Get field mapping api should honour pretty flag

src/main/java/org/elasticsearch/action/admin/indices/mapping/get/GetFieldMappingsResponse.java

@@ -115,7 +115,11 @@ public boolean isNull() {
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.field("full_name", fullName);
-            XContentHelper.writeRawField("mapping", source, builder, params);
+            if (params.paramAsBoolean("pretty", false)) {
+                builder.field("mapping", sourceAsMap());
+            } else {
+                builder.rawField("mapping", source);
+            }
             return builder;
         }
     }

src/main/java/org/elasticsearch/rest/action/admin/indices/mapping/get/RestGetFieldMappingAction.java

@@ -28,7 +28,6 @@
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.rest.*;
 import org.elasticsearch.rest.action.support.RestBuilderListener;
@@ -81,7 +80,7 @@ public RestResponse buildResponse(GetFieldMappingsResponse response, XContentBui
                     status = NOT_FOUND;
                 }
                 builder.startObject();
-                response.toXContent(builder, ToXContent.EMPTY_PARAMS);
+                response.toXContent(builder, request);
                 builder.endObject();
                 return new BytesRestResponse(status, builder);
             }

src/test/java/org/elasticsearch/indices/mapping/SimpleGetFieldMappingsTests.java

@@ -19,8 +19,9 @@
 
 package org.elasticsearch.indices.mapping;
 
+import com.google.common.collect.Maps;
 import org.elasticsearch.action.admin.indices.mapping.get.GetFieldMappingsResponse;
-import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.*;
 import org.elasticsearch.test.ElasticsearchIntegrationTest;
 import org.hamcrest.Matchers;
 import org.junit.Test;
@@ -146,4 +147,38 @@ public void simpleGetFieldMappingsWithDefaults() throws Exception {
 
 
     }
+
+    //fix #6552
+    @Test
+    public void simpleGetFieldMappingsWithPretty() throws Exception {
+        assertAcked(prepareCreate("index").addMapping("type", getMappingForType("type")));
+        Map<String, String> params = Maps.newHashMap();
+        params.put("pretty", "true");
+        ensureYellow();
+        GetFieldMappingsResponse response = client().admin().indices().prepareGetFieldMappings("index").setTypes("type").setFields("field1", "obj.subfield").get();
+        XContentBuilder responseBuilder = XContentFactory.jsonBuilder().prettyPrint();
+        responseBuilder.startObject();
+        response.toXContent(responseBuilder, new ToXContent.MapParams(params));
+        responseBuilder.endObject();
+        String responseStrings = responseBuilder.string();
+
+
+        XContentBuilder prettyJsonBuilder = XContentFactory.jsonBuilder().prettyPrint();
+        prettyJsonBuilder.copyCurrentStructure(XContentFactory.xContent(responseStrings).createParser(responseStrings));
+        assertThat(responseStrings, equalTo(prettyJsonBuilder.string()));
+
+        params.put("pretty", "false");
+
+        response = client().admin().indices().prepareGetFieldMappings("index").setTypes("type").setFields("field1","obj.subfield").get();
+        responseBuilder = XContentFactory.jsonBuilder().prettyPrint().lfAtEnd();
+        responseBuilder.startObject();
+        response.toXContent(responseBuilder, new ToXContent.MapParams(params));
+        responseBuilder.endObject();
+        responseStrings = responseBuilder.string();
+
+        prettyJsonBuilder = XContentFactory.jsonBuilder().prettyPrint();
+        prettyJsonBuilder.copyCurrentStructure(XContentFactory.xContent(responseStrings).createParser(responseStrings));
+        assertThat(responseStrings,not(equalTo(prettyJsonBuilder.string())));
+
+    }
 }