1 files changed, 64 insertions, 0 deletions
diff --git a/container-search/src/main/java/com/yahoo/search/yql/FieldFilter.java b/container-search/src/main/java/com/yahoo/search/yql/FieldFilter.java
new file mode 100644
index 00000000000..b44fdadd17b
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/search/yql/FieldFilter.java
@@ -0,0 +1,64 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.search.yql;
+
+import java.util.Iterator;
+import java.util.Map.Entry;
+import java.util.Set;
+
+import com.google.common.annotations.Beta;
+import com.yahoo.component.chain.dependencies.After;
+import com.yahoo.component.chain.dependencies.Before;
+import com.yahoo.prelude.fastsearch.FastHit;
+import com.yahoo.processing.request.CompoundName;
+import com.yahoo.search.Query;
+import com.yahoo.search.Result;
+import com.yahoo.search.Searcher;
+import com.yahoo.search.result.Hit;
+import com.yahoo.search.searchchain.Execution;
+
+/**
+ * Remove fields which are not explicitly requested, if any field is explicitly
+ * requested. Disable using FieldFilter.disable=true in request.
+ *
+ * @author <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
+ */
+@Beta
+@After(MinimalQueryInserter.EXTERNAL_YQL)
+@Before("com.yahoo.search.yql.FieldFiller")
+public class FieldFilter extends Searcher {
+
+    public static final CompoundName FIELD_FILTER_DISABLE = new CompoundName("FieldFilter.disable");
+
+    @Override
+    public Result search(Query query, Execution execution) {
+        Result result = execution.search(query);
+        filter(result);
+        return result;
+    }
+
+    @Override
+    public void fill(Result result, String summaryClass, Execution execution) {
+        execution.fill(result, summaryClass);
+        filter(result);
+    }
+
+    private void filter(Result result) {
+        Set<String> requestedFields;
+
+        if (result.getQuery().properties().getBoolean(FIELD_FILTER_DISABLE)) return;
+        if (result.getQuery().getPresentation().getSummaryFields().isEmpty()) return;
+
+        requestedFields = result.getQuery().getPresentation().getSummaryFields();
+        for (Iterator<Hit> i = result.hits().unorderedDeepIterator(); i.hasNext();) {
+            Hit h = i.next();
+            if (h.isMeta()) continue;
+            for (Iterator<Entry<String, Object>> fields = h.fieldIterator(); fields.hasNext();) {
+                Entry<String, Object> field = fields.next();
+                if ( ! requestedFields.contains(field.getKey()))
+                    fields.remove();
+            }
+
+        }
+    }
+
+}