Fix get mappings HEAD requests

Get mappings HEAD requests incorrectly return a content-length header of
0. This commit addresses this by removing the special handling for get
mappings HEAD requests, and just relying on the general mechanism that
exists for handling HEAD requests in the REST layer.

Author: jasontedor

core/src/main/java/org/elasticsearch/action/ActionModule.java

@@ -262,7 +262,6 @@
 import org.elasticsearch.rest.action.admin.indices.RestRolloverIndexAction;
 import org.elasticsearch.rest.action.admin.indices.RestShrinkIndexAction;
 import org.elasticsearch.rest.action.admin.indices.RestSyncedFlushAction;
-import org.elasticsearch.rest.action.admin.indices.RestTypesExistsAction;
 import org.elasticsearch.rest.action.admin.indices.RestUpdateSettingsAction;
 import org.elasticsearch.rest.action.admin.indices.RestUpgradeAction;
 import org.elasticsearch.rest.action.admin.indices.RestValidateQueryAction;
@@ -524,7 +523,6 @@ public void initRestHandlers(Supplier<DiscoveryNodes> nodesInCluster) {
         registerHandler.accept(new RestDeleteSnapshotAction(settings, restController));
         registerHandler.accept(new RestSnapshotsStatusAction(settings, restController));
 
-        registerHandler.accept(new RestTypesExistsAction(settings, restController));
         registerHandler.accept(new RestGetIndicesAction(settings, restController, indexScopedSettings, settingsFilter));
         registerHandler.accept(new RestIndicesStatsAction(settings, restController));
         registerHandler.accept(new RestIndicesSegmentsAction(settings, restController));

core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestGetMappingAction.java

@@ -42,30 +42,32 @@
 import java.io.IOException;
 
 import static org.elasticsearch.rest.RestRequest.Method.GET;
+import static org.elasticsearch.rest.RestRequest.Method.HEAD;
 import static org.elasticsearch.rest.RestStatus.OK;
 
 public class RestGetMappingAction extends BaseRestHandler {
-    public RestGetMappingAction(Settings settings, RestController controller) {
+
+    public RestGetMappingAction(final Settings settings, final RestController controller) {
         super(settings);
         controller.registerHandler(GET, "/{index}/{type}/_mapping", this);
         controller.registerHandler(GET, "/{index}/_mappings/{type}", this);
         controller.registerHandler(GET, "/{index}/_mapping/{type}", this);
+        controller.registerWithDeprecatedHandler(HEAD, "/{index}/_mapping/{type}", this, HEAD, "/{index}/{type}", deprecationLogger);
         controller.registerHandler(GET, "/_mapping/{type}", this);
     }
 
     @Override
     public RestChannelConsumer prepareRequest(final RestRequest request, final NodeClient client) throws IOException {
         final String[] indices = Strings.splitStringByCommaToArray(request.param("index"));
         final String[] types = request.paramAsStringArrayOrEmptyIfAll("type");
-        GetMappingsRequest getMappingsRequest = new GetMappingsRequest();
+        final GetMappingsRequest getMappingsRequest = new GetMappingsRequest();
         getMappingsRequest.indices(indices).types(types);
         getMappingsRequest.indicesOptions(IndicesOptions.fromRequest(request, getMappingsRequest.indicesOptions()));
         getMappingsRequest.local(request.paramAsBoolean("local", getMappingsRequest.local()));
         return channel -> client.admin().indices().getMappings(getMappingsRequest, new RestBuilderListener<GetMappingsResponse>(channel) {
             @Override
-            public RestResponse buildResponse(GetMappingsResponse response, XContentBuilder builder) throws Exception {
-
-                ImmutableOpenMap<String, ImmutableOpenMap<String, MappingMetaData>> mappingsByIndex = response.getMappings();
+            public RestResponse buildResponse(final GetMappingsResponse response, final XContentBuilder builder) throws Exception {
+                final ImmutableOpenMap<String, ImmutableOpenMap<String, MappingMetaData>> mappingsByIndex = response.getMappings();
                 if (mappingsByIndex.isEmpty()) {
                     if (indices.length != 0 && types.length != 0) {
                         return new BytesRestResponse(OK, builder.startObject().endObject());
@@ -81,27 +83,28 @@ public RestResponse buildResponse(GetMappingsResponse response, XContentBuilder
                 }
 
                 builder.startObject();
-                for (ObjectObjectCursor<String, ImmutableOpenMap<String, MappingMetaData>> indexEntry : mappingsByIndex) {
-                    if (indexEntry.value.isEmpty()) {
-                        continue;
-                    }
-                    builder.startObject(indexEntry.key);
-                    builder.startObject(Fields.MAPPINGS);
-                    for (ObjectObjectCursor<String, MappingMetaData> typeEntry : indexEntry.value) {
-                        builder.field(typeEntry.key);
-                        builder.map(typeEntry.value.sourceAsMap());
+                {
+                    for (final ObjectObjectCursor<String, ImmutableOpenMap<String, MappingMetaData>> indexEntry : mappingsByIndex) {
+                        if (indexEntry.value.isEmpty()) {
+                            continue;
+                        }
+                        builder.startObject(indexEntry.key);
+                        {
+                            builder.startObject("mappings");
+                            {
+                                for (final ObjectObjectCursor<String, MappingMetaData> typeEntry : indexEntry.value) {
+                                    builder.field(typeEntry.key, typeEntry.value.sourceAsMap());
+                                }
+                            }
+                            builder.endObject();
+                        }
+                        builder.endObject();
                     }
-                    builder.endObject();
-                    builder.endObject();
                 }
-
                 builder.endObject();
                 return new BytesRestResponse(OK, builder);
             }
         });
     }
 
-    static class Fields {
-        static final String MAPPINGS = "mappings";
-    }
 }

core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestTypesExistsAction.java

@@ -74,8 +74,10 @@ public void testIndexExists() throws IOException {
 
     public void testTypeExists() throws IOException {
         createTestDoc();
-        headTestCase("/test/test", emptyMap(), equalTo(0));
-        headTestCase("/test/test", singletonMap("pretty", "true"), equalTo(0));
+        headTestCase("/test/_mapping/test", emptyMap(), greaterThan(0));
+        headTestCase("/test/_mapping/test", singletonMap("pretty", "true"), greaterThan(0));
+        headTestCase("/test/test", emptyMap(), greaterThan(0));
+        headTestCase("/test/test", singletonMap("pretty", "true"), greaterThan(0));
     }
 
     public void testAliasExists() throws IOException {