GUACAMOLE-36: Define REST API transfer mechanism for translatable messages.

guacamole-ext/src/main/java/org/apache/guacamole/language/Translatable.java

@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.language;
+
+/**
+ * An interface which requires the definition of a translatable message that
+ * can be passed through an arbitrary translation service, producing a
+ * human-readable message in the user's native language.
+ *
+ * @author Michael Jumper
+ */
+public interface Translatable {
+
+    /**
+     * Returns a message which can be translated using a translation service,
+     * consisting of a translation key and optional set of substitution
+     * variables.
+     *
+     * @return
+     *     A message which can be translated using a translation service.
+     */
+    TranslatableMessage getTranslatableMessage();
+
+}

guacamole-ext/src/main/java/org/apache/guacamole/language/TranslatableMessage.java

@@ -0,0 +1,96 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole.language;
+
+/**
+ * A message which can be translated using a translation service, providing a
+ * translation key and optional set of values to be substituted into the
+ * translation string associated with that key.
+ *
+ * @author Michael Jumper
+ */
+public class TranslatableMessage {
+
+    /**
+     * The arbitrary key which can be used to look up the message to be
+     * displayed in the user's native language.
+     */
+    private final String key;
+
+    /**
+     * An arbitrary object whose properties should be substituted for the
+     * corresponding placeholders within the string associated with the key.
+     */
+    private final Object variables;
+
+    /**
+     * Creates a new TranslatableMessage associated with the given translation
+     * key, without any associated variables.
+     *
+     * @param key
+     *     The translation key to associate with the TranslatableMessage.
+     */
+    public TranslatableMessage(String key) {
+        this(key, null);
+    }
+
+    /**
+     * Creates a new TranslatableMessage associated with the given translation
+     * key and associated variables.
+     *
+     * @param key
+     *     The translation key to associate with the TranslatableMessage.
+     *
+     * @param variables
+     *     An arbitrary object whose properties should be substituted for the
+     *     corresponding placeholders within the string associated with the
+     *     given translation key.
+     */
+    public TranslatableMessage(String key, Object variables) {
+        this.key = key;
+        this.variables = variables;
+    }
+
+    /**
+     * Returns the arbitrary key which can be used to look up the message to be
+     * displayed in the user's native language.
+     *
+     * @return
+     *     The arbitrary key associated with the human-readable message.
+     */
+    public String getKey() {
+        return key;
+    }
+
+    /**
+     * Returns an arbitrary object whose properties should be substituted for
+     * the corresponding placeholders within the string associated with the key.
+     * If not applicable, null is returned.
+     *
+     * @return
+     *     An arbitrary object whose properties should be substituted for the
+     *     corresponding placeholders within the string associated with the key,
+     *     or null if not applicable.
+     */
+    public Object getVariables() {
+        return variables;
+    }
+
+}

guacamole/src/main/java/org/apache/guacamole/rest/APIError.java

@@ -25,6 +25,8 @@ import org.apache.guacamole.GuacamoleException;
 import org.apache.guacamole.GuacamoleResourceNotFoundException;
 import org.apache.guacamole.GuacamoleSecurityException;
 import org.apache.guacamole.form.Field;
+import org.apache.guacamole.language.Translatable;
+import org.apache.guacamole.language.TranslatableMessage;
 import org.apache.guacamole.net.auth.credentials.GuacamoleCredentialsException;
 import org.apache.guacamole.net.auth.credentials.GuacamoleInsufficientCredentialsException;
 import org.apache.guacamole.net.auth.credentials.GuacamoleInvalidCredentialsException;
@@ -39,10 +41,15 @@ import org.apache.guacamole.tunnel.GuacamoleStreamException;
 public class APIError {
 
     /**
-     * The error message.
+     * The human-readable error message.
      */
     private final String message;
 
+    /**
+     * A translatable message representing the error that occurred.
+     */
+    private final TranslatableMessage translatableMessage;
+
     /**
      * The associated Guacamole protocol status code.
      */
@@ -148,7 +155,9 @@ public class APIError {
 
     /**
      * Creates a new APIError which exposes the details of the given
-     * GuacamoleException.
+     * GuacamoleException. If the given GuacamoleException implements
+     * Translatable, then its translation string and values will be exposed as
+     * well.
      *
      * @param exception
      *     The GuacamoleException from which the details of the new APIError
@@ -176,6 +185,14 @@ public class APIError {
         else
             this.statusCode = null;
 
+        // Pull translatable message and values if available
+        if (exception instanceof Translatable) {
+            Translatable translatable = (Translatable) exception;
+            this.translatableMessage = translatable.getTranslatableMessage();
+        }
+        else
+            this.translatableMessage = new TranslatableMessage(this.message);
+
     }
 
     /**
@@ -223,4 +240,16 @@ public class APIError {
         return message;
     }
 
+    /**
+     * Returns a translatable message describing the error that occurred. If no
+     * translatable message is associated with the error, this will be null.
+     *
+     * @return
+     *     A translatable message describing the error that occurred, or null
+     *     if there is no such message defined.
+     */
+    public TranslatableMessage getTranslatableMessage() {
+        return translatableMessage;
+    }
+
 }

guacamole/src/main/webapp/app/rest/types/Error.js

@@ -42,6 +42,15 @@ angular.module('rest').factory('Error', [function defineError() {
          */
         this.message = template.message;
 
+        /**
+         * A message which can be translated using the translation service,
+         * consisting of a translation key and optional set of substitution
+         * variables.
+         *
+         * @type TranslatableMessage
+         */
+        this.translatableMessage = template.translatableMessage;
+
         /**
          * The Guacamole protocol status code associated with the error that
          * occurred. This is only valid for errors of type STREAM_ERROR.

guacamole/src/main/webapp/app/rest/types/TranslatableMessage.js

@@ -0,0 +1,63 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Service which defines the TranslatableMessage class.
+ */
+angular.module('rest').factory('TranslatableMessage', [function defineTranslatableMessage() {
+
+    /**
+     * The object returned by REST API calls when representing a message which
+     * can be translated using the translation service, providing a translation
+     * key and optional set of values to be substituted into the translation
+     * string associated with that key.
+     *
+     * @constructor
+     * @param {TranslatableMessage|Object} [template={}]
+     *     The object whose properties should be copied within the new
+     *     TranslatableMessage.
+     */
+    var TranslatableMessage = function TranslatableMessage(template) {
+
+        // Use empty object by default
+        template = template || {};
+
+        /**
+         * The key associated with the translation string that used when
+         * displaying this message.
+         *
+         * @type String
+         */
+        this.key = template.key;
+
+        /**
+         * The object which should be passed through to the translation service
+         * for the sake of variable substitution. Each property of the provided
+         * object will be substituted for the variable of the same name within
+         * the translation string.
+         *
+         * @type Object
+         */
+        this.variables = template.variables;
+
+    };
+
+    return TranslatableMessage;
+
+}]);