Simplify RestResponse Implementations (#87504)

This sets up chunked encoding rest responses. Make it so we only have
a single REST response implementation (+the security filtering override)
throughout the codebase. The test implementations were all redundant,
removing them made the abstract base class redundant.
A follow-up to this will change the signature of the `content()` method
to an abstraction that allows for chunked encoding and simplify
the very complicated resource handling associated with REST responses in
`org.elasticsearch.http.DefaultRestChannel#sendResponse` based on the
simplification in here.

Author: original-brownbear

client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/RestNoopBulkAction.java

@@ -18,7 +18,6 @@
 import org.elasticsearch.client.internal.node.NodeClient;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.rest.BaseRestHandler;
-import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestChannel;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.RestResponse;
@@ -107,7 +106,7 @@ public RestResponse buildResponse(BulkRequest bulkRequest, XContentBuilder build
             }
             builder.endArray();
             builder.endObject();
-            return new BytesRestResponse(OK, builder);
+            return new RestResponse(OK, builder);
         }
     }
 

client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java

@@ -60,7 +60,7 @@
 import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.index.reindex.UpdateByQueryRequest;
 import org.elasticsearch.plugins.spi.NamedXContentProvider;
-import org.elasticsearch.rest.BytesRestResponse;
+import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.search.aggregations.Aggregation;
 import org.elasticsearch.search.aggregations.bucket.adjacency.AdjacencyMatrixAggregationBuilder;
@@ -1143,7 +1143,7 @@ protected final ElasticsearchStatusException parseResponseException(ResponseExce
             elasticsearchException = new ElasticsearchStatusException(responseException.getMessage(), restStatus, responseException);
         } else {
             try {
-                elasticsearchException = parseEntity(entity, BytesRestResponse::errorFromXContent);
+                elasticsearchException = parseEntity(entity, RestResponse::errorFromXContent);
                 elasticsearchException.addSuppressed(responseException);
             } catch (Exception e) {
                 elasticsearchException = new ElasticsearchStatusException("Unable to parse response body", restStatus, responseException);

modules/reindex/src/main/java/org/elasticsearch/reindex/AbstractBaseReindexRestHandler.java

@@ -17,8 +17,8 @@
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.BulkByScrollTask;
 import org.elasticsearch.rest.BaseRestHandler;
-import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.tasks.LoggingTaskListener;
 import org.elasticsearch.tasks.Task;
@@ -109,7 +109,7 @@ private RestChannelConsumer sendTask(String localNodeId, Task task) {
                 builder.startObject();
                 builder.field("task", localNodeId + ":" + task.getId());
                 builder.endObject();
-                channel.sendResponse(new BytesRestResponse(RestStatus.OK, builder));
+                channel.sendResponse(new RestResponse(RestStatus.OK, builder));
             }
         };
     }

modules/reindex/src/main/java/org/elasticsearch/reindex/BulkIndexByScrollResponseContentListener.java

@@ -11,7 +11,6 @@
 import org.elasticsearch.action.bulk.BulkItemResponse.Failure;
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.ScrollableHitSource.SearchFailure;
-import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestChannel;
 import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.RestStatus;
@@ -38,7 +37,7 @@ public RestResponse buildResponse(BulkByScrollResponse response, XContentBuilder
         builder.startObject();
         response.toXContent(builder, new ToXContent.DelegatingMapParams(params, channel.request()));
         builder.endObject();
-        return new BytesRestResponse(getStatus(response), builder);
+        return new RestResponse(getStatus(response), builder);
     }
 
     private RestStatus getStatus(BulkByScrollResponse response) {

modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4BadRequestTests.java

@@ -21,9 +21,9 @@
 import org.elasticsearch.common.util.concurrent.ThreadContext;
 import org.elasticsearch.http.HttpServerTransport;
 import org.elasticsearch.http.HttpTransportSettings;
-import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestChannel;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.threadpool.TestThreadPool;
@@ -70,7 +70,7 @@ public void dispatchRequest(RestRequest request, RestChannel channel, ThreadCont
             public void dispatchBadRequest(RestChannel channel, ThreadContext threadContext, Throwable cause) {
                 try {
                     final Exception e = cause instanceof Exception ? (Exception) cause : new ElasticsearchException(cause);
-                    channel.sendResponse(new BytesRestResponse(channel, RestStatus.BAD_REQUEST, e));
+                    channel.sendResponse(new RestResponse(channel, RestStatus.BAD_REQUEST, e));
                 } catch (final IOException e) {
                     throw new UncheckedIOException(e);
                 }

modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4HttpServerTransportTests.java

@@ -57,9 +57,9 @@
 import org.elasticsearch.http.HttpServerTransport;
 import org.elasticsearch.http.HttpTransportSettings;
 import org.elasticsearch.http.NullDispatcher;
-import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestChannel;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.test.rest.FakeRestRequest;
 import org.elasticsearch.threadpool.TestThreadPool;
 import org.elasticsearch.threadpool.ThreadPool;
@@ -157,7 +157,7 @@ private void runExpectHeaderTest(
         final HttpServerTransport.Dispatcher dispatcher = new HttpServerTransport.Dispatcher() {
             @Override
             public void dispatchRequest(RestRequest request, RestChannel channel, ThreadContext threadContext) {
-                channel.sendResponse(new BytesRestResponse(OK, BytesRestResponse.TEXT_CONTENT_TYPE, new BytesArray("done")));
+                channel.sendResponse(new RestResponse(OK, RestResponse.TEXT_CONTENT_TYPE, new BytesArray("done")));
             }
 
             @Override
@@ -263,7 +263,7 @@ public void dispatchBadRequest(final RestChannel channel, final ThreadContext th
                 causeReference.set(cause);
                 try {
                     final ElasticsearchException e = new ElasticsearchException("you sent a bad request and you should feel bad");
-                    channel.sendResponse(new BytesRestResponse(channel, BAD_REQUEST, e));
+                    channel.sendResponse(new RestResponse(channel, BAD_REQUEST, e));
                 } catch (final IOException e) {
                     throw new AssertionError(e);
                 }
@@ -333,7 +333,7 @@ private void testLargeResponse(boolean compressed) throws InterruptedException {
             @Override
             public void dispatchRequest(final RestRequest request, final RestChannel channel, final ThreadContext threadContext) {
                 if (url.equals(request.uri())) {
-                    channel.sendResponse(new BytesRestResponse(OK, responseString));
+                    channel.sendResponse(new RestResponse(OK, responseString));
                 } else {
                     logger.error("--> Unexpected successful uri [{}]", request.uri());
                     throw new AssertionError();

qa/smoke-test-http/src/javaRestTest/java/org/elasticsearch/http/TestResponseHeaderRestAction.java

@@ -9,7 +9,6 @@
 
 import org.elasticsearch.client.internal.node.NodeClient;
 import org.elasticsearch.rest.BaseRestHandler;
-import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.RestStatus;
@@ -33,11 +32,11 @@ public String getName() {
     @Override
     public RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) {
         if ("password".equals(request.header("Secret"))) {
-            RestResponse response = new BytesRestResponse(RestStatus.OK, "Access granted");
+            RestResponse response = new RestResponse(RestStatus.OK, "Access granted");
             response.addHeader("Secret", "granted");
             return channel -> channel.sendResponse(response);
         } else {
-            RestResponse response = new BytesRestResponse(RestStatus.UNAUTHORIZED, "Access denied");
+            RestResponse response = new RestResponse(RestStatus.UNAUTHORIZED, "Access denied");
             response.addHeader("Secret", "required");
             return channel -> channel.sendResponse(response);
         }