adds scorer to AggregateRequest (#3409)

* adds scorer to AggregateRequest

* fix linting

* update tests for BM25

* enum for aggregation scorer

* update signature

* revert back to string input

---------

Co-authored-by: Vladyslav Vildanov <117659936+vladvildanov@users.noreply.github.com>

redis/commands/search/aggregation.py

@@ -112,6 +112,7 @@ def __init__(self, query: str = "*") -> None:
         self._cursor = []
         self._dialect = None
         self._add_scores = False
+        self._scorer = "TFIDF"
 
     def load(self, *fields: List[str]) -> "AggregateRequest":
         """
@@ -300,6 +301,17 @@ def add_scores(self) -> "AggregateRequest":
         self._add_scores = True
         return self
 
+    def scorer(self, scorer: str) -> "AggregateRequest":
+        """
+        Use a different scoring function to evaluate document relevance.
+        Default is `TFIDF`.
+
+        :param scorer: The scoring function to use
+                       (e.g. `TFIDF.DOCNORM` or `BM25`)
+        """
+        self._scorer = scorer
+        return self
+
     def verbatim(self) -> "AggregateRequest":
         self._verbatim = True
         return self
@@ -323,6 +335,9 @@ def build_args(self) -> List[str]:
         if self._verbatim:
             ret.append("VERBATIM")
 
+        if self._scorer:
+            ret.extend(["SCORER", self._scorer])
+
         if self._add_scores:
             ret.append("ADDSCORES")
 
@@ -332,6 +347,7 @@ def build_args(self) -> List[str]:
         if self._loadall:
             ret.append("LOAD")
             ret.append("*")
+
         elif self._loadfields:
             ret.append("LOAD")
             ret.append(str(len(self._loadfields)))

tests/test_asyncio/test_search.py

@@ -1556,6 +1556,61 @@ async def test_aggregations_add_scores(decoded_r: redis.Redis):
         assert res.rows[1] == ["__score", "0.2"]
 
 
+@pytest.mark.redismod
+@skip_ifmodversion_lt("2.10.05", "search")
+async def test_aggregations_hybrid_scoring(decoded_r: redis.Redis):
+    assert await decoded_r.ft().create_index(
+        (
+            TextField("name", sortable=True, weight=5.0),
+            TextField("description", sortable=True, weight=5.0),
+            VectorField(
+                "vector",
+                "HNSW",
+                {"TYPE": "FLOAT32", "DIM": 2, "DISTANCE_METRIC": "COSINE"},
+            ),
+        )
+    )
+
+    assert await decoded_r.hset(
+        "doc1",
+        mapping={
+            "name": "cat book",
+            "description": "an animal book about cats",
+            "vector": np.array([0.1, 0.2]).astype(np.float32).tobytes(),
+        },
+    )
+    assert await decoded_r.hset(
+        "doc2",
+        mapping={
+            "name": "dog book",
+            "description": "an animal book about dogs",
+            "vector": np.array([0.2, 0.1]).astype(np.float32).tobytes(),
+        },
+    )
+
+    query_string = "(@description:animal)=>[KNN 3 @vector $vec_param AS dist]"
+    req = (
+        aggregations.AggregateRequest(query_string)
+        .scorer("BM25")
+        .add_scores()
+        .apply(hybrid_score="@__score + @dist")
+        .load("*")
+        .dialect(4)
+    )
+
+    res = await decoded_r.ft().aggregate(
+        req,
+        query_params={"vec_param": np.array([0.11, 0.22]).astype(np.float32).tobytes()},
+    )
+
+    if isinstance(res, dict):
+        assert len(res["results"]) == 2
+    else:
+        assert len(res.rows) == 2
+        for row in res.rows:
+            len(row) == 6
+
+
 @pytest.mark.redismod
 @skip_if_redis_enterprise()
 async def test_search_commands_in_pipeline(decoded_r: redis.Redis):

tests/test_search.py

@@ -1466,6 +1466,61 @@ def test_aggregations_add_scores(client):
         assert res.rows[1] == ["__score", "0.2"]
 
 
+@pytest.mark.redismod
+@skip_ifmodversion_lt("2.10.05", "search")
+async def test_aggregations_hybrid_scoring(client):
+    client.ft().create_index(
+        (
+            TextField("name", sortable=True, weight=5.0),
+            TextField("description", sortable=True, weight=5.0),
+            VectorField(
+                "vector",
+                "HNSW",
+                {"TYPE": "FLOAT32", "DIM": 2, "DISTANCE_METRIC": "COSINE"},
+            ),
+        )
+    )
+
+    client.hset(
+        "doc1",
+        mapping={
+            "name": "cat book",
+            "description": "an animal book about cats",
+            "vector": np.array([0.1, 0.2]).astype(np.float32).tobytes(),
+        },
+    )
+    client.hset(
+        "doc2",
+        mapping={
+            "name": "dog book",
+            "description": "an animal book about dogs",
+            "vector": np.array([0.2, 0.1]).astype(np.float32).tobytes(),
+        },
+    )
+
+    query_string = "(@description:animal)=>[KNN 3 @vector $vec_param AS dist]"
+    req = (
+        aggregations.AggregateRequest(query_string)
+        .scorer("BM25")
+        .add_scores()
+        .apply(hybrid_score="@__score + @dist")
+        .load("*")
+        .dialect(4)
+    )
+
+    res = client.ft().aggregate(
+        req,
+        query_params={"vec_param": np.array([0.11, 0.21]).astype(np.float32).tobytes()},
+    )
+
+    if isinstance(res, dict):
+        assert len(res["results"]) == 2
+    else:
+        assert len(res.rows) == 2
+        for row in res.rows:
+            len(row) == 6
+
+
 @pytest.mark.redismod
 @skip_ifmodversion_lt("2.0.0", "search")
 def test_index_definition(client):