001package ca.uhn.fhir.rest.client.interceptor;
002
003/*-
004 * #%L
005 * HAPI FHIR - Client Framework
006 * %%
007 * Copyright (C) 2014 - 2023 Smile CDR, Inc.
008 * %%
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 *
013 *      http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 * #L%
021 */
022
023import ca.uhn.fhir.interceptor.api.Hook;
024import ca.uhn.fhir.interceptor.api.Pointcut;
025import ca.uhn.fhir.rest.client.api.IHttpRequest;
026
027import java.util.ArrayList;
028import java.util.HashMap;
029import java.util.List;
030import java.util.Map;
031import java.util.Objects;
032
033/**
034 * This interceptor adds arbitrary header values to requests made by the client.
035 *
036 * This is now also possible directly on the Fluent Client API by calling
037 * {@link ca.uhn.fhir.rest.gclient.IClientExecutable#withAdditionalHeader(String, String)}
038 */
039public class AdditionalRequestHeadersInterceptor {
040        private final Map<String, List<String>> myAdditionalHttpHeaders;
041
042        /**
043         * Constructor
044         */
045        public AdditionalRequestHeadersInterceptor() {
046                myAdditionalHttpHeaders = new HashMap<>();
047        }
048
049        /**
050         * Constructor
051         *
052         * @param theHeaders The additional headers to add to every request
053         */
054        public AdditionalRequestHeadersInterceptor(Map<String, List<String>> theHeaders) {
055                this();
056                if (theHeaders != null) {
057                        myAdditionalHttpHeaders.putAll(theHeaders);
058                }
059        }
060
061        /**
062         * Adds the given header value.
063         * Note that {@code headerName} and {@code headerValue} cannot be null.
064         * @param headerName the name of the header
065         * @param headerValue the value to add for the header
066         * @throws NullPointerException if either parameter is {@code null}
067         */
068        public void addHeaderValue(String headerName, String headerValue) {
069                Objects.requireNonNull(headerName, "headerName cannot be null");
070                Objects.requireNonNull(headerValue, "headerValue cannot be null");
071
072                getHeaderValues(headerName).add(headerValue);
073        }
074
075        /**
076         * Adds the list of header values for the given header.
077         * Note that {@code headerName} and {@code headerValues} cannot be null.
078         * @param headerName the name of the header
079         * @param headerValues the list of values to add for the header
080         * @throws NullPointerException if either parameter is {@code null}
081         */
082        public void addAllHeaderValues(String headerName, List<String> headerValues) {
083                Objects.requireNonNull(headerName, "headerName cannot be null");
084                Objects.requireNonNull(headerValues, "headerValues cannot be null");
085
086                getHeaderValues(headerName).addAll(headerValues);
087        }
088
089        /**
090         * Gets the header values list for a given header.
091         * If the header doesn't have any values, an empty list will be returned.
092         * @param headerName the name of the header
093         * @return the list of values for the header
094         */
095        private List<String> getHeaderValues(String headerName) {
096                if (myAdditionalHttpHeaders.get(headerName) == null) {
097                        myAdditionalHttpHeaders.put(headerName, new ArrayList<>());
098                }
099                return myAdditionalHttpHeaders.get(headerName);
100        }
101
102        /**
103         * Adds the additional header values to the HTTP request.
104         * @param theRequest the HTTP request
105         */
106        @Hook(Pointcut.CLIENT_REQUEST)
107        public void interceptRequest(IHttpRequest theRequest) {
108                for (Map.Entry<String, List<String>> header : myAdditionalHttpHeaders.entrySet()) {
109                        for (String headerValue : header.getValue()) {
110                                if (headerValue != null) {
111                                        theRequest.addHeader(header.getKey(), headerValue);
112                                }
113                        }
114                }
115        }
116
117}