Use geohash cell instead of just a corner in geo_bounding_box

docs/reference/migration/migrate_7_0/search.asciidoc

@@ -12,6 +12,9 @@
 *   Purely negative queries (only MUST_NOT clauses) now return a score of `0`
     rather than `1`.
 
+*   The boundary specified using geohashes in the `geo_bounding_box` query
+    now include entire geohash cell, instead of just geohash center.
+
 ==== Adaptive replica selection enabled by default
 
 Adaptive replica selection has been enabled by default. If you wish to return to

docs/reference/query-dsl/geo-bounding-box-query.asciidoc

@@ -231,6 +231,38 @@ GET /_search
 --------------------------------------------------
 // CONSOLE
 
+
+When geohashes are used to specify the bounding the edges of the
+bounding box, the geohashes are treated as rectangles. The bounding
+box is defined in such a way that its top left corresponds to the top
+left corner of the geohash specified in the `top_left` parameter and
+its bottom right is defined as the bottom right of the geohash
+specified in the `bottom_right` parameter.
+
+In order to specify a bounding box that would match entire area of a
+geohash the geohash can be specified in both `top_left` and
+`bottom_right` parameters:
+
+[source,js]
+--------------------------------------------------
+GET /_search
+{
+    "query": {
+        "geo_bounding_box" : {
+            "pin.location" : {
+                "top_left" : "dr",
+                "bottom_right" : "dr"
+            }
+        }
+    }
+}
+--------------------------------------------------
+// CONSOLE
+
+In this example, the geohash `dr` will produce the bounding box
+query with the top left corner at `45.0,-78.75` and the bottom right
+corner at `39.375,-67.5`.
+
 [float]
 ==== Vertices
 

server/src/main/java/org/elasticsearch/common/geo/GeoPoint.java

@@ -22,6 +22,7 @@
 import org.apache.lucene.document.LatLonDocValuesField;
 import org.apache.lucene.document.LatLonPoint;
 import org.apache.lucene.geo.GeoEncodingUtils;
+import org.apache.lucene.geo.Rectangle;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.util.BitUtil;
 import org.apache.lucene.util.BytesRef;
@@ -85,21 +86,27 @@ public GeoPoint resetFromString(String value) {
 
     public GeoPoint resetFromString(String value, final boolean ignoreZValue) {
         if (value.contains(",")) {
-            String[] vals = value.split(",");
-            if (vals.length > 3) {
-                throw new ElasticsearchParseException("failed to parse [{}], expected 2 or 3 coordinates "
-                    + "but found: [{}]", vals.length);
-            }
-            double lat = Double.parseDouble(vals[0].trim());
-            double lon = Double.parseDouble(vals[1].trim());
-            if (vals.length > 2) {
-                GeoPoint.assertZValue(ignoreZValue, Double.parseDouble(vals[2].trim()));
-            }
-            return reset(lat, lon);
+            return resetFromCoordinates(value, ignoreZValue);
         }
         return resetFromGeoHash(value);
     }
 
+
+    public GeoPoint resetFromCoordinates(String value, final boolean ignoreZValue) {
+        String[] vals = value.split(",");
+        if (vals.length > 3) {
+            throw new ElasticsearchParseException("failed to parse [{}], expected 2 or 3 coordinates "
+                + "but found: [{}]", vals.length);
+        }
+        double lat = Double.parseDouble(vals[0].trim());
+        double lon = Double.parseDouble(vals[1].trim());
+        if (vals.length > 2) {
+            GeoPoint.assertZValue(ignoreZValue, Double.parseDouble(vals[2].trim()));
+        }
+        return reset(lat, lon);
+    }
+
+
     public GeoPoint resetFromIndexHash(long hash) {
         lon = GeoHashUtils.decodeLongitude(hash);
         lat = GeoHashUtils.decodeLatitude(hash);

server/src/main/java/org/elasticsearch/common/geo/GeoUtils.java

@@ -387,6 +387,25 @@ public static GeoPoint parseGeoPoint(Object value, final boolean ignoreZValue) t
         }
     }
 
+    /**
+     * Represents the point of the geohash cell that should be used as the value of geohash
+     */
+    public enum EffectivePoint {
+        TOP_LEFT,
+        TOP_RIGHT,
+        BOTTOM_LEFT,
+        BOTTOM_RIGHT
+    }
+
+    /**
+     * Parse a geopoint represented as an object, string or an array. If the geopoint is represented as a geohash,
+     * the left bottom corner of the geohash cell is used as the geopoint coordinates.GeoBoundingBoxQueryBuilder.java
+     */
+    public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, final boolean ignoreZValue)
+            throws IOException, ElasticsearchParseException {
+        return parseGeoPoint(parser, point, ignoreZValue, EffectivePoint.BOTTOM_LEFT);
+    }
+
     /**
      * Parse a {@link GeoPoint} with a {@link XContentParser}. A geopoint has one of the following forms:
      *
@@ -401,7 +420,7 @@ public static GeoPoint parseGeoPoint(Object value, final boolean ignoreZValue) t
      * @param point A {@link GeoPoint} that will be reset by the values parsed
      * @return new {@link GeoPoint} parsed from the parse
      */
-    public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, final boolean ignoreZValue)
+    public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, final boolean ignoreZValue, EffectivePoint effectivePoint)
             throws IOException, ElasticsearchParseException {
         double lat = Double.NaN;
         double lon = Double.NaN;
@@ -458,7 +477,7 @@ public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, fina
                 if(!Double.isNaN(lat) || !Double.isNaN(lon)) {
                     throw new ElasticsearchParseException("field must be either lat/lon or geohash");
                 } else {
-                    return point.resetFromGeoHash(geohash);
+                    return parseGeoHash(point, geohash, effectivePoint);
                 }
             } else if (numberFormatException != null) {
                 throw new ElasticsearchParseException("[{}] and [{}] must be valid double values", numberFormatException, LATITUDE,
@@ -489,12 +508,36 @@ public static GeoPoint parseGeoPoint(XContentParser parser, GeoPoint point, fina
             }
             return point.reset(lat, lon);
         } else if(parser.currentToken() == Token.VALUE_STRING) {
-            return point.resetFromString(parser.text(), ignoreZValue);
+            String val = parser.text();
+            if (val.contains(",")) {
+                return point.resetFromString(val, ignoreZValue);
+            } else {
+                return parseGeoHash(point, val, effectivePoint);
+            }
+
         } else {
             throw new ElasticsearchParseException("geo_point expected");
         }
     }
 
+    private static GeoPoint parseGeoHash(GeoPoint point, String geohash, EffectivePoint effectivePoint) {
+        if (effectivePoint == EffectivePoint.BOTTOM_LEFT) {
+            return point.resetFromGeoHash(geohash);
+        } else {
+            Rectangle rectangle = GeoHashUtils.bbox(geohash);
+            switch (effectivePoint) {
+                case TOP_LEFT:
+                    return point.reset(rectangle.maxLat, rectangle.minLon);
+                case TOP_RIGHT:
+                    return point.reset(rectangle.maxLat, rectangle.maxLon);
+                case BOTTOM_RIGHT:
+                    return point.reset(rectangle.minLat, rectangle.maxLon);
+                default:
+                    throw new IllegalArgumentException("Unsupported effective point " + effectivePoint);
+            }
+        }
+    }
+
     /**
      * Parse a precision that can be expressed as an integer or a distance measure like "1km", "10m".
      *

server/src/main/java/org/elasticsearch/index/query/GeoBoundingBoxQueryBuilder.java

@@ -491,19 +491,19 @@ public static Rectangle parseBoundingBox(XContentParser parser) throws IOExcepti
                     right = parser.doubleValue();
                 } else {
                     if (TOP_LEFT_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
-                        GeoUtils.parseGeoPoint(parser, sparse);
+                        GeoUtils.parseGeoPoint(parser, sparse, false, GeoUtils.EffectivePoint.TOP_LEFT);
                         top = sparse.getLat();
                         left = sparse.getLon();
                     } else if (BOTTOM_RIGHT_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
-                        GeoUtils.parseGeoPoint(parser, sparse);
+                        GeoUtils.parseGeoPoint(parser, sparse, false, GeoUtils.EffectivePoint.BOTTOM_RIGHT);
                         bottom = sparse.getLat();
                         right = sparse.getLon();
                     } else if (TOP_RIGHT_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
-                        GeoUtils.parseGeoPoint(parser, sparse);
+                        GeoUtils.parseGeoPoint(parser, sparse, false, GeoUtils.EffectivePoint.TOP_RIGHT);
                         top = sparse.getLat();
                         right = sparse.getLon();
                     } else if (BOTTOM_LEFT_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
-                        GeoUtils.parseGeoPoint(parser, sparse);
+                        GeoUtils.parseGeoPoint(parser, sparse, false, GeoUtils.EffectivePoint.BOTTOM_LEFT);
                         bottom = sparse.getLat();
                         left = sparse.getLon();
                     } else {
@@ -515,7 +515,8 @@ public static Rectangle parseBoundingBox(XContentParser parser) throws IOExcepti
             }
         }
         if (envelope != null) {
-            if ((Double.isNaN(top) || Double.isNaN(bottom) || Double.isNaN(left) || Double.isNaN(right)) == false) {
+            if (Double.isNaN(top) == false || Double.isNaN(bottom) == false || Double.isNaN(left) == false ||
+                Double.isNaN(right) == false) {
                 throw new ElasticsearchParseException("failed to parse bounding box. Conflicting definition found "
                     + "using well-known text and explicit corners.");
             }

server/src/test/java/org/elasticsearch/index/query/GeoBoundingBoxQueryBuilderTests.java

@@ -24,6 +24,7 @@
 import org.apache.lucene.search.IndexOrDocValuesQuery;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.Query;
+import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.geo.GeoPoint;
 import org.elasticsearch.common.geo.GeoUtils;
 import org.elasticsearch.index.mapper.MappedFieldType;
@@ -450,6 +451,64 @@ public void testFromWKT() throws IOException {
         assertEquals(expectedJson, GeoExecType.MEMORY, parsed.type());
     }
 
+    public void testFromGeohash() throws IOException {
+        String json =
+            "{\n" +
+                "  \"geo_bounding_box\" : {\n" +
+                "    \"pin.location\" : {\n" +
+                "      \"top_left\" : \"dr\",\n" +
+                "      \"bottom_right\" : \"dq\"\n" +
+                "    },\n" +
+                "    \"validation_method\" : \"STRICT\",\n" +
+                "    \"type\" : \"MEMORY\",\n" +
+                "    \"ignore_unmapped\" : false,\n" +
+                "    \"boost\" : 1.0\n" +
+                "  }\n" +
+                "}";
+
+        String expectedJson =
+            "{\n" +
+                "  \"geo_bounding_box\" : {\n" +
+                "    \"pin.location\" : {\n" +
+                "      \"top_left\" : [ -78.75, 45.0 ],\n" +
+                "      \"bottom_right\" : [ -67.5, 33.75 ]\n" +
+                "    },\n" +
+                "    \"validation_method\" : \"STRICT\",\n" +
+                "    \"type\" : \"MEMORY\",\n" +
+                "    \"ignore_unmapped\" : false,\n" +
+                "    \"boost\" : 1.0\n" +
+                "  }\n" +
+                "}";
+        GeoBoundingBoxQueryBuilder parsed = (GeoBoundingBoxQueryBuilder) parseQuery(json);
+        checkGeneratedJson(expectedJson, parsed);
+        assertEquals(json, "pin.location", parsed.fieldName());
+        assertEquals(json, -78.75, parsed.topLeft().getLon(), 0.0001);
+        assertEquals(json, 45.0, parsed.topLeft().getLat(), 0.0001);
+        assertEquals(json, -67.5, parsed.bottomRight().getLon(), 0.0001);
+        assertEquals(json, 33.75, parsed.bottomRight().getLat(), 0.0001);
+        assertEquals(json, 1.0, parsed.boost(), 0.0001);
+        assertEquals(json, GeoExecType.MEMORY, parsed.type());
+    }
+
+    public void testMalformedGeohashes() {
+        String jsonGeohashAndWkt =
+            "{\n" +
+                "  \"geo_bounding_box\" : {\n" +
+                "    \"pin.location\" : {\n" +
+                "      \"top_left\" : [ -78.75, 45.0 ],\n" +
+                "      \"wkt\" : \"BBOX (-74.1, -71.12, 40.73, 40.01)\"\n" +
+                "    },\n" +
+                "    \"validation_method\" : \"STRICT\",\n" +
+                "    \"type\" : \"MEMORY\",\n" +
+                "    \"ignore_unmapped\" : false,\n" +
+                "    \"boost\" : 1.0\n" +
+                "  }\n" +
+                "}";
+
+        ElasticsearchParseException e1 = expectThrows(ElasticsearchParseException.class, () -> parseQuery(jsonGeohashAndWkt));
+        assertThat(e1.getMessage(), containsString("Conflicting definition found using well-known text and explicit corners."));
+    }
+
     @Override
     public void testMustRewrite() throws IOException {
         assumeTrue("test runs only when at least a type is registered", getCurrentTypes().length > 0);

server/src/test/java/org/elasticsearch/index/search/geo/GeoUtilsTests.java

@@ -610,6 +610,20 @@ public void testPrefixTreeCellSizes() {
         }
     }
 
+    public void testParseGeoPointGeohashPositions() throws IOException {
+        assertNormalizedPoint(parseGeohash("drt5", GeoUtils.EffectivePoint.TOP_LEFT), new GeoPoint(42.890625, -71.71875));
+        assertNormalizedPoint(parseGeohash("drt5", GeoUtils.EffectivePoint.TOP_RIGHT), new GeoPoint(42.890625, -71.3671875));
+        assertNormalizedPoint(parseGeohash("drt5", GeoUtils.EffectivePoint.BOTTOM_LEFT), new GeoPoint(42.71484375, -71.71875));
+        assertNormalizedPoint(parseGeohash("drt5", GeoUtils.EffectivePoint.BOTTOM_RIGHT), new GeoPoint(42.71484375, -71.3671875));
+        assertNormalizedPoint(parseGeohash("drtk", GeoUtils.EffectivePoint.BOTTOM_LEFT), new GeoPoint(42.890625, -71.3671875));
+    }
+
+    private GeoPoint parseGeohash(String geohash, GeoUtils.EffectivePoint effectivePoint) throws IOException {
+        XContentParser parser = createParser(jsonBuilder().startObject().field("geohash", geohash).endObject());
+        parser.nextToken();
+        return GeoUtils.parseGeoPoint(parser, new GeoPoint(), randomBoolean(), effectivePoint);
+    }
+
     private static void assertNormalizedPoint(GeoPoint input, GeoPoint expected) {
         GeoUtils.normalizePoint(input);
         if (Double.isNaN(expected.lat())) {