GUAC-1345: Add 'allowed-languages' property. Restrict loaded languages to keys explicitly listed, if any.

guacamole/src/main/java/org/glyptodon/guacamole/net/basic/extension/ExtensionModule.java

@@ -100,7 +100,7 @@ public class ExtensionModule extends ServletModule {
     /**
      * Service for adding and retrieving language resources.
      */
-    private final LanguageResourceService languageResourceService = new LanguageResourceService();
+    private final LanguageResourceService languageResourceService;
     
     /**
      * Returns the classloader that should be used as the parent classloader
@@ -139,6 +139,7 @@ public class ExtensionModule extends ServletModule {
      */
     public ExtensionModule(Environment environment) {
         this.environment = environment;
+        this.languageResourceService = new LanguageResourceService(environment);
     }
 
     /**

guacamole/src/main/java/org/glyptodon/guacamole/net/basic/extension/LanguageResourceService.java

@@ -36,6 +36,9 @@ import org.codehaus.jackson.JsonNode;
 import org.codehaus.jackson.map.ObjectMapper;
 import org.codehaus.jackson.node.JsonNodeFactory;
 import org.codehaus.jackson.node.ObjectNode;
+import org.glyptodon.guacamole.GuacamoleException;
+import org.glyptodon.guacamole.environment.Environment;
+import org.glyptodon.guacamole.net.basic.properties.BasicGuacamoleProperties;
 import org.glyptodon.guacamole.net.basic.resource.ByteArrayResource;
 import org.glyptodon.guacamole.net.basic.resource.Resource;
 import org.glyptodon.guacamole.net.basic.resource.WebApplicationResource;
@@ -76,6 +79,13 @@ public class LanguageResourceService {
      */
     private static final Pattern LANGUAGE_KEY_PATTERN = Pattern.compile(".*/([a-z]+(_[A-Z]+)?)\\.json");
 
+    /**
+     * The set of all language keys which are explicitly listed as allowed
+     * within guacamole.properties, or null if all defined languages should be
+     * allowed.
+     */
+    private final Set<String> allowedLanguages;
+
     /**
      * Map of all language resources by language key. Language keys are
      * language and country code pairs, separated by an underscore, like
@@ -86,6 +96,35 @@ public class LanguageResourceService {
      */
     private final Map<String, Resource> resources = new HashMap<String, Resource>();
 
+    /**
+     * Creates a new service for tracking and parsing available translations
+     * which reads its configuration from the given environment.
+     *
+     * @param environment
+     *     The environment from which the configuration properties of this
+     *     service should be read.
+     */
+    public LanguageResourceService(Environment environment) {
+
+        Set<String> parsedAllowedLanguages;
+
+        // Parse list of available languages from properties
+        try {
+            parsedAllowedLanguages = environment.getProperty(BasicGuacamoleProperties.ALLOWED_LANGUAGES);
+            logger.debug("Available languages will be restricted to: {}", parsedAllowedLanguages);
+        }
+
+        // Warn of failure to parse
+        catch (GuacamoleException e) {
+            parsedAllowedLanguages = null;
+            logger.error("Unable to parse list of allowed languages: {}", e.getMessage());
+            logger.debug("Error parsing list of allowed languages.", e);
+        }
+
+        this.allowedLanguages = parsedAllowedLanguages;
+
+    }
+
     /**
      * Derives a language key from the filename within the given path, if
      * possible. If the filename is not a valid language key, null is returned.
@@ -184,6 +223,31 @@ public class LanguageResourceService {
 
     }
 
+    /**
+     * Returns whether a language having the given key should be allowed to be
+     * loaded. If language availability restrictions are imposed through
+     * guacamole.properties, this may return false in some cases. By default,
+     * this function will always return true. Note that just because a language
+     * key is allowed to be loaded does not imply that the language key is
+     * valid.
+     *
+     * @param languageKey
+     *     The language key of the language to test.
+     *
+     * @return
+     *     true if the given language key should be allowed to be loaded, false
+     *     otherwise.
+     */
+    private boolean isLanguageAllowed(String languageKey) {
+
+        // If no list is provided, all languages are implicitly available
+        if (allowedLanguages == null)
+            return true;
+
+        return allowedLanguages.contains(languageKey);
+
+    }
+
     /**
      * Adds or overlays the given language resource, which need not exist in
      * the ServletContext. If a language resource is already defined for the
@@ -202,6 +266,12 @@ public class LanguageResourceService {
      */
     public void addLanguageResource(String key, Resource resource) {
 
+        // Skip loading of language if not allowed
+        if (!isLanguageAllowed(key)) {
+            logger.debug("OMITTING language: \"{}\"", key);
+            return;
+        }
+
         // Merge language resources if already defined
         Resource existing = resources.get(key);
         if (existing != null) {

guacamole/src/main/java/org/glyptodon/guacamole/net/basic/properties/BasicGuacamoleProperties.java

@@ -24,6 +24,7 @@ package org.glyptodon.guacamole.net.basic.properties;
 
 import org.glyptodon.guacamole.properties.FileGuacamoleProperty;
 import org.glyptodon.guacamole.properties.IntegerGuacamoleProperty;
+import org.glyptodon.guacamole.properties.StringGuacamoleProperty;
 
 /**
  * Properties used by the default Guacamole web application.
@@ -73,4 +74,17 @@ public class BasicGuacamoleProperties {
 
     };
 
+    /**
+     * Comma-separated list of all allowed languages, where each language is
+     * represented by a language key, such as "en" or "en_US". If specified,
+     * only languages within this list will be listed as available by the REST
+     * service.
+     */
+    public static final StringSetProperty ALLOWED_LANGUAGES = new StringSetProperty() {
+
+        @Override
+        public String getName() { return "allowed-languages"; }
+
+    };
+
 }