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 org.apache.juneau.http.response.*;
016import org.apache.juneau.rest.*;
017import org.apache.juneau.svl.*;
018
019/**
020 * Request query variable resolver.
021 *
022 * <p>
023 * The format for this var is <js>"$RQ{key1[,key2...]}"</js>.
024 *
025 * <p>
026 * Used to resolve values returned by {@link RestRequest#getQueryParam(String)}.
027 * <br>When multiple keys are used, returns the first non-null/empty value.
028 *
029 * <h5 class='section'>Example:</h5>
030 * <p class='bjava'>
031 *    <jc>// URI = "...?foo=X&amp;bar=Y"</jc>
032 *    String <jv>foo</jv> = <jv>restRequest</jv>.getVarResolver().resolve(<js>"$RQ{foo}"</js>);
033 *    String <jv>fooOrBar</jv> = <jv>restRequest</jv>.getVarResolver().resolve(<js>"$RHQ{foo,bar}"</js>);
034 * </p>
035 *
036 * <h5 class='section'>Notes:</h5><ul>
037 *    <li class='note'>
038 *       This variable resolver requires that a {@link RestRequest} bean be available in the session bean store.
039 *    <li class='note'>
040 *       For security reasons, nested and recursive variables are not resolved.
041 * </ul>
042 *
043 * <h5 class='section'>See Also:</h5><ul>
044 *    <li class='link'><a class="doclink" href="../../../../../index.html#jm.SvlVariables">SVL Variables</a>
045 * </ul>
046 */
047public class RequestQueryVar extends MultipartResolvingVar {
048
049   /** The name of this variable. */
050   public static final String NAME = "RQ";
051
052   /**
053    * Constructor.
054    */
055   public RequestQueryVar() {
056      super(NAME);
057   }
058
059   @Override /* Var */
060   protected boolean allowNested() {
061      return false;
062   }
063
064   @Override /* Var */
065   protected boolean allowRecurse() {
066      return false;
067   }
068
069   @Override /* Var */
070   public String resolve(VarResolverSession session, String key) {
071      return session.getBean(RestRequest.class).orElseThrow(InternalServerError::new).getQueryParam(key).orElse(null);
072   }
073
074   @Override /* Var */
075   public boolean canResolve(VarResolverSession session) {
076      return session.getBean(RestRequest.class).isPresent();
077   }
078}