GUACAMOLE-1239: Configurable username letter case

guacamole-ext/src/main/java/org/apache/guacamole/environment/Environment.java

@@ -68,6 +68,13 @@ public interface Environment {
 
     };
 
+    public static final StringGuacamoleProperty USERNAME_LETTER_CASE = new StringGuacamoleProperty() {
+
+        @Override
+        public String getName() { return "username-letter-case"; }
+
+    };
+
     /**
      * Returns the Guacamole home directory as determined when this Environment
      * object was created. The Guacamole home directory is found by checking, in

guacamole/src/main/java/org/apache/guacamole/rest/auth/TokenRESTService.java

@@ -23,6 +23,7 @@
 import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 import javax.inject.Inject;
 import javax.servlet.http.HttpServletRequest;
 import javax.ws.rs.DELETE;
@@ -36,6 +37,7 @@
 import javax.ws.rs.core.MultivaluedMap;
 import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleResourceNotFoundException;
+import org.apache.guacamole.environment.Environment;
 import org.apache.guacamole.net.auth.AuthenticatedUser;
 import org.apache.guacamole.net.auth.Credentials;
 import org.apache.guacamole.net.auth.UserContext;
@@ -55,13 +57,22 @@ public class TokenRESTService {
      * Logger for this class.
      */
     private static final Logger logger = LoggerFactory.getLogger(TokenRESTService.class);
+    private static final String DEFAULT_LETTER_CASE = "mixed-case";
+
 
     /**
      * Service for authenticating users and managing their Guacamole sessions.
      */
     @Inject
     private AuthenticationService authenticationService;
 
+
+    /**
+     * The Guacamole server environment.
+     */
+    @Inject
+    private Environment environment;
+
     /**
      * Returns the credentials associated with the given request, using the
      * provided username and password.
@@ -122,6 +133,35 @@ private Credentials getCredentials(HttpServletRequest request,
 
     }
 
+    /**
+     * Alters letter casing of username, if configured.
+     * Configuration options:
+     * <ul>
+     *     <li>mixed-case (default)</li>
+     *     <li>lower-case</li>
+     *     <li>upper-case</li>
+     * </ul>
+     * @param credentials
+     *     The Credentials provided by the user in the most recent
+     *     authentication attempt.
+     * @throws GuacamoleException If an error occurs while parsing the value
+     *                            for the given property in
+     *                            guacamole.properties, or if the property is
+     *                            not specified.
+     */
+    private void adaptUsernameLetterCase(Credentials credentials) throws GuacamoleException {
+        switch (environment.getProperty(Environment.USERNAME_LETTER_CASE,DEFAULT_LETTER_CASE)){
+            case "lower-case":
+                Optional.ofNullable(credentials.getUsername()).map(String::toLowerCase).ifPresent(credentials::setUsername);
+                break;
+            case "upper-case":
+                Optional.ofNullable(credentials.getUsername()).filter(un -> !"guacadmin".equals(un)).map(String::toUpperCase).ifPresent(credentials::setUsername);
+                break;
+            default:
+                /* don't change */
+        }
+    }
+
     /**
      * Authenticates a user, generates an auth token, associates that auth token
      * with the user's UserContext for use by further requests. If an existing
@@ -169,7 +209,7 @@ public APIAuthenticationResult createToken(@FormParam("username") String usernam
 
         // Build credentials from request
         Credentials credentials = getCredentials(request, username, password);
-
+        adaptUsernameLetterCase(credentials);
         // Create/update session producing possibly-new token
         token = authenticationService.authenticate(credentials, token);