLoggerService, InitializingBea
                         + "."
                         + i
                         + ".csv");
-                try ( CloseableHttpClient hc = HttpClientBuilder.create().build(); ) {
+                try (CloseableHttpClient hc = DSpaceHttpClientFactory.getInstance().buildWithoutProxy()) {
                     HttpResponse response = hc.execute(get);
                     csvInputstream = response.getEntity().getContent();
                     //Write the csv output to a file !
@@ -1350,7 +1350,7 @@ public class SolrLoggerServiceImpl implements SolrLoggerService, InitializingBea
 
                 HttpGet get = new HttpGet(solrRequestUrl);
                 List<String[]> rows;
-                try ( CloseableHttpClient hc = HttpClientBuilder.create().build(); ) {
+                try (CloseableHttpClient hc = DSpaceHttpClientFactory.getInstance().buildWithoutProxy()) {
                     HttpResponse response = hc.execute(get);
                     InputStream csvOutput = response.getEntity().getContent();
                     Reader csvReader = new InputStreamReader(csvOutput);

dspace-api/src/main/java/org/dspace/statistics/export/service/OpenUrlServiceImpl.java

@@ -15,13 +15,13 @@ import java.time.LocalDate;
 import java.util.List;
 
 import org.apache.commons.lang.StringUtils;
-import org.apache.http.HttpResponse;
-import org.apache.http.client.HttpClient;
 import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
-import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.dspace.app.client.DSpaceHttpClientFactory;
 import org.dspace.core.Context;
 import org.dspace.statistics.export.OpenURLTracker;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -69,16 +69,16 @@ public class OpenUrlServiceImpl implements OpenUrlService {
      * @throws IOException
      */
     protected int getResponseCodeFromUrl(final String urlStr) throws IOException {
+        try (CloseableHttpClient httpClient = getHttpClient(getHttpClientRequestConfig())) {
             HttpGet httpGet = new HttpGet(urlStr);
-        HttpClient httpClient = getHttpClient(getHttpClientRequestConfig());
+            try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
-        HttpResponse httpResponse = httpClient.execute(httpGet);
                 return httpResponse.getStatusLine().getStatusCode();
             }
+        }
+    }
 
-    protected HttpClient getHttpClient(RequestConfig requestConfig) {
+    protected CloseableHttpClient getHttpClient(RequestConfig requestConfig) {
-        return HttpClientBuilder.create()
+        return DSpaceHttpClientFactory.getInstance().buildWithRequestConfig(requestConfig);
-            .setDefaultRequestConfig(requestConfig)
-            .build();
     }
 
     protected RequestConfig getHttpClientRequestConfig() {

dspace-api/src/test/java/org/dspace/app/client/DSpaceHttpClientFactoryTest.java

@@ -0,0 +1,256 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.app.client;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.arrayWithSize;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import okhttp3.mockwebserver.RecordedRequest;
+import org.apache.http.HttpRequestInterceptor;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpResponseInterceptor;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.conn.routing.HttpRoute;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.protocol.HttpContext;
+import org.dspace.services.ConfigurationService;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+/**
+ * Unit tests for {@link DSpaceHttpClientFactory}.
+ *
+ * @author Luca Giamminonni (luca.giamminonni at 4science.it)
+ *
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class DSpaceHttpClientFactoryTest {
+
+    @InjectMocks
+    private DSpaceHttpClientFactory httpClientFactory;
+
+    @Mock
+    private ConfigurationService configurationService;
+
+    private MockWebServer mockProxy;
+
+    private MockWebServer mockServer;
+
+    @Before
+    public void init() {
+        this.httpClientFactory.setProxyRoutePlanner(new DSpaceProxyRoutePlanner(configurationService));
+        this.mockProxy = new MockWebServer();
+        this.mockProxy.enqueue(new MockResponse().setResponseCode(200).addHeader("From", "Proxy"));
+        this.mockServer = new MockWebServer();
+        this.mockServer.enqueue(new MockResponse().setResponseCode(200).addHeader("From", "Server"));
+    }
+
+    @Test
+    public void testBuildWithProxyConfigured() throws Exception {
+        setHttpProxyOnConfigurationService();
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(0));
+        CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(httpResponse.getHeaders("From"), arrayWithSize(1));
+        assertThat(httpResponse.getHeaders("From")[0].getValue(), is("Proxy"));
+        assertThat(mockProxy.getRequestCount(), is(1));
+        assertThat(mockServer.getRequestCount(), is(0));
+        RecordedRequest request = mockProxy.takeRequest(100, TimeUnit.MILLISECONDS);
+        assertThat(request, notNullValue());
+        assertThat(request.getRequestUrl(), is(mockProxy.url("")));
+        assertThat(request.getRequestLine(), is("GET " + mockServer.url("").toString() + " HTTP/1.1"));
+        verify(configurationService).getProperty("http.proxy.host");
+        verify(configurationService).getProperty("http.proxy.port");
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithProxyConfiguredAndHostToIgnoreSet() throws Exception {
+        setHttpProxyOnConfigurationService(mockServer.getHostName());
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(0));
+        CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(httpResponse.getHeaders("From"), arrayWithSize(1));
+        assertThat(httpResponse.getHeaders("From")[0].getValue(), is("Server"));
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(1));
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithProxyConfiguredAndHostPrefixToIgnoreSet() throws Exception {
+        setHttpProxyOnConfigurationService("local*", "www.test.com");
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(0));
+        CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(httpResponse.getHeaders("From"), arrayWithSize(1));
+        assertThat(httpResponse.getHeaders("From")[0].getValue(), is("Server"));
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(1));
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithProxyConfiguredAndHostSuffixToIgnoreSet() throws Exception {
+        setHttpProxyOnConfigurationService("www.test.com", "*host");
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(0));
+        CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(httpResponse.getHeaders("From"), arrayWithSize(1));
+        assertThat(httpResponse.getHeaders("From")[0].getValue(), is("Server"));
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(1));
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithoutConfiguredProxy() throws Exception {
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(0));
+        CloseableHttpResponse httpResponse = httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(httpResponse.getHeaders("From"), arrayWithSize(1));
+        assertThat(httpResponse.getHeaders("From")[0].getValue(), is("Server"));
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(1));
+        RecordedRequest request = mockServer.takeRequest(100, TimeUnit.MILLISECONDS);
+        assertThat(request, notNullValue());
+        assertThat(request.getRequestUrl(), is(mockServer.url("")));
+        assertThat(request.getRequestLine(), is("GET / HTTP/1.1"));
+        verify(configurationService).getProperty("http.proxy.host");
+        verify(configurationService).getProperty("http.proxy.port");
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithoutProxy() throws Exception {
+        CloseableHttpClient httpClient = httpClientFactory.buildWithoutProxy();
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(0));
+        httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(mockServer.getRequestCount(), is(1));
+        assertThat(mockProxy.getRequestCount(), is(0));
+        RecordedRequest request = mockServer.takeRequest(100, TimeUnit.MILLISECONDS);
+        assertThat(request, notNullValue());
+        assertThat(request.getRequestUrl(), is(mockServer.url("")));
+        assertThat(request.getRequestLine(), is("GET / HTTP/1.1"));
+        verifyNoInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithoutAutomaticRetries() throws Exception {
+        setHttpProxyOnConfigurationService("www.test.com");
+        CloseableHttpClient httpClient = httpClientFactory.buildWithoutAutomaticRetries(10);
+        httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(mockProxy.getRequestCount(), is(1));
+        assertThat(mockServer.getRequestCount(), is(0));
+        RecordedRequest request = mockProxy.takeRequest(100, TimeUnit.MILLISECONDS);
+        assertThat(request, notNullValue());
+        assertThat(request.getRequestUrl(), is(mockProxy.url("")));
+        assertThat(request.getRequestLine(), is("GET " + mockServer.url("").toString() + " HTTP/1.1"));
+        verify(configurationService).getProperty("http.proxy.host");
+        verify(configurationService).getProperty("http.proxy.port");
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    @Test
+    public void testBuildWithHttpRequestInterceptor() throws Exception {
+        setHttpProxyOnConfigurationService("*test.com", "www.dspace.com");
+        AtomicReference<HttpContext> contextReference = new AtomicReference<HttpContext>();
+        HttpRequestInterceptor interceptor = (request, context) -> contextReference.set(context);
+        httpClientFactory.setRequestInterceptors(List.of(interceptor));
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(mockProxy.getRequestCount(), is(1));
+        assertThat(mockServer.getRequestCount(), is(0));
+        HttpContext httpContext = contextReference.get();
+        assertThat(httpContext, notNullValue());
+        Object httpRouteObj = httpContext.getAttribute("http.route");
+        assertThat(httpRouteObj, notNullValue());
+        assertThat(httpRouteObj, instanceOf(HttpRoute.class));
+        HttpRoute httpRoute = (HttpRoute) httpRouteObj;
+        assertThat(httpRoute.getHopCount(), is(2));
+        assertThat(httpRoute.getHopTarget(0).getPort(), is(mockProxy.getPort()));
+        assertThat(httpRoute.getHopTarget(1).getPort(), is(mockServer.getPort()));
+    }
+
+    @Test
+    public void testBuildWithHttpResponseInterceptor() throws Exception {
+        AtomicReference<HttpResponse> responseReference = new AtomicReference<HttpResponse>();
+        HttpResponseInterceptor responseInterceptor = (response, context) -> responseReference.set(response);
+        httpClientFactory.setResponseInterceptors(List.of(responseInterceptor));
+        CloseableHttpClient httpClient = httpClientFactory.build();
+        httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(mockProxy.getRequestCount(), is(0));
+        assertThat(mockServer.getRequestCount(), is(1));
+        HttpResponse httpResponse = responseReference.get();
+        assertThat(httpResponse, notNullValue());
+        assertThat(httpResponse.getHeaders("From"), arrayWithSize(1));
+        assertThat(httpResponse.getHeaders("From")[0].getValue(), is("Server"));
+    }
+
+    @Test
+    public void testBuildWithRequestConfig() throws Exception {
+        setHttpProxyOnConfigurationService();
+        RequestConfig requestConfig = RequestConfig.custom()
+                .setConnectTimeout(2500)
+                .build();
+        AtomicReference<HttpContext> contextReference = new AtomicReference<HttpContext>();
+        HttpRequestInterceptor interceptor = (request, context) -> contextReference.set(context);
+        httpClientFactory.setRequestInterceptors(List.of(interceptor));
+        CloseableHttpClient httpClient = httpClientFactory.buildWithRequestConfig(requestConfig);
+        httpClient.execute(new HttpGet(mockServer.url("").toString()));
+        assertThat(mockProxy.getRequestCount(), is(1));
+        assertThat(mockServer.getRequestCount(), is(0));
+        HttpContext httpContext = contextReference.get();
+        assertThat(httpContext, notNullValue());
+        Object httpRequestConfigObj = httpContext.getAttribute("http.request-config");
+        assertThat(httpRequestConfigObj, notNullValue());
+        assertThat(httpRequestConfigObj, instanceOf(RequestConfig.class));
+        assertThat(((RequestConfig) httpRequestConfigObj).getConnectTimeout(), is(2500));
+        verify(configurationService).getProperty("http.proxy.host");
+        verify(configurationService).getProperty("http.proxy.port");
+        verify(configurationService).getArrayProperty("http.proxy.hosts-to-ignore");
+        verifyNoMoreInteractions(configurationService);
+    }
+
+    private void setHttpProxyOnConfigurationService(String... hostsToIgnore) {
+        when(configurationService.getProperty("http.proxy.host")).thenReturn(mockProxy.getHostName());
+        when(configurationService.getProperty("http.proxy.port")).thenReturn(String.valueOf(mockProxy.getPort()));
+        when(configurationService.getArrayProperty("http.proxy.hosts-to-ignore")).thenReturn(hostsToIgnore);
+    }
+}

dspace-api/src/test/java/org/dspace/statistics/export/service/OpenUrlServiceImplTest.java

@@ -25,9 +25,9 @@ import java.sql.SQLException;
 import java.time.LocalDate;
 import java.util.List;
 
-import org.apache.http.HttpResponse;
 import org.apache.http.StatusLine;
-import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.impl.client.CloseableHttpClient;
 import org.dspace.core.Context;
 import org.dspace.statistics.export.OpenURLTracker;
 import org.junit.Before;
@@ -52,7 +52,7 @@ public class OpenUrlServiceImplTest {
     private FailedOpenURLTrackerService failedOpenURLTrackerService;
 
     @Mock
-    private HttpClient httpClient;
+    private CloseableHttpClient httpClient;
 
     @Before
     public void setUp() throws Exception {
@@ -71,11 +71,11 @@ public class OpenUrlServiceImplTest {
      * @param statusCode the http status code to use in the mock.
      * @return a mocked http response.
      */
-    protected HttpResponse createMockHttpResponse(int statusCode) {
+    protected CloseableHttpResponse createMockHttpResponse(int statusCode) {
         StatusLine statusLine = mock(StatusLine.class);
         when(statusLine.getStatusCode()).thenReturn(statusCode);
 
-        HttpResponse httpResponse = mock(HttpResponse.class);
+        CloseableHttpResponse httpResponse = mock(CloseableHttpResponse.class);
         when(httpResponse.getStatusLine()).thenReturn(statusLine);
 
         return httpResponse;

dspace/config/dspace.cfg

@@ -411,6 +411,8 @@ http.proxy.host =
 # port number of proxy server
 http.proxy.port =
 
+http.proxy.hosts-to-ignore = 127.0.0.1, localhost
+
 # If enabled, the logging and the Solr statistics system will look for an X-Forwarded-For header.
 # If it finds it, it will use this for the user IP address.
 # NOTE: This is required to be enabled if you plan to use the Angular UI, as the server-side rendering provided in

dspace/config/spring/api/core-services.xml

@@ -162,6 +162,9 @@
     <bean class="org.dspace.authorize.ValidatePasswordServiceImpl"/>
     <bean class="org.dspace.authorize.RegexPasswordValidator" />
 
+    <bean id="org.dspace.app.client.DSpaceHttpClientFactory" class="org.dspace.app.client.DSpaceHttpClientFactory"/>
+    <bean class="org.dspace.app.client.DSpaceProxyRoutePlanner"/>
+
     <bean class="org.dspace.supervision.SupervisionOrderServiceImpl"/>
 
     <bean class="org.dspace.content.ItemFilterServiceImpl"/>

pom.xml

@@ -1746,6 +1746,12 @@
                 <version>2.3.232</version>
                 <scope>test</scope>
             </dependency>
+            <dependency>
+                <groupId>com.squareup.okhttp3</groupId>
+                <artifactId>mockwebserver</artifactId>
+                <version>4.12.0</version>
+                <scope>test</scope>
+            </dependency>
 
             <!-- Findbugs annotations -->
             <dependency>