switch CLI search command to python implementation

nominatim/api/v1/helpers.py

@@ -9,6 +9,8 @@ Helper function for parsing parameters and and outputting data
 specifically for the v1 version of the API.
 """
 
+from nominatim.api.results import SearchResult, SearchResults, SourceTable
+
 REVERSE_MAX_RANKS = [2, 2, 2,   # 0-2   Continent/Sea
                      4, 4,      # 3-4   Country
                      8,         # 5     State
@@ -29,3 +31,41 @@ def zoom_to_rank(zoom: int) -> int:
     """ Convert a zoom parameter into a rank according to the v1 API spec.
     """
     return REVERSE_MAX_RANKS[max(0, min(18, zoom))]
+
+
+def deduplicate_results(results: SearchResults, max_results: int) -> SearchResults:
+    """ Remove results that look like duplicates.
+
+        Two results are considered the same if they have the same OSM ID
+        or if they have the same category, display name and rank.
+    """
+    osm_ids_done = set()
+    classification_done = set()
+    deduped = SearchResults()
+    for result in results:
+        if result.source_table == SourceTable.POSTCODE:
+            assert result.names and 'ref' in result.names
+            if any(_is_postcode_relation_for(r, result.names['ref']) for r in results):
+                continue
+        classification = (result.osm_object[0] if result.osm_object else None,
+                          result.category,
+                          result.display_name,
+                          result.rank_address)
+        if result.osm_object not in osm_ids_done \
+           and classification not in classification_done:
+            deduped.append(result)
+        osm_ids_done.add(result.osm_object)
+        classification_done.add(classification)
+        if len(deduped) >= max_results:
+            break
+
+    return deduped
+
+
+def _is_postcode_relation_for(result: SearchResult, postcode: str) -> bool:
+    return result.source_table == SourceTable.PLACEX \
+           and result.osm_object is not None \
+           and result.osm_object[0] == 'R' \
+           and result.category == ('boundary', 'postal_code') \
+           and result.names is not None \
+           and result.names.get('ref') == postcode