Added support for NTLM proxies (#395).

src/main/java/org/gitlab4j/api/ProxyClientConfig.java

@@ -3,6 +3,11 @@ package org.gitlab4j.api;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.apache.http.auth.AuthScope;
+import org.apache.http.auth.NTCredentials;
+import org.apache.http.client.CredentialsProvider;
+import org.apache.http.impl.client.BasicCredentialsProvider;
+import org.glassfish.jersey.apache.connector.ApacheClientProperties;
 import org.glassfish.jersey.client.ClientProperties;
 
 /**
@@ -45,4 +50,28 @@ public class ProxyClientConfig {
 
         return (clientConfig);
     }
+
+    /**
+     * Create a Map instance set up to use an NTLM proxy server that can be passed to the GitLabAPi constructors 
+     * and login methods to configure the GitLabApi instance to use an NTLM proxy server.
+     *
+     * @param proxyUri the URI of the proxy server
+     * @param username the user name. This should not include the domain to authenticate with.
+     * For example: "user" is correct whereas "DOMAIN\user" is not.
+     * @param password the password
+     * @param workstation the workstation the authentication request is originating from. Essentially, the computer name for this machine.
+     * @param domain the domain to authenticate within
+     * @return a Map set up to allow GitLabApi to use an NTLM proxy server
+     */
+    public static Map<String, Object> createNtlmProxyClientConfig(String proxyUri, String username, String password, String workstation, String domain) {
+
+        Map<String, Object> clientConfig = new HashMap<>();
+        clientConfig.put(ClientProperties.PROXY_URI, proxyUri);
+
+        CredentialsProvider credentials = new BasicCredentialsProvider();
+        credentials.setCredentials(AuthScope.ANY, new NTCredentials(username, password, workstation, domain));
+        clientConfig.put(ApacheClientProperties.CREDENTIALS_PROVIDER, credentials);
+
+        return (clientConfig);
+    }
 }