001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.rest.vars;
014
015import jakarta.servlet.http.*;
016
017import org.apache.juneau.http.response.*;
018import org.apache.juneau.rest.*;
019import org.apache.juneau.svl.*;
020
021/**
022 * Request attribute variable resolver.
023 *
024 * <p>
025 * The format for this var is <js>"$RA{key1[,key2...]}"</js>.
026 *
027 * <p>
028 * Used to resolve values returned by {@link HttpServletRequest#getAttribute(String)}.
029 * <br>When multiple keys are used, returns the first non-null/empty value.
030 *
031 * <h5 class='section'>Example:</h5>
032 * <p class='bjava'>
033 *    String <jv>foo</jv> = <jv>restRequest</jv>.getVarResolver().resolve(<js>"$RA{foo}"</js>);
034 *    String <jv>fooOrBar</jv> = <jv>restRequest</jv>.getVarResolver().resolve(<js>"$RA{foo,bar}"</js>);
035 * </p>
036 *
037 * <h5 class='section'>Notes:</h5><ul>
038 *    <li class='note'>
039 *       This variable resolver requires that a {@link RestRequest} bean be available in the session bean store.
040 *    <li class='note'>
041 *       For security reasons, nested and recursive variables are not resolved.
042 * </ul>
043 *
044 * <h5 class='section'>See Also:</h5><ul>
045 *    <li class='link'><a class="doclink" href="../../../../../index.html#jm.SvlVariables">SVL Variables</a>
046 * </ul>
047 */
048public class RequestAttributeVar extends MultipartResolvingVar {
049
050   /** The name of this variable. */
051   public static final String NAME = "RA";
052
053   /**
054    * Constructor.
055    */
056   public RequestAttributeVar() {
057      super(NAME);
058   }
059
060   @Override /* Var */
061   protected boolean allowNested() {
062      return false;
063   }
064
065   @Override /* Var */
066   protected boolean allowRecurse() {
067      return false;
068   }
069
070   @Override /* Var */
071   public String resolve(VarResolverSession session, String key) {
072      RestRequest req = session.getBean(RestRequest.class).orElseThrow(InternalServerError::new);
073      return req.getAttribute(key).asString().orElse(null);
074   }
075
076   @Override /* Var */
077   public boolean canResolve(VarResolverSession session) {
078      return session.getBean(RestRequest.class).isPresent();
079   }
080}