SOLR-9520: Kerberos delegation support in SolrJ

solr/solrj/src/java/org/apache/solr/client/solrj/impl/DelegationTokenHttpSolrClient.java

@@ -0,0 +1,73 @@
+/*
+ * 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.solr.client.solrj.impl;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.TreeSet;
+
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpRequestBase;
+import org.apache.solr.client.solrj.ResponseParser;
+import org.apache.solr.client.solrj.SolrRequest;
+import org.apache.solr.client.solrj.SolrServerException;
+import org.apache.solr.common.params.ModifiableSolrParams;
+import org.apache.solr.common.params.SolrParams;
+
+public class DelegationTokenHttpSolrClient extends HttpSolrClient {
+  public final static String DELEGATION_TOKEN_PARAM = "delegation";
+  private final String delegationToken;
+
+  public DelegationTokenHttpSolrClient(String baseURL,
+                                       HttpClient client,
+                                       ResponseParser parser,
+                                       boolean allowCompression,
+                                       String delegationToken) {
+    super(baseURL, client, parser, allowCompression);
+    if (delegationToken == null) {
+      throw new IllegalArgumentException("Delegation token cannot be null");
+    }
+    this.delegationToken = delegationToken;
+    setQueryParams(new TreeSet<>(Arrays.asList(DELEGATION_TOKEN_PARAM)));
+    invariantParams = new ModifiableSolrParams();
+    invariantParams.set(DELEGATION_TOKEN_PARAM, delegationToken);
+  }
+
+  @Override
+  protected HttpRequestBase createMethod(final SolrRequest request, String collection) throws IOException, SolrServerException {
+    SolrParams params = request.getParams();
+    if (params.getParams(DELEGATION_TOKEN_PARAM) != null) {
+      throw new IllegalArgumentException(DELEGATION_TOKEN_PARAM + " parameter not supported");
+    }
+    return super.createMethod(request, collection);
+  }
+
+  @Override
+  public void setQueryParams(Set<String> queryParams) {
+    queryParams = queryParams == null ?
+        Collections.unmodifiableSet(new HashSet<String>(Arrays.asList(DELEGATION_TOKEN_PARAM))): queryParams;
+    if (!queryParams.contains(DELEGATION_TOKEN_PARAM)) {
+      queryParams = new HashSet<String>(queryParams);
+      queryParams.add(DELEGATION_TOKEN_PARAM);
+      queryParams = Collections.unmodifiableSet(queryParams);
+    }
+    super.setQueryParams(queryParams);
+  }
+}